Folsom City Council
June 23, 2026

06/23/2026 Item No.18.

Attachment 22
Arborist Report,
dated April 2025

06/23/2026 Item No.18.

Arborist Report
for the
Toll Brothers at Alder Creek Property Project
Sacramento County, California
Prepared For:

Toll Brothers, Inc.

Prepared By:
2525 Warren Drive
Rocklin, CA 95677
April 2025

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
i April 2025
2024-012

CONTENTS

1.0 INTRODUCTION ...................................................................................................................................................................1

2.0 PROJECT LOCATION AND DESCRIPTION...................................................................................................................1

3.0 OAK RESOURCES IN THE FOLSOM PLAN AREA......................................................................................................3

3.1 Folsom Tree Preservation Ordinance..........................................................................................................3

3.1.1 Tree Ordinance....................................................................................................................................3

4.0 METHODS...............................................................................................................................................................................4

5.0 OAK RESOURCES IN THE PROJECT AREA ............................................................................................................... 10

5.1 Oak Woodland.................................................................................................................................................. 10

5.2 Isolated Oak Trees ........................................................................................................................................... 10

6.0 MITIGATION REQUIREMENTS ..................................................................................................................................... 10

6.1 Direct Impact – Tree Removal..................................................................................................................... 10

6.2 Indirect Impact – Preserved Trees ............................................................................................................. 11

6.2.1 Tree Protection Zones ................................................................................................................... 11

6.2.2 Protected Trees ................................................................................................................................ 11

6.2.3 Indirect Impact Monitoring ......................................................................................................... 12

7.0 CONCLUSION..................................................................................................................................................................... 13

8.0 REFERENCES........................................................................................................................................................................ 14

LIST OF TABLES
Table 1. American Society of Consulting Arborists Tree Rating System ........................................................................9

LIST OF FIGURES
Figure 1. Project Location and Vicinity ........................................................................................................................................2 Figure 2. Alder Creek Property Tree Survey Results ...............................................................................................................5

LIST OF APPENDICES
Appendix A – Individual Tree Survey Data

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
ii April 2025
2024-012

LIST OF ACRONYMS AND ABBREVIATIONS
Term Definition
City City of Folsom
Client Toll Brothers, Inc
DSH Diameter at Standard Height
ECORP ECORP Consulting, Inc.

EIR/EIS Environmental Impact Report/Environmental Impact Statement FPA Folsom Plan Area
FPASP Folsom Plan Area Specific Plan
ILF In-Lieu Fee
ISA International Society of Arboriculture
Project Toll Brothers at Alder Creek Property Project
TPZ Tree Protection Zone
Tree Ordinance Folsom Tree Preservation Ordinance
USGS U.S. Geological Survey

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
1 April 2025
2024-012

1.0 INTRODUCTION
On behalf of Toll Brothers, Inc. (Client), ECORP Consulting, Inc. (ECORP) prepared this Arborist Report for the proposed Toll Brothers at Alder Creek Project (Project) located in Sacramento County, California in the City of Folsom (City). The purpose of this report is to quantify oak woodlands within the Project Area and provide a general assessment of the size and condition of individual trees to facilitate site planning and decision-making. This report also presents mitigation requirements for impacts to oak woodlands based on approved methods outlined in the Folsom Plan Area Specific Plan (FPASP; Torrence Planning et al. 2011) and the approved FPASP Environmental Impact Report/Environmental Impact Statement (EIR/EIS; U.S. Army Corps of Engineers and City 2011). This Arborist Report is intended to assist with the entitlement process of the Project and does not provide information regarding specific impacts or propose specific mitigation measures to offset impacts. A mitigation plan will be included as part of the Tree Removal Application once final impacts to oak resources are determined for the Project.

2.0 PROJECT LOCATION AND DESCRIPTION
The approximately 447.34-acre Project is located within the FPASP, south of Highway 50, west of East Bidwell Street, north of White Rock Road, and east of Prairie City Road (Figure 1). The Project Area corresponds to Section 17, 18, 19, 20, Township 9 North, Range 8 East (Mount Diablo Base Meridian) of the Clarksville, California 7.5-minute quadrangle (U.S. Geological Survey [USGS] 1980, NAD 27). The approximate center of the Project Area corresponds to latitude 38.628935º and longitude -121.140193º within the Lower American and Upper Cosumnes Watersheds (Hydrologic Unit Code #18020111 and #18040013; Natural Resources Conservation Service et. al. 2016).

The Project Area consists of relatively flat to rolling terrain with predominantly undeveloped annual grassland and blue oak woodland. Livestock shelters, a livestock corral with loading chute, and a large shed structure exist within the eastern section of the Project Area. A powerline bisects the center of the Project Area running roughly north-south with a few access roads through the eastern section of the Project Area. The Project Area is situated at an elevational range of approximately 280 to 370 feet above mean sea level.

Land use surrounding the immediate Project Area consists of primarily undeveloped annual grassland and oak woodlands that were historically used for cattle grazing, with a residential development to the southeast of the Project Area. A rural house exists along the eastern section of the Project Area. Buildout of the FPASP has generally progressed from east to west, and residential developments are present east of East Bidwell Street and north of White Rock Road. Highway 50 and dense commercial and residential developments are located north of the FPASP boundary.

06/23/2026 Item No.18.

Figure 1. Project Location and Vicinity
2024-012 Toll Brothers at Alder Creek Property Project
I 0 1,000 2,000
Scale in Feet
Clarksville (1980, NAD27)
CA 7.5-minute Topographic Quadrangle
US Geological Survey
Location: J:\GIS_Maps\2005-429_Folsom_Area_South_Group\Site_Vicinity\AlderCreek_LnV_20240204.mxd (MAG)-mguidry 4/4/2025 Sacramento County, California
§17,18, 19, 20 T.09N, R.08E, MDBM
Latitude (NAD83): 38.628935°
Longitude (NAD83): -121.140193°
Watersheds: Lower American (18020111) &
Upper Cosumnes (18040013)
Project Area - 447.34 acres
Map Date: 4/4/2025
iService Layer Credits: ESRI, USGS

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
3 April 2025
2024-012

3.0 OAK RESOURCES IN THE FOLSOM PLAN AREA
Two types of oak resources occur within the Folsom Plan Area (FPA): oak woodland and isolated oak trees.

Oak woodland for the entire FPA was previously mapped and presented in the Conceptual Oak Tree Mitigation and Monitoring Plan for the FPASP (ECORP 2017). For the purposes of determining impacts and mitigation requirements for oak resources within the FPASP, oak woodland habitat was defined as stands of oak trees 1 with greater than 10-percent cover plus a 30-foot buffer as measured from the outer edge of the tree canopy (ECORP 2017). Any oak trees not included within the oak woodland were identified as isolated oak trees.

The approved EIR/EIS for the FPA requires Project applicants to conduct arborist surveys for isolated oak trees within all portions of a project site where tree removal or encroachment of development may occur.

For each isolated tree, the arborist must record the Diameter at Standard Height (DSH), drip line radius, and general condition, along with uniquely tagging and mapping the location of each oak tree. These data are summarized and provided to the City to support the entitlement process and determine project impacts and mitigation requirements.

Standard arborist surveys for individual oaks within all oak woodlands in the FPA were deemed infeasible due to the number of trees within the woodlands. Impacts and mitigation for oak woodlands are generally assessed based on acreage of oak woodland canopy impacted or removed. However, the Specific Plan and EIR/EIS state that attempts must be made to preserve and protect oak resources within the FPA wherever practical. As such, the City has requested additional data (i.e., an arborist survey) on specific oak woodland trees that may be subject to removal or encroachment to determine whether additional avoidance or preservation measures are practicable and should be required.

3.1 Folsom Tree Preservation Ordinance
In addition to the requirements of the FPASP and the EIR/EIS, the Folsom Tree Preservation Ordinance (Tree Ordinance; City 2020) establishes standards and measures for preservation of trees within the City.

The Tree Ordinance defines various Protected Trees within the City and provides methodology for data collection and mitigation measures for impacts - either direct or indirect - to Protected Trees. This report addresses these requirements where applicable.

3.1.1 Tree Ordinance
ECORP conducted the arborist survey according to the City’s Tree Ordinance (City 2020) and used the following definitions to guide data collection:
 Native Oak Tree: Any tree with a single stem over six inches in DSH of the genus Quercus and species lobata (valley oak), douglasii (blue oak), wislizenii (interior live oak), agrifolia (coast live Oak woodlands were identified using geographic information systems technology, rectified aerial photographs, and field observation.

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
4 April 2025
2024-012
oak), or hybrids thereof; or any multi-trunked native oak tree having an aggregate DSH of 20 inches or more.
 Protected Trees: Native Oak Trees, Heritage Trees, Landmark Trees, and Regulated Trees.  Heritage Tree: A tree on the City’s Master Tree List with a single stem over 30 inches in DSH, or multi-trunked tree having an aggregate DSH of 50 inches or more. Excludes trees listed at “Not Eligible for Heritage Status.”
 Landmark Trees: A tree or group of trees determined by the Folsom City Council to confer a significant community benefit to the general public due to its size, age, location, historic association, or ecological value.
 Regulated Tree: Trees required by the City’s Zoning Code (such as parking lot shading trees and street trees), or required as conditions of development project approval (such as landscape buffer or screening trees), or required as mitigation for the removal of Protected Trees.

4.0 METHODS
The Client requested an arborist survey for isolated oaks within the Project Area, to support site planning and the evaluation of alternative Project layouts within the parcel. The Study Area for this survey excluded any trees within designated oak woodlands. Collecting this information will help quantify the size and condition of the trees within the oak woodlands and inform the Client’s decisions related to Project design and potential oak woodland impacts.

ECORP arborist Jennifer West (International Society of Arboriculture [ISA] Certification # WE-14444A) and biologist Roxanne Kessler conducted a field survey on December 2, 2024. During the field survey, individual oak trees were assessed within the isolated oak woodlands and location data for each tree was recorded with sub-meter accuracy.

Data collected for individually assessed oak trees included species, tree tag number, DSH, dripline radius, and condition.

06/23/2026 Item No.18.

G
G G
G
G
GG
G
GG
G

PRAIRIE CITY RD

WHITE ROCK RD
Map Date: 4/4/2025
Figure 2.

Alder Creek Tree Survey
Overview
I
0 400 800
Sca le i n F ee t 2024-012 Alder Creek Photo Source: NAIP (2024) 1 ECORP, MSCE and Foothill Associates (MAG)-mguidry 4/4/2025 Location: J:\GIS_Maps\2005-429_Folsom_Area_South_Group\Draft_Maps_Data\2024-01-11 Alder Creek Due Dilligence\AlderCreek_Oaks_20250331.mxd Map Features
Service Layer Credits: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Alder Creek Project Area - 447.34 acres
KKK
KKK
Development Area
Backbone Infrastructure
Already Mitigated
Tree Survey Results
Good (7)
Fair (41)
Poor (15)
G
Hazardous or non-correctable (2)
G
Dead (9)
Not Impacted Oak Woodland - 59.55 acres
Impacted Oak Woodland - 111.49 acres
Impacted Isolated Oaks
Impacted Already Mitigated
Backbone Infrastructure 11.01 23.12
Project Development 100.48 <.01
Grand Total 111.49 23.12
Oak Woodland Impacts

06/23/2026 Item No.18.

PRAIRIE CITY RD
115
701
703 137
135 136
134 133
131 132
130 129
128 126
125
124
123
120
119
121
122
118
117 116
Map Date: 4/4/2025
Figure 2.

Alder Creek Tree Survey
Detail 1 of 3
I
0 50
Sca le i n F ee t 2024-012 Alder Creek Photo Source: NAIP (2024) 1 ECORP, MSCE and Foothill Associates (MAG)-mguidry 4/4/2025 Location: J:\GIS_Maps\2005-429_Folsom_Area_South_Group\Draft_Maps_Data\2024-01-11 Alder Creek Due Dilligence\AlderCreek_Oaks_20250331.mxd Map Features
Service Layer Credits: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Alder Creek Project Area - 447.34 acres
KKK
KKK
Development Area
Backbone Infrastructure
Tree Survey Results
Good (4)
Fair (14)
Poor (6)
Impacted Isolated Oaks
Impacted Already Mitigated
Backbone Infrastructure 11.01 23.12
Project Development 100.48 <.01
Grand Total 111.49 23.12
Oak Woodland Impacts

06/23/2026 Item No.18.
704 705
220
Map Date: 4/4/2025
Figure 2.

Alder Creek Tree Survey
Detail 2 of 3
I
0 100 200
Sca le i n F ee t 2024-012 Alder Creek Photo Source: NAIP (2024) 1 ECORP, MSCE and Foothill Associates (MAG)-mguidry 4/4/2025 Location: J:\GIS_Maps\2005-429_Folsom_Area_South_Group\Draft_Maps_Data\2024-01-11 Alder Creek Due Dilligence\AlderCreek_Oaks_20250331.mxd Map Features
Service Layer Credits: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Alder Creek Project Area - 447.34 acres
KKK
KKK
Development Area
Backbone Infrastructure
Already Mitigated
Tree Survey Results
Good (2)
Poor (1)
Not Impacted Oak Woodland - 59.55 acres
Impacted Oak Woodland - 111.49 acres
Impacted Isolated Oaks
Impacted Already Mitigated
Backbone Infrastructure 11.01 23.12
Project Development 100.48 <.01
Grand Total 111.49 23.12
Oak Woodland Impacts

06/23/2026 Item No.18.

G
G G
G
G
G
G
G
GG
G
1157
1160
1159 1158 706 1164
1163
1169
707
708
709
710
1168
1166
711
1161
712
713
460 714 715
716
717 718
719
720
721
722
723
724
725 726
727
728
729
730 731 461
Map Date: 4/4/2025
Figure 2.

Alder Creek Tree Survey
Detail 3 of 3
I
0 100 200
Sca le i n F ee t 2024-012 Alder Creek Photo Source: NAIP (2024) 1 ECORP, MSCE and Foothill Associates (MAG)-mguidry 4/4/2025 Location: J:\GIS_Maps\2005-429_Folsom_Area_South_Group\Draft_Maps_Data\2024-01-11 Alder Creek Due Dilligence\AlderCreek_Oaks_20250331.mxd Map Features
Service Layer Credits: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Alder Creek Project Area - 447.34 acres
KKK
KKK
Development Area
Backbone Infrastructure
Already Mitigated
Tree Survey Results
Good (1)
Fair (27)
Poor (8)
G
Hazardous or non-correctable (2)
G
Dead (9)
Not Impacted Oak Woodland - 59.55 acres
Impacted Oak Woodland - 111.49 acres
Impacted Isolated Oaks
Impacted Already Mitigated
Backbone Infrastructure 11.01 23.12
Project Development 100.48 <.01
Grand Total 111.49 23.12
Oak Woodland Impacts

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
9 April 2025
2024-012
The survey results are intended for general Project planning purposes only. These results should not be considered a detailed tree analysis (i.e., these results do not include hazard assessment, tree health diagnosis, preservation/removal recommendations, or pruning advisement). The following terms define the collected data:
 DSH: Trunk diameter at 4.5 feet above the ground while standing on the high side of the tree. For a tree other than a multi-trunked tree that branches at or below 4.5 feet, DSH shall mean the diameter at the narrowest point between the grade and the lowest branching point. For multitrunked trees (trees with multiple stems originating from a single root mass), this report lists the extrapolated DSH by taking the square root of the sum of each individual stem’s DSH squared.  Dripline Radius: A perfect circle around the tree with the radius being equal to the longest branch of the tree.
 Condition: An estimate of the tree's overall health. This includes evaluation of foliage, evidence of wound healing, evidence of fungal attack, density of insect galls, and the amount and condition of attached deadwood, as well as the obvious potential for structural failure of one or more major branches or trunks, the environment and condition of the root crown, symmetry of the canopy, and any noticeable effects of crowding caused by adjacent trees. ECORP rated each tree’s condition according to the American Society of Consulting Arborists tree rating system (see Table 1).

Table 1. American Society of Consulting Arborists Tree Rating System Rating Rating Number Rating Description
Excellent 5 No problem(s)
Good 4 No apparent problem(s)
Fair 3 Minor problem(s)
Poor 2 Major problem(s)
Hazardous or non-correctable 1 Extreme problem(s)
Dead 0 Dead
In addition, where appropriate, the surveyors noted any unusual features (e.g., large trunk cavities, obvious damage or disease, or girdling by barbed wire).

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
10 April 2025
2024-012

5.0 OAK RESOURCES IN THE PROJECT AREA
The results of the oak woodland assessment and tree survey for the Project are presented in the following sections and shown on Figure 2. Appendix A provides detailed data for the assessed trees.

5.1 Oak Woodland
Prior to the adoption of the FPASP, Torrence Planning mapped oak woodland for the entire FPA using aerial data that was available during the development of the Conceptual Oak Tree Mitigation and Monitoring Plan (ECORP 2017). There are a total of approximately 194.17 acres of oak woodland within the Project Area, with 11.01 acres previously impacted by the Backbone Phase 1 project, 82.68 acres that will be preserved, and up to approximately 100.48 acres proposed for impact. However, the acreage of oak woodland proposed for impact may change as project impact limits are finalized prior to preparation of tree permit applications, when the tree canopy is ground verified as stated in the EIR/EIS.

5.2 Isolated Oak Trees
Seventy-four (74) isolated oak trees occur within the Project Area. The survey recorded 9 dead, 2 hazardous or non-correctable, 15 poor, 41 fair, and 7 good trees.

6.0 MITIGATION REQUIREMENTS
Mitigation for tree impacts within the FPA follows the requirements of the EIR/EIS, rather than the current Tree Ordinance (City 2020). The following sections provide a general outline of the applicable mitigation requirements.

6.1 Direct Impact – Tree Removal
Per the FPASP, there are three options for mitigation of oak woodland and isolated oak tree impacts:

1. Preserve offsite oak woodland habitat. Existing, unprotected oak woodland habitat within Sacramento and El Dorado Counties may be secured and placed under conservation easement to be managed as oak woodland habitat in perpetuity.

2. Use of the In-Lieu Fee (ILF) program. The City has established an ILF program to compensate for tree removal. The fee is $150 per DSH inch removed. If the ILF is used as mitigation for oak woodland impacts, the oak woodland trees must be individually assessed for DSH, or a conversion calculation must be applied to convert acres of impacted woodland to DSH.

3. Create oak woodlands onsite. Onsite oak woodland creation is the City’s preferred method for mitigation. However, onsite planting is not always feasible within the boundaries of a Project because there may be insufficient open space areas to support the plantings. If suitable planting areas are not available onsite, a deferred planting plan may also be an option; such a plan would be conducted in conjunction with a future project or phase of a project within the FPA where planting locations will be available. Under this mitigation alternative, all impacted oak woodland

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
11 April 2025
2024-012
trees must be individually assessed to obtain the DSH, or woodland acreage must be converted to DSH to implement the following planting options per the EIR/EIS:
a. Option 1: 24-inch box oak tree; one of these replaces two DSH inches removed. b. Option 2: 15-gallon container oak tree; one of these replaces one DSH inch removed. c. Option 3: five-gallon container oak tree; one of these replaces 0.5 DSH inch removed. d. Option 4: A combination of the above options.

6.2 Indirect Impact – Preserved Trees
Protected Trees are trees that will be preserved onsite and not removed by construction. Constructionrelated activities can also result in indirect impacts to Protected Trees. Indirect impacts include activities such as, but not limited to, grading, trenching, paving, soil disturbance, and pruning of a tree within the Tree Protection Zone (TPZ; as defined in the City’s 2020 Tree Ordinance).

6.2.1 Tree Protection Zones
The City has established standards for the TPZs of all Protected Trees during construction. These standards include the following:
 A pre-construction meeting between the Project Arborist, City Arborist, construction foreman/superintendent, and all applicable parties.
 High-visibility exclusionary fencing shall be shown on the Project plans and installed to protect the TPZ of all Protected Trees in proximity to the regulated activity. Unless the Project construction goes through the TPZ, the fencing shall encompass the entire TPZ.  Weatherproof warning signs shall be attached to the TPZ fencing.  Where construction access through the TPZ is necessary, the soil shall be protected via the installation of an access path. The access path shall consist minimally of 1-inch minimum thickness plyboards laid over a 4-inch layer of mulch. Additionally, trunk protection or high-visibility fencing shall be placed around the trunk.  Tree pruning will be completed by an experienced arborist, preferably prior to the start of construction.

6.2.2 Protected Trees
During construction, the following measures are required for Protected Trees:
 If any follow-up pruning is discovered, tree pruning will be completed by an experienced contractor under the direct supervision of the Project Arborist.  Any necessary root severance shall be performed with sharp, sterile hand tools. Roots that have been ripped, torn, or crushed shall be traced back to undamaged tissue and cut cleanly, resulting in a flat surface with the adjacent bark firmly attached.

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
12 April 2025
2024-012
 Roots exposed from grade cuts or trenching shall not be allowed to dry out. If roots will be exposed overnight or if directed by the Project Arborist, the cut faces shall be moistened and covered until they can be backfilled.
 The following actions are prohibited within the TPZ of Protected Trees:
• Parking of vehicles, equipment, or storage of material within the TPZ, unless otherwise approved by the City.
• Breaking roots with a backhoe or crushing them with a grader. • Wounding or breaking tree trunks or branches through contact with vehicles or heavy equipment.
• Contaminating soil by washing out equipment or conducting vehicle maintenance.

6.2.3 Indirect Impact Monitoring
In addition to these standards of protection during construction, the FPASP and the City’s Tree Ordinance require monitoring of trees that are indirectly impacted by construction. Whether they are located onsite or offsite, these trees will generally experience indirect impacts due to some level of construction within their TPZ. The following measures are recommended to monitor indirect impacts:
 Prior to grading, an arborist will tag and assess the trees that will be subject to indirect impacts (both onsite and offsite).
 Monitor the health of all Protected Trees potentially impacted by the construction activities throughout the duration of development of the Project. Per discussion with the City Arborist, this means the Project Arborist will be present onsite at the following times: the first one to two days of work within the Project Area when in the vicinity of Protected Trees, all construction activities within the TPZ of Protected Trees, and during all tree pruning. In addition, the Project Arborist will be on-call for questions related to work under all trees when not onsite. Because the Project Arborist will not likely be needed each day, a minimum of one weekly site visit will be conducted to check on the status of the trees within the Project Area when work is being conducted in the vicinity of Protected Trees.
 Prepare a certificate of compliance at the conclusion of the Project attesting compliance with the standards outlined in the Maintenance Standards and the conditions of the tree permit.  Monitor the health of all Indirectly Impacted Protected Trees annually for a period of five years. If any monitored tree appears to be dead or dying within 5 years of Project implementation, the tree shall be replaced using the Direct Impact mitigation described above. Alternatively, if an Indirectly Impacted Tree is assessed as part of a future entitlement project and subject to removal as part of that project, monitoring may cease once the entitlement process is approved by the City and mitigation for that tree has been addressed.

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
13 April 2025
2024-012

7.0 CONCLUSION
This Arborist Report is intended to support the Project’s planning and entitlement process. Oak woodlands are identified in the FPASP as a valuable natural resource, and the City Charter requires thirty percent of the FPA to be preserved in open space. The FPASP contains a policy to protect approximately 396.52 acres of existing oak woodland in perpetuity. The FPASP identifies approximately 131 acres of unavoidable impacts for construction of backbone infrastructure, and an additional approximately 114.62 acres of oak woodlands subject to impacts from residential and non-residential development.

The Project Area contains up to approximately 100.48 acres of oak woodland proposed for impact in the FPASP. For those areas where oak woodlands are identified for impact, the FPASP states an objective to “Preserve oak woodlands and isolated oak trees in residential and non-residential development parcels wherever practical.” This report was conducted to support compliance with this objective and allow evaluation of the practicability of additional oak woodland habitat preservation in light of site constraints such as mass grading needed to create level building pads.

After final Project plans are developed, the information in this report will be used to assess oak woodland impacts and develop final mitigation requirements. Additional tree survey data may be collected as needed to support evaluation of individual tree impacts, ground verification of oak woodland, identification of Protected Trees, and applications for Tree Work Permits or Tree Removal Permits.

06/23/2026 Item No.18.

Arborist Report
ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
14 April 2025
2024-012

8.0 REFERENCES
City of Folsom (City). 2020. Tree Preservation. Title 12. Chapter 12.16 Tree Preservation. http://www.codepublishing.com/CA/Folsom/#!/Folsom12/Folsom1216.html.

Accessed December 2024.

ECORP Consulting, Inc. (ECORP). 2017. Conceptual Oak Tree Mitigation and Monitoring Plan for the Folsom Plan Area Specific Plan. Prepared for the City of Folsom.

Natural Resources Conservation Service, U.S. Geological Survey (USGS), and U.S. Environmental Protection Agency. 2016. Watershed Boundary Dataset for California. https://datagateway.nrcs.usda.gov.

Torrence Planning, MacKay & Somps Civil Engineers, Jeffrey DeMure + Associates, ECORP Consulting, Inc. 2011. Folsom Plan Area Specific Plan. Dated June 28, 2011, as amended in 2018. Adopted by the City of Folsom, Resolution No. 8863.

U.S. Army Corps of Engineers and City of Folsom (City). 2011. Final EIR/EIS Folsom South of U.S. Highway 50 Specific Plan Project. SCH#2008092051. May 2011.

U.S. Geological Survey (USGS). 1980. Folsom, California 7.5-minute Quadrangle. Geological Survey. Denver, Colorado.

06/23/2026 Item No.18.

LIST OF APPENDICES
Appendix A – Individual Tree Survey Data

06/23/2026 Item No.18.

APPENDIX A
Individual Tree Survey Data

06/23/2026 Item No.18.

Appendix A – Individual Tree Survey Data (December 2, 2024) ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
A–1 April 2025
2024–012
Tree
Tag #
Common
Name Scientific Name
DSH
(inches)
Individual Stems
(if multi–stemmed)
Dripline
(feet)
ASCA
Rating
Heritage
Tree Field Notes
115 Blue Oak Quercus douglasii 30.6 – 30 Good Yes –
116 Blue Oak Quercus douglasii 7.2 – 10 Poor No Poor structure, basal wound 117 Blue Oak Quercus douglasii 31.3 – 38 Fair Yes Thinning bark 118 Blue Oak Quercus douglasii 25.3 – 25 Fair No –
119 Blue Oak Quercus douglasii 24.7 – 25 Poor No Very sparse canopy 120 Blue Oak Quercus douglasii 16.8 – 28 Fair No –
121 Blue Oak Quercus douglasii 8.2 – 15 Good No –
122 Blue Oak Quercus douglasii 30.1 – 25 Fair Yes Watersprouts 123 Blue Oak Quercus douglasii 13 – 20 Poor No Dead branches 124 Blue Oak Quercus douglasii 19.6 – 35 Fair No –
125 Blue Oak Quercus douglasii 16.5 – 25 Fair No –
126 Blue Oak Quercus douglasii 14 – 23 Poor No Watersprouts 128 Blue Oak Quercus douglasii 22.5 – 30 Fair No –
129 Blue Oak Quercus douglasii 9.1 – 18 Poor No Poor structure, watersprouts 130 Blue Oak Quercus douglasii 14.5 – 30 Fair No –
131 Blue Oak Quercus douglasii 30.5 – 40 Fair No Basal wound, codominant stems
132 Blue Oak Quercus douglasii 13.6 – 30 Good No –
133 Blue Oak Quercus douglasii 15.4 – 25 Fair No Basal rot 134 Blue Oak Quercus douglasii 41.0 31.6, 26.2 35 Fair Yes Codominant stems 135 Blue Oak Quercus douglasii 10.5 – 30 Poor No Basal rot 136 Blue Oak Quercus douglasii 12.3 – 25 Fair No –

06/23/2026 Item No.18.

Appendix A – Individual Tree Survey Data (December 2, 2024) ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
A–2 April 2025
2024–012
Tree
Tag #
Common
Name Scientific Name
DSH
(inches)
Individual Stems
(if multi–stemmed)
Dripline
(feet)
ASCA
Rating
Heritage
Tree Field Notes
137 Blue Oak Quercus douglasii 13.4 – 25 Fair No –
220 Blue Oak Quercus douglasii – – – – – –
460 Blue Oak Quercus douglasii 40.3 – 40 Fair Yes
One branch fell and hit a
couple others but rest of
tree good
461 Blue Oak Quercus douglasii 43.9 – 42 Fair Yes –
701 Blue Oak Quercus douglasii 37 – 35 Good Yes –
703 Blue Oak Quercus douglasii 16.1 – 18 Fair No –
704 Valley Oak Quercus lobata 42.6 – 40 Good Yes –
705 Valley Oak Quercus lobata 61.2 – 35 Poor Yes Structural damage with healthy canopy
706 Blue Oak Quercus douglasii 45.1 – 40 Fair Yes –
707 Interior Live Oak Quercus wislizeni 25.2 – 12
Hazardous
or non–
correctable
No Main branches down
708 Interior Live Oak Quercus wislizeni 36.1 – 30 Fair Yes – 709 Interior Live Oak Quercus wislizeni 30.4 – 12 Poor Yes Many dead branches, trunk wounds
710 Interior Live Oak Quercus wislizeni 16.2 – 15 Fair No – 711 Blue Oak Quercus douglasii 36 – 35 Fair Yes –
712 Blue Oak Quercus douglasii 26.1 – 30 Fair No Watersprouts and mistltoe 713 Blue Oak Quercus douglasii 38 – 30 Fair Yes –
714 Blue Oak Quercus douglasii 50.9 – 45 Poor Yes
Main branch failure, unusual
whirled/concentric ring
growth at dead branches

06/23/2026 Item No.18.

Appendix A – Individual Tree Survey Data (December 2, 2024) ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
A–3 April 2025
2024–012
Tree
Tag #
Common
Name Scientific Name
DSH
(inches)
Individual Stems
(if multi–stemmed)
Dripline
(feet)
ASCA
Rating
Heritage
Tree Field Notes
715 Blue Oak Quercus douglasii 28.6 – 20 Fair No Somewhat sparse canopy, mistletoe
716 Blue Oak Quercus douglasii 30.6 – 30 Fair Yes Sparse canopy 717 Blue Oak Quercus douglasii 27.4 – 35
Hazardous
or non–
correctable
No Many dead branches
718 Blue Oak Quercus douglasii 30.5 – 32 Good Yes –
719 Blue Oak Quercus douglasii 29.2 – 35 Fair No –
720 Blue Oak Quercus douglasii 39.2 – 40 Fair Yes Watersprouts 721 Valley Oak Quercus lobata 26.5 – 25 Fair No Watersprouts 722 Blue Oak Quercus douglasii 49.5 – 40 Fair Yes Watersprouts 723 Blue Oak Quercus douglasii 37.4 – 40 Poor Yes Watersprouts, codominant stems
724 Blue Oak Quercus douglasii 45.6 – 35 Fair Yes Some watersprouts, a couple of downed branches
725 Blue Oak Quercus douglasii 26.7 – 32 Poor No Sparse canopy, thinning bark 726 Blue Oak Quercus douglasii 34.1 – 35 Fair Yes Thin canopy, some watersprouts
727 Blue Oak Quercus douglasii 30 – 35 Poor Yes Sparse canopy, codominant stems, mistletoe
728 Blue Oak Quercus douglasii 31.4 – 20 Fair Yes Sparse canopy 729 Blue Oak Quercus douglasii 42.6 – 32 Fair Yes Codominant stems 730 Blue Oak Quercus douglasii 41.2 – 35 Fair Yes –
731 Blue Oak Quercus douglasii 49.2 – 45 Fair Yes Large branch down

06/23/2026 Item No.18.

Appendix A – Individual Tree Survey Data (December 2, 2024) ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
A–4 April 2025
2024–012
Tree
Tag #
Common
Name Scientific Name
DSH
(inches)
Individual Stems
(if multi–stemmed)
Dripline
(feet)
ASCA
Rating
Heritage
Tree Field Notes
1157 Blue Oak Quercus douglasii 40.5 – 45 Fair Yes
One large branch broken off
main stem but obviously old
wound, healthy canopy
1158 Blue Oak Quercus douglasii 35.1 – 45 Fair Yes –
1159 Blue Oak Quercus douglasii 22.1 – 40 Fair No Leaning structure 1160 Blue Oak Quercus douglasii 43.2 – 45 Poor Yes Trunk wound and rot, sparse canopy
1161 Blue Oak Quercus douglasii 30 – 40 Fair Yes Watersprouts 1163 Blue Oak Quercus douglasii 34.1 – 40 Fair Yes –
1164 Blue Oak Quercus douglasii 12.1 – 15 Fair No –
1166 Blue Oak Quercus douglasii 28.8 – 28 Poor No
Maybe dead, no leaf litter
below, still has fine branches,
barn owl roosting evidence
1168 Interior Live Oak Quercus wislizeni 13.1 – 20 Fair No – 1169 Blue Oak Quercus douglasii 53.5 – 25 Poor Yes Main branch down 5000 – – – – – Dead – –
5001 – – – – – Dead – –
5002 – – – – – Dead – –
5003 – – – – – Dead – –
5004 – – – – – Dead – –
5005 – – – – – Dead – –
5006 – – – – – Dead – –
5007 – – – – – Dead – –

06/23/2026 Item No.18.

Appendix A – Individual Tree Survey Data (December 2, 2024) ECORP Consulting, Inc.

Toll Brothers at Alder Creek Property Project
A–5 April 2025
2024–012
Tree
Tag #
Common
Name Scientific Name
DSH
(inches)
Individual Stems
(if multi–stemmed)
Dripline
(feet)
ASCA
Rating
Heritage
Tree Field Notes
5008 – – – – – Dead – –
Notes: ASCA = American Society of Consulting Arborists; DSH = Diameter at Standard Height

06/23/2026 Item No.18.

Attachment 23
Folsom Plan Area Oak Woodlands Exhibit,
dated June 12, 2026

06/23/2026 Item No.18.
2005-
429FolsomPlanArea
MapDate:6/12/2026
PhotoSource:2024,NAIP
Basedonbestavailableinformationtodate.

FolsomPlanAreaOakWoodland
Location: J:\GIS_Maps\2005-429_Folsom_Area_South_Group\Tree_Data\Oak_Canopy\FPASP_OakImpact_Ledger_20260225_ansiD.mxd (MAG)-mguidry 6/12/2026 I
01,0002,000
ScaleinFeet
MapContents
SpecificPlanBoundary
FPASPLandUse
AlderCreekAnticipatedGrading
SlopeLimit
TotalOakWoodland642.16
TollBrothersatAlderCreekAnticipatedGradingLimits97.32
TollBrothersatAlderCreekAnticipatedGradingLimitBuffer10.10 PreviouslyImpactedtoDate65.01
FutureBackboneImpact44.08
RemainingOakWoodland425.66
FPASPwillpermanentlypreserveandprotectapproximately
396.52acresofoakwoodlands
06/23/2026 Item No.18.

Attachment 24
Resident Comment Letter, dated April 21, 2026

06/23/2026 Item No.18.
1 Jessica Brandt
From: Linda Silacci-Smith < >
Sent: Tuesday, April 21, 2026 3:34 PM
To: Jessica Brandt
Subject: Toll Brothers at Alder Creek - MSTR25-00084
Follow Up Flag: Follow up
Flag Status: Flagged
CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.

Hi Jessica,
I will not be able to attend this meeting and have the following questions:

When will this project start?
Will Prairie City Road be upgraded?
Will Mangini Parkway be extended?
I believe there is an elementary school to be built in this development. Will it be built before the homes? All the Folsom schools are so impacted.

Will any lights be added to Mangini Parkway between Oak Avenue and East Bidwell? It's a freeway on this stretch of the road! It is very rare any of the vehicles are traveling the posted 35 mph even though the speed is posted in several places and there are electronic signs in each direction letting you know how fast your vehicle is traveling.

Thank you in advance for your time,
Linda
You don't often get email from . Learn why this is important

06/23/2026 Item No.18.

Attachment 25
Lozeau Drury Comment Letter, dated June 8, 2026

06/23/2026 Item No.18.

June 8, 2026
Mayor Justin Raithel
Vice-Mayor Anna Rohrbough
Councilmember Sarah Aquino
Councilmember Mike Kozlowski
Councilmember Barbara Leary
Folsom City Council
Folsom City Hall
City Council Chambers, First Floor
50 Natoma Street
Folsom, CA 95630
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
Jessica Brandt, Principal Planner
Planning Services
50 Natoma Street
Folsom, CA 95630
[email protected]
Re: Toll Brothers at Alder Creek Project, File # MSTR25-00084, June 9, 2026 Meeting of the City Council, Agenda Item 10
Dear Mayor Raithel, Vice-Mayor Rohrbough, Councilmembers Aquino, Kozlowski, and Leary, and Ms. Brandt,
The following comments are submitted on behalf of Laborers Union of North America, Local Union 185 (“LIUNA”) on Agenda Item No. 10 of the upcoming June 9, 2026 City Council hearing for the Toll Brothers at Alder Creek Project (File # MSTR25-00084) (“Project”). The Project would include the development of 1,424 single family dwelling units with varying densities covering 464.2 acres. The Project is located on undeveloped lands within the Folsom Plan Area Specific Plan (FPASP or Plan Area).

To comply with the California Environmental Quality Act (“CEQA”), staff has proposed that the Project is exempt from CEQA pursuant to CEQA Guidelines § 15182(c) and Government Code § 65457. These provisions provide an exemption from CEQA for residential development projects which implement and are consistent with a specific plan for which an environmental impact report (“EIR”) has been previously certified. However, the exemption does not apply where new information or mitigation measures addressing

06/23/2026 Item No.18.

LIUNA Comments
Toll Brothers at Alder Creek Project
June 8, 2026

significant impacts become available after the adoption of the specific plan’s EIR. “However, if after adoption of the specific plan, an event as specified in Section 21166 of the Public Resources Code occurs, the exemption provided by this subdivision does not apply unless and until a supplemental environmental impact report for the specific plan is prepared and certified….” (Gov. Code § 65457.) These events include:
(a) Substantial changes are proposed in the project which will require major revisions of the environmental impact report.
(b) Substantial changes occur with respect to the circumstances under which the project is being undertaken which will require major revisions in the environmental impact report.
(c) New information, which was not known and could not have been known at the time the environmental impact report was certified as complete, becomes available.
(Pub. Res. Code § 21166(c).) The CEQA Guidelines further elaborate on this exception to the Specific Plan Exemption, providing that a subsequent EIR must be prepared if there is substantial evidence of any of the following events:
(1) Substantial changes that are proposed in project which will require major revisions to the previous EIR must be due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified significant effects;
(2) Substantial changes that occur with respect to the circumstances under which the project is undertaken must be due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified significant effects;
(3) New information of substantial importance, which was not known and could not have been known at the time the previous EIR was certified means that the new information could not have been known with the exercise of reasonable diligence and shows:
(A) The project will have one or more significant effects not discussed in the previous EIR;
(B) Significant effects previously examined will be substantially more severe that shown in the previous EIR;
(C) Mitigation measures or alternatives previously found not to be feasible would in fact be feasible and would substantially reduce one or more significant effects of the project, but the project proponents decline to adopt the mitigation measure or alternative; or
(D) Mitigation measures or alternatives which are considerably different from those analyzed in the previous EIR would substantially reduce one or more significant effects on the environment, but the project proponents decline to adopt the mitigation measure or alternative.

06/23/2026 Item No.18.

LIUNA Comments
Toll Brothers at Alder Creek Project
June 8, 2026

(14 Cal. Admin. Code § 15162(a).)
Substantial evidence of the presence of a special status species in an area of a proposed project the activities of which “have the potential to result in significant impacts to [the] species” has been held to be significant new information requiring a supplemental EIR pursuant to Section 21166(c). (Moss v. Cnty. of Humboldt (2008) 162 Cal.App.4th 1041, 1065–66 [presence of special status fish species in area of project that were “only recently brought to [county’s] attention” where project’s activities have the potential to result in significant impacts was new formation of substantial importance requiring supplemental EIR].) New information can be with respect to the project itself, but can also be in the form of better information with regard to calculating environmental impacts and new technologies available for the purposes of mitigation. (Sec. Envt’l Sys. v South Coast Air Quality Mgmt. Dist. (1991) 229 Cal.App.3d 110, 119 [requiring the preparation of an EIR prior to repermitting where new information revealed that initial assumptions and estimates greatly underestimated air pollution impacts and new technological controls had become available].)
In regard to considering new feasible mitigations for a project’s impacts previously determined by a lead agency to be significant and unavoidable, CEQA requires a lead agency to prepare a statement of overriding consideration and specified findings to address a project’s remaining significant and unavoidable adverse impacts. (See Pub.

Res. Code §§ 21094, 21081(a); 14 CCR §15091(a).) “The requirement of a statement of overriding considerations is central to CEQA’s role as a public accountability statute; it requires public officials, in approving environmental detrimental projects, to justify their decisions based on counterbalancing social, economic or other benefits, and to point to substantial evidence in support.” (Communities for a Better Environment v. Cal.

Resources Agency (2002) 103 Cal.App.4th 98, 124.) “The required findings constitute the principal means chosen by the Legislature to enforce the state’s declared policy ‘that public agencies should not approve projects as proposed if there are feasible alternatives or feasible mitigation measures available which would substantially lessen the significant environmental effects of such projects…” (City of Marina v. Bd. of Trs. of California State Univ. (2006) 39 Cal.4th 341, 350 [quoting PRC §21002].) If, after all feasible mitigation measures and alternatives have been imposed, a project still has significant environmental impacts, the project may be approved only if the lead agency makes an express written statement “that specific overriding economic, legal, social, technological, or other benefits of the project outweigh the significant effects on the environment.” (PRC §21081(b).)
On June 14, 2011, the City certified an EIR for the FPASP. Among other concerns, the 2011 EIR determined that operation of the large residential Project would result in significant and unavoidable impacts from construction emissions of PM-10 on sensitive receptors (DEIR, pp. ES-22-23), long-term operational emissions of reactive organic gases (ROGs) and nitrogen oxides (NOx) (DEIR, pp. ES-23-24), habitat loss and direct impacts on certain endangered, threatened and special status species (DEIR, ES-38 – 47), and construction-generated greenhouse gas emissions (DEIR, ES-61).

06/23/2026 Item No.18.

LIUNA Comments
Toll Brothers at Alder Creek Project
June 8, 2026

LIUNA has retained several expert consultants to review the 2011 EIR and the recent conformity analysis for the Project. LIUNA retained expert wildlife biologist, Dr.

Shawn Smallwood, Ph.D. to determine whether any species that were not identified as special status species in 2011 have been subsequently designated special status by the California Department of Fish & Wildlife (“CDFW”) or the United States Fish & Wildlife Service (“USFWS”) and will be affected by the Project. Dr. Smallwood’s analysis and curriculum vitae are attached as Exhibit A. Baseline Environmental Consulting has prepared expert comments reviewing the mitigation measures adopted in 2011 for the Project’s significant and unavoidable operational pollution emissions and identified feasible mitigations that have come to light since that time and thus far have been overlooked by staff’s reports. Baseline’s comments and relevant curriculum vitae are attached as Exhibit B. LIUNA also has retained indoor air quality expert, Francis Offermann, PE, CIH. Mr. Offermann, a Certified Industrial Hygienist and Professional Mechanical Engineer provides a review of new technical information that has come to light since 2011 demonstrating that significant health risks will occur even if finishing materials compliant with the California Air Resources Board’s Airborne Toxic Control Measure to Reduce Formaldehyde Emissions from Composite Wood Products (“Formaldehyde ATCM”) are used for the Project. Based on this new information, Mr.

Offermann concludes that the Project will expose future residents to significant impacts resulting from emissions of the cancer-causing chemical formaldehyde. Mr. Offerman’s comment letter and curriculum vitae are attached as Exhibit C.

A. Substantial Evidence Identifies New Information and Substantial Changes in Circumstances Regarding Special Status Species That Will be Adversely Affected by the Project.

The 2011 EIR confined its evaluation of the Specific Plan’s wildlife impacts to special status species identified at the time. A number of species that were not identified by CDFW as special status in 2011 are now identified by the agency as special status species. Many species that have been identified as special status since 2011 occur within the Project area and will be affected by the proposed large scale residential development.

CDFW’s identification of these special status species subsequent to 2011 is new information of substantial importance which was not available in 2011. The 2011 EIR did not mention these newly identified special status species nor were the Project’s impacts on these species or their habitat discussed. As a result, the City must prepare a supplemental EIR to address this important new information. (See Moss v. Cnty. of Humboldt (2008) 162 Cal.App.4th 1041, 1065–66.)
Special status species are those which “may be protected as threatened or endangered under state or federal law or are otherwise being tracked by the California Department of Fish and Wildlife (or the United States Fish and Wildlife Service) or a private organization such as the California Native Plant Society because the species are declining at a rate that could lead to their being listed or are otherwise sufficiently rare or threatened enough to warrant monitoring.” (Practice Under the California Environmental Quality Act (2d. ed. Cal. CEB 2024 § 20.53.) Appendix G of the Guidelines requires agencies to consider whether a project may “[h]ave a substantial adverse effect . . . on any species identified as . . . special status [] in local or regional plans, policies, or

06/23/2026 Item No.18.

LIUNA Comments
Toll Brothers at Alder Creek Project
June 8, 2026

regulations, or by the California Department of Fish and Wildlife or the U.S. Fish and Wildlife Service.” (CEQA Guidelines, App. G § (IV)(a).) Dr. Smallwood maintains a database tracking the conservation status assigned to species in California by various wildlife agencies and professional wildlife organizations.

Dr. Smallwood reviewed the species identified as special status species as of the 2011 DEIR. (Smallwood Comments, attached as Exhibit A.) He then compiled a list of all species that existing databases document occurring in the vicinity of the Project that have been identified by CDFW as special status since 2011 and which currently are included on the agency’s special status species list. (Id.) Dr. Smallwood also identifies species identified by the United States Fish & Wildlife Service (“USFWS”) as Birds of Conservation Concern, that also meet the definition of special status species. (Id.) The 2011 EIR addressed a total of 28 animal species identified in 2011 as special status species. (DEIR, pp. 3A.3-11 – 3A.3-14.) These included thirteen bird species, five amphibians or reptiles, four invertebrates, and six mammals. (Id.) CDFW identifies special status species on its “Special Animals List.” (https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=109406&inline.) “This list is also referred to as the list of ‘species at risk’ or ‘special status species.’” (Id., p. i.) Species added to CDFW’s special animals list since 2011 include species that are now identified as threatened or endangered, candidates for listing as threatened or endangered, as well as species at risk of being listed.

Species likely present within the Project area that have been added to the special status list and listed as endangered or threatened since 2011 include the Foothill yellowlegged frog (federal and state threatened) and the Western yellow-billed cuckoo (federally threatened and state endangered). (Smallwood Comment.) Neither of these more recently listed species is mentioned or evaluated in the 2011 EIR. Potential significant impacts to newly listed species that were not addressed in the prior EIR is new information of substantial importance requiring a supplemental EIR. (Moss, 162 Cal.App.4th at 1065–66.) Although the City’s conformity analysis would not satisfy the City’s duty to prepare a supplemental EIR to evaluate impacts to these new special status species, it is notable that the conformity analysis also makes no mention of this new information despite its purported purpose to review new information.

Several invertebrate species expected to occur in the Project area have become special status species since 2011 by being identified as candidates for listing as either endangered or threatened. These include Monarch butterfly, Western bumble bee, and Crotch bumble bee. (Smallwood Comment.) None of these species were mentioned or evaluated in the 2011 EIR. Their identification as special status species and formal candidates for listing is new information of substantial importance that must be addressed in a supplemental EIR.

The Conformity Analysis does not address either Monarch butterfly or Western bumble bee. As for the Crotch bumble bee, the Conformity Analysis confirms that the Project area “has potential foraging, nesting, and overwintering habitat for Crotch bumble Page 1165 06/23/2026 Item No.18.

LIUNA Comments
Toll Brothers at Alder Creek Project
June 8, 2026

bee.” (Conformity Analysis, p. 3-32.) The analysis also confirms that the bumble bee was not discussed or examined in the 2011 DEIR. As a result, rather than the truncated speculations regarding potential mitigation measures for the Crotch bumble bee, uninformed by any on-site surveys, the new information for this species should be vetted in a supplemental EIR and informed by public and agency comments.

Another species that has been identified as a special status species by CDFW since 2011 and which has been documented very close to the Project area is the Cackling goose (Aleutian). (Smallwood Comment.) No mention was made of this species in the 2011 EIR or the Conformity Analysis. A supplemental EIR must evaluate the Project’s impacts on this new special status species.

Pursuant to the federal Fish & Wildlife Conservation Act (“FWCA”), 16 U.S.C. § 2901, the United States Fish & Wildlife Service (“USFWS”) is required to maintain a list of birds of conservation concern. The FWCA mandates that USFWS “identify species, subspecies, and populations of all migratory nongame birds that, without additional conservation actions, are likely to become candidates for listing under the Endangered Species Act.” (16 U.S.C. § 2912(a)(3).) USFWS’s Birds of Conservation Concern (“BCC”) list is the agency’s “effort to carry out this mandate.” (https://www.fws.gov/sites/default/files/documents/birds-of-conservation-concern2021.pdf.) “The overall goal of this report is to identify those bird taxa (beyond those already designated as federally threatened or endangered) that represent the highest conservation priorities of the USFWS.” (Id.) Accordingly, species included on USFWS’s BCC list meet the criteria set forth in the CEQA Guidelines for lead agencies to assess species “identified as . . . special status … by the U.S. Fish and Wildlife Service.” (CEQA Guidelines, App. G § (IV)(a).) Birds identified as BCC are “being tracked by … the United States Fish and Wildlife Service … because the species are declining at a rate that could lead to their being listed or are otherwise sufficiently rare or threatened enough to warrant monitoring.” (CEB 2024 § 20.53.)
USFWS has identified at least 14 bird species occurring in the Project area as Birds of Conservation Concern since 2011. (Smallwood Comment.) These include Western grebe, Clark’s grebe, Calliope hummingbird, American avocet, Pectoral sandpiper, Lesser yellowlegs, Willet, Franklin’s gull, Heermann’s gull, Western gull, Wrentit, California thrasher, Cassin’s finch and Bullock’s oriole. (Id.) Because USFWS has identified these species as BCC, they are special status species as defined by Appendix G. None of these species were mentioned or evaluated in the 2011 EIR.

USFWS’s heightened concern for these species that are likely to become candidates for listing unless conservation measures are implemented is new information of substantial importance that must be addressed in a supplemental EIR.

06/23/2026 Item No.18.

LIUNA Comments
Toll Brothers at Alder Creek Project
June 8, 2026

B. Substantial Evidence Identifies New Feasible Mitigation Measures That Would Further Mitigate the Project’s Significant and Unavoidable Air Quality and Greenhouse Gas Impacts.

The 2011 EIR determined that the Project’s emissions of ROG, NOx, PM10, PM2.5 and ozone would cause significant air quality impacts by exceeding the SMAQMDrecommended threshold of 65 lb/day for ROG and NOX and conflict with air quality planning efforts in the Sacramento Valley Air Basin. (DEIR, p. 3A.2-44.) In order to mitigate this significant impact, the 2011 EIR established Mitigation Measure 3A.2-2 which required the Project to “implement all measures prescribed in the SMAQMDapproved Folsom Plan Area Specific Plan Air Quality Mitigation Plan (AQMP) (Torrence Planning 2008).” (Id., p. 3A.2-43.) The AQMP established mitigation measures focused on promoting bicycle use, pedestrian safety, bus shelters, traffic calming, minimizing parking, providing for grid-style street routing, prohibiting wood burning stoves, requiring Energy Star roofing materials, providing complimentary electric lawnmowers to each single family detached dwelling homeowner. (AQMP, pp. 12-21.) The Conformity Analysis describes Mitigation Measure 3A.2-2 and only addresses whether the Project would increase the severity of the significant operational air quality impacts identified in the 2011 EIR. It makes no effort to review or assess new mitigation measures that could reduce the impacts. (See Conformity Analysis, p. 3-24.) Without any explanation of any evidence, the Conformity Analysis merely asserts that “[t]here is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.” (Conformity Analysis, p. 3-30.) Contrary to that unsupported conclusion, there are significant, feasible mitigation measures available that must either be adopted by the City or evaluated in a supplemental EIR. Baseline Environmental Consulting reviewed the Project, the 2011 EIR and the Conformity Analysis and identified two mitigation measures that are considerably different from those analyzed in the 2011 EIR which would substantially reduce the Project’s significant operational air quality impacts. (Baseline Comments, attached as Exhibit B; 14 Cal. Admin. Code § 15162(a).) The two measures include:

Mitigation Measure 1. For each single-family dwelling unit, at least one Level 2 EV charger shall be installed with a dedicated 208/240-volt 40-ampere branch circuit between the main service or subpanel and a listed cabinet, box or other enclosure near the Level 2 EV charger. A battery electric storage system designed to support the Level 2 EV charger shall be installed and integrated with the solar photovoltaic system required for the dwelling unit.

New Mitigation Measure 2. During construction, super-compliant volatile organic compound (VOC) paints with a maximum VOC content of 10 grams per liter shall be used on the exterior and interior of each single-family dwelling unit. The project sponsor shall submit a signed certification statement to the City of Folsom Planning Department confirming that the super-compliant VOC requirement has been incorporated into the construction contract specifications, for review and approval.

06/23/2026 Item No.18.

LIUNA Comments
Toll Brothers at Alder Creek Project
June 8, 2026

Baseline’s expert review indicates that these two mitigation measures are readily available and would substantially reduce the Project’s previously assessed air pollution levels. Given the existing Energy Code requirements for new homes to be electric-ready for electricity heat pumps and appliances, the addition of Level 2 EV chargers is a nominal addition to each new home proposed in the Project. Likewise, new supercompliant VOC paints would be an insignificant incremental cost for each home. Neither of these mitigations were available in 2011 and are considerably different from Mitigation Measure 3A.2-2. Thus, should the City decline to include these mitigations, a supplementary EIR must be prepared.

C. Substantial Evidence Identifies New Information of Significant Health Impacts from Indoor Air Pollution and the Project’s Emissions of Carcinogenic Formaldehyde.

New information has come to light since the 2011 EIR establishing a significant risk to the health of future residents from the Project’s use of composite wood finishing materials in the Project’s interior spaces that will emit formaldehyde at levels resulting in cancer risks greatly exceeding the 10 in a million cancer risk threshold identified by the SMAQMD. (See 2011 DEIR, p. 3A.2-24.) The new information shows that these excessive health risks will occur even if finishing materials compliant with the California Air Resources Board’s Airborne Toxic Control Measure to Reduce Formaldehyde Emissions from Composite Wood Products (Formaldehyde ATCM”) are used for the Project. (Offermann Comments, attached as Exhibit C.)
Mr. Offermann explains that many composite wood products typically used in modern home construction contain formaldehyde-based glues which off-gas formaldehyde over a very long time period. He states, “The primary source of formaldehyde indoors is composite wood products manufactured with urea-formaldehyde resins, such as plywood, medium density fiberboard, and particleboard. These materials are commonly used in building construction for flooring, cabinetry, baseboards, window shades, interior doors, and window and door trims.” (Offermann Comments, p. 3.) Mr. Offermann concludes that future residents of the Project will be exposed to a cancer risk from formaldehyde of approximately 120 per million, even assuming that all materials are compliant with the California Air Resources Board’s formaldehyde airborne toxics control measure. (Offermann Comments, p. 4.) This exceeds SMAQMD’s CEQA significance threshold for airborne cancer risk of 10 per million. Importantly, Mr.

Offermann’s conclusions are based on studies conducted in 2019 and therefore were not available when the 2011 EIR was approved. (Id., p. 3.)
The CARB requirements are known as the Airborne Toxic Control Measure to Reduce Formaldehyde Emissions from Composite Wood Products (“Formaldehyde ATCM”). (17 Cal.Code Regs. § 93120-93120.12.) Composite wood products include hardwood plywood, particleboard (“PB”), and medium density fiberboard (“MDF”). (Id., § 93120(b); § 93120.1(a)(8).) The rules rely on prohibiting the sale, distribution, supply, or manufacturing of plywood, PB, and MDF that exceed formaldehyde emission standards established by the rule. (Id., § 93120.2(a).). The standards were phased in over a period

06/23/2026 Item No.18.

LIUNA Comments
Toll Brothers at Alder Creek Project
June 8, 2026

of years. By January 1, 2009, composite wood products had to comply with the Phase 1 emission standards established for each type of product. (Id., § 93120.2(a) (a certain category of hardwood plywood products had until July 1, 2009 to meet the standard applicable to those products).). Each product category then had several years to comply with a lower Phase 2 standard. (Id., § 93120.2(a).). Thus, by January 1, 2010, no hardwood plywood with a veneer core could be sold in California without meeting its Phase 2 formaldehyde emission standard. (Id.) Particle board and MDF products had to comply with their Phase 2 standard by January 1, 2011. Thin MDF had to comply with its applicable standard by January 1, 2012. (Id.) The remaining plywoods with composite cores had to comply no later than July 1, 2012. (Id.)
Mr. Offermann explains that residences using materials that comply with the Phase 2 formaldehyde emissions standards will pose significant cancer risks based on his participation in a follow-up 2020 study by Brett C. Singer prepared for the Lawrence Berkeley National Laboratory, co-authored by Mr. Offermann, as well as his own extensive experience studying and evaluating formaldehyde emissions from products and buildings. The 2020 Singer study measured formaldehyde levels in homes built after the CARB rules went into effect. (Offermann Comment, p. 3; Singer, B.C., et al., “Indoor Air Quality in California Homes with Code-Required Mechanical Ventilation” (2020) [attached as Exhibit D].) Thus, most of the homes included in the study were constructed with materials that were subject to the Phase 2 emission standards. The 2020 Singer Study was the first study documenting that, even where a residential structure was constructed from composite wood materials that comply with CARB’s Formaldehyde ATCM, a significant amount of formaldehyde will nevertheless be emitted to the indoor air of homes. Mr. Offermann’s calculations applying that newer study confirm that the health risks posed by those formaldehyde concentrations greatly exceed the significance threshold for airborne TACs of a 10 in 1 million risk of cancer.

The Folsom Plan Area Specific Plan relies substantively on CARB’s Formaldehyde ATCM, providing at Policy 10.81 that “Particleboard, medium density fiberboard (MDF) and hardwood plywood shall comply with low formaldehyde emission standards.” (FPASP, p. 10-35.) The impacts of formaldehyde emissions to indoor air in residential projects was not addressed in the 2011 EIR. Although Policy 10.81 surely was intended to protect future residents, the new information contained in the 2020 Singer study indicates that the CARB Formaldehyde ATCM does not lower cancer risks from indoor formaldehyde emissions to less than significant levels.

This indoor air quality impact could not have been known until 2020 when the Singer study was published showing that buildings using composite wood products that comply with the CARB formaldehyde standards vastly exceed CEQA significance thresholds for cancer risk. (Offerman, pp. 3-4.) Therefore, this impact was not known and could not have been known when the 2011 EIR was approved. When scientific information was not available at the time of prior CEQA review, more recent studies showing that a project may have more serious human health or environmental impacts constitute significant new information requiring a subsequent EIR. (Security Envt'l Sys. v South Coast Air Quality Mgmt. Dist. (1991) 229 Cal.App.3d 110, 124; Meridian Ocean Sys. v. State Lands Com. (1990) 222 Cal.App.3d 153, 169). As such, the staff report’s Page 1169 06/23/2026 Item No.18.

LIUNA Comments
Toll Brothers at Alder Creek Project
June 8, 2026

conclusion that an exemption is warranted is improper under Gov’t Code § 65457 and CEQA Guidelines § 15182 and supplemental environmental review is required. Mr.

Offerman’s expert comments are substantial evidence of new significant information and significant effect to air quality and health risks, precluding the City’s reliance on these CEQA exemption provisions.

The City has a duty to investigate issues relating to a project’s potential environmental impacts. (See County Sanitation Dist. No. 2 v. County of Kern (2005) 127 Cal.App.4th 1544, 1597–98. [“[U]nder CEQA, the lead agency bears a burden to investigate potential environmental impacts.”].) This is especially true for toxic air contaminants such as formaldehyde. The proposed Project will have significant impacts on air quality and health risks by emitting cancer-causing levels of formaldehyde into the air that will expose future residents and employees to cancer risks in excess of SMAQMD’s threshold of significance for cancer health risks of 10 per million.

Additionally, Mr. Offermann suggests mitigating the Project’s indoor air quality impacts by requiring all composite wood products used in construction of the Project to be manufactured with CARB-approved no-added formaldehyde (NAF) resins. (Offermann Comments, pp. 11-13.) Because indoor air quality impacts were not analyzed in the 2011 EIR, the City has not considered the use of NAF composite wood products. Furthermore, such products have only become readily available recently and, thus, could not have been considered in 2011. These mitigation measures also are new information of substantial importance triggering an additional CEQA review. (14 Cal. Admin. Code § 15162(a)(3)(C) & (D).) Notably, even compliance with California’s green building standards does not address this impact because the building standards do not change the CARB regulations. As Mr. Offermann explains, the use of CARB-compliant composite wood materials pursuant to the green building code does not prevent health risks as high as 12 times the 10 in a million cancer risk threshold. (Offerman Comments, pp. 3-4.) For all of the above reasons, staff is incorrect in relying on Gov’t Code § 65457 and CEQA Guidelines § 15182. The City must prepare a supplemental EIR to address the new information and mitigation measures discussed above. Thank you for considering these comments.

Sincerely,
Michael Lozeau
Lozeau Drury LLP

06/23/2026 Item No.18.

EXHIBIT A

06/23/2026 Item No.18.
1 Shawn Smallwood, PhD
3108 Finch Street
Davis, CA 95616
Michael Lozeau
Lozeau | Drury LLP
1939 Harrison St., Suite 150
Oakland, CA 94612 6 June 2026
RE: Alder Creek Parkway
Dear Mr. Lozeau,
As you requested, I compared the 2011 and 2026 California Department of Fish and Wildlife (CDFW) Special Animal Lists for the presence and status of those species of wildlife with a reasonable likelihood of occurrence on or near the Alder Creek Parkway, near Folsom California. Of the 113 special-status species in Table 1, seven have been downgraded in status (light green shade in Table 1), and 31 have been upgraded in status (light orange shade in Table 1) between 2011 and 2026, where downgraded means that one or more listings had been removed, and upgraded means the opposite.

I note that CDFW’s Special Animal Lists do not identify birds protected by California’s Birds of Prey Code. Additionally, the Lists do not identify the birds (golden eagle and bald eagle) protected by the Bald and Eagle Protection Act (BGEPA). Please be aware that in Table 1, I report the Species of Special Concern (SSC) rankings of 1, 2, and 3, but these rankings do not appear on the Special Animals Lists. I included these rankings because they are reported in Shuford and Gardali (2008), which was commissioned by CDFW.

There are various complications in my comparison. For one, FP, which stands for federally proposed for listing, appears on the 2011 Special Animals List for mountain plover, but although the definition remains on the 2026 Special Animals List, it is not assigned to any species. I suspect it is no longer applied. Another is that the 2011 List reports some species as BCC, even though they were not on the 2008 BCC list, and the 2011 List fails to report some species as BCC, even though they were on the 2008 BCC list. Also, Western Bats Working Group (WBWG) rankings do not appear on the 2026 Special Animals List, possibly because the WBWG is no longer active. The WBWG web site still exists, but it has lost functionality. Additional complications are explained in Table footnotes.

Best Regards,
______________________
Shawn Smallwood, Ph.D.

06/23/2026 Item No.18.
2 LITERATURE CITED
Shuford, W. D., and T. Gardali, [eds.]. 2008. California bird species of special concern: a ranked assessment of species, subspecies, and distinct populations of birds of immediate conservation concern in California. Studies of Western Birds 1. Western Field Ornithologists, Camarillo, California.

06/23/2026 Item No.18.
3 Table 1. Occurrence likelihoods of special-status species of wildlife at or near the proposed project site, according to eBird/iNaturalist records (https://eBird.org, https://www.inaturalist.org), and based on survey findings by environmental consults or myself at or near the project site (bold font), where ‘Very close’ indicates within 1.5 miles of the site, “nearby” indicates within 1.5 and 4 miles, and “in region” indicates within 4 and 30 miles, and ‘in range’ means the species’ geographic range overlaps the site. Status is compared between the 2011 and 2026 CDFW Special Animals Lists, of which light orange shade indicates that status was either added or upgraded between 2011 and 2026, and light green shade indicates status was downgraded.

Common name Species name Status1
2011 2026
Conservancy fairy shrimp Branchinecta conservatio FE FE In range Vernal pool fairy shrimp Branchinecta lynchi FT FT Nearby Vernal pool tadpole shrimp Lepidurus packardi FE FE In region Valley elderberry longhorn
beetle
Desmocerus californicus
dimorphus
FT FT In region
Monarch Danaus plexippus None FC 2019 Very close
Crotch’s bumble bee Bombus crotchii CCE 2019 Very close Western bumble bee Bombus occidentalis CCE 2019 In range California tiger salamander Ambystoma californiense FT, CT, SSC FT, CT, WL In region Western spadefoot Spea hammondii SSC FC, SSC; CCT
petition to be
decided 16 June
2026
2023 In region
Foothill yellow-legged frog Rana boylii SSC FT, CT 2020, 2021
Nearby
California red-legged frog Rana draytonii FT, SSC FT, SSC In region Western pond turtle Actinemys marmorata SSC FC, SSC 2023 On site Coast horned lizard Phrynosoma blainvillii SSC SSC Nearby Brant Branta bernicla SSC2 SSC2 In region
Cackling goose (Aleutian) Branta hutchinsii leucopareia None WL 2018 Very close Redhead Aythya americana SSC2 SSC2 Very close
Barrow’s goldeneye Bucephala islandica SSC SSC Very close

06/23/2026 Item No.18.
4 Common name Species name Status1
2011 2026
Western grebe Aechmophorus occidentalis BCC 2021 Very close Clark’s grebe Aechmophorus clarkii BCC 2021 Nearby
Western yellow-billed cuckoo Coccyzus americanus
occidentalis
FC, CE, BCC FT, CE 2014 In region
Black swift Cypseloides niger BCC, SSC3 BCC, SSC3 Nearby Vaux’s swift Chaetura vauxi SSC2 SSC2 Very close
Costa’s hummingbird Calypte costae BCC BCC Nearby
Calliope hummingbird Selasphorus calliope BCC 2021 Nearby Rufous hummingbird Selasphorus rufus BCC BCC Very close Allen’s hummingbird Selasphorus sasin BCC BCC In region Lesser sandhill crane Antigone canadensis canadensis SSC3 SSC3 Very close Greater sandhill crane Antigone canadensis tabida CT, CFP CT, CFP In region American avocet Recurvirostra americana BCC 2021 Very close Mountain plover Charadrius montanus FP, BCC, SSC2 BCC, SSC2 In region Snowy plover Charadrius nivosus BCC BCC2 In region
Western snowy plover Charadrius nivosus nivosus FT, BCC, SSC FT, BCC, SSC In region Long-billed curlew Numenius americanus BCC, WL WL Nearby Marbled godwit Limosa fedoa BCC BCC Nearby
Pectoral sandpiper Calidris melanotos BCC 2021 In region Short-billed dowitcher Limnodromus griseus BCC BCC In region Lesser yellowlegs Tringa flavipes BCC 2021 Very close
Willet Tringa semipalmata BCC 2021 In region
Franklin’s gull Leucophaeus pipixcan BCC 2021 In region Heermann’s gull Larus heermanni BCC 2021 In region
Western gull Larus occidentalis BCC 2021 Nearby
California gull Larus californicus WL BCC, WL 2021 Very close California least tern Sternula antillarum browni FE, CE, CFP FE, CE, CFP In region Black tern Chlidonias niger SSC2 SSC2, BCC 2021 Nearby
Common loon Gavia immer SSC SSC Nearby

06/23/2026 Item No.18.
5 Common name Species name Status1
2011 2026
Double-crested cormorant Phalacrocorax auritus WL WL Very close American white pelican Pelacanus erythrorhynchos SSC1 BCC, SSC1 2021 Very close Least bittern Ixobrychus exilis BCC3, SSC2 SSC2 In region White-faced ibis Plegadis chihi WL WL Very close
Osprey Pandion haliaetus WL WL Very close
White-tailed kite Elanus luecurus CFP CFP On site
Golden eagle Aquila chrysaetos BCC2, CFP, WL CFP, WL On site Northern harrier Circus cyaneus SSC3 BCC, SSC3 2021 On site Sharp-shinned hawk Accipiter striatus WL WL Very close
Cooper’s hawk Accipiter cooperii WL WL Very close
American goshawk Accipiter atricapillus SSC2 SSC2 In region Bald eagle Haliaeetus leucocephalus BCC, CE, CFP CE, CFP On site Swainson’s hawk Buteo swainsoni BCC3, CT CT Very close
Ferruginous hawk Buteo regalis BCC4, WL WL On site
California spotted owl Strix occidentalis occidentalis BCC, SSC BCC, SSC In region Burrowing owl Athene cunicularia BCC, SSC2 BCC, CCE,
SSC2
2025 On site
Long-eared owl Asio otus SSC3 BCC, SSC3, 2021 In region Short-eared owl Asia flammeus SSC3 BCC, SSC3, 2021 Nearby Lewis’s woodpecker Melanerpes lewis BCC BCC On site
Nuttall’s woodpecker Picoides nuttallii BCC BCC On site White-headed woodpecker Dryobates albolarvatus BCC BCC In region Merlin Falco columbarius WL WL On site
Peregrine falcon Falco peregrinus BCC, CFP Very close
Prairie falcon Falco mexicanus BCC3, WL WL On site
Olive-sided flycatcher Contopus cooperi BCC, SSC2 BCC, SSC2 2011 Very close Willow flycatcher Empidonax trailii BCC, CE CE Very close Vermilion flycatcher Pyrocephalus rubinus SSC2 SSC2 In region Least Bell’s vireo Vireo bellii pusillus FE, CE FE, CE In region

06/23/2026 Item No.18.
6 Common name Species name Status1
2011 2026
Loggerhead shrike Lanius ludovicianus BCC, SSC2 SSC2 On site Yellow-billed magpie Pica nuttalli BCC BCC On site
Oak titmouse Baeolophus inornatus BCC BCC On site
California horned lark Eremophila alpestris actia WL WL On site Bank swallow Riparia riparia CT CT Nearby
Purple martin Progne subis SSC2 SSC2 Very close
Wrentit Chamaea fasciata BCC 2021 Very close
California thrasher Toxostoma redivivum BCC 2021 Nearby Cassin’s finch Haemorhous cassinii BCC 2021 Nearby
Lawrence’s goldfinch Spinus lawrencei BCC BCC Very close Grasshopper sparrow Ammodramus savannarum SSC2 SSC2 Nearby Black-chinned sparrow Spizella atrogularis BCC BCC In region Bell’s sparrow Amphispiza b. belli BCC, WL WL Nearby
Oregon vesper sparrow Pooecetes gramineus affinis BCC, SSC2 BCC, SSC2 Very close Modesto song sparrow Melospiza melodia mailliardi BCC3, SSC1 SSC3 On site Yellow-breasted chat Icteria virens SSC3 SSC3 Nearby
Yellow-headed blackbird Xanthocephalus xanthocephalus SSC3 SSC3 On site Bullock’s oriole Icterus bullockii BCC 2021 Very close
Tricolored blackbird Agelaius tricolor BCC, SSC1 CT, BCC, SSC1 2018 On site Virginia’s warbler Leiothlypis virginiae BCC, WL BCC, WL In region Northern yellow warbler Setophaga aestiva BCC, SSC2 SSC2 Very close Summer tanager Piranga rubra SSC1 SSC1 Nearby
Little brown bat Myotis lucifugus WBWG:M None In region Yuma myotis Myotis yumanensis WBWG:LM None In region
Long-eared myotis Myotis evotis WBWG:M None In range
Fringed myotis Myotis thysanodes WBWG:H None In range
Long-legged myotis Myotis volans WBWG:H None In range
Small-footed myotis Myotis ciliolabrum WBWG:M None In region Canyon bat Parastrellus hesperus WBWG:M None In region

06/23/2026 Item No.18.
7 Common name Species name Status1
2011 2026
Silver-haired bat Lasionycteris noctivagans WBWG:M None In region Hoary bat Lasiurus cinereus WBWG:M None In region
Western red bat Lasiurus blossevillii SSC, WBWG:H SSC In region Townsend’s big-eared bat Corynorhinus townsendii SSC, WBWG:H SSC In region Spotted bat Euderma maculatum SSC, WBWG:H SSC In range
Pallid bat Antrozous pallidus SSC, WBWG:H SSC In region Western mastiff bat Eumops perotis SSC, WBWG:H SSC In region Ringtail Bassariscus astutus CFP5 CFP In region
Sacramento Valley red fox Vulpes vulpes patwin None In region American badger Taxidea taxus SSC SSC In region
Mountain lion Puma concolor SA6 SA In region
1 Listed on CDFW’s Special Animals List (https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=109406) as None = on the List, but no special-status listing is reported; FT or FE = federal threatened or endangered; FC = federal candidate for listing; FP = federal proposed for listing; BGEPA = Bald and Golden Eagle Protection Act; BCC = U.S. Fish and Wildlife Service’s Bird of Conservation Concern (https://www.fws.gov/sites/default/files/documents/birds-of-conservation-concern-2021.pdf); CT or CE = California threatened or endangered; CCT or CCE = Candidate California threatened or endangered; CFP = California Fully Protected (California Fish and Game Code 3511); SSCi = California Species of Special Concern with i = priorities 1, 2 and 3; WL = CDFW’s Taxa to Watch List; WBWG = Western Bat Working Group with priority rankings, of low (L), moderate (M) and high (H); and SA = Specially Protected Mammal under California Wildlife Protection Act of 1990. 2 Does not appear on 2026 Special Animals List as BCC, but it is listed by USFWS as BCC. 3 Listed on 2011 Special Animals List as BCC, but it did not appear on 2008 USFWS BCC list. 4 BCC listing applied only to desert region.
5 Does not appear on 2011 Special Animals List other than to report that ringtail is not tracked by CNDDB. Nonetheless, it was a California Fully Protected Species at the time.
6 Mountain lion (other than the Yuma subspecies) does not appear on the 2011 Special Animals List even though it was a Special Animal at the time.

06/23/2026 Item No.18.
1 Kenneth Shawn Smallwood
Curriculum Vitae
3108 Finch Street Born May 3, 1963 in
Davis, CA 95616 Sacramento, California.

Phone (530) 756-4598 Married, father of two.

Cell (530) 601-6857
[email protected]
Ecologist
Expertise
• Finding solutions to controversial problems related to wildlife interactions with human industry, infrastructure, and activities;
• Wildlife monitoring and field study using GPS, thermal imaging, behavior surveys; • Using systems analysis and experimental design principles to identify meaningful ecological patterns that inform management decisions.

Education
Ph.D. Ecology, University of California, Davis. September 1990.

M.S. Ecology, University of California, Davis. June 1987.

B.S. Anthropology, University of California, Davis. June 1985.

Corcoran High School, Corcoran, California. June 1981.

Experience
 762 professional reports, including:
 90 peer reviewed publications
 24 in non-reviewed proceedings
 646 reports, declarations, posters and book reviews
 8 in mass media outlets
 92 public presentations of research results
Editing for scientific journals: Guest Editor, Wildlife Society Bulletin, 2012-2013, of invited papers representing international views on the impacts of wind energy on wildlife and how to mitigate the impacts. Associate Editor, Journal of Wildlife Management, March 2004 to 30 June 2007.

Editorial Board Member, Environmental Management, 10/1999 to 8/2004. Associate Editor, Biological Conservation, 9/1994 to 9/1995.

Member, Alameda County Scientific Review Committee (SRC), August 2006 to April 2011. The five-member committee investigated causes of bird and bat collisions in the Altamont Pass Wind Resource Area, and recommended mitigation and monitoring measures. The SRC reviewed the science underlying the Alameda County Avian Protection Program, and advised

06/23/2026 Item No.18.

Smallwood CV 2
the County on how to reduce wildlife fatalities.

Consulting Ecologist, 2004-2007, California Energy Commission (CEC). Provided consulting services as needed to the CEC on renewable energy impacts, monitoring and research, and produced several reports. Also collaborated with Lawrence-Livermore National Lab on research to understand and reduce wind turbine impacts on wildlife.

Consulting Ecologist, 1999-2013, U.S. Navy. Performed endangered species surveys, hazardous waste site monitoring, and habitat restoration for the endangered San Joaquin kangaroo rat, California tiger salamander, California red-legged frog, California clapper rail, western burrowing owl, salt marsh harvest mouse, and other species at Naval Air Station Lemoore; Naval Weapons Station, Seal Beach, Detachment Concord; Naval Security Group Activity, Skaggs Island; National Radio Transmitter Facility, Dixon; and, Naval Outlying Landing Field Imperial Beach.

Part-time Lecturer, 1998-2005, California State University, Sacramento. Instructed Mammalogy, Behavioral Ecology, and Ornithology Lab, Contemporary Environmental Issues, Natural Resources Conservation.

Senior Ecologist, 1999-2005, BioResource Consultants. Designed and implemented research and monitoring studies related to avian fatalities at wind turbines, avian electrocutions on electric distribution poles across California, and avian fatalities at transmission lines.

Chairman, Conservation Affairs Committee, The Wildlife Society--Western Section, 1999-2001.

Prepared position statements and led efforts directed toward conservation issues, including travel to Washington, D.C. to lobby Congress for more wildlife conservation funding.

Systems Ecologist, 1995-2000, Institute for Sustainable Development. Headed ISD’s program on integrated resources management. Developed indicators of ecological integrity for large areas, using remotely sensed data, local community involvement and GIS.

Associate, 1997-1998, Department of Agronomy and Range Science, University of California, Davis. Worked with Shu Geng and Mingua Zhang on several studies related to wildlife interactions with agriculture and patterns of fertilizer and pesticide residues in groundwater across a large landscape.

Lead Scientist, 1996-1999, National Endangered Species Network. Informed academic scientists and environmental activists about emerging issues regarding the Endangered Species Act and other environmental laws. Testified at public hearings on endangered species issues.

Ecologist, 1997-1998, Western Foundation of Vertebrate Zoology. Conducted field research to determine the impact of past mercury mining on the status of California red-legged frogs in Santa Clara County, California.

Senior Systems Ecologist, 1994-1995, EIP Associates, Sacramento, California. Provided consulting services in environmental planning, and quantitative assessment of land units for their conservation and restoration opportunities basedon ecological resource requirements of 29 special-status species. Developed ecological indicators for prioritizing areas within Yolo County

06/23/2026 Item No.18.

Smallwood CV 3
to receive mitigation funds for habitat easements and restoration.

Post-Graduate Researcher, 1990-1994, Department of Agronomy and Range Science, U.C. Davis.

Under Dr. Shu Geng’s mentorship, studied landscape and management effects on temporal and spatial patterns of abundance among pocket gophers and species of Falconiformes and Carnivora in the Sacramento Valley. Managed and analyzed a data base of energy use in California agriculture. Assisted with landscape (GIS) study of groundwater contamination across Tulare County, California.

Work experience in graduate school: Co-taught Conservation Biology with Dr. Christine Schonewald, 1991 & 1993, UC Davis Graduate Group in Ecology; Reader for Dr. Richard Coss’s course on Psychobiology in 1990, UC Davis Department of Psychology; Research Assistant to Dr. Walter E. Howard, 1988-1990, UC Davis Department of Wildlife and Fisheries Biology, testing durable baits for pocket gopher management in forest clearcuts; Research Assistant to Dr. Terrell P. Salmon, 1987-1988, UC Wildlife Extension, Department of Wildlife and Fisheries Biology, developing empirical models of mammal and bird invasions in North America, and a rating system for priority research and control of exotic species based on economic, environmental and human health hazards in California. Student Assistant to Dr. E.

Lee Fitzhugh, 1985-1987, UC Cooperative Extension, Department of Wildlife and Fisheries Biology, developing and implementing statewide mountain lion track count for long-term monitoring.

Fulbright Research Fellow, Indonesia, 1988. Tested use of new sampling methods for numerical monitoring of Sumatran tiger and six other species of endemic felids, and evaluated methods used by other researchers.

Projects
Repowering wind energy projects through careful siting of new wind turbines using map-based collision hazard models to minimize impacts to volant wildlife. Funded by wind companies (principally NextEra Renewable Energy, Inc.), California Energy Commission and East Bay Regional Park District, I have collaborated with a GIS analyst and managed a crew of five field biologists performing golden eagle behavior surveys and nocturnal surveys on bats and owls. The goal is to quantify flight patterns for development of predictive models to more carefully site new wind turbines in repowering projects. Focused behavior surveys began May 2012 and continue.

Collision hazard models have been prepared for seven wind projects, three of which were built.

Planning for additional repowering projects is underway.

Test avian safety of new mixer-ejector wind turbine (MEWT). Designed and implemented a beforeafter, control-impact experimental design to test the avian safety of a new, shrouded wind turbine developed by Ogin Inc. (formerly known as FloDesign Wind Turbine Corporation). Supported by a $718,000 grant from the California Energy Commission’s Public Interest Energy Research program and a 20% match share contribution from Ogin, I managed a crew of seven field biologists who performed periodic fatality searches and behavior surveys, carcass detection trials, nocturnal behavior surveys using a thermal camera, and spatial analyses with the collaboration of a GIS analyst. Field work began 1 April 2012 and ended 30 March 2015 without Ogin installing its MEWTs, but we still achieved multiple important scientific advances.

06/23/2026 Item No.18.

Smallwood CV 4
Reduce avian mortality due to wind turbines at Altamont Pass. Studied wildlife impacts caused by 5,400 wind turbines at the world’s most notorious wind resource area. Studied how impacts are perceived by monitoring and how they are affected by terrain, wind patterns, food resources, range management practices, wind turbine operations, seasonal patterns, population cycles, infrastructure management such as electric distribution, animal behavior and social interactions.

Reduce avian mortality on electric distribution poles. Directed research toward reducing bird electrocutions on electric distribution poles, 2000-2007. Oversaw 5 founds of fatality searches at 10,000 poles from Orange County to Glenn County, California, and produced two large reports.

Cook et al. v. Rockwell International et al., No. 90-K-181 (D. Colorado). Provided expert testimony on the role of burrowing animals in affecting the fate of buried and surface-deposited radioactive and hazardous chemical wastes at the Rocky Flats Plant, Colorado. Provided expert reports based on four site visits and an extensive document review of burrowing animals. Conducted transect surveys for evidence of burrowing animals and other wildlife on and around waste facilities.

Discovered substantial intrusion of waste structures by burrowing animals. I testified in federal court in November 2005, and my clients were subsequently awarded a $553,000,000 judgment by a jury. After appeals the award was increased to two billion dollars.

Hanford Nuclear Reservation Litigation. Provided expert testimony on the role of burrowing animals in affecting the fate of buried radioactive wastes at the Hanford Nuclear Reservation, Washington. Provided three expert reports based on three site visits and extensive document review.

Predicted and verified a certain population density of pocket gophers on buried waste structures, as well as incidence of radionuclide contamination in body tissue. Conducted transect surveys for evidence of burrowing animals and other wildlife on and around waste facilities. Discovered substantial intrusion of waste structures by burrowing animals.

Expert testimony and declarations on proposed residential and commercial developments, gas-fired power plants, wind, solar and geothermal projects, water transfers and water transfer delivery systems, endangered species recovery plans, Habitat Conservation Plans and Natural Communities Conservation Programs. Testified before multiple government agencies, Tribunals, Boards of Supervisors and City Councils, and participated with press conferences and depositions. Prepared expert witness reports and court declarations, which are summarized under Reports (below).

Protocol-level surveys for special-status species. Used California Department of Fish and Wildlife and US Fish and Wildlife Service protocols to search for California red-legged frog, California tiger salamander, arroyo southwestern toad, blunt-nosed leopard lizard, western pond turtle, giant kangaroo rat, San Joaquin kangaroo rat, San Joaquin kit fox, western burrowing owl, Swainson’s hawk, Valley elderberry longhorn beetle and other special-status species.

Conservation of San Joaquin kangaroo rat. Performed research to identify factors responsible for the decline of this endangered species at Lemoore Naval Air Station, 2000-2013, and implemented habitat enhancements designed to reverse the trend and expand the population.

Impact of West Nile Virus on yellow-billed magpies. Funded by Sacramento-Yolo Mosquito and Vector Control District, 2005-2008, compared survey results pre- and post-West Nile Virus epidemic for multiple bird species in the Sacramento Valley, particularly on yellow-billed magpie and American crow due to susceptibility to WNV.

06/23/2026 Item No.18.

Smallwood CV 5
Workshops on HCPs. Assisted Dr. Michael Morrison with organizing and conducting a 2-day workshop on Habitat Conservation Plans, sponsored by Southern California Edison, and another 1- day workshop sponsored by PG&E. These Workshops were attended by academics, attorneys, and consultants with HCP experience. We guest-edited a Proceedings published in Environmental Management.

Mapping of biological resources along Highways 101, 46 and 41. Used GPS and GIS to delineate vegetation complexes and locations of special-status species along 26 miles of highway in San Luis Obispo County, 14 miles of highway and roadway in Monterey County, and in a large area north of Fresno, including within reclaimed gravel mining pits.

GPS mapping and monitoring at restoration sites and at Caltrans mitigation sites. Monitored the success of elderberry shrubs at one location, the success of willows at another location, and the response of wildlife to the succession of vegetation at both sites. Also used GPS to monitor the response of fossorial animals to yellow star-thistle eradication and natural grassland restoration efforts at Bear Valley in Colusa County and at the decommissioned Mather Air Force Base in Sacramento County.

Mercury effects on Red-legged Frog. Assisted Dr. Michael Morrison and US Fish and Wildlife Service in assessing the possible impacts of historical mercury mining on the federally listed California red-legged frog in Santa Clara County. Also measured habitat variables in streams.

Opposition to proposed No Surprises rule. Wrote a white paper and summary letter explaining scientific grounds for opposing the incidental take permit (ITP) rules providing ITP applicants and holders with general assurances they will be free of compliance with the Endangered Species Act once they adhere to the terms of a “properly functioning HCP.” Submitted 188 signatures of scientists and environmental professionals concerned about No Surprises rule US Fish and Wildlife Service, National Marine Fisheries Service, all US Senators.

Natomas Basin Habitat Conservation Plan alternative. Designed narrow channel marsh to increase the likelihood of survival and recovery in the wild of giant garter snake, Swainson’s hawk and Valley Elderberry Longhorn Beetle. The design included replication and interspersion of treatments for experimental testing of critical habitat elements. I provided a report to Northern Territories, Inc.

Assessments of agricultural production system and environmental technology transfer to China.

Twice visited China and interviewed scientists, industrialists, agriculturalists, and the Directors of the Chinese Environmental Protection Agency and the Department of Agriculture to assess the need and possible pathways for environmental clean-up technologies and trade opportunities between the US and China.

Yolo County Habitat Conservation Plan. Conducted landscape ecology study of Yolo County to spatially prioritize allocation of mitigation efforts to improve ecosystem functionality within the County from the perspective of 29 special-status species of wildlife and plants. Used a hierarchically structured indicators approach to apply principles of landscape and ecosystem ecology, conservation biology, and local values in rating land units. Derived GIS maps to help guide the conservation area design, and then developed implementation strategies.

06/23/2026 Item No.18.

Smallwood CV 6
Mountain lion track count. Developed and conducted a carnivore monitoring program throughout California since 1985. Species counted include mountain lion, bobcat, black bear, coyote, red and gray fox, raccoon, striped skunk, badger, and black-tailed deer. Vegetation and land use are also monitored. Track survey transect was established on dusty, dirt roads within randomly selected quadrats.

Sumatran tiger and other felids. Upon award of Fulbright Research Fellowship, I designed and initiated track counts for seven species of wild cats in Sumatra, including Sumatran tiger, fishing cat, and golden cat. Spent four months on Sumatra and Java in 1988, and learned Bahasa Indonesia, the official Indonesian language.

Wildlife in agriculture. Beginning as post-graduate research, I studied pocket gophers and other wildlife in 40 alfalfa fields throughout the Sacramento Valley, and I surveyed for wildlife along a 200 mile road transect since 1989 with a hiatus of 1996-2004. The data are analyzed using GIS and methods from landscape ecology, and the results published and presented orally to farming groups in California and elsewhere. I also conducted the first study of wildlife in cover crops used on vineyards and orchards.

Agricultural energy use and Tulare County groundwater study. Developed and analyzed a data base of energy use in California agriculture, and collaborated on a landscape (GIS) study of groundwater contamination across Tulare County, California.

Pocket gopher damage in forest clear-cuts. Developed gopher sampling methods and tested various poison baits and baiting regimes in the largest-ever field study of pocket gopher management in forest plantations, involving 68 research plots in 55 clear-cuts among 6 National Forests in northern California.

Risk assessment of exotic species in North America. Developed empirical models of mammal and bird species invasions in North America, as well as a rating system for assigning priority research and control to exotic species in California, based on economic, environmental, and human health hazards.

Peer Reviewed Publications
Smallwood, K. S. 2022. Utility-scale solar impacts to volant wildlife. Journal of Wildlife Management: e22216. https://doi.org/10.1002/jwmg.22216
Smallwood, K. S., and N. L. Smallwood. 2021. Breeding Density and Collision Mortality of Loggerhead Shrike (Lanius ludovicianus) in the Altamont Pass Wind Resource Area. Diversity 13, 540. https://doi.org/10.3390/d13110540.

Smallwood, K. S. 2020. USA wind energy-caused bat fatalities increase with shorter fatality search intervals. Diversity 12(98); https://doi.org/10.3390/d12030098 Smallwood, K. S., D. A. Bell, and S. Standish. 2020. Dogs detect larger wind energy impacts on bats and birds. Journal of Wildlife Management 84:852-864. DOI: 10.1002/jwmg.21863.

Smallwood, K. S., and D. A. Bell. 2020. Relating bat passage rates to wind turbine fatalities.

06/23/2026 Item No.18.

Smallwood CV 7
Diversity 12(84); doi:10.3390/d12020084.

Smallwood, K. S., and D. A. Bell. 2020. Effects of wind turbine curtailment on bird and bat fatalities. Journal of Wildlife Management 84:684-696. DOI: 10.1002/jwmg.21844 Kitano, M., M. Ino, K. S. Smallwood, and S. Shiraki. 2020. Seasonal difference in carcass persistence rates at wind farms with snow, Hokkaido, Japan. Ornithological Science 19: 63 –

71. Smallwood, K. S. and M. L. Morrison. 2018. Nest-site selection in a high-density colony of burrowing owls. Journal of Raptor Research 52:454-470.

Smallwood, K. S., D. A. Bell, E. L. Walther, E. Leyvas, S. Standish, J. Mount, B. Karas. 2018.

Estimating wind turbine fatalities using integrated detection trials. Journal of Wildlife Management 82:1169-1184.

Smallwood, K. S. 2017. Long search intervals under-estimate bird and bat fatalities caused by wind turbines. Wildlife Society Bulletin 41:224-230.

Smallwood, K. S. 2017. The challenges of addressing wildlife impacts when repowering wind energy projects. Pages 175-187 in Köppel, J., Editor, Wind Energy and Wildlife Impacts:

Proceedings from the CWW2015 Conference. Springer. Cham, Switzerland.

May, R., Gill, A. B., Köppel, J. Langston, R. H.W., Reichenbach, M., Scheidat, M., Smallwood, S., Voigt, C. C., Hüppop, O., and Portman, M. 2017. Future research directions to reconcile wind turbine–wildlife interactions. Pages 255-276 in Köppel, J., Editor, Wind Energy and Wildlife Impacts: Proceedings from the CWW2015 Conference. Springer. Cham, Switzerland.

Smallwood, K. S. 2017. Monitoring birds. M. Perrow, Ed., Wildlife and Wind Farms - Conflicts and Solutions, Volume 2. Pelagic Publishing, Exeter, United Kingdom. www.bit.ly/2v3cR9Q Smallwood, K. S., L. Neher, and D. A. Bell. 2017. Turbine siting for raptors: an example from Repowering of the Altamont Pass Wind Resource Area. M. Perrow, Ed., Wildlife and Wind Farms - Conflicts and Solutions, Volume 2. Pelagic Publishing, Exeter, United Kingdom. www.bit.ly/2v3cR9Q
Johnson, D. H., S. R. Loss, K. S. Smallwood, W. P. Erickson. 2016. Avian fatalities at wind energy facilities in North America: A comparison of recent approaches. Human–Wildlife Interactions 10(1):7-18.

Sadar, M. J., D. S.-M. Guzman, A. Mete, J. Foley, N. Stephenson, K. H. Rogers, C. Grosset, K. S.

Smallwood, J. Shipman, A. Wells, S. D. White, D. A. Bell, and M. G. Hawkins. 2015. Mange Caused by a novel Micnemidocoptes mite in a Golden Eagle (Aquila chrysaetos). Journal of Avian Medicine and Surgery 29(3):231-237.

Smallwood, K. S. 2015. Habitat fragmentation and corridors. Pages 84-101 in M. L. Morrison and H. A. Mathewson, Eds., Wildlife habitat conservation: concepts, challenges, and solutions.

John Hopkins University Press, Baltimore, Maryland, USA.

06/23/2026 Item No.18.

EXHIBIT B

06/23/2026 Item No.18.
388 17th Street, Suite 230, Oakland, CA 94612 | (510) 420-8686 | www.baseline-env.com Mailing Address: PO Box 18586, Oakland, CA 94619
June 6, 2026
26235-00
Michael Lozeau
Lozeau Drury LLP
1939 Harrison St., Suite 150
Oakland, CA 94612
Subject: Review of Air Quality Impacts Analyzed for Toll Brothers at Alder Creek Project Dear Mr. Lozeau:

Baseline Environmental Consulting (Baseline) has reviewed the Conformity Analysis1 for the Toll Brothers at Alder Creek Project (project) in the southeastern portion of the City of Folsom (City). The project proposes to construct 1,424 single-family homes in accordance with the Folsom Plan Area Specific Plan (FPASP). The purpose of the Conformity Analysis was to identify and assess project compliance with the program-level FPASP Environmental Impact Report and Environmental Impact Statement (EIR/EIS) that was approved in 2011.2 Pursuant to CEQA Guidelines Section 15182, the Conformity Analysis evaluated if any of the events described in CEQA Guidelines Section 15162 (Subsequent EIRs and Negative Declarations) have occurred and were not considered in the FPASP. The purpose of our review was to determine whether additional mitigation measures can be incorporated into the proposed project to reduce the severity of significant air quality impacts identified in the FPASP EIR/EIS.

Long-term Criteria Air Pollutant Emissions
The analysis under the FPASP EIR/EIS found that the long-term increase of criteria air pollutants resulting from implementation of the FPASP would be a significant and unavoidable impact. As described in the Conformity Analysis, the project would comply with mitigation measure 3A.2-2 from the FPASP EIR/EIS, which requires the project to implement all measures prescribed in the 2009 FPASP Air Quality Mitigation Plan (AQMP). As stated on page 3-23 of the Conformity Analysis, the AQMP includes the following measures:
 Provide bicycle parking at commercial land uses.
 Provide integrated pedestrian/bicycle path network.
1 ECORP Consulting, Inc., 2025. Section 15182 and 15162 Conformity Analysis for the Toll Brothers Property, Alder Creek Subdivision Tentative Map, City of Folsom, California. August. 2 AECOM and RMC Water and Environment, 2011. Final EIR/EIS, Folsom South of U.S. Highway 50 Specific Plan Project, SCH #2008092051. May.

06/23/2026 Item No.18.

June 8, 2026

 Provide transit stops with shelters.
 Prohibit the use the wood-burning fireplaces.
 Require Energy Star roofing materials.
 Provide electric lawn mowers provided to homeowners at no charge.  Provide on-site transportation alternatives to passenger vehicles (including light rail) that provide connectivity with other local and regional alternative transportation networks.

Many of these measures from the 2009 AQMP do not appear to be directly applicable to development of proposed 1,424 single-family homes and it’s unclear how the project’s compliance with the 2009 AQMP would reduce the severity of the significant and unavoidable impact identified in the FPASP EIR/EIS for long-term emissions of criteria air pollutants. As discussed below, there are additional mitigation measures that could be evaluated and implemented under the proposed project that were not considered and/or were not readily available when the FPASP EIR/EIS was certified in 2011.

New Mitigation Measures
Vehicle emissions were identified as a substantial source of long-term criteria air pollutant emissions in the Folsom Plan Area for which the FPASP EIR/EIS identified as a significant and unavoidable impact. According to the California Energy Commission, access to home charging for electric vehicles (EV) is a critical strategy to encourage the electrification of California’s transportation system and lower fleetwide vehicle emissions, particularly access to faster Level 2 EV chargers as the battery sizes and ranges of EVs continue to increase.3 Under the current California Energy Code (2025), newly constructed single-family homes are required to be equipped with solar photovoltaic systems designed to offset the home's annual electricity usage. To maximize solar efficiency, the project could integrate the solar photovoltaic system for each home with a battery electric storage system and Level 2 EV charger to encourage the adoption of EV vehicles and substantially reduce the overall criteria air pollutant emissions from vehicles in the Folsom Plan Area. To reduce the severity of this impact, Baseline recommends that the project implement the following mitigation measure (or similar):
 New Mitigation Measure 1. For each single-family dwelling unit, at least one Level 2 EV charger shall be installed with a dedicated 208/240-volt 40-ampere branch circuit between the main service or subpanel and a listed cabinet, box or other enclosure near the Level 2 EV charger. A battery electric storage system designed to support the Level 2 EV charger shall be installed and integrated with the solar photovoltaic system required for the dwelling unit.
3 California Energy Commission, 2022. Staff Report, Home Charging Access in California, CEC-600-2022-021.

January.

06/23/2026 Item No.18.

June 8, 2026

Architectural coatings are a major source of reactive organic gas (ROG) emissions, a precursor for the formation of ground-level ozone, which the FPASP EIR/EIS identified as a significant and unavoidable impact. Under Sacramento Metropolitan Air Quality Management District Rule 442, all interior and exterior architectural coatings of paint for newly constructed single-family homes are limited to a maximum volatile organic compound (VOC) content of 50 grams per liter. In recent years, paint manufacturers have developed super-compliant VOC paints with a maximum VOC content of 10 grams per liter for widespread use in California, which were not readily available when the FPASP EIR/EIS was certified in 2011. To reduce the severity of this impact, Baseline recommends that the project implement the following mitigation measure (or similar):
 New Mitigation Measure 2. During construction, super-compliant volatile organic compound (VOC) paints with a maximum VOC content of 10 grams per liter shall be used on the exterior and interior of each single-family dwelling unit. The project sponsor shall submit a signed certification statement to the City of Folsom Planning Department confirming that the super-compliant VOC requirement has been incorporated into the construction contract specifications, for review and approval.

According to 14 CCR 15162 (a)(3)(D), additional CEQA review is required if mitigation measures which are considerably different from those analyzed in the previous EIR would substantially reduce one or more significant effects on the environment. As described above, there are readily available mitigation measures that would substantially reduce long-term emissions of criteria air pollutants related to the proposed project; therefore, additional CEQA review of the project is warranted to evaluate, mitigate, and disclose the severity of potential air quality impacts to the public.

Conclusion
Based on our review of the Conformity Analysis and FPASP EIR/EIS, the significant and unavoidable impacts related to long-term criteria air pollutant emissions can be substantially reduced with the incorporation of new mitigation measures into the project design. In accordance with 14 CCR 15162 (a)(3)(D), additional CEQA review of the project is required to evaluate, mitigate, and disclose the severity of potential air quality impacts to the public.

Sincerely,

Patrick Sutton
Principal Environmental Engineer

06/23/2026 Item No.18.

ATTACHMENT A
Staff Resume

06/23/2026 Item No.18.

Patrick Sutton, P.E.

Principal Environmental Engineer
Areas of Expertise
Air Quality, GHGs, Noise, Hazardous
Materials, Geology, and Hydrology
Education
M.S., Civil and Environmental
Engineering, University of
California – Davis
B.S., Environmental Science,
Dickinson College
Registration
Professional Engineer No. 13609 (RI)
Years of Experience
20 Years
Patrick Sutton is an environmental engineer who specializes in the assessment of hazardous materials released into the environment.

Mr. Sutton prepares technical reports in support of environmental review, such as Phase I/II Environmental Site Investigations, Air Quality Reports, and Health Risk Assessments. He has prepared numerous CEQA/NEPA evaluations for air quality, GHGs, noise, energy, geology, hazardous materials, and water quality related to residential, commercial, and industrial projects, as well as large infrastructure developments. His proficiency in a wide range of modeling software (AERMOD, CalEEMod, RCEM, CT-EMFAC) as well as relational databases, GIS, and graphics design allows him to thoroughly and efficiently assess and mitigate environmental concerns.

For mixed-use development projects, Mr. Sutton has prepared health risk assessments for sensitive receptors exposed to toxic air contaminants based on air dispersion modeling. For large transportation improvement projects, Mr. Sutton has prepared air quality and hazardous materials technical reports in accordance with Caltrans requirements. The air quality assessments include the evaluation of criteria air pollutants, mobile source air toxics, and GHG emissions to support environmental review of the project under CEQA/NEPA and to determine conformity with the State
Implementation Plan. The hazardous materials investigations include sampling and statistically analysis of aerially-deposited lead adjacent to highway corridors. Mr. Sutton is also an active member of ASTM International and is the author of the Standard Practice for Low-Flow Purging and Sampling Used for Groundwater Monitoring.

Project Experience
Alameda CTC I-80/Ashby Avenue Interchange Improvements. Prepared Phase I/II ESAs to evaluate contaminants of potential concern in soil and groundwater. Prepared Air Quality Report to determine the project’s conformity to federal air quality regulations and support CEQA/NEPA environmental review.

Oakland Downtown Specific Plan EIR. Prepared a program- and project-level Air Quality and GHG Emissions analysis. Developed a mitigation measure with performance standards to ensure GHG emissions from future projects comply with the Citywide 2030 GHG reduction target.

Alameda CTC I-680 Express Lanes from SR 84 to Alcosta Boulevard Project. Prepared Initial Site Assessment and Preliminary Site Investigation to evaluate contaminants of potential concern in soil and groundwater. Prepared Air Quality Report to determine the project’s conformity to federal air quality regulations and to support environmental review of the project under CEQA and NEPA.

Altamont Corridor Expressway (ACE/Forward) Project EIR/EIS. Prepared a program- and project-level Hazardous Materials analysis for over 120 miles of railroad corridor from San Jose to Merced. Hazardous materials concerns, such as release sites, petroleum pipelines, agricultural pesticides, and nearby school sites were evaluated in GIS.

BART Silicon Valley Extension Project. Prepared Initial Site Assessment and Hazardous Materials EIS/EIR section for extending 6 miles of proposed BART service through the Cities of San Jose and Santa Clara.

06/23/2026 Item No.18.

EXHIBIT C

06/23/2026 Item No.18.

INDOOR ENVIRONMENTAL ENGINEERING
1448 Pine Street, Suite 103 San Francisco, California 94109 Telephone: (415) 567-7700
E-mail: [email protected]
http://www.iee-sf.com
Date: June 2, 2026
To: Michael Lozeau
Lozeau | Drury LLP
1939 Harrison Street, Suite 150
Oakland, California 94612
From: Francis J. Offermann PE CIH
Subject: Indoor Air Quality: Toll Brothers Property Project, Folsom, CA (IEE File Reference: P-4960)
Pages: 18
Indoor Air Quality Impacts
I am writing this letter as there is new information of substantial importance, which was not known and could not have been known with the exercise of reasonable diligence at the time the Draft Environmental Impact Report (City of Sacramento, 2010), that shows the Project will have significant effects from formaldehyde emission not discussed in the previous DEIR. This new information relates to the recent Singer 2020 study that shows that new residences built with composite wood products that are CARB Phase 2 certified, do not ensure indoor formaldehyde concentrations that are below the CEQA cancer risk of 10 per million.

Indoor air quality (IAQ) directly impacts the comfort and health of building occupants, and the achievement of acceptable IAQ in newly constructed and renovated buildings is a wellrecognized design objective. For example, IAQ is addressed by major high-performance building rating systems and building codes (California Building Standards Commission, 2014; USGBC, 2014). Indoor air quality in homes is particularly important because occupants, on average, spend approximately ninety percent of their time indoors with the

06/23/2026 Item No.18.
2 of 18
majority of this time spent at home (EPA, 2011). Some segments of the population that are most susceptible to the effects of poor IAQ, such as the very young and the elderly, occupy their homes almost continuously. Additionally, an increasing number of adults are working from home at least some of the time during the workweek. Indoor air quality also is a serious concern for workers in hotels, offices and other business establishments.

The concentrations of many air pollutants often are elevated in homes and other buildings relative to outdoor air because many of the materials and products used indoors contain and release a variety of pollutants to air (Hodgson et al., 2002; Offermann and Hodgson, 2011). With respect to indoor air contaminants for which inhalation is the primary route of exposure, the critical design and construction parameters are the provision of adequate ventilation and the reduction of indoor sources of the contaminants.

Indoor Formaldehyde Concentrations Impact. In the California New Home Study (CNHS) of 108 new homes in California (Offermann, 2009), 25 air contaminants were measured, and formaldehyde was identified as the indoor air contaminant with the highest cancer risk as determined by the California Proposition 65 Safe Harbor Levels (OEHHA, 2017a), No Significant Risk Levels (NSRL) for carcinogens. The NSRL is the daily intake level calculated to result in one excess case of cancer in an exposed population of 100,000 (i.e., ten in one million cancer risk) and for formaldehyde is 40 µg/day. The NSRL concentration of formaldehyde that represents a daily dose of 40 µg is 2 µg/m3, assuming a continuous 24-hour exposure, a total daily inhaled air volume of 20 m3, and 100% absorption by the respiratory system. All of the CNHS homes exceeded this NSRL concentration of 2 µg/m3 .

The median indoor formaldehyde concentration was 36 µg/m3 , and ranged from 4.8 to 136
µg/m3, which corresponds to a median exceedance of the 2 µg/m3 NSRL concentration of 18 and a range of 2.3 to 68.

Therefore, the cancer risk of a resident living in a California home with the median indoor formaldehyde concentration of 36 µg/m3, is 180 per million as a result of formaldehyde alone. The CEQA significance threshold for airborne cancer risk is 10 per million, as established by the Sacramento Metropolitan Air Quality Management District (SMAQMD, 2020).

06/23/2026 Item No.18.
3 of 18
Besides being a human carcinogen, formaldehyde is also a potent eye and respiratory irritant. In the CNHS, many homes exceeded the non-cancer reference exposure levels (RELs) prescribed by California Office of Environmental Health Hazard Assessment (OEHHA, 2017b). The percentage of homes exceeding the RELs ranged from 98% for the Chronic REL of 9 µg/m3 to 28% for the Acute REL of 55 µg/m3 .

The primary source of formaldehyde indoors is composite wood products manufactured with urea-formaldehyde resins, such as plywood, medium density fiberboard, and particleboard. These materials are commonly used in building construction for flooring, cabinetry, baseboards, window shades, interior doors, and window and door trims.

In January 2009, the California Air Resources Board (CARB) adopted an airborne toxics control measure (ATCM) to reduce formaldehyde emissions from composite wood products, including hardwood plywood, particleboard, medium density fiberboard, and also furniture and other finished products made with these wood products (California Air Resources Board 2009). While this formaldehyde ATCM has resulted in reduced emissions from composite wood products sold in California, they do not preclude that homes built with composite wood products meeting the CARB ATCM will have indoor formaldehyde concentrations that are below cancer and non-cancer exposure guidelines.

A follow up study to the California New Home Study (CNHS) was conducted in 2016-2018 (Singer et. al., 2020) and found that the median indoor formaldehyde in new homes built after 2009 with CARB Phase 2 Formaldehyde ATCM materials had lower indoor formaldehyde concentrations, with a median indoor concentrations of 22.4 µg/m3 (18.2 ppb) as compared to a median of 36 µg/m3 found in the 2007 CNHS. Unlike in the CNHS study where formaldehyde concentrations were measured with pumped DNPH samplers, the formaldehyde concentrations in the HENGH study were measured with passive samplers, which were estimated to under-measure the true indoor formaldehyde concentrations by approximately 7.5%. Applying this correction to the HENGH indoor formaldehyde concentrations results in a median indoor concentration of 24.1 µg/m3 , which is 33% lower
than the 36 µg/m3 found in the 2007 CNHS.

06/23/2026 Item No.18.
4 of 18
Thus, while new homes built after the 2009 CARB formaldehyde ATCM have a 33% lower median indoor formaldehyde concentration and cancer risk, the median lifetime cancer risk is still 120 per million for homes built with CARB compliant composite wood products, which is more than 12 times the OEHHA 10 in a million cancer risk threshold (OEHHA, 2017a).

With respect to this Project, the buildings in the Toll Brothers Property Project, Folsom, CA consist of a residential spaces.

The residential occupants will potentially have continuous exposure (e.g. 24 hours per day, 52 weeks per year). These exposures are anticipated to result in significant cancer risks resulting from exposures to formaldehyde released by the building materials and furnishing commonly found in residential construction.

Because these residences will be constructed with CARB Phase 2 Formaldehyde ATCM materials, and be ventilated with the minimum code required amount of outdoor air, the indoor residential formaldehyde concentrations are likely similar to those concentrations observed in residences built with CARB Phase 2 Formaldehyde ATCM materials, which is a median of 24.1 µg/m3 (Singer et. al., 2020)
Assuming that the residential occupants inhale 20 m3 of air per day, the average 70-year lifetime formaldehyde daily dose is 482 µg/day for continuous exposure in the residences.

This exposure represents a cancer risk of 120 per million, which is more than 12 times the CEQA cancer risk of 10 per million. For occupants that do not have continuous exposure, the cancer risk will be proportionally less but still substantially over the CEQA cancer risk of 10 per million (e.g. for 12/hour/day occupancy, more than 6 times the CEQA cancer risk of 10 per million).

In addition, we note that the average outdoor air concentration of formaldehyde in California is 3 ppb, or 3.7 µg/m3
, (California Air Resources Board, 2004), and thus
represents an average pre-existing background airborne cancer risk of 1.85 per million.

06/23/2026 Item No.18.
5 of 18
Thus, the indoor air formaldehyde exposures describe above exacerbate this pre-existing risk resulting from outdoor air formaldehyde exposures.

Appendix A, Indoor Formaldehyde Concentrations and the CARB Formaldehyde ATCM, provides analyses that show utilization of CARB Phase 2 Formaldehyde ATCM materials will not ensure acceptable cancer risks with respect to formaldehyde emissions from composite wood products.

Even composite wood products manufactured with CARB certified ultra low emitting formaldehyde (ULEF) resins do not insure that the indoor air will have concentrations of formaldehyde the meet the OEHHA cancer risks that substantially exceed 10 per million.

The permissible emission rates for ULEF composite wood products are only 11-15% lower than the CARB Phase 2 emission rates. Only use of composite wood products made with no-added formaldehyde resins (NAF), such as resins made from soy, polyvinyl acetate, or methylene diisocyanate can insure that the OEHHA cancer risk of 10 per million is met.

The following describes a method that should be used prior to construction in the environmental review under CEQA, for determining whether the indoor concentrations resulting from the formaldehyde emissions of the specific building materials/furnishings selected for the building exceed cancer and non-cancer guidelines. Such a design analyses can be used to identify those materials/furnishings prior to the completion of the City’s CEQA review and project approval, that have formaldehyde emission rates that contribute to indoor concentrations that exceed cancer and non-cancer guidelines, so that alternative lower emitting materials/furnishings may be selected and/or higher minimum outdoor air ventilation rates can be increased to achieve acceptable indoor concentrations and incorporated as mitigation measures for this project.

Pre-Construction Building Material/Furnishing Formaldehyde Emissions Assessment.

This formaldehyde emissions assessment should be used in the environmental review under CEQA to assess the indoor formaldehyde concentrations from the proposed loading of building materials/furnishings, the area-specific formaldehyde emission rate data for

06/23/2026 Item No.18.
6 of 18
building materials/furnishings, and the design minimum outdoor air ventilation rates. This assessment allows the applicant (and the City) to determine before the conclusion of the environmental review process and the building materials/furnishings are specified, purchased, and installed if the total chemical emissions will exceed cancer and non-cancer guidelines, and if so, allow for changes in the selection of specific material/furnishings and/or the design minimum outdoor air ventilations rates such that cancer and non-cancer guidelines are not exceeded.

1.) Define Indoor Air Quality Zones. Divide the building into separate indoor air quality zones, (IAQ Zones). IAQ Zones are defined as areas of well-mixed air. Thus, each ventilation system with recirculating air is considered a single zone, and each room or group of rooms where air is not recirculated (e.g. 100% outdoor air) is considered a separate zone. For IAQ Zones with the same construction material/furnishings and design minimum outdoor air ventilation rates. (e.g. hotel rooms, apartments, condominiums, etc.) the formaldehyde emission rates need only be assessed for a single IAQ Zone of that type.

2.) Calculate Material/Furnishing Loading. For each IAQ Zone, determine the building material and furnishing loadings (e.g., m2 of material/m2 floor area, units of furnishings/m2 floor area) from an inventory of all potential indoor formaldehyde sources, including flooring, ceiling tiles, furnishings, finishes, insulation, sealants, adhesives, and any products constructed with composite wood products containing urea-formaldehyde resins (e.g., plywood, medium density fiberboard, particleboard).

3.) Calculate the Formaldehyde Emission Rate. For each building material, calculate the formaldehyde emission rate (µg/h) from the product of the area-specific formaldehyde emission rate (µg/m2-h) and the area (m2) of material in the IAQ Zone, and from each furnishing (e.g. chairs, desks, etc.) from the unit-specific formaldehyde emission rate (µg/unit-h) and the number of units in the IAQ Zone.

NOTE: As a result of the high-performance building rating systems and building codes (California Building Standards Commission, 2014; USGBC, 2014), most manufacturers of building materials furnishings sold in the United States conduct chemical emission rate tests using the California Department of Health “Standard Method for the Testing and

06/23/2026 Item No.18.
7 of 18
Evaluation of Volatile Organic Chemical Emissions for Indoor Sources Using Environmental Chambers”, (CDPH, 2017), or other equivalent chemical emission rate testing methods. Most manufacturers of building furnishings sold in the United States conduct chemical emission rate tests using ANSI/BIFMA M7.1 Standard Test Method for Determining VOC Emissions (BIFMA, 2018), or other equivalent chemical emission rate testing methods.

CDPH, BIFMA, and other chemical emission rate testing programs, typically certify that a material or furnishing does not create indoor chemical concentrations in excess of the maximum concentrations permitted by their certification. For instance, the CDPH emission rate testing requires that the measured emission rates when input into an office, school, or residential model do not exceed one-half of the OEHHA Chronic Exposure Guidelines (OEHHA, 2017b) for the 35 specific VOCs, including formaldehyde, listed in Table 4-1 of the CDPH test method (CDPH, 2017). These certifications themselves do not provide the actual area-specific formaldehyde emission rate (i.e., µg/m2 -h) of the product, but rather
provide data that the formaldehyde emission rates do not exceed the maximum rate allowed for the certification. Thus for example, the data for a certification of a specific type of flooring may be used to calculate that the area-specific emission rate of formaldehyde is less than 31 µg/m2-h, but not the actual measured specific emission rate, which may be 3, 18, or 30 µg/m2-h. These area-specific emission rates determined from the product certifications of CDPH, BIFA, and other certification programs can be used as an initial estimate of the formaldehyde emission rate.

If the actual area-specific emission rates of a building material or furnishing is needed (i.e. the initial emission rates estimates from the product certifications are higher than desired), then that data can be acquired by requesting from the manufacturer the complete chemical emission rate test report. For instance if the complete CDPH emission test report is requested for a CDHP certified product, that report will provide the actual area-specific emission rates for not only the 35 specific VOCs, including formaldehyde, listed in Table 4-1 of the CDPH test method (CDPH, 2017), but also all of the cancer and reproductive/developmental chemicals listed in the California Proposition 65 Safe Harbor Levels (OEHHA, 2017a), all of the toxic air contaminants (TACs) in the California Air

06/23/2026 Item No.18.
8 of 18
Resources Board Toxic Air Contamination List (CARB, 2011), and the 10 chemicals with the greatest emission rates.

Alternatively, a sample of the building material or furnishing can be submitted to a chemical emission rate testing laboratory, such as Berkeley Analytical Laboratory (https://berkeleyanalytical.com), to measure the formaldehyde emission rate.

4.) Calculate the Total Formaldehyde Emission Rate. For each IAQ Zone, calculate the total formaldehyde emission rate (i.e. µg/h) from the individual formaldehyde emission rates from each of the building material/furnishings as determined in Step 3.

5.) Calculate the Indoor Formaldehyde Concentration. For each IAQ Zone, calculate the indoor formaldehyde concentration (µg/m3) from Equation 1 by dividing the total formaldehyde emission rates (i.e. µg/h) as determined in Step 4, by the design minimum outdoor air ventilation rate (m3/h) for the IAQ Zone.

𝐶𝐶𝑖𝑖𝑖𝑖 = 𝐸𝐸𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡
𝑄𝑄 (Equation 1)
where:

Cin = indoor formaldehyde concentration (µg/m3)
Etotal = total formaldehyde emission rate (µg/h) into the IAQ Zone.

Qoa = design minimum outdoor air ventilation rate to the IAQ Zone (m3/h) The above Equation 1 is based upon mass balance theory, and is referenced in Section

3.10.2 “Calculation of Estimated Building Concentrations” of the California Department of Health “Standard Method for the Testing and Evaluation of Volatile Organic Chemical Emissions for Indoor Sources Using Environmental Chambers”, (CDPH, 2017).

6.) Calculate the Indoor Exposure Cancer and Non-Cancer Health Risks. For each IAQ Zone, calculate the cancer and non-cancer health risks from the indoor formaldehyde concentrations determined in Step 5 and as described in the OEHHA Air Toxics Hot Spots Program Risk Assessment Guidelines; Guidance Manual for Preparation of Health Risk Assessments (OEHHA, 2015).

06/23/2026 Item No.18.
9 of 18

7.) Mitigate Indoor Formaldehyde Exposures of exceeding the CEQA Cancer and/or NonCancer Health Risks. In each IAQ Zone, provide mitigation for any formaldehyde exposure risk as determined in Step 6, that exceeds the CEQA cancer risk of 10 per million or the CEQA non-cancer Hazard Quotient of 1.0.

Provide the source and/or ventilation mitigation required in all IAQ Zones to reduce the health risks of the chemical exposures below the CEQA cancer and non-cancer health risks.

Source mitigation for formaldehyde may include:

1.) reducing the amount materials and/or furnishings that emit formaldehyde

2.) substituting a different material with a lower area-specific emission rate of formaldehyde

Ventilation mitigation for formaldehyde emitted from building materials and/or furnishings may include:

1.) increasing the design minimum outdoor air ventilation rate to the IAQ Zone.

NOTE: Mitigating the formaldehyde emissions through use of less material/furnishings, or use of lower emitting materials/furnishings, is the preferred mitigation option, as mitigation with increased outdoor air ventilation increases initial and operating costs associated with the heating/cooling systems.

Further, we are not asking that the builder to “speculate” on what and how much composite materials be used, but rather at the design stage to select composite wood materials based on the formaldehyde emission rates that manufacturers routinely conduct using the California Department of Health “Standard Method for the Testing and Evaluation of Volatile Organic Chemical Emissions for Indoor Sources Using Environmental Chambers”, (CDPH, 2017), and use the procedure described earlier (i.e. Pre-Construction Building Material/Furnishing Formaldehyde Emissions Assessment) to insure that the materials selected achieve acceptable cancer risks from material off gassing of formaldehyde.

06/23/2026 Item No.18.
10 of 18
Outdoor Air Ventilation Impact. Another important finding of the CNHS, was that the outdoor air ventilation rates in the homes were very low. Outdoor air ventilation is a very important factor influencing the indoor concentrations of air contaminants, as it is the primary removal mechanism of all indoor air generated contaminants. Lower outdoor air exchange rates cause indoor generated air contaminants to accumulate to higher indoor air concentrations. Many homeowners rarely open their windows or doors for ventilation as a result of their concerns for security/safety, noise, dust, and odor concerns (Price, 2007). In the CNHS field study, 32% of the homes did not use their windows during the 24‐hour Test Day, and 15% of the homes did not use their windows during the entire preceding week.

Most of the homes with no window usage were homes in the winter field session. Thus, a substantial percentage of homeowners never open their windows, especially in the winter season. The median 24‐hour measurement was 0.26 air changes per hour (ach), with a range of 0.09 ach to 5.3 ach. A total of 67% of the homes had outdoor air exchange rates below the minimum California Building Code (2001) requirement of 0.35 ach. Thus, the relatively tight envelope construction, combined with the fact that many people never open their windows for ventilation, results in homes with low outdoor air exchange rates and higher indoor air contaminant concentrations.

The Toll Brothers Property Project, Folsom, CA is close to roads with moderate to high traffic (e.g., White Rock Road, Scott Road, Oak Avenue Parkway, Gateway Drive, Mangini Parkway, etc.). Thus, the Project is located in an urban area with ambient noise levels impacted by motor vehicle traffic.

According to the Conformity Analysis for the Toll Brothers Property, Alder Creek Subdivision, City of Folsom, CA (ECORP Consulting, 2026), there has been just four short-term 15 minute measurements of the ambient noise level conducted between 13:02 and 13:13 on Tuesday, February 25, 2025, and modeled ambient traffic noise levels. In Section 13.13.3.4 “Operational Traffic Noise” the modeled ambient noise level was 75.1 dBA CNEL
In order to design the building for this Project such that interior noise levels are acceptable, an acoustic study with actual on-site measurements of the existing ambient noise levels and

06/23/2026 Item No.18.
11 of 18
modeled future ambient noise levels needs to be conducted. The acoustic study of the existing ambient noise levels should be conducted over a minimum of a one-week period and report the dBA CNEL or Ldn. This study will allow for the selection of a building envelope and windows with a sufficient STC such that the indoor noise levels are acceptable. A mechanical supply of outdoor air ventilation to allow for a habitable interior environment with closed windows and doors will also be required. Such a ventilation system would allow windows and doors to be kept closed at the occupant’s discretion to control exterior noise within building interiors.

PM2.5 Outdoor Concentrations Impact. An additional impact of the nearby motor vehicle traffic associated with this project, are the outdoor concentrations of PM2.5. According to the Conformity Analysis for the Toll Brothers Property, Alder Creek Subdivision, City of Folsom, CA (ECORP Consulting, 2026), the Project is located in the Sacramento Metropolitan Air Quality Management District, which is a State and Federal non-attainment area for PM2.5.

An air quality analyses should be conducted to determine the concentrations of PM2.5 in the outdoor and indoor air that people inhale each day. This air quality analyses needs to consider the cumulative impacts of the project related emissions, existing and projected future emissions from local PM2.5 sources (e.g. stationary sources, motor vehicles, and airport traffic) upon the outdoor air concentrations at the Project site. If the outdoor concentrations are determined to exceed the California and National annual average PM2.5 exceedence concentration of 12 µg/m3, or the National 24-hour average exceedence concentration of 35 µg/m3, then the buildings need to have a mechanical supply of outdoor air that has air filtration with sufficient removal efficiency, such that the indoor concentrations of outdoor PM2.5 particles is less than the California and National PM2.5 annual and 24-hour standards.

It is my experience that based on the projected high traffic noise levels, the annual average concentration of PM2.5 will exceed the California and National PM2.5 annual and 24-hour standards and warrant installation of high efficiency air filters (i.e. at least MERV 13, or

06/23/2026 Item No.18.
12 of 18
possibly MERV 14 or 15 depending on the results of the Project ambient PM2.5 concentrations) in all mechanically supplied outdoor air ventilation systems.

Indoor Air Quality Impact Mitigation Measures
The following are recommended mitigation measures to minimize the impacts upon indoor quality:

Indoor Formaldehyde Concentrations Mitigation. Use only composite wood materials (e.g. hardwood plywood, medium density fiberboard, particleboard) for all interior finish systems that are made with CARB approved no-added formaldehyde (NAF) resins (CARB, 2009). CARB Phase 2 certified composite wood products, or ultra-low emitting formaldehyde (ULEF) resins, do not insure indoor formaldehyde concentrations that are below the CEQA cancer risk of 10 per million. Only composite wood products manufactured with CARB approved no-added formaldehyde (NAF) resins, such as resins made from soy, polyvinyl acetate, or methylene diisocyanate can insure that the OEHHA cancer risk of 10 per million is met.

Alternatively, conduct the previously described Pre-Construction Building Material/Furnishing Chemical Emissions Assessment, to determine that the combination of formaldehyde emissions from building materials and furnishings do not create indoor formaldehyde concentrations that exceed the CEQA cancer and non-cancer health risks.

It is important to note that we are not asking that the builder to “speculate” on what and how much composite materials be used, but rather at the design stage to select composite wood materials based on the formaldehyde emission rates that manufacturers routinely conduct using the California Department of Health “Standard Method for the Testing and Evaluation of Volatile Organic Chemical Emissions for Indoor Sources Using Environmental Chambers”, (CDPH, 2017), and use the procedure described earlier (i.e. Pre-Construction Building Material/Furnishing Formaldehyde Emissions Assessment) to insure that the materials selected achieve acceptable cancer risks from material off gassing of formaldehyde.

06/23/2026 Item No.18.
13 of 18
References
BIFA. 2018. BIFMA Product Safety and Performance Standards and Guidelines. www.bifma.org/page/standardsoverview
California Air Resources Board. 2009. Airborne Toxic Control Measure to Reduce Formaldehyde Emissions from Composite Wood Products. California Environmental Protection Agency, Sacramento, CA.
https://www.arb.ca.gov/regact/2007/compwood07/fro-final.pdf California Air Resources Board. 2011. Toxic Air Contaminant Identification List.

California Environmental Protection Agency, Sacramento, CA. https://www.arb.ca.gov/toxics/id/taclist.htm
California Building Code. 2001. California Code of Regulations, Title 24, Part 2 Volume 1, Appendix Chapter 12, Interior Environment, Division 1, Ventilation, Section 1207: 2001 California Building Code, California Building Standards Commission. Sacramento, CA.

California Building Standards Commission (2014). 2013 California Green Building Standards Code. California Code of Regulations, Title 24, Part 11. California Building Standards Commission, Sacramento, CA http://www.bsc.ca.gov/Home/CALGreen.aspx.

California Energy Commission, PIER Program. CEC-500-2007-033. Final Report, ARB Contract 03-326. Available at: www.arb.ca.gov/research/apr/past/03-326.pdf.

California Energy Commission, 2015. 2016 Building Energy Efficiency Standards for Residential and Nonresidential Buildings, California Code of Regulations, Title 24, Part 6. http://www.energy.ca.gov/2015publications/CEC-400-2015-037/CEC-400-2015-037- CMF.pdf

06/23/2026 Item No.18.
14 of 18
CDPH. 2017. Standard Method forthe Testing andEvaluation of Volatile OrganicChemical Emissions forIndoor Sources Using Environmental Chambers,Version 1.1. California Department of Public Health, Richmond, CA. https://www.cdph.ca.gov/Programs/CCDPHP/ DEODC/EHLB/IAQ/Pages/VOC.aspx.

ECORP Consulting. 2026. Conformity Analysis for the Toll Brothers Property, Alder Creek Subdivision, City of Folsom, CA.

EPA. 2011. Exposure Factors Handbook: 2011 Edition, Chapter 16 – Activity Factors.

Report EPA/600/R-09/052F, September 2011. U.S. Environmental Protection Agency, Washington, D.C.

Hodgson, A. T., D. Beal, J.E.R. McIlvaine. 2002. Sources of formaldehyde, other aldehydes and terpenes in a new manufactured house. Indoor Air 12: 235–242.

OEHHA (Office of Environmental Health Hazard Assessment). 2015. Air Toxics Hot Spots Program Risk Assessment Guidelines; Guidance Manual for Preparation of Health Risk Assessments.

OEHHA (Office of Environmental Health Hazard Assessment). 2017a. Proposition 65 Safe Harbor Levels. No Significant Risk Levels for Carcinogens and Maximum Allowable Dose Levels for Chemicals Causing Reproductive Toxicity. Available at:
http://www.oehha.ca.gov/prop65/pdf/safeharbor081513.pdf OEHHA - Office of Environmental Health Hazard Assessment. 2017b. All OEHHA Acute, 8-hour and Chronic Reference Exposure Levels. Available at:
http://oehha.ca.gov/air/allrels.html
Offermann, F. J. 2009. Ventilation and Indoor Air Quality in New Homes. California Air Resources Board and California Energy Commission, PIER Energy‐Related Environmental Research Program. Collaborative Report. CEC-500-2009-085. https://www.arb.ca.gov/research/apr/past/04-310.pdf

06/23/2026 Item No.18.
15 of 18
Offermann, F. J. and A. T. Hodgson. 2011. Emission Rates of Volatile Organic Compounds in New Homes. Proceedings Indoor Air 2011 (12th International Conference on Indoor Air Quality and Climate 2011), June 5-10, 2011, Austin, TX USA.

Sacramento Metropolitan Air Quality Management District (SMAQMD). 2020. CEQA Guidance and Tools. http://www.airquality.org/Businesses/CEQA-Land-UsePlanning/CEQA-Guidance-Tools Singer, B.C, Chan, W.R, Kim, Y., Offermann, F.J., and Walker I.S. 2020. Indoor Air Quality in California Homes with Code-Required Mechanical Ventilation. Indoor Air, Vol 30, Issue 5, 885-899.

USGBC. 2014. LEED BD+C Homes v4. U.S. Green Building Council, Washington, D.C. http://www.usgbc.org/credits/homes/v4

06/23/2026 Item No.18.
16 of 18

APPENDIX A

INDOOR FORMALDEHYDE CONCENTRATIONS

AND THE

CARB FORMALDEHYDE ATCM
With respect to formaldehyde emissions from composite wood products, the CARB ATCM regulations of formaldehyde emissions from composite wood products, do not assure healthful indoor air quality. The following is the stated purpose of the CARB ATCM regulation - The purpose of this airborne toxic control measure is to “reduce formaldehyde emissions from composite wood products, and finished goods that contain composite wood products, that are sold, offered for sale, supplied, used, or manufactured for sale in California”. In other words, the CARB ATCM regulations do not “assure healthful indoor air quality”, but rather “reduce formaldehyde emissions from composite wood products”.

Just how much protection do the CARB ATCM regulations provide building occupants from the formaldehyde emissions generated by composite wood products ? Definitely some, but certainly the regulations do not “assure healthful indoor air quality” when CARB Phase 2 products are utilized. As shown in the Singer 2020 study of new California homes, the median indoor formaldehyde concentration was of 22.4 µg/m3 (18.2 ppb), which corresponds to a cancer risk of 112 per million for occupants with continuous exposure, which is more than 11 times the CEQA cancer risk of 10 per million.

Another way of looking at how much protection the CARB ATCM regulations provide building occupants from the formaldehyde emissions generated by composite wood products is to calculate the maximum number of square feet of composite wood product that can be in a residence without exceeding the CEQA cancer risk of 10 per million for occupants with continuous occupancy.

For this calculation I utilized the floor area (2,272 ft2 ), the ceiling height (8.5 ft), and the
number of bedrooms (4) as defined in Appendix B (New Single-Family Residence Scenario) of the StandardMethod fortheTestingandEvaluation of Volatile OrganicChemical EmissionsforIndoor Sources UsingEnvironmental Chambers,Version1.1, 2017, California Department of Public Health,

06/23/2026 Item No.18.
17 of 18
Richmond, CA. https://www.cdph.ca.gov/Programs/CCDPHP/
DEODC/EHLB/IAQ/Pages/VOC.aspx.

For the outdoor air ventilation rate I used the 2019 Title 24 code required mechanical ventilation rate (ASHRAE 62.2) of 106 cfm (180 m3
/h) calculated for this model residence.

For the composite wood formaldehyde emission rates I used the CARB ATCM Phase 2 rates.

The calculated maximum number of square feet of composite wood product that can be in a residence, without exceeding the CEQA cancer risk of 10 per million for occupants with continuous occupancy are as follows for the different types of regulated composite wood products.

Medium Density Fiberboard (MDF) – 15 ft2 (0.7% of the floor area), or Particle Board – 30 ft2 (1.3% of the floor area), or
Hardwood Plywood – 54 ft2 (2.4% of the floor area), or
Thin MDF – 46 ft2 (2.0 % of the floor area).

For offices and hotels the calculated maximum amount of composite wood product (% of floor area) that can be used without exceeding the CEQA cancer risk of 10 per million for occupants, assuming 8 hours/day occupancy, and the California Mechanical Code minimum outdoor air ventilation rates are as follows for the different types of regulated composite wood products.

Medium Density Fiberboard (MDF) – 3.6 % (offices) and 4.6% (hotel rooms), or Particle Board – 7.2 % (offices) and 9.4% (hotel rooms), or Hardwood Plywood – 13 % (offices) and 17% (hotel rooms), or Thin MDF – 11 % (offices) and 14 % (hotel rooms)
Clearly the CARB ATCM does not regulate the formaldehyde emissions from composite wood products such that the potentially large areas of these products, such as for flooring, baseboards, interior doors, window and door trims, and kitchen and bathroom cabinetry, could be used without causing indoor formaldehyde concentrations that result in CEQA

06/23/2026 Item No.18.
18 of 18
cancer risks that substantially exceed 10 per million for occupants with continuous occupancy.

Even composite wood products manufactured with CARB certified ultra low emitting formaldehyde (ULEF) resins do not insure that the indoor air will have concentrations of formaldehyde the meet the OEHHA cancer risks that substantially exceed 10 per million.

The permissible emission rates for ULEF composite wood products are only 11-15% lower than the CARB Phase 2 emission rates. Only use of composite wood products made with no-added formaldehyde resins (NAF), such as resins made from soy, polyvinyl acetate, or methylene diisocyanate can insure that the OEHHA cancer risk of 10 per million is met.

If CARB Phase 2 compliant or ULEF composite wood products are utilized in construction, then the resulting indoor formaldehyde concentrations should be determined in the design phase using the specific amounts of each type of composite wood product, the specific formaldehyde emission rates, and the volume and outdoor air ventilation rates of the indoor spaces, and all feasible mitigation measures employed to reduce this impact (e.g. use less formaldehyde containing composite wood products and/or incorporate mechanical systems capable of higher outdoor air ventilation rates). See the procedure described earlier (i.e.

Pre-Construction Building Material/Furnishing Formaldehyde Emissions Assessment) to insure that the materials selected achieve acceptable cancer risks from material off gassing of formaldehyde.

Alternatively, and perhaps a simpler approach, is to use only composite wood products (e.g. hardwood plywood, medium density fiberboard, particleboard) for all interior finish systems that are made with CARB approved no-added formaldehyde (NAF) resins.

06/23/2026 Item No.18.

Francis J. Offermann III PE, CIH
Indoor Environmental Engineering
1448 Pine Street, Suite 103, San Francisco, CA 94109
Phone: 415-567-7700
Email: [email protected]
http://www.iee-sf.com
Education
M.S. Mechanical Engineering (1985)
Stanford University, Stanford, CA.

Graduate Studies in Air Pollution Monitoring and Control (1980) University of California, Berkeley, CA.

B.S. in Mechanical Engineering (1976)
Rensselaer Polytechnic Institute, Troy, N.Y.

Professional Experience
President: Indoor Environmental Engineering, San Francisco, CA. December, 1981 - present.

Direct team of environmental scientists, chemists, and mechanical engineers in conducting State and Federal research regarding indoor air quality instrumentation development, building air quality field studies, ventilation and air cleaning performance measurements, and chemical emission rate testing.

Provide design side input to architects regarding selection of building materials and ventilation system components to ensure a high quality indoor environment.

Direct Indoor Air Quality Consulting Team for the winning design proposal for the new State of Washington Ecology Department building.

Develop a full-scale ventilation test facility for measuring the performance of air diffusers; ASHRAE 129, Air Change Effectiveness, and ASHRAE 113, Air Diffusion Performance Index.

Develop a chemical emission rate testing laboratory for measuring the chemical emissions from building materials, furnishings, and equipment, including 3D-printers, fireproofed respirators, candles, self-cleaning ovens, spray polyurethane foam (SPF), laminate flooring, fireproofed building joists.

Principle Investigator of the California New Homes Study (2005-2007). Measured ventilation and indoor air quality in 108 new single family detached homes in northern and southern California.

06/23/2026 Item No.18.
2-23
Develop and teach IAQ professional development workshops to building owners, managers, hygienists, and engineers.

Air Pollution Engineer: Earth Metrics Inc., Burlingame, CA, October, 1985 to March, 1987.

Responsible for development of an air pollution laboratory including installation a forced choice olfactometer, tracer gas electron capture chromatograph, and associated calibration facilities. Field team leader for studies of fugitive odor emissions from sewage treatment plants, entrainment of fume hood exhausts into computer chip fabrication rooms, and indoor air quality investigations.

Staff Scientist: Building Ventilation and Indoor Air Quality Program, Energy and Environment Division, Lawrence Berkeley Laboratory, Berkeley, CA. January, 1980 to August, 1984.

Deputy project leader for the Control Techniques group; responsible for laboratory and field studies aimed at evaluating the performance of indoor air pollutant control strategies (i.e. ventilation, filtration, precipitation, absorption, adsorption, and source control).

Coordinated field and laboratory studies of air-to-air heat exchangers including evaluation of thermal performance, ventilation efficiency, cross-stream contaminant transfer, and the effects of freezing/defrosting.

Developed an in situ test protocol for evaluating the performance of air cleaning systems and introduced the concept of effective cleaning rate (ECR) also known as the Clean Air Delivery Rate (CADR).

Coordinated laboratory studies of portable and ducted air cleaning systems and their effect on indoor concentrations of respirable particles and radon progeny.

Co-designed an automated instrument system for measuring residential ventilation rates and radon concentrations.

Designed hardware and software for a multi-channel automated data acquisition system used to evaluate the performance of air-to-air heat transfer equipment.

Assistant Chief Engineer: Alta Bates Hospital, Berkeley, CA, October, 1979 to January, 1980.

Responsible for energy management projects involving installation of power factor correction capacitors on large inductive electrical devices and installation of steam meters on physical plant steam lines. Member of Local 39, International Union of Operating Engineers.

Manufacturing Engineer: American Precision Industries, Buffalo, NY, October, 1977 to October, 1979.

06/23/2026 Item No.18.
3-23
Responsible for reorganizing the manufacturing procedures regarding production of shell and tube heat exchangers. Designed customized automatic assembly, welding, and testing equipment. Designed a large paint spray booth. Prepared economic studies justifying new equipment purchases. Safety Director.

Project Engineer: Arcata Graphics, Buffalo, N.Y. June, 1976 to October, 1977.

Responsible for the design and installation of a bulk ink storage and distribution system and high speed automatic counting and marking equipment. Also coordinated material handling studies which led to the purchase and installation of new equipment.

PROFESSIONAL ORGANIZATION MEMBERSHIP
American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) • Chairman of SPC-145P, Standards Project Committee - Test Method for Assessing the Performance of Gas Phase Air Cleaning Equipment (1991-1992) • Member SPC-129P, Standards Project Committee - Test Method for Ventilation Effectiveness (1986-97)
- Member of Drafting Committee
• Member Environmental Health Committee (1992-1994, 1997-2001, 2007-2010) - Chairman of EHC Research Subcommittee
- Member of Man Made Mineral Fiber Position Paper Subcommittee - Member of the IAQ Position Paper Committee
- Member of the Legionella Position Paper Committee
- Member of the Limiting Indoor Mold and Dampness in Buildings Position Paper Committee
• Member SSPC-62, Standing Standards Project Committee - Ventilation for .

Acceptable Indoor Air Quality (1992 to 2000)
- Chairman of Source Control and Air Cleaning Subcommittee • Member SSPC-55, Standing Standards Project Committee – Thermal Environmental Conditions for Human Occupancy (2017 to present) • Chairman of TC-4.10, Indoor Environmental Modeling (1988-92) - Member of Research Subcommittee
• Chairman of TC-2.3, Gaseous Air Contaminants and Control Equipment (1989-92) - Member of Research Subcommittee
• Member of TG2, Reactive Air and Surface Disinfection (2021-present) American Society for Testing and Materials (ASTM)
• D-22 Sampling and Analysis of Atmospheres (1992-present) - Member of Indoor Air Quality Subcommittee
• E-06 Performance of Building Constructions (1992-present) American Board of Industrial Hygiene (ABIH)

06/23/2026 Item No.18.
4-23
American Conference of Governmental Industrial Hygienists (ACGIH) • Bioaerosols Committee (2007-present)
• Bioaerosols Assessment and Control Book
Revision Committee Member (2020-2024)
American Industrial Hygiene Association (AIHA)
Cal-OSHA Indoor Air Quality Advisory Committee
International Society of Indoor Air Quality and Climate (ISIAQ) • Co-Chairman of Task Force on HVAC Hygiene (1999-2002) U. S. Green Building Council (USGBC)
- Member of the IEQ Technical Advisory Group (2007-2009) - Member of the IAQ Performance Testing Work Group (2010-2012) Western Construction Consultants (WESTCON)

PROFESSIONAL CREDENTIALS
Licensed Professional Engineer - Mechanical Engineering Certified Industrial Hygienist - American Board of Industrial Hygienists

OTHER CERTIFICATIONS
Bronze Cross – Royal Life Saving Society of Canada

SCIENTIFIC MEETINGS AND SYMPOSIA
Biological Contamination, Diagnosis, and Mitigation, Indoor Air’90, Toronto, Canada, August, 1990.

Models for Predicting Air Quality, Indoor Air’90, Toronto, Canada, August, 1990.

Microbes in Building Materials and Systems, Indoor Air ’93, Helsinki, Finland, July, 1993.

Microorganisms in Indoor Air Assessment and Evaluation of Health Effects and Probable Causes, Walnut Creek, CA, February 27, 1997.

Controlling Microbial Moisture Problems in Buildings, Walnut Creek, CA, February 27, 1997.

06/23/2026 Item No.18.
5-23
Scientific Advisory Committee, Roomvent 98, 6th International Conference on Air Distribution in Rooms, KTH, Stockholm, Sweden, June 14-17, 1998.

Moisture and Mould, Indoor Air ’99, Edinburgh, Scotland, August, 1999.

Ventilation Modeling and Simulation, Indoor Air ’99, Edinburgh, Scotland, August, 1999.

Microbial Growth in Materials, Healthy Buildings 2000, Espoo, Finland, August, 2000.

Co-Chair, Bioaerosols X- Exposures in Residences, Indoor Air 2002, Monterey, CA, July 2002.

Chair, Environmental Tobacco Smoke in Multi-Family Homes, Indoor Air 2008, Copenhagen, Denmark, July 2008.

Co-Chair, ISIAQ Task Force Workshop; HVAC Hygiene, Indoor Air 2002, Monterey, CA, July 2002.

Chair, ETS in Multi-Family Housing: Exposures, Controls, and Legalities Forum, Healthy Buildings 2009, Syracuse, CA, September 14, 2009.

Chair, Energy Conservation and IAQ in Residences Workshop, Indoor Air 2011, Austin, TX, June 6, 2011.

Chair, Electronic Cigarettes: Chemical Emissions and Exposures Colloquium, Indoor Air 2016, Ghent, Belgium, July 4, 2016.

Co-Chair, Thermal Comfort and Perception, Indoor Air 2024, Honolulu, HI, July 2, 2024.

SPECIAL CONSULTATION
Provide consultation to the American Home Appliance Manufacturers on the development of a standard for testing portable air cleaners, AHAM Standard AC-1.

Served as an expert witness and special consultant for the U.S. Federal Trade Commission regarding the performance claims found in advertisements of portable air cleaners and residential furnace filters.

Conducted a forensic investigation for a San Mateo, CA pro se defendant, regarding an alleged homicide where the victim was kidnapped in a steamer trunk. Determined the air exchange rate in the steamer trunk and how long the person could survive.

Conducted in situ measurement of human exposure to toluene fumes released during nailpolish application for a plaintiffs attorney pursuing a California Proposition 65 product labeling case. June, 1993.

06/23/2026 Item No.18.
6-23
Conducted a forensic in situ investigation for the Butte County, CA Sheriff’s Department of the emissions of a portable heater used in the bedroom of two twin one year old girls who suffered simultaneous crib death.

Consult with OSHA on the 1995 proposed new regulation regarding indoor air quality and environmental tobacco smoke.

Consult with EPA on the proposed Building Alliance program and with OSHA on the proposed new OSHA IAQ regulation.

Johnson Controls Audit/Certification Expert Review; Milwaukee, WI. May 28-29, 1997.

Winner of the nationally published 1999 Request for Proposals by the State of Washington to conduct a comprehensive indoor air quality investigation of the Washington State Department of Ecology building in Lacey, WA.

Selected by the State of California Attorney General’s Office in August, 2000 to conduct a comprehensive indoor air quality investigation of the Tulare County Court House.

Lawrence Berkeley Laboratory IAQ Experts Workshop: “Cause and Prevention of Sick Building Problems in Offices: The Experience of Indoor Environmental Quality Investigators”, Berkeley, California, May 26-27, 2004.

Provide consultation and chemical emission rate testing to the State of California Attorney General’s Office in 2011regarding formaldehyde emissions from Brazilian Blowout hair straitening product.

Provide hazard assessment to the State of California Attorney General’s Office in 2013- 2015 regarding the chemical emissions from e-cigarettes.

Consult with the California Department of Public Health Indoor Air Section regarding ventilation and air filtration in schools during the COVID-19 pandemic, 2020-2022.

PEER-REVIEWED PUBLICATIONS :

F.J.Offermann, C.D.Hollowell, and G.D.Roseme, "Low-Infiltration Housing in Rochester, New York: A Study of Air Exchange Rates and Indoor Air Quality," Environment International, 8, pp. 435-445, 1982.

W.W.Nazaroff, F.J.Offermann, and A.W.Robb, "Automated System for Measuring Air Exchange Rate and Radon Concentration in Houses," Health Physics, 45, pp. 525-537, 1983.

F.J.Offermann, W.J.Fisk, D.T.Grimsrud, B.Pedersen, and K.L.Revzan, "Ventilation Efficiencies of Wall- or Window-Mounted Residential Air-to-Air Heat Exchangers," ASHRAE Annual Transactions, 89-2B, pp 507-527, 1983.

06/23/2026 Item No.18.
7-23
W.J.Fisk, K.M.Archer, R.E Chant, D. Hekmat, F.J.Offermann, and B.Pedersen, "Onset of Freezing in Residential Air-to-Air Heat Exchangers," ASHRAE Annual Transactions, 91- 1B, 1984.

W.J.Fisk, K.M.Archer, R.E Chant, D. Hekmat, F.J.Offermann, and B.Pedersen, "Performance of Residential Air-to-Air Heat Exchangers During Operation with Freezing and Periodic Defrosts," ASHRAE Annual Transactions, 91-1B, 1984.

R.G.Sextro, F.J.Offermann, W.W.Nazaroff, and A.V.Nero, "Effects of Aerosol Concentrations on Radon Progeny," Aerosols, Science, & Technology, and Industrial Applications of Airborne Particles, editors B.Y.H.Liu, D.Y.H.Pui, and H.J.Fissan, p525, Elsevier, 1984.

K.Sexton, S.Hayward, F.Offermann, R.Sextro, and L.Weber, "Characterization of Particulate and Organic Emissions from Major Indoor Sources, Third International Conference on Indoor Air Quality and Climate, Stockholm, Sweden, August 20-24, 1984.

F.J.Offermann, R.G.Sextro, W.J.Fisk, D.T.Grimsrud, W.W.Nazaroff, A.V.Nero, and K.L.Revzan, "Control of Respirable Particles with Portable Air Cleaners," Atmospheric Environment, Vol. 19, pp.1761-1771, 1985.

R.G.Sextro, F.J.Offermann, W.W.Nazaroff, A.V.Nero, K.L.Revzan, and J.Yater, "Evaluation of Indoor Control Devices and Their Effects on Radon Progeny Concentrations," Atmospheric Environment, 12, pp. 429-438, 1986.

W.J. Fisk, R.K.Spencer, F.J.Offermann, R.K.Spencer, B.Pedersen, R.Sextro, "Indoor Air Quality Control Techniques," Noyes Data Corporation, Park Ridge, New Jersey, (1987).

F.J.Offermann, "Ventilation Effectiveness and ADPI Measurements of a Forced Air Heating System," ASHRAE Transactions , Volume 94, Part 1, pp 694-704, 1988.

F.J.Offermann and D. Int-Hout "Ventilation Effectiveness Measurements of Three Supply/Return Air Configurations," Environment International , Volume 15, pp 585-592 1989.

F.J. Offermann, S.A. Loiselle, M.C. Quinlan, and M.S. Rogers, "A Study of Diesel Fume Entrainment in an Office Building," IAQ '89, The Human Equation: Health and Comfort, pp 179-183, ASHRAE, Atlanta, GA, 1989.

R.G.Sextro and F.J.Offermann, "Reduction of Residential Indoor Particle and Radon Progeny Concentrations with Ducted Air Cleaning Systems," submitted to Indoor Air, 1990.

L.A. Gundel, J.M. Daisey, and F.J. Offermann, "A Sampling and Analytical Method for Gas Phase Polycyclic Aromatic Hydrocarbons", Proceedings of the 5th International Conference on Indoor Air Quality and Climate, Indoor Air '90, July 29-August 1990.

06/23/2026 Item No.18.
8-23
A.T. Hodgson, J.M. Daisey, and F.J. Offermann "Development of an Indoor Sampling and Analytical Method for Particulate Polycyclic Aromatic Hydrocarbons", Proceedings of the 5th International Conference on Indoor Air Quality and Climate, Indoor Air '90, July 29- August, 1990.

S.A.Loiselle, A.T.Hodgson, and F.J.Offermann, "Development of An Indoor Air Sampler for Polycyclic Aromatic Compounds", Indoor Air , Vol 2, pp 191-210, 1991.

F.J.Offermann, S.A.Loiselle, A.T.Hodgson, L.A. Gundel, and J.M. Daisey, "A Pilot Study to Measure Indoor Concentrations and Emission Rates of Polycyclic Aromatic Compounds", Indoor Air , Vol 4, pp 497-512, 1991.

F.J. Offermann, S. A. Loiselle, R.G. Sextro, "Performance Comparisons of Six Different Air Cleaners Installed in a Residential Forced Air Ventilation System," IAQ'91, Healthy Buildings, pp 342-350, ASHRAE, Atlanta, GA (1991).

F.J. Offermann, J. Daisey, A. Hodgson, L. Gundell, and S. Loiselle, "A Pilot Study to Measure Indoor Concentrations and Emission Rates of Polycyclic Aromatic Compounds", Indoor Air, Vol 4, pp 497-512 (1991).

F.J. Offermann, S. A. Loiselle, R.G. Sextro, "Performance of Air Cleaners Installed in a Residential Forced Air System," ASHRAE Journal, pp 51-57, July, 1992.

F.J. Offermann and S. A. Loiselle, "Performance of an Air-Cleaning System in an Archival Book Storage Facility," IAQ'92, ASHRAE, Atlanta, GA, 1992.

S.B. Hayward, K.S. Liu, L.E. Alevantis, K. Shah, S. Loiselle, F.J. Offermann, Y.L. Chang, L. Webber, “Effectiveness of Ventilation and Other Controls in Reducing Exposure to ETS in Office Buildings,” Indoor Air ’93, Helsinki, Finland, July 4-8, 1993.

F.J. Offermann, S. A. Loiselle, G. Ander, H. Lau, "Indoor Contaminant Emission Rates Before and After a Building Bake-out," IAQ'93, Operating and Maintaining Buildings for Health, Comfort, and Productivity, pp 157-163, ASHRAE, Atlanta, GA, 1993.

L.E. Alevantis, Hayward, S.B., Shah, S.B., Loiselle, S., and Offermann, F.J. "Tracer Gas Techniques for Determination of the Effectiveness of Pollutant Removal From Local Sources," IAQ '93, Operating and Maintaining Buildings for Health, Comfort, and Productivity, pp 119-129, ASHRAE, Atlanta, GA, 1993.

L.E. Alevantis, Liu, L.E., Hayward, S.B., Offermann, F.J., Shah, S.B., Leiserson, K. Tsao, E., and Huang, Y., "Effectiveness of Ventilation in 23 Designated Smoking Areas in California Buildings," IAQ '94, Engineering Indoor Environments, pp 167-181, ASHRAE, Atlanta, GA, 1994.

L.E. Alevantis, Offermann, F.J., Loiselle, S., and Macher, J.M., “Pressure and Ventilation Requirements of Hospital Isolation Rooms for Tuberculosis (TB) Patients: Existing

06/23/2026 Item No.18.
9-23
Guidelines in the United States and a Method for Measuring Room Leakage”, Ventilation and Indoor Air Quality in Hospitals, M. Maroni, editor, Kluwer Academic publishers, Netherlands, 1996.

F.J. Offermann, M. A. Waz, A.T. Hodgson, and H.M. Ammann, "Chemical Emissions from a Hospital Operating Room Air Filter," IAQ'96, Paths to Better Building Environments, pp 95-99, ASHRAE, Atlanta, GA, 1996.

F.J. Offermann, "Professional Malpractice and the Sick Building Investigator," IAQ'96, Paths to Better Building Environments, pp 132-136, ASHRAE, Atlanta, GA, 1996.

F.J. Offermann, “Standard Method of Measuring Air Change Effectiveness,” Indoor Air, Vol 1, pp.206-211, 1999.

F. J. Offermann, A. T. Hodgson, and J. P. Robertson, “Contaminant Emission Rates from PVC Backed Carpet Tiles on Damp Concrete”, Healthy Buildings 2000, Espoo, Finland, August 2000.

K.S. Liu, L.E. Alevantis, and F.J. Offermann, “A Survey of Environmental Tobacco Smoke Controls in California Office Buildings”, Indoor Air, Vol 11, pp. 26-34, 2001.

F.J. Offermann, R. Colfer, P. Radzinski, and J. Robertson, “Exposure to Environmental Tobacco Smoke in an Automobile”, Indoor Air 2002, Monterey, California, July 2002.

F. J. Offermann, J.P. Robertson, and T. Webster, “The Impact of Tracer Gas Mixing on Airflow Rate Measurements in Large Commercial Fan Systems”, Indoor Air 2002, Monterey, California, July 2002.

M. J. Mendell, T. Brennan, L. Hathon, J.D. Odom, F.J.Offermann, B.H. Turk, K.M.

Wallingford, R.C. Diamond, W.J. Fisk, “Causes and prevention of Symptom Complaints in Office Buildings: Distilling the Experience of Indoor Environmental Investigators”, Indoor Air 2005, Beijing, China, September 4-9, 2005.

F.J. Offermann, “Ventilation and IAQ in New Homes With and Without Mechanical Outdoor Air Systems”, Healthy Buildings 2009, Syracuse, CA, September 14, 2009.

F.J. Offermann and A.T. Hodgson, “Emission Rates of Volatile Organic Compounds in New Homes”, Indoor Air 2011, Austin, TX, June, 2011.

P. Jenkins, R. Johnson, T. Phillips, and F. Offermann, “Chemical Concentrations in New California Homes and Garages”, Indoor Air 2011, Austin, TX, June, 2011.

W. J. Mills, B. J. Grigg, F. J. Offermann, B. E. Gustin, and N. E. Spingarm, “Toluene and Methyl Ethyl Ketone Exposure from a Commercially Available Contact Adhesive”, Journal of Occupational and Environmental Hygiene, 9:D95-D102 May, 2012.

F. J. Offermann, R. Maddalena, J. C. Offermann, B. C. Singer, and H, Wilhelm, “The

06/23/2026 Item No.18.
10-23
Impact of Ventilation on the Emission Rates of Volatile Organic Compounds in Residences”, HB 2012, Brisbane, AU, July, 2012.

F. J. Offermann, A. T. Hodgson, P. L. Jenkins, R. D. Johnson, and T. J. Phillips, “Attached Garages as a Source of Volatile Organic Compounds in New Homes”, HB 2012, Brisbane, CA, July, 2012.

R. Maddalena, N. Li, F. Offermann, and B. Singer, “Maximizing Information from Residential Measurements of Volatile Organic Compounds”, HB 2012, Brisbane, AU, July, 2012.

W. Chen, A. Persily, A. Hodgson, F. Offermann, D. Poppendieck, and K. Kumagai, “AreaSpecific Airflow Rates for Evaluating the Impacts of VOC emissions in U.S. Single-Family Homes”, Building and Environment, Vol. 71, 204-211, February, 2014.

F. J. Offermann, A. Eagan A. C. Offermann, and L. J. Radonovich, “Infectious Disease Aerosol Exposures With and Without Surge Control Ventilation System Modifications”, Indoor Air 2014, Hong Kong, July, 2014.

F. J. Offermann, A. Eagan A. C. Offermann, S. Subhash, S. Miller, and L. J. Radonovich, “Potential airborne pathogen transmission in a hospital with and without surge control ventilation system modifications. Building and Environment, Volume 106, Pages 175-180.

F. J. Offermann, “Chemical Emissions from E-Cigarettes: Direct and Indirect Passive Exposures”, Building and Environment, Vol. 93, Part 1, 101-105, November, 2015.

F. J. Offermann, “Formaldehyde Emission Rates From Lumber Liquidators Laminate Flooring Manufactured in China”, Indoor Air 2016, Belgium, Ghent, July, 2016.

F. J. Offermann, “Formaldehyde and Acetaldehyde Emission Rates for E-Cigarettes”, Indoor Air 2016, Belgium, Ghent, July, 2016.

F. J. Offermann, “Formaldehyde Emission Rates From Laminate Flooring”, ASHRAE Journal, Atlanta, GA, March, 2017.

F. J. Offermann and A.T. Hodgson, “Accuracy of Three Types of Formaldehyde Passive Samplers”, Indoor Air 2018, Philadelphia, PA, July, 2018.

F. J. Offermann and M. Nicas, “Use With Adequate Ventilation ?”, ASHRAE Journal, Atlanta, GA, May, 2018.

B. C. Singer, W.R. Chan, Y-S Kim, F.J. Offermann, I.A. Walker, “Indoor Air Quality in California Homes with Code-Required Mechanical Ventilation”. Indoor Air, 2020.

F J. Offermann. “Chemical Emissions from Spray Polyurethane Foam (SPF) Insulation in Residences”, Indoor Air 2022, Kuopio, Finland, June, 2022.

06/23/2026 Item No.18.
11-23
F.J. Offermann, “Mitigation of Spray Polyurethane Foam with High Chemical Emission Rates”, Indoor Air 2024, Honolulu, HI, July, 2024.

OTHER REPORTS:

W.J.Fisk, P.G.Cleary, and F.J.Offermann, "Energy Saving Ventilation with Residential Heat Exchangers," a Lawrence Berkeley Laboratory brochure distributed by the Bonneville Power Administration, 1981.

F.J.Offermann, J.R.Girman, and C.D.Hollowell, "Midway House Tightening Project: A Study of Indoor Air Quality," Lawrence Berkeley Laboratory, Berkeley, CA, Report LBL12777, 1981.

F.J.Offermann, J.B.Dickinson, W.J.Fisk, D.T.Grimsrud, C.D.Hollowell, D.L.Krinkle, and G.D.Roseme, "Residential Air-Leakage and Indoor Air Quality in Rochester, New York," Lawrence Berkeley Laboratory, Berkeley, CA, Report LBL-13100, 1982.

F.J.Offermann, W.J.Fisk, B.Pedersen, and K.L.Revzan, Residential Air-to-Air Heat Exchangers: A Study of the Ventilation Efficiencies of Wall- or Window- Mounted Units," Lawrence Berkeley Laboratory, Berkeley, CA, Report LBL-14358, 1982.

F.J.Offermann, W.J.Fisk, W.W.Nazaroff, and R.G.Sextro, "A Review of Portable Air Cleaners for Controlling Indoor Concentrations of Particulates and Radon Progeny," An interim report for the Bonneville Power Administration, 1983.

W.J.Fisk, K.M.Archer, R.E.Chant, D.Hekmat, F.J.Offermann, and B.S. Pedersen, "Freezing in Residential Air-to-Air Heat Exchangers: An Experimental Study," Lawrence Berkeley Laboratory, Berkeley, CA, Report LBL-16783, 1983.

R.G.Sextro, W.W.Nazaroff, F.J.Offermann, and K.L.Revzan, "Measurements of Indoor Aerosol Properties and Their Effect on Radon Progeny," Proceedings of the American Association of Aerosol Research Annual Meeting, April, 1983.

F.J.Offermann, R.G.Sextro, W.J.Fisk, W.W. Nazaroff, A.V.Nero, K.L.Revzan, and J.Yater, "Control of Respirable Particles and Radon Progeny with Portable Air Cleaners," Lawrence Berkeley Laboratory, Berkeley, CA, Report LBL-16659, 1984.

W.J.Fisk, R.K.Spencer, D.T.Grimsrud, F.J.Offermann, B.Pedersen, and R.G.Sextro, "Indoor Air Quality Control Techniques: A Critical Review," Lawrence Berkeley Laboratory, Berkeley, CA, Report LBL-16493, 1984.

R.Otto, J.Girman, F.Offermann, and R.Sextro, "A New Method for the Collection and Comparison of Respirable Particles in the Indoor Environment," Lawrence Berkeley Laboratory, Berkeley, CA, Special Director Fund's Study, 1984.

A.T.Hodgson and F.J.Offermann, "Examination of a Sick Office Building," Lawrence Berkeley Laboratory, Berkeley, CA, an informal field study, 1984.

06/23/2026 Item No.18.
12-23
F.J.Offermann, "Tracer Gas Measurements of Laboratory Fume Entrainment at a SemiConductor Manufacturing Plant," an Indoor Environmental Engineering R&D Report, 1986.

F.J.Offermann, "Tracer Gas Measurements of Ventilation Rates in a Large Office Building," an Indoor Environmental Engineering R&D Report, 1986.

F.J.Offermann, "Measurements of Volatile Organic Compounds in a New Large Office Building with Adhesive Fastened Carpeting," an Indoor Environmental Engineering R&D Report, 1986.

F.J.Offermann, "Designing and Operating Healthy Buildings", an Indoor Environmental Engineering R&D Report, 1986.

F.J.Offermann, "Measurements and Mitigation of Indoor Spray-Applicated Pesticides", an Indoor Environmental Engineering R&D Report, 1988.

F.J.Offermann and S. Loiselle, "Measurements and Mitigation of Indoor Mold Contamination in a Residence", an Indoor Environmental Engineering R&D Report, 1989.

F.J.Offermann and S. Loiselle, "Performance Measurements of an Air Cleaning System in a Large Archival Library Storage Facility", an Indoor Environmental Engineering R&D Report, 1989.

F.J. Offermann, J.M. Daisey, L.A. Gundel, and A.T. Hodgson, S. A. Loiselle, "Sampling, Analysis, and Data Validation of Indoor Concentrations of Polycyclic Aromatic Hydrocarbons", Final Report, Contract No. A732-106, California Air Resources Board, March, 1990.

F.J. Offermann, J.O. Sateri, “Tracer Gas Measurements in Large Multi-Room Buildings”, Indoor Air ’93, Helsinki, Finland, July 4-8, 1993.

F.J.Offermann, M. T. O’Flaherty, and M. A. Waz “Validation of ASHRAE 129 - Standard Method of Measuring Air Change Effectiveness”, Final Report of ASHRAE Research Project 891, December 8, 1997.

S.E. Guffey, F.J. Offermann et. al., “Proceedings of the Workshop on Ventilation Engineering Controls for Environmental Tobacco smoke in the Hospitality Industry”, U.S.

Department of Labor Occupational Safety and Health Administration and ACGIH, 1998.

F.J. Offermann, R.J. Fiskum, D. Kosar, and D. Mudaari, “A Practical Guide to Ventilation Practices & Systems for Existing Buildings”, Heating/Piping/Air Conditioning Engineering supplement to April/May 1999 issue.

F.J. Offermann, P. Pasanen, “Workshop 18: Criteria for Cleaning of Air Handling Systems”, Healthy Buildings 2000, Espoo, Finland, August 2000.

06/23/2026 Item No.18.
13-23
F.J. Offermann, Session Summaries: Building Investigations, and Design & Construction, Healthy Buildings 2000, Espoo, Finland, August 2000.

F.J. Offermann, “Cleaning Up Fire Smoke and Soot Residues Fact Sheet”, October, 2007.

F.J. Offermann, “The IAQ Top 10”, Engineered Systems, November, 2008.

L. Kincaid and F.J. Offermann, “Unintended Consequences: Formaldehyde Exposures in Green Homes, AIHA Synergist, February, 2010.

F.J. Offermann, “ IAQ in Air Tight Homes”, ASHRAE Journal, November, 2010.

F.J. Offermann, “The Hazards of E-Cigarettes”, ASHRAE Journal, June, 2014.

F.J. Offermann, A.T. Hodgson, and R. Tannous, Commissioning Indoor Air in Office Buildings, August 5, 2017.

F.J. Offermann, Building Protection Factor Fact Sheet, November, 2017.

F.J. Offermann, “Chemical Emissions From Polyurethane Spray Foam”, Indoor Environmental Engineering R&D Report, 2020.

F.J. Offermann, “Building Protection Factors”, Indoor Environmental Engineering R&D Report, 2020.

F.J. Offermann in collaboration with California Department of Public Health, Indoor Air Quality Section “The Role of Building Ventilation and Filtration in Reducing Risk of Airborne Viral Transmission in Schools, Illustrated with SARS-COV-2”. September 1, 2020.

F.J. Offermann, “Beware The COVID-19 Snake Oil Salesmen Are Here”. November 5, 2020.

F.J. Offermann in collaboration with California Department of Public Health, Indoor Air Quality Section, “Ventilation and Filtration to Reduce Long-Range Airborne Transmission of COVID-19 and Other Respiratory Infections: Considerations for Reopened Schools”, July, 2021.

F.J. Offermann in collaboration with California Department of Public Health, Indoor Air Quality Section, “Information for School Districts on Purchase of Filtration and Air Cleaning Devices”, August 2021.

06/23/2026 Item No.18.
14-23
PRESENTATIONS :
"Low-Infiltration Housing in Rochester, New York: A Study of Air Exchange Rates and Indoor Air Quality," Presented at the International Symposium on Indoor Air Pollution, Health and Energy Conservation, Amherst, MA, October 13-16,1981. "Ventilation Efficiencies of Wall- or Window-Mounted Residential Air-to-Air Heat Exchangers," Presented at the American Society of Heating, Refrigeration, and Air Conditioning Engineers Summer Meeting, Washington, DC, June, 1983. "Controlling Indoor Air Pollution from Tobacco Smoke: Models and Measurements," Presented at the Third International Conference on Indoor Air Quality and Climate, Stockholm, Sweden, August 20-24, 1984.
"Indoor Air Pollution: An Emerging Environmental Problem", Presented to the Association of Environmental Professionals, Bar Area/Coastal Region 1, Berkeley, CA, May 29, 1986. "Ventilation Measurement Techniques," Presented at the Workshop on Sampling and Analytical Techniques, Georgia Institute of Technology, Atlanta, Georgia, September 26, 1986 and September 25, 1987.
"Buildings That Make You Sick: Indoor Air Pollution", Presented to the Sacramento Association of Professional Energy Managers, Sacramento, CA, November 18, 1986. "Ventilation Effectiveness and Indoor Air Quality", Presented to the American Society of Heating, Refrigeration, and Air Conditioning Engineers Northern Nevada Chapter, Reno, NV, February 18, 1987, Golden Gate Chapter, San Francisco, CA, October 1, 1987, and the San Jose Chapter, San Jose, CA, June 9, 1987.
"Tracer Gas Techniques for Studying Ventilation," Presented at the Indoor Air Quality Symposium, Georgia Tech Research Institute, Atlanta, GA, September 22-24, 1987. "Indoor Air Quality Control: What Works, What Doesn't," Presented to the Sacramento Association of Professional Energy Managers, Sacramento, CA, November 17, 1987. "Ventilation Effectiveness and ADPI Measurements of a Forced Air Heating System," Presented at the American Society of Heating, Refrigeration, and Air Conditioning Engineers Winter Meeting, Dallas, Texas, January 31, 1988. "Indoor Air Quality, Ventilation, and Energy in Commercial Buildings", Presented at the Building Owners &Managers Association of Sacramento, Sacramento, CA, July 21, 1988. "Controlling Indoor Air Quality: The New ASHRAE Ventilation Standards and How to Evaluate Indoor Air Quality", Presented at a conference "Improving Energy Efficiency and Indoor Air Quality in Commercial Buildings," National Energy Management Institute, Reno, Nevada, November 4, 1988.

06/23/2026 Item No.18.
15-23
"A Study of Diesel Fume Entrainment Into an Office Building," Presented at Indoor Air '89: The Human Equation: Health and Comfort, American Society of Heating, Refrigeration, and Air Conditioning Engineers, San Diego, CA, April 17-20, 1989. "Indoor Air Quality in Commercial Office Buildings," Presented at the Renewable Energy Technologies Symposium and International Exposition, Santa Clara, CA June 20, 1989. "Building Ventilation and Indoor Air Quality", Presented to the San Joaquin Chapter of the American Society of Heating, Refrigeration, and Air Conditioning Engineers, September 7, 1989.
"How to Meet New Ventilation Standards: Indoor Air Quality and Energy Efficiency," a workshop presented by the Association of Energy Engineers; Chicago, IL, March 20-21, 1989; Atlanta, GA, May 25-26, 1989; San Francisco, CA, October 19-20, 1989; Orlando, FL, December 11-12, 1989; Houston, TX, January 29-30, 1990; Washington D.C., February 26-27, 1990; Anchorage, Alaska, March 23, 1990; Las Vegas, NV, April 23-24, 1990; Atlantic City, NJ, September 27-28, 1991; Anaheim, CA, November 19-20, 1991; Orlando, FL, February 28 - March 1, 1991; Washington, DC, March 20-21, 1991; Chicago, IL, May 16-17, 1991; Lake Tahoe, NV, August 15-16, 1991; Atlantic City, NJ, November 18-19, 1991; San Jose, CA, March 23-24, 1992.
"Indoor Air Quality," a seminar presented by the Anchorage, Alaska Chapter of the American Society of Heating, Refrigeration, and Air Conditioning Engineers, March 23, 1990.
"Ventilation and Indoor Air Quality", Presented at the 1990 HVAC & Building Systems Congress, Santa, Clara, CA, March 29, 1990.

"Ventilation Standards for Office Buildings", Presented to the South Bay Property Managers Association, Santa Clara, May 9, 1990.
"Indoor Air Quality", Presented at the Responsive Energy Technologies Symposium & International Exposition (RETSIE), Santa Clara, CA, June 20, 1990. "Indoor Air Quality - Management and Control Strategies", Presented at the Association of Energy Engineers, San Francisco Bay Area Chapter Meeting, Berkeley, CA, September 25, 1990.
"Diagnosing Indoor Air Contaminant and Odor Problems", Presented at the ASHRAE Annual Meeting, New York City, NY, January 23, 1991.
"Diagnosing and Treating the Sick Building Syndrome", Presented at the Energy 2001, Oklahoma, OK, March 19, 1991.
"Diagnosing and Mitigating Indoor Air Quality Problems" a workshop presented by the Association of Energy Engineers, Chicago, IL, October 29-30, 1990; New York, NY, January 24-25, 1991; Anaheim, April 25-26, 1991; Boston, MA, June 10-11, 1991; Atlanta,

06/23/2026 Item No.18.
16-23
GA, October 24-25, 1991; Chicago, IL, October 3-4, 1991; Las Vegas, NV, December 16- 17, 1991; Anaheim, CA, January 30-31, 1992; Atlanta, GA, March 5-6, 1992; Washington, DC, May 7-8, 1992; Chicago, IL, August 19-20, 1992; Las Vegas, NV, October 1-2, 1992; New York City, NY, October 26-27, 1992, Las Vegas, NV, March 18-19, 1993; Lake Tahoe, CA, July 14-15, 1994; Las Vegas, NV, April 3-4, 1995; Lake Tahoe, CA, July 11- 12, 1996; Miami, FL, December 9-10, 1996.
"Sick Building Syndrome and the Ventilation Engineer", Presented to the San Jose Engineers Club, May 21, 1991.
"Duct Cleaning: Who Needs It ? How Is It Done ? What Are The Costs ?" What Are the Risks ?, Moderator of Forum at the ASHRAE Annual Meeting, Indianapolis ID, June 23, 1991.
"Operating Healthy Buildings", Association of Plant Engineers, Oakland, CA, November 14, 1991.
"Duct Cleaning Perspectives", Moderator of Seminar at the ASHRAE Semi-Annual Meeting, Indianapolis, IN, June 24, 1991.
"Duct Cleaning: The Role of the Environmental Hygienist," ASHRAE Annual Meeting, Anaheim, CA, January 29, 1992.
"Emerging IAQ Issues", Fifth National Conference on Indoor Air Pollution, University of Tulsa, Tulsa, OK, April 13-14, 1992.
"International Symposium on Room Air Convection and Ventilation Effectiveness", Member of Scientific Advisory Board, University of Tokyo, July 22-24, 1992. "Guidelines for Contaminant Control During Construction and Renovation Projects in Office Buildings," Seminar paper at the ASHRAE Annual Meeting, Chicago, IL, January 26, 1993.
"Outside Air Economizers: IAQ Friend or Foe", Moderator of Forum at the ASHRAE Annual Meeting, Chicago, IL, January 26, 1993.
"Orientation to Indoor Air Quality," an EPA two and one half day comprehensive indoor air quality introductory workshop for public officials and building property managers; Sacramento, September 28-30, 1992; San Francisco, February 23-24, 1993; Los Angeles, March 16-18, 1993; Burbank, June 23, 1993; Hawaii, August 24-25, 1993; Las Vegas, August 30, 1993; San Diego, September 13-14, 1993; Phoenix, October 18-19, 1993; Reno, November 14-16, 1995; Fullerton, December 3-4, 1996; Fresno, May 13-14, 1997. "Building Air Quality: A Guide for Building Owners and Facility Managers," an EPA one half day indoor air quality introductory workshop for building owners and facility managers. Presented throughout Region IX 1993-1995.

06/23/2026 Item No.18.
17-23
“Techniques for Airborne Disease Control”, EPRI Healthcare Initiative Symposium; San Francisco, CA; June 7, 1994.
“Diagnosing and Mitigating Indoor Air Quality Problems”, CIHC Conference; San Francisco, September 29, 1994.
”Indoor Air Quality: Tools for Schools,” an EPA one day air quality management workshop for school officials, teachers, and maintenance personnel; San Francisco, October 18-20, 1994; Cerritos, December 5, 1996; Fresno, February 26, 1997; San Jose, March 27, 1997; Riverside, March 5, 1997; San Diego, March 6, 1997; Fullerton, November 13, 1997; Santa Rosa, February 1998; Cerritos, February 26, 1998; Santa Rosa, March 2, 1998.

ASHRAE 62 Standard “Ventilation for Acceptable IAQ”, ASCR Convention; San Francisco, CA, March 16, 1995.
“New Developments in Indoor Air Quality: Protocol for Diagnosing IAQ Problems”, AIHA-NC; March 25, 1995.
"Experimental Validation of ASHRAE SPC 129, Standard Method of Measuring Air Change Effectiveness", 16th AIVC Conference, Palm Springs, USA, September 19-22, 1995.
“Diagnostic Protocols for Building IAQ Assessment”, American Society of Safety Engineers Seminar: ‘Indoor Air Quality – The Next Door’; San Jose Chapter, September 27, 1995; Oakland Chapter, 9, 1997.
“Diagnostic Protocols for Building IAQ Assessment”, Local 39; Oakland, CA, October 3, 1995.
“Diagnostic Protocols for Solving IAQ Problems”, CSU-PPD Conference; October 24, 1995.
“Demonstrating Compliance with ASHRAE 62-1989 Ventilation Requirements”, AIHA; October 25, 1995.
“IAQ Diagnostics: Hands on Assessment of Building Ventilation and Pollutant Transport”, EPA Region IX; Phoenix, AZ, March 12, 1996; San Francisco, CA, April 9, 1996; Burbank, CA, April 12, 1996.
“Experimental Validation of ASHRAE 129P: Standard Method of Measuring Air Change Effectiveness”, Room Vent ‘96 / International Symposium on Room Air Convection and Ventilation Effectiveness"; Yokohama, Japan, July 16-19, 1996. “IAQ Diagnostic Methodologies and RFP Development”, CCEHSA 1996 Annual Conference, Humboldt State University, Arcata, CA, August 2, 1996.

06/23/2026 Item No.18.
18-23
“The Practical Side of Indoor Air Quality Assessments”, California Industrial Hygiene Conference ‘96, San Diego, CA, September 2, 1996.
“ASHRAE Standard 62: Improving Indoor Environments”, Pacific Gas and Electric Energy Center, San Francisco, CA, October 29, 1996.
“Operating and Maintaining Healthy Buildings”, April 3-4, 1996, San Jose, CA; July 30, 1997, Monterey, CA.
“IAQ Primer”, Local 39, April 16, 1997; Amdahl Corporation, June 9, 1997; State Compensation Insurance Fund’s Safety & Health Services Department, November 21, 1996.
“Tracer Gas Techniques for Measuring Building Air Flow Rates”, ASHRAE, Philadelphia, PA, January 26, 1997.
“How to Diagnose and Mitigate Indoor Air Quality Problems”; Women in Waste; March 19, 1997.
“Environmental Engineer: What Is It?”, Monte Vista High School Career Day; April 10, 1997.
“Indoor Environment Controls: What’s Hot and What’s Not”, Shaklee Corporation; San Francisco, CA, July 15, 1997.
“Measurement of Ventilation System Performance Parameters in the US EPA BASE Study”, Healthy Buildings/IAQ’97, Washington, DC, September 29, 1997. “Operations and Maintenance for Healthy and Comfortable Indoor Environments”, PASMA; October 7, 1997.
“Designing for Healthy and Comfortable Indoor Environments”, Construction Specification Institute, Santa Rosa, CA, November 6, 1997. “Ventilation System Design for Good IAQ”, University of Tulsa 10th Annual Conference, San Francisco, CA, February 25, 1998.
“The Building Shell”, Tools For Building Green Conference and Trade Show, Alameda County Waste Management Authority and Recycling Board, Oakland, CA, February 28, 1998.
“Identifying Fungal Contamination Problems In Buildings”, The City of Oakland Municipal Employees, Oakland, CA, March 26, 1998.
“Managing Indoor Air Quality in Schools: Staying Out of Trouble”, CASBO, Sacramento, CA, April 20, 1998.

06/23/2026 Item No.18.
19-23
“Indoor Air Quality”, CSOOC Spring Conference, Visalia, CA, April 30, 1998. “Particulate and Gas Phase Air Filtration”, ACGIH/OSHA, Ft. Mitchell, KY, June 1998. “Building Air Quality Facts and Myths”, The City of Oakland / Alameda County Safety Seminar, Oakland, CA, June 12, 1998.
“Building Engineering and Moisture”, Building Contamination Workshop, University of California Berkeley, Continuing Education in Engineering and Environmental Management, San Francisco, CA, October 21-22, 1999.
“Identifying and Mitigating Mold Contamination in Buildings”, Western Construction Consultants Association, Oakland, CA, March 15, 2000; AIG Construction Defect Seminar, Walnut Creek, CA, May 2, 2001; City of Oakland Public Works Agency, Oakland, CA, July 24, 2001; Executive Council of Homeowners, Alamo, CA, August 3, 2001.
“Using the EPA BASE Study for IAQ Investigation / Communication”, Joint Professional Symposium 2000, American Industrial Hygiene Association, Orange County & Southern California Sections, Long Beach, October 19, 2000.
“Ventilation,” Indoor Air Quality: Risk Reduction in the 21st Century Symposium, sponsored by the California Environmental Protection Agency/Air Resources Board, Sacramento, CA, May 3-4, 2000.
“Workshop 18: Criteria for Cleaning of Air Handling Systems”, Healthy Buildings 2000, Espoo, Finland, August, 2000.
“Closing Session Summary: ‘Building Investigations’ and ‘Building Design & Construction’, Healthy Buildings 2000, Espoo, Finland, August, 2000. “Managing Building Air Quality and Energy Efficiency, Meeting the Standard of Care”, BOMA, MidAtlantic Environmental Hygiene Resource Center, Seattle, WA, May 23rd, 2000; San Antonio, TX, September 26-27, 2000.
“Sensory Stimuli and Ventilation Control”. Emerging Issues, ASHRAE IAQ Applications/Summer, 2000.
“Diagnostics & Mitigation in Sick Buildings: When Good Buildings Go Bad,” University of California Berkeley, September 18, 2001.
“Mold Contamination: Recognition and What To Do and Not Do”, Redwood Empire Remodelers Association; Santa Rosa, CA, April 16, 2002. “Investigative Tools of the IAQ Trade”, Healthy Indoor Environments 2002; Austin, TX; April 22, 2002.

06/23/2026 Item No.18.
20-23
“Finding Hidden Mold: Case Studies in IAQ Investigations”, AIHA Northern California Professionals Symposium; Oakland, CA, May 8, 2002.
“Assessing and Mitigating Fungal Contamination in Buildings”, Cal/OSHA Training; Oakland, CA, February 14, 2003 and West Covina, CA, February 20-21, 2003. “Use of External Containments During Fungal Mitigation”, Healthy Indoor Environments, Anaheim, CA, April 3, 2003 and ACGIH Mold Remediation Symposium (Invited Speaker), Orlando, FL, November 3-5, 2003.

Building Operator Certification (BOC), 106-IAQ Training Workshops, Northwest Energy Efficiency Council; Stockton, CA, December 3, 2003; San Francisco, CA, December 9, 2003; Irvine, CA, January 13, 2004; San Diego, January 14, 2004; Irwindale, CA, January 27, 2004; Downey, CA, January 28, 2004; Santa Monica, CA, March 16, 2004; Ontario, CA, March 17, 2004; Ontario, CA, November 9, 2004, San Diego, CA, November 10, 2004; San Francisco, CA, November 17, 2004; San Jose, CA, November 18, 2004; Sacramento, CA, March 15, 2005.
“HVAC Systems Maintenance”, Cal/OSHA Training, Oakland and West Covina, CA, March 11, 2003.
“Mold Remediation: The National QUEST for Uniformity Symposium”, Invited Speaker, Orlando, Florida, November 3-5, 2003.
“Mold and Moisture Control”, Indoor Air Quality workshop for The Collaborative for High Performance Schools (CHPS), San Francisco, December 11, 2003. “Advanced Perspectives In Mold Prevention & Control Symposium”, Invited Speaker, Las Vegas, Nevada, November 7-9, 2004.
“Building Sciences: Understanding and Controlling Moisture in Buildings”, American Industrial Hygiene Association, San Francisco, CA, February 14-16, 2005. “Indoor Air Quality Diagnostics and Healthy Building Design”, University of California Berkeley, Berkeley, CA, March 2, 2005.
“Managing IAQ in Buildings and the USGBC Certification Program”, BOMA Environmental Committee, San Francisco, CA, June 1, 2006. “Improving IAQ = Reduced Tenant Complaints”, Northern California Facilities Exposition, Santa Clara, CA, September 27, 2007.
“Defining Safe Building Air”, Criteria for Safe Air and Water in Buildings, ASHRAE Winter Meeting, Chicago, IL, January 27, 2008.
“USGBC LEED and Indoor Air Quality : Leading or Lagging ?”, Bay Area LEED Users Group (BAyLUG), San Francisco, CA, June 5, 2008

06/23/2026 Item No.18.
21-23
“Window Usage, Ventilation, and Formaldehyde Concentrations in New California Homes”, Indoor Air 2008, Copenhagen, Denmark.
“ETS in Multi-Family Housing: Exposures, Controls, and Legalities”, Indoor Air 2008, Copenhagen, Denmark.
“Update on USGBC LEED and Air Filtration”, Invited Speaker, NAFA 2008 Convention, San Francisco, CA, September 19, 2008.
“Indoor Air Quality Requirements of Green Buildings”, Northern California Facilities Exposition, Santa Clara, CA, September 25, 2008.
“Ventilation and Indoor air Quality in New California Homes”, National Center of Healthy Housing, October 20, 2008.
“Indoor Air Quality in New Homes”, California Energy and Air Quality Conference, October 29, 2008.
“Mechanical Outdoor air Ventilation Systems and IAQ in New Homes”, ACI Home Performance Conference, Kansas City, MO, April 29, 2009. “Student Performance and Absenteeism Related to IAQ”, Balancing IAQ and Energy Conservation/Efficiency Objectives in Schools ASHRAE Summer Meeting, Louisville, KY, June 21, 2009
“Ventilation and IAQ in New Homes with and without Mechanical Outdoor Air Systems”, Healthy Buildings 2009, Syracuse, CA, September 14, 2009. “Ten Ways to Improve Your Air Quality”, Northern California Facilities Exposition, Santa Clara, CA, September 30, 2009.
“New Developments in Ventilation and Indoor Air Quality in Residential Buildings”, Westcon meeting, Alameda, CA, March 17, 2010.
“Intermittent Residential Mechanical Outdoor Air Ventilation Systems and IAQ”, ASHRAE SSPC 62.2 Meeting, Austin, TX, April 19, 2010.
“ASHRAE 62.2 Intermittent Residential Ventilation: What’s It Good For, Intermittently Poor IAQ”, IAQVEC 2010, Syracuse, CA, April 21, 2010.
“Measured IAQ in Homes”, ACI Home Performance Conference, Austin, TX, April 21, 2010.
“Respiration: IEQ and Ventilation”, AIHCE 2010, How IH Can LEED in Green Buildings, Denver, CO, May 23, 2010.

06/23/2026 Item No.18.
22-23
“IAQ Considerations for Net Zero Energy Buildings (NZEB)”, Northern California Facilities Exposition, Santa Clara, CA, September 22, 2010. “Energy Conservation and Health in Buildings”, Berkeley High School Green Career Week, Berkeley, CA, April 12, 2011.
“What Pollutants are Really There ?”, ACI Home Performance Conference, San Francisco, CA, March 30, 2011.
“Energy Conservation and Health in Residences Workshop”, Indoor Air 2011, Austin, TX, June 6, 2011.
“Assessing IAQ and Improving Health in Residences”, US EPA Weatherization Plus Health, September 7, 2011.
“Ventilation: What a Long Strange Trip It’s Been”, Westcon, May 21, 2014. “Chemical Emissions from E-Cigarettes: Direct and Indirect Passive Exposures”, Indoor Air 2014, Hong Kong, July, 2014.
“Infectious Disease Aerosol Exposures With and Without Surge Control Ventilation System Modifications”, Indoor Air 2014, Hong Kong, July, 2014. “Chemical Emissions from E-Cigarettes”, IMF Health and Welfare Fair, Washington, DC, February 18, 2015.
“Chemical Emissions and Health Hazards Associated with E-Cigarettes”, Roswell Park Cancer Institute, Buffalo, NY, August 15, 2014.
“Formaldehyde Indoor Concentrations, Material Emission Rates, and the CARB ATCM”, Harris Martin’s Lumber Liquidators Flooring Litigation Conference, WQ Minneapolis Hotel, May 27, 2015.
“Chemical Emissions from E-Cigarettes: Direct and Indirect Passive Exposure”, FDA Public Workshop: Electronic Cigarettes and the Public Health, Hyattsville, MD June 2, 2015.
“Creating Healthy Homes, Schools, and Workplaces”, Chautauqua Institution, Athenaeum Hotel, August 24, 2015.
“Diagnosing IAQ Problems and Designing Healthy Buildings”, University of California Berkeley, Berkeley, CA, October 6, 2015.
“Diagnosing Ventilation and IAQ Problems in Commercial Buildings”, BEST Center Annual Institute, Lawrence Berkeley National Laboratory, January 6, 2016. “A Review of Studies of Ventilation and Indoor Air Quality in New Homes and Impacts

06/23/2026 Item No.18.
23-23
of Environmental Factors on Formaldehyde Emission Rates From Composite Wood Products”, AIHce2016, May, 21-26, 2016.
“Admissibility of Scientific Testimony”, Science in the Court, Proposition 65 Clearinghouse Annual Conference, Oakland, CA, September 15, 2016. “Indoor Air Quality and Ventilation”, ASHRAE Redwood Empire, Napa, CA, December 1, 2016.
“Energy Conservation and Health in Buildings”, Berkeley High School Green Career Week, Berkeley, CA, March 8, 2017.
“What Does ‘Use With Adequate Ventilation’ Mean ?”, Indoor Air 2018, Philadelphia, PA, July, 2018.
“Ventilation, Air Filtration, and COVID-19, Avoiding the Snake Oil Salesman”, IAQ Radio, January 29, 2021.
“How to Prevent Snake Oil Sales from the IAQ Industry”. Healthy Indoors Live Show, April 15, 2021.
“Ventilation, Air Filtration, and COVID-19: Avoiding the Snake Oil Salesman” OCFMA Presentation, June 3, 2021.
“Ventilation, Air Filtration, and COVID-19, Avoiding the Snake Oil Salesman”, Ontario College Facilities Management Association, June 23, 2021. “Air Quality Expert Warns of COVID-19 Snake Oil Salesmen”. NBC Bay Area, August 4, 2021.
“Managing Wildfire Smoke Indoors During COVID 19”, ASHRAE Golden Gate Chapter, San Francisco, CA, February 17, 2022.
“Chemical Emissions from Spray Polyurethane Foam (SPF) Insulation in Residences, Indoor Air 2022, Kuopio, Finland, June, 2022.
“How good is your ventilation? Indoor Air Quality and the passenger experience within Airports”. 2022 Greenbuild International Conference & Expo, November 1-3, 2022. “Assessing and Mitigating Fungal Contamination in Buildings”. Cal/OSHA Training.

Oakland, CA (February 14, 2003) West Covina, CA (February 20 and 21, 2003). “Mold Contamination in Buildings”, Tenant Law Group – Lunch and Learn, April, 19, 2023.
“Ventilation / Filtration and Tenants” Regional Asthma Management and Prevention, June 29, 2023 Webinar.

06/23/2026 Item No.18.

EXHIBIT D

06/23/2026 Item No.18.

Lawrence Berkeley National Laboratory
LBL Publications
Title
Indoor air quality in California homes with code‐required mechanical ventilation Permalink
https://escholarship.org/uc/item/5284d4tk
Journal
Indoor Air, 30(5)
ISSN
0905-6947
Authors
Singer, Brett C
Chan, Wanyu R
Kim, Yang‐Seon
et al.

Publication Date
2020-05-12
DOI

10.1111/ina.12676
Peer reviewed
eScholarship.org Powered by the California Digital Library University of California Page 1235
06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 1
1 Indoor Air Quality in California Homes with Code-Required Mechanical Ventilation Brett C. Singer1, Wanyu R. Chan1, Yang-Seon Kim1,2, Francis J. Offermann 3 , Iain S. Walker1 2
1 3 Residential Buildings Systems Group and Indoor Environment Group, Lawrence Berkeley 4 National Laboratory, Berkeley, California, USA
2 5 Department of Mechanical Engineering, Wichita State University, Wichita, Kansas, USA 3 6 Indoor Environmental Engineering, San Francisco California, USA 7 Acknowledgements
8 This work was supported by the California Energy Commission through Contract PIR-14-007 9 and the U.S. Department of Energy Building America Program via Contract DE-AC02- 10 05CH11231. The Southern California Gas Company (SoCalGas) provided direct funding to the 11 Gas Technology Institute (GTI) and staff resources to support an online survey and field data 12 collection. The Pacific Gas & Electric Company (PG&E) funded Misti Bruceri & Associates 13 (MBA) to provide a field technician. SoCalGas and PG&E deployed Gas Service Technicians to 14 conduct appliance safety inspections in study homes. Data collection in homes was conducted by 15 Luke Bingham, Erin Case, and Shawn Scott of GTI; Guy Lawrence of MBA; Eric Barba, Mary 16 Nones, Ara Arouthinounian, and Ricardo Torres of SoCalGas; and Woody Delp of LBNL. Rick 17 Chitwood assisted with data collection and guidance on measuring airflow in supply ventilation 18 systems. Max Sherman (retired from LBNL) helped develop the project and served as the initial 19 Principal Investigator. Genese Scott of SoCalGas helped with online survey recruitment. Marion 20 Russell of LBNL led the chemical analysis of air samples. Kelly Perce transferred survey and 21 activity log data from paper to the survey database. The CalCERTS and CHEERS organizations 22 provided Title 24 compliance records for many study homes. Neil Leslie, Larry Brand, and Rob 23 Kamisky of GTI provided management support.
24 25

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 2
1 Abstract
2 Data were collected in 70 detached houses built in 2011-2017 in compliance with the mechanical 3 ventilation requirements of California’s building energy efficiency standards. Each home was 4 monitored for a one-week period with windows closed and the central mechanical ventilation 5 system operating. Pollutant measurements included time-resolved fine particulate matter (PM2.5) 6 indoors and outdoors and formaldehyde and carbon dioxide (CO2) indoors. Time-integrated 7 measurements were made for formaldehyde, NO2 and nitrogen oxides (NOX) indoors and 8 outdoors. Operation of the cooktop, range hood and other exhaust fans was continuously 9 recorded during the monitoring period. One-time diagnostic measurements included mechanical 10 airflows and envelope and duct system air leakage. All homes met or were very close to meeting 11 the ventilation requirements. On average the dwelling unit ventilation fan moved 50% more 12 airflow than the minimum requirement. Pollutant concentrations were similar or lower than those 13 reported in a 2006-2007 study of California new homes built in 2002-2005. Mean and median 14 indoor concentrations were lower by 44% and 38% for formaldehyde and 44% and 54% for 15 PM2.5. Ventilation fans were operating in only 26% of homes when first visited and the control 16 switches in many homes did not have informative labels as required by building standards. 17 Keywords: ASHRAE 62.2, Healthy Efficient New Gas Home Study, Carbon dioxide, Fine 18 particulate matter, Formaldehyde, Nitrogen dioxide
19 Practical Implications
20 High performance home standards and building codes and regulations require mechanical 21 ventilation equipment to help manage moisture and air pollutants emitted indoors. This paper 22 demonstrates the success of a new construction residential ventilation requirement instituted in 23 the state of California in 2008, with almost all studied homes having compliant ventilation 24 equipment. The study found that the combination of mechanical ventilation and implementation 25 of a standard that reduced the allowable formaldehyde emissions from manufactured wood 26 products resulted in formaldehyde concentrations that were lower by 44% and 38% at mean and

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 3
1 median levels than in homes built prior to the standards. This study affirms that new homes can 2 be built to stringent efficiency standards while maintaining indoor air quality. 3 1. Introduction
4 Since 2008, California’s statewide residential building code has included requirements for 5 mechanical ventilation to protect indoor air quality (IAQ). Ventilation requirements were 6 implemented to mitigate any negative impacts of reducing uncontrolled air infiltration by 7 envelope air-sealing to reduce energy use. Lower air infiltration reduces dilution of pollutants 8 emitted inside the home, leading to higher concentrations if no other actions are taken. Although 9 mechanical ventilation in new homes has become commonplace in many developed countries, it 10 is uncommon in the U.S., particularly in single-family dwellings. Many state and local building 11 codes in the U.S. have implicitly relied on natural ventilation through leaky envelopes or for 12 occupants to manage IAQ using natural ventilation.
13 The presumption that occupants effectively utilize natural ventilation to manage moisture and 14 chronic exposure to formaldehyde and other pollutants from indoor sources in homes was 15 examined in two large studies conducted in California in the mid-2000s. In 2003, a mail-based 16 survey was sent to a statewide representative sample of homes built in 2002-2003 to query IAQ satisfaction, ventilation practices, activities, and equipment use that can impact IAQ1 17 . Based on 18 self-reported window use, the researchers assessed that most homes were substantially underventilated relative to the target of 0.35 h -1 19 , from the ASHRAE 62-1999 ventilation standard.
20 The California New Home Study (CNHS), conducted in 2006-2007, collected data in 108 homes built in 2002–20052 21 . The study included a thorough characterization of the building and thermal 22 and mechanical equipment; measurements of envelope and garage-to-house air leakage; an 23 occupant questionnaire that covered many of the same topics as the earlier mailed survey; 24 monitoring of window use over a week; and measurements of air exchange and various IAQ 25 parameters over a single 24-hour period. Sampling was roughly split between winter and summer

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 4
1 and between Northern and Southern California. Monitoring was repeated in 4 homes to 2 investigate day-to-day and seasonal variability. The study found that actual window use differed 3 from what participants reported generally for the season in which measurements were made (i.e., 4 52% under-reported and 8.3% over-reported), indicating that self-reported window use in the 5 mailout survey may have been biased low. The field study also found that air exchange rates (AERs) in the majority of new homes were below the target of 0.35 h -1 6 and that formaldehyde
7 was substantially above state exposure guidelines in almost all homes. The results of these two 8 studies suggested that new homes were not being adequately ventilated and that relying on 9 occupants and natural ventilation is not an acceptable approach. 10 Starting with the 2008 statewide Title 24 Building Standards, California instituted mechanical 11 ventilation requirements that were a hybrid of the requirements in the 2007 and 2010 versions of the ASHRAE Standard 62.2 for residential ventilation3 12 . The California standard required exhaust 13 fans in the kitchen and every bathroom and general ventilation for the dwelling unit that could be 14 satisfied with a continuous or intermittent system, utilizing exhaust, supply or balanced airflows. 15 A severe slowdown in new home starts in 2008-2010 delayed implementation as most homes 16 built during these years had been approved under the prior building code. The ventilation 17 requirements were not fully incorporated until at least 2010. 18 The Healthy Efficient New Gas Home (HENGH) study, described herein, was performed to 19 evaluate IAQ in California homes built to meet the 2008 building standards for ventilation. The 20 study focused on homes with natural gas because the sponsoring research program is financed by 21 a surcharge on investor-owned, gas utility customers and because gas cooking burners are an important source of air pollutants4, 5 22 . The study included a web-based survey of homes built since 23 2002, a simulation-based study of the energy impacts of ventilation, and the field study described in this paper. A report summarizing results of all three component studies is available6 24 . 25 This paper presents the methods and results of the HENGH field study and compares findings 26 from homes built with mechanical ventilation in 2011-2017 to the CNHS homes built in 2002-

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 5
1 2005 mostly without mechanical ventilation. Homes studied in HENGH also were built with materials that complied with an air toxic control measure (ATCM) for composite wood products7 2 3 that was implemented to reduce formaldehyde emissions. 4 The study goal was to provide empirical evidence of the impacts of ventilation and emission 5 standards in the most populous U.S. state. Findings may inform other states and nations 6 considering standards for residential mechanical ventilation. 7 2. Methods
8 2.1. Field Study Overview
9 Overview of Data Collection in Homes. The study was designed to assess how homes were 10 meeting the mechanical ventilation requirements and how the installed ventilation equipment 11 impacts indoor air quality. The study sought to characterize performance of installed equipment; 12 quantify the use of mechanical ventilation, gas cooking appliances and equipment that can 13 impact IAQ; measure key IAQ parameters over a weeklong monitoring period; and obtain data 14 from building occupants on IAQ and comfort satisfaction and IAQ-relevant activities. A core 15 goal was to evaluate IAQ in homes employing general (dwelling unit) mechanical ventilation but 16 not natural ventilation because the previous studies showed that many California homes do not 17 routinely open windows or doors for natural ventilation during one or more seasons of the year. 18 The study protocol was approved by the LBNL institutional review board. Methods are summarized in ensuing subsections and detailed protocols are available 8 19 . 20 Each study home was visited three times. On the first visit, the field team obtained written 21 consent, confirmed that code-required ventilation equipment was present and operable, and 22 started to record house, appliance, and mechanical equipment characteristics. A utility service 23 technician conducted a safety inspection of the gas appliances. In a few homes, the inspection 24 identified a minor issue that the technician resolved on the spot or during a follow-up visit, and 25 field measurements proceeded. During the second visit, the team completed equipment and

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 6
1 house characterization, conducted ventilation diagnostics, installed air quality measurement 2 equipment indoors and outdoors, and installed devices to track ventilation and gas cooking 3 appliance use. The participant was provided with an activity log for each day of the study and 4 asked to partake in normal household activities with the exception that windows and doors 5 should not be used for routine ventilation. Most homes were monitored for seven days, five were 6 sampled for 8 days and one for 6 days. On the third visit, all IAQ and mechanical equipment 7 monitoring devices were removed, the survey and activity logs were collected and a $350 gift 8 card to a home improvement store was provided to the participant. 9 Eligibility and Recruitment. The study was limited to owner-occupied, detached California 10 houses, built 2011 or later, with gas appliances, mechanical ventilation, and no smoking allowed. 11 Homes had to be customers of SoCalGas or PG&E. Homes with unusual filtration or ventilation 12 systems were excluded. Code compliance records obtained for 23 homes verified they were 13 certified to meet 2008 or more recent standards. The presence of compliant or close to compliant 14 mechanical ventilation equipment was verified in all homes ultimately included in the study. 15 Most participants were recruited through postcards (see SI) mailed to addresses identified on a 16 real estate website (Zillow.com), targeting single-family, detached homes built 2011 or later. 17 Some participants learned of the study via referrals. Details about the number of respondents, 18 early withdraws and non-qualifying homes is provided in the SI. 19 2.2. Field Data Collection Procedures
20 House and Equipment Characterization. The information collected about each home and its 21 mechanical equipment is summarized in the SI.
22 Air Leakage. Air leakage of the building envelope and the forced air heating/cooling system 23 were measured with the DeltaQ test (ASTM-E1554-2013, Method A) using a TEC Minneapolis 24 Blower Door System with DG-700 digital manometer (energyconservatory.com). The test 25 quantifies air leakage of the forced air system to outside of the living space under normal

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 7
1 operating conditions. Testing was conducted with software that automatically operated the 2 blower door fan through pressurization and depressurization, recorded airflow and pressure 3 differences, calculated envelope and duct leakage, and assessed if the measured parameters were 4 stable enough to provide both parameters. Air leakage was converted to air changes per hour at 5 50 Pa indoor-outdoor pressure difference (ACH50) using the estimated home volume. 6 Ventilation Airflows. Airflows of bath and laundry exhaust fans were measured using a TEC 7 Exhaust Fan Flow Meter (energyconservatory.com). Range hood airflows were measured using a balanced-pressure flow hood method described by Walker and Wray9 8 . A TEC Minneapolis Duct 9 Blaster, which is a calibrated, pressure-controlled, variable-speed fan, was connected to either 10 the exhaust inlet (preferred) or outlet. If connected at the inlet, a transition piece was adapted 11 onsite to cover the entire underside of the range hood or over-the-range microwave exhaust fan 12 (OTR). The flow through the Duct Blaster was adjusted to achieve neutral pressure between the 13 surrounding environment and the range hood inlet (or outlet) and airflow was determined from 14 the pre-calibrated fan speed versus airflow relationship. The measurement was repeated for the 15 lowest and highest settings and at least one medium setting if available. OTRs were tested in a 16 modified configuration: the top air inlet was covered with tape and the rate of air flowing into the 17 OTR was measured only at the bottom inlet. Subsequent testing at LBNL revealed that this 18 approach produces a biased measurement of total airflow occurring under the normal operating 19 configuration. Correction factors for most of the OTRs seen in the field were determined by 20 comparing the airflow into the bottom inlet when the top was taped to the total flow measured at 21 the exhaust duct outlet in laboratory experiments. The correction factors were applied to the field 22 measured airflows at each OTR setting.
23 Supply fan flow rates were not measured because the air inlets – usually on roofs or at the eave 24 level – could not be quickly and safely accessed by the field teams. It was also not feasible to 25 measure flows using in-duct velocity probes because the supply ducts were encased in spray 26 foam insulation in the attics. Supply airflows were inferred for two devices based on ratings.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 8
1 Equipment Usage Monitoring. Operation of exhaust fans, range hoods, and clothes dryers were 2 determined using one of the following: motor on/off sensor (Onset HOBO UX90-004), vane 3 anemometer (Digisense WD-20250-22), or plug load logger (Onset HOBO UX120-018). The 4 field team chose an appropriate sensor for each fan configuration. Range hoods or OTRs were 5 monitored with anemometers and the velocity at each setting was determined at installation to 6 enable tracking of airflows for AER calculations. State sensors (Onset HOBO UX90-001) were 7 used to monitor the most often used exterior doors. Although participants were asked to keep 8 doors and windows closed during monitoring, it was deemed valuable to check for any extended 9 natural ventilation that could affect pollutant measurements and patio doors were assessed as 10 most likely to be left open. Cooktop and oven use were monitored using Maxim iButton 11 DS1922T temperature sensors. Burner use was inferred from analysis of the temperature signals. 12 Air Quality Measurements. Air quality parameters were measured outdoors on the premises 13 and at several locations indoors, as summarized in Table 1. The central indoor site was generally 14 in a large open room on the first floor that included the kitchen and/or living room, but monitors 15 were not placed directly in the kitchen. Performance specifications of air quality measurement 16 devices are provided in Table 1 with additional information in Table S1 of the SI. Table S2 17 provides a summary comparison of the methods used to collect air quality data in HENGH and 18 the CNHS. At the HENGH central indoor site, equipment was mounted on a stacked crate 19 system that allowed free airflow. The outdoor monitoring station was mounted on a tripod with 20 air sampling at roughly 2 m height and the station placed at least 3 m from any exterior wall or 21 pollutant source such as a grill. Outdoor formaldehyde and NOX passive samplers were placed 22 inside a 10 cm diameter PVC cap for rain protection. The ES-642 photometer is housed in a 23 weatherproof enclosure that incorporates a sharp-cut cyclone to exclude particles larger than 2.5 24 m aerodynamic diameter and an inlet heater to maintain a minimum relative humidity in the 25 incoming sample stream; it also auto-zeroes each hour. Monitors used to collect time-resolved air 26 quality data were purchased new at the start of the study and thus expected to perform according

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 9
1 to manufacturer specifications. Performance checks during the study are summarized below and 2 additional details are provided in the SI.
3 For the CO2 monitors, an initial visual check was conducted by operating all units together in the 4 warehouse used to prepare equipment for Northern California homes; but no formal calibration 5 was conducted at that time. In most homes, CO2 monitors were collocated during setup and 6 confirmed to read within 100 ppm of each other before deployment. Extech CO2 monitors were 7 checked against a calibrated PP Systems EGM-4 monitor during two collocation events at 8 LBNL, as described in the SI. Averaged over full spike-decay intervals, differences between 9 individual Extech units and the EGM-4 ranged from -20 ppm to 84 ppm. No corrections were 10 made to CO2 data and the possibility of larger deviations in some homes cannot be ruled out. 11 The ES-642 and BT-645 are aerosol photometers that translate light scattering measurements to 12 an estimated PM2.5 concentration based on a device-specific laboratory calibration using a 13 traceable reference of 0.6 m diameter polystyrene latex spheres. Since photometer response 14 varies with aerosol size distribution and optical properties, their accuracy for ambient (outdoor) or indoor PM2.5 can vary substantially as the qualities of the aerosol vary10-14 15 . The recommended 16 practice is to conduct a collocated gravimetric PM2.5 measurement and determine an environment 17 specific adjustment factor. In this study, we sought to check both the calibration factor and the 18 time-response of the Met One photometers by deploying Thermo pDR-1500 photometers with 19 onboard filter sampling indoors and outdoors at 8 homes. Due to power interruptions, valid 20 outdoor co-location data were obtained at only 5 homes and the results were too varied to 21 provide study-wide adjustment factors. To fill this gap, we obtained data from up to three 22 regulatory air quality monitoring stations closest to each house (Figure S1 of the SI) and 23 calculated outdoor PM2.5 for the study period at the house. As a second check on performance, at 24 most homes the indoor and outdoor photometers were operated side by side (typically outdoors) 25 for roughly an hour (Figure S2). Details about quality assurance for the air quality monitors are 26 provided in the SI.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 10
1 The standard software for the formaldehyde FM-801 monitor reports readings below 10 ppb as 2 “<LOD”. By special arrangement, GrayWolf provided modified software to enable us to access 3 device readings below this nominal detection limit, which we used in 25 homes. Prior research 4 indicates that the device may provide quantitative if more uncertain measurements below 10 ppb15. Some FM-801 formaldehyde was removed because of interference by high NO2 16 5 from
6 gas cooking burner use. Details about both adjustments are provided in the SI. 7 Duplicates and field blanks were collected to evaluate reliability for the passive samplers, and all 8 available duplicate samples were averaged to improve precision. Four Ogawa samplers prepared 9 according to manufacturer protocols were deployed at each home to measure NO2 and NOX: one 10 outdoors, two at the central indoor station (duplicates), and one field blank. The field blank was 11 opened either at the indoor or outdoor station, then packaged and stored in a refrigerator for the 12 monitoring week. At least four UMEx 100 formaldehyde samplers were deployed at each home:
13 one outdoors, two in the central indoor station (duplicates) and one in the bedroom. In most of 14 the sampled homes, a fifth sampler was opened indoors as a field blank, then immediately 15 packed and stored in a refrigerator during the monitoring week. The procedures used to analyze 16 passive samplers are summarized in the SI. The sampling rates for NO2 and NOX samples were 17 calculated based on measured average temperature and humidity according to Ogawa protocols. 18 For UMEx samplers we used the sampling rate of 20.4 mL/min recommended by the 19 manufacturer for air velocities <300 cm/min and 1 to 7 days of sampling. Offermann and 20 Hodgson have shown that sampling rates for the UMEx and other passive monitors start to drop sharply when air velocity falls below about 75 cm/min17 21 . Presenting measurements from six occupied houses and one unoccupied research house, Matthews et al.18 22 reported that such low air 23 velocities were infrequent. Since we did not measure velocities around the passive samplers and 24 did not verify measured concentrations with pumped samples, it is possible that sampling rates 25 could have been lower than the assumed standard values at some times in some homes.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 11
1 Survey and Activity Log. Participants were asked to complete a survey about the household 2 occupants and their general activities that impact ventilation and IAQ and also to complete an 3 activity log for each day of monitoring. The survey was a condensed version of the online survey 4 used to collect data about California detached homes built since 2002. Recruitment for the online 5 survey was conducted primarily through emails sent by SoCalGas to customers who lived in 6 homes that use natural gas and were thought to meet the requirement of being constructed in 7 2002 or later. A summary of findings from the survey is provided in the HENGH final project report6 8 . The abridged survey tool used for the field study and the daily activity log are included 9 in the SI to this paper.
10 Calculated Outdoor Air Exchange Rate (AER). The rate of outdoor air exchange – including 11 both mechanical ventilation and air infiltration – was calculated minute-by-minute in each home 12 following the Enhanced Model described in the 2017 ASHRAE Handbook– Fundamentals, as 13 summarized in the SI. The calculation assumed that windows and doors were closed throughout 14 the monitoring week (as required), so natural ventilation was negligible. The AER over the full 15 monitoring period in each home was calculated as the harmonic mean of the minute-by-minute estimates. Measured AERs in CNHS houses2 16 that did not have mechanical ventilation and did 17 not open windows were analyzed to assess the accuracy of the infiltration portion of the AER 18 calculation, as described in the SI.
19 3. Results and Discussion
20 3.1. Locations and Seasons of Home Visits
21 The field study collected data from 48 homes in the San Francisco Bay Area and Central Valley 22 regions and 22 homes in Southern California, as shown in Figure 1. The breakdown by gas utility 23 service territory, California climate zone, and city is provided in Table S3. Sampling occurred 24 throughout the year, with slightly more homes visited in the months corresponding to summer 25 seasonal conditions (June–September, n=27 homes) than each of the other seasons, in which 13

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 12
1 to 16 homes were studied (Table S4). None of the homes were within 300 m of a freeway, 2 highway, or high-volume arterial road.
3 3.2. House and Household Characteristics
4 Characteristics of HENGH homes with selected comparisons to the CNHS and California data 5 from the 2017 American Housing Study (AHS) are reported in SI Tables S5–S15 and Table 2. 6 HENGH and CNHS samples had similar distributions of home size and occupant density; but 7 HENGH homes were newer when tested and more commonly had gas cooking appliances (Table 8 2). HENGH included one 2.5-story, 42 two-story, and 27 one-story houses (Table S8) and all but 9 one had an attached garage. HENGH homes mostly had three (n=20), four (n=28) or five (n=17) 10 bedrooms and almost all had multiple bathrooms (Tables S9–S10). Thirty-two HENGH homes 11 had vented gas fireplaces (Table S11).
12 HENGH households were similar in size to the AHS, with slightly more having 1-2 occupants 13 (46% vs. 41%), fewer with 3-4 occupants (34% vs. 42%) and similar 5+ occupants (17% vs. 14 15%) (Table S12). HENGH households had similar age demographics as the AHS, with 40% of 15 each having at least one resident under age 18 and 26-28% with at least one resident aged 65 or 16 older (Table S13). Relative to the AHS, the HENGH sample was skewed in terms of income and 17 education. In HENGH, 88% of the 66 participants who provided the information had a household 18 income of $100,000 or greater; in the AHS sample, only 60% reported such income (Table S14). 19 Of the 67 HENGH heads of household that reported education level, 88% had a college degree 20 and 54% had a graduate or professional degree; in the AHS, 56% had someone with a college 21 degree and 26% had someone with a graduate or professional degree (Table S15). 22 With the important caveat that the CNHS asked about medically diagnosed conditions and 23 HENGH asked simply about the conditions, HENGH households more commonly reported 24 someone with allergies (56% vs. 36%) or asthma (26% vs. 16%); CNHS also reported chemical 25 sensitivity in 3.7% of homes (HENGH survey did not ask about this condition).

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 13
1 3.3. Envelope Air Tightness
2 The distribution of measured envelope air tightness, expressed as the air changes per hour at a 50 3 Pascal indoor-outdoor pressure difference (ACH50), are shown in Figure S3. The mean, median, and 10th–90th 4 range of envelope air tightness from depressurization tests were 4.6, 4.4, and 3.4– 5 6.0 ACH50. Measured air leakage under pressurization was higher than depressurization by 20% 6 on average due to “valving” of some air leakage pathways, e.g., from exhaust fan backdraft 7 dampers being pushed open during pressurization. Only four homes had envelope leakage less 8 than 3 ACH50, the level required for compliance with the 2018 International Energy 9 Conservation Code. Overall, HENGH homes had air leakage values similar to California homes 10 built in the early 2000s, as reported in the online residential diagnostics database (resdb.lbl.gov)19 11 and in the CNHS, which had a mean ACH50 of 4.8. 12 3.4. Ventilation and Filtration Equipment
13 All 70 HENGH homes had ventilation equipment that was mostly or completely compliant with 14 the statewide standards. As summarized in Table S16, dwelling unit ventilation was provided by 15 an exhaust system in 64 homes and by a supply system in 6 homes. Fifty-five of the exhaust 16 systems used a continuous fan and 43 of those exhausted air from the laundry room; the others 17 exhausted from a bathroom. Three of the exhaust systems had remote fans located in the attic 18 and the others were upgraded laundry or bath exhaust fans. All supply systems were integrated 19 into the central forced air heating and cooling system; four had inline fans and two relied on the 20 central system fan operating on a timer to pull in outdoor air through a duct connecting the return 21 to the outdoors. In all but two of the homes with measured airflow, the flow exceeded the code minimum requirement. The mean minimum requirement was 107 m3 h -1 22 and the mean installed
flow was 163 m3 h
-1 23 , about 50% higher. In many homes, the “extra” airflow could be explained 24 by use of a common fan size set to maximum capacity, i.e., not adjusted down to meet minimum 25 requirements. Very importantly, the general ventilation equipment was running in only 26% of 26 homes (18/70) when the field researcher(s) arrived for the initial visit. Systems with easily

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 14
1 understandable signage at the power switch for the system were much more likely to be 2 operating (see Table S17).
3 All of the homes had exhaust fans in the kitchen and in each bathroom, as required by the 4 standards. Kitchen ventilation was provided by a range hood in 32 homes and an over the range 5 (OTR) microwave in 38 homes. Twenty-two (69%) of the range hoods moved the required 50 L s
-1 6 or 100 cfm on the lowest speed setting, seven met the standard on a medium setting, and three 7 did so only at the highest setting. Of the 38 OTRs for which airflows were measured in homes, 8 method correction factors were obtained and applied to 22 devices. For this group, the estimated 9 airflow met the code requirement for 8 installed units (36%) on the lowest setting, 14 (64%) on a 10 medium or higher setting, and 20 (91%) on high or boost setting. The setting needed to produce 11 the required airflow is important because the code also requires that the fan operate at a sound 12 level of 3 sone or less, with the rationale that kitchen exhaust may not be used as needed if it is too loud. Over 85% of the full bathrooms had exhaust fans that met the requirement of 25 L s -1 13
14 or 50 cfm, as shown in Figure S4. Exhaust fans in the toilet room or shower of the master 15 bathroom suite are not required to meet the airflow standard if the main exhaust fan in the bathroom suite does so. These fans had lower measured airflows and only 60% met the 25 L s-1 16 benchmark. The median exhaust flows were 41, 37 and 31 L s -1 17 (87, 78 and 65 cfm) for master
18 bath, other bathroom and toilet/shower compartments. 19 Of the 69 homes with a forced air thermal conditioning system, 22 had only one filter, 34 had 20 two filters, 10 had three filters and 3 had four or more filters (with one filter per return duct). As 21 shown in Table S18, 96% (107/111) of the filters for which a performance rating could be 22 determined were MERV8 or better and 30% (33/111) were MERV11 or better. In the CNHS, 23 filter ratings were determined in 97 of the 108 homes: 49% (48) had MERV8 or better and 32% 24 (31) had MERV11 or better. In HENGH homes, we were able to determine the last date of 25 change for 85 filters: 58% (49) had been changed within the last 6 months, 22% (19) had not 26 been changed in the past year and 11 of those had never been changed (Table S19). Table S20

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 15
1 shows that 20 homes had filters that were clean or like new, 29 homes had filters that appeared 2 used or somewhat loaded, and 18 homes had at least one very dirty filter. There were a few 3 homes in which, at the owner’s request, the research team replaced (n=2) or installed (n=1) air 4 filters in the forced air systems during the first or second field visit, prior to monitoring. 5 3.5. Ventilation During the Week of Monitoring
6 Field teams set dwelling unit mechanical ventilation systems to operate during the monitoring 7 period in each home. The two homes with supply ventilation powered by their central thermal 8 conditioning system fans were ventilated during the study by running their laundry exhaust fans 9 continuously. The average air exchange rate (AER) resulting from infiltration and mechanical 10 equipment operating during the monitoring week was estimated for 63 homes, with results 11 provided in Figure S5. AER was not estimated for four homes with supply ventilation fans 12 because the system airflow could not be measured and for three homes that did not have a valid 13 envelope air leakage measurement, which is needed to calculate infiltration. Five homes that had 14 their dwelling unit exhaust fans stopped (presumably turned off by occupants) during the week had low calculated AERs: 0.07–0.15 h
-1 15 . A sixth home, which had an intermittent exhaust fan 16 that was not programmed to provide sufficient ventilation (by error of the field team), also had a low AER, of 0.06 h
-1 17 . For the 57 homes that had measured airtightness and mechanical 18 ventilation system airflows and their systems operated throughout the week of monitoring, the mean, median and 10th–90th 19 percentiles of the estimated infiltration + mechanical AERs were

0.33, 0.30, and 0.20–0.46 h
-1 20 . Mechanical ventilation provided substantially higher outdoor air 21 exchange rates than would have occurred by infiltration only, as shown in Figure S6. 22 The AERs estimated for HENGH homes operating with code-compliant systems and windows 23 presumed closed were marginally higher than in the CNHS (before ventilation was required), which reported sample median AERs of 0.26 h
-1 24 for 107 homes measured during a single
monitoring day and 0.24 h
-1 25 for 21 homes measured over a 2-week period that included window 26 use. Twenty-two CNHS homes had mechanical equipment to provide dwelling unit ventilation;

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 16
1 these included 8 with heat recovery ventilators (HRV) and 14 with ducts connecting the forced 2 air heating/cooling system return duct to the outdoors. Of the 14 with outdoor air ducts, only 4 3 had controllers to operate the FAU for mechanical ventilation when no heating or cooling was 4 needed. During the day of CNHS monitoring, all of the HRVs but only 34% of the outdoor5 connected FAU systems met the ASHRAE 62.2-2004 standard applicable at the time. 6 In several of the HENGH study homes, the actual outdoor air exchange over the week was likely 7 higher than the calculated values owing to use of natural ventilation. In six homes, the occupants 8 reported opening the house-to-patio and/or garage door(s) for more than 3 h per day on average. 9 The calculated AERs also could be roughly 20% higher based on the potential bias in infiltration 10 calculation indicated by the analysis of CNHS data from homes without mechanical ventilation. 11 3.6. Sources of Air Pollutants Reported in the General Survey 12 Almost all HENGH homes reported being completely smoke free; one reported that smoking 13 occurred a few times per year and one acknowledged informally that a family member smoked 14 daily in a bedroom, with the window open. Occasional candle burning was fairly common, with 15 16 HENGH participants reporting candle use a few times per month, 11 using a few times per 16 week, and 5 every day (Table S21). Thirty-four households had at least one furry pet and twelve 17 reported two or more; 20 reported no pets and 16 did not respond to the pet question (Table S22). 18 3.7. Occupancy and Activities During the Week of Monitoring 19 Data from the HENGH daily activity logs are provided for occupancy (Tables S23–S24) and 20 cooking (Tables S25–S27). Most of the homes had one to three occupants at home at any given 21 time when occupied and 88% of those reporting were occupied during time intervals totaling 16 22 or more hours per day on average. Thirty-four of 68 homes with daily log data reported using the 23 cooktop at least 7–14 times per week; oven use was less common. Cooktop use events were <30 24 min on average in most homes. Oven use was typically longer. Cooking and other activities 25 reported in the CNHS homes are provided in Table S28.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 17
1 3.8. Air Pollutant Concentrations: Formaldehyde
2 Multiple measurements of formaldehyde in each HENGH home indicated very good sampling 3 precision and mostly similar concentrations in the master bedroom and central indoor sampling 4 location. The average mass on field blanks corresponded to 0.6 ppb for a 7-day collection period 5 and the 66 paired indoor samples agreed to within 1.0 ppb on average (median = 0.7 ppb). 6 Sample-period averaged concentrations calculated from half-hourly resolved GrayWolf (Shinyei) 7 multimode monitor data agreed well with the time-integrated sampler results as summarized in 8 Table S29 of the SI. Figure 2 presents the formaldehyde concentrations measured in the master 9 bedrooms and central indoor locations of each home by UMEx passive sampler. Among the 66 10 homes with valid samples in both locations, formaldehyde in the bedroom was >10% higher than in the living room in 20 homes and less than 90% in 7 homes. The median and 10th–90th 11 ratios of 12 bedroom to living room concentrations were 1.02 and 0.90–1.27. Period-averaged formaldehyde 13 determined by the multimode monitor indicated a similar trend of the master bedroom having 14 higher concentrations than the central area more frequently than the opposite. And the overnight 15 concentration in the bedroom was even higher than the period-average at that location. (See SI 16 for details). These findings suggest that for many people exposure to formaldehyde at home may 17 be higher than indicated by average concentrations at a central indoor site. 18 Figure 3 shows that homes built in 2011–2017 and mostly operating with mechanical ventilation 19 (HENGH) had formaldehyde concentrations substantially lower than those built in 2002-2005 20 and mostly not using mechanical ventilation (CNHS). Mean and median formaldehyde levels in 21 HENGH homes were 44% and 38% lower than in CNHS (Table 3). Differences between the 22 HENGH and CNHS indoor formaldehyde concentrations were found to be significant based on a 23 two-tailed Student’s t-test with equal variance comparing log-transformed concentrations (p24 value = 3.4e-8) and the nonparametric Mann-Whitney test (p-value = 1.5e-7). The highest 25 formaldehyde measured in any home in the current study was 44 ppb while 28% of the CNHS 26 homes had a formaldehyde concentration over 44 ppb. Indoor emissions were the primary source

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 18
1 in both studies; but based on median indoor and outdoor values, the fraction contributed by 2 outdoor air increased from 6% in the mid-2000s to 15% more recently. 3 Formaldehyde levels in HENGH homes were all well below the World Health Organization 4 (WHO) indoor air guideline of 80 ppb and also below non-U.S. national guideline levels as summarized by Salthammer 20. However, all homes were still above the 7 ppb (9 g/m3 5 ) Chronic 6 Reference Exposure Level set by the California Office of Environmental Health Hazard 7 Assessment, which is the applicable target in California. 8 The substantial reduction in formaldehyde compared to the CNHS a decade earlier appears to 9 result both from fewer homes being severely under-ventilated and from lower emissions. For 32 CNHS homes with measured air exchange rates below 0.2 h-1 10 , mean and median formaldehyde 11 concentrations were 57 and 45 ppb. By contrast, in the HENGH dataset, only eight of the 63 homes for which overall AER was estimated had outdoor AERs below 0.2 h-1 12 ; and the mean and 13 median formaldehyde concentrations for these homes were 25 and 23 ppb. 14 Formaldehyde emission rates were calculated for 61 HENGH homes using the measured 15 concentrations and estimated AERs. The median and mean emission rates were 5.8 and 6.1 g/m3-h compared to median and mean values of 11 and 13 g/m3 16 -h calculated from 99 homes 17 with the required component data in CNHS (Table 45 of Offermann et al., 2009). CNHS homes had more varied formaldehyde emission rates, with a 10th to 90th 18 percentile range of 4.0 to 23 g/m3-h whereas the range for HENGH homes was 2.8 to 8.3 g/m3 19 -h. For this comparison, it is 20 important to note that the CNHS measured AERs with a PFT tracer gas whereas the HENGH 21 AERs were estimated by combining the measured mechanical ventilation airflows and calculated 22 air infiltration assuming no contributions from open windows or door. To the extent that actual 23 AERs in HENGH homes were higher than calculated – e.g. from a possible ~20% bias in the 24 calculated air exchange rates as discussed in the SI, or from use of windows and doors – the 25 formaldehyde emission rates in HENGH homes would have been higher than stated above.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 19
1 3.9. Air Pollutant Concentrations: Fine Particulate Matter (PM2.5) 2 Time-resolved PM2.5 concentrations reported by indoor photometers were adjusted based on 3 comparison to gravimetric analysis of filter samples collected in 8 homes (Table S30). Indoor 4 photometer measurements were adjusted by a multiplier of 1.23 for the BT-645, and 0.90 for the 5 pDR-1500. Aside from the gravimetric adjustment, pDR-1500 also measured time-resolved 6 PM2.5 for comparison with BT-645. Hourly indoor readings from the 8 homes collected by the two photometers were highly correlated (R
2 7 = 0.96-0.99) and, after applying the respective
multipliers, agreed to within 1 g/m3for 84% of the hourly readings, and 2 g/m3 8 for 96% of 9 the hourly readings.
10 Distributions of indoor PM2.5 in HENGH and CNHS are shown in Figure 4. Mean and median 11 indoor PM2.5 concentrations in HENGH were 44% and 54% lower than in CNHS homes (Table 12 3). Even with uncertainty in the photometer adjustment factors, these data indicate substantially 13 lower indoor PM2.5 in the more recently constructed homes. The difference in log-transformed 14 indoor PM2.5 concentrations measured by the two studies are statistically significant using 15 Student’s t-test (p-value = 2e-6) and nonparametric Mann-Whitney test (p-value = 2e-5).

Since outdoor air is a major source of PM2.5 inside U.S. homes21-25 16 , it is important to consider if 17 the observed difference could be entirely attributed to lower PM2.5 outdoors during HENGH. The 18 CNHS reported 11 samples of outdoor PM2.5; based on the clustering sampling approach used in 19 that study, those measurements represent 28 homes. For the HENGH study, the 5 weeks of 20 collocated outdoor photometer and gravimetric samples had such varied ratios (see Table S30 of 21 SI) that they could not be used to adjust all of the outdoor photometer data. Data from regulatory 22 ambient air monitoring stations nearby to HENGH homes provide a second set of estimates of 23 areawide outdoor PM2.5 during the study. Table S31 and Figure S7 of the SI show that outdoor 24 PM2.5 estimates from the air monitoring stations are higher than those from unadjusted outdoor 25 photometer data. This is directionally consistent with outdoor photometer reading lower than the 26 indoor photometer in side-by-side monitoring and suggests that the outdoor photometer may be

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 20
1 understating the outdoor PM2.5. Summary statistics of outdoor PM2.5 from both data sets applied 2 for the HENGH study are compared to CNHS data in Table 3. While limitations of both data sets 3 make the comparison uncertain, the results in Table 3 do not indicate substantially lower PM2.5 4 outside of HENGH versus CNHS homes. The lower PM2.5 inside HENGH homes can therefore 5 not be attributed to lower outdoor PM2.5.
6 The lower indoor PM2.5 in HENGH homes could result from reduced penetration of particles 7 during air infiltration, lower indoor emissions (from cooking, candles, cleaning, etc.), more 8 effective kitchen ventilation, and/or improved filtration. Reduced particle entry during air 9 infiltration is not likely a major factor as the envelope air tightness was very similar in the two 10 samples and the higher median outdoor air exchange rates in the HENGH study would tend to 11 slightly increase indoor concentrations of outdoor particles as higher AERs bring in outdoor air 12 more quickly and leave less time for particles to deposit onto indoor surfaces. 13 Assessing the impact of filtration overall requires consideration of filter quality, airflow and 14 operating cycles of the central forced air system, and use of portable air filtration units. While the 15 full analysis is beyond the scope of this paper, it was reported above that HENGH homes more 16 commonly had at least a medium performance (MERV8) filter compared to CNHS homes. There 17 also may have been more portable air cleaner use in HENGH homes. Of the 64 HENGH 18 participants who answered the question, 14 (22%) reported using a standalone air cleaner. Air 19 cleaner use was self-reported in 17% of CNHS homes and 15% of respondents to the statewide survey in 2002-4
1 20 .
21 While it is difficult to compare the impact of all particle emitting activities – since emissions 22 vary so widely even for a defined activity – we can at least compare the frequency of cooking 23 and range hood use. In the CNHS study, during the day of IAQ monitoring, 87 homes (81%) 24 reported at least one use of the cooktop or oven and 81 (75%) reported at least one cooking event 25 involving frying, sautéing, baking or broiling. Despite this relatively high frequency of cooking 26 that can emit substantial quantities of PM2.5, only 22% of the CNHS occupant activity logs

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 21
1 reported any range hood use during the day of IAQ measurements and 44% reported some range 2 hood use during the prior week. Over the roughly one-week monitoring in HENGH homes, 34 of 3 the 68 submitted activity logs (50%) reported cooking with the cooktop or oven at least 7 or 4 more times during the week, i.e. once per day on average. The HENGH activity log did not ask 5 about the type of cooking. In the general survey responses, 50% of HENGH participants reported 6 using their range hood “most of the time” (4 of 5 times) or more and another 23% reported using 7 the range hood “sometimes” (2–3 out of 5 times). Initial analysis of cooktop temperature and 8 range hood/OTR use data indicate that kitchen ventilation was employed in some capacity during 9 roughly 29% of cooktop uses and 22% of oven uses and actual use during the monitored week 10 was much less than usage reported by survey. The range hood was operated for most or all of the 11 duration of cooktop use during 8% of cooktop use events and 3% of oven use events. 12 3.10. Air Pollutant Concentrations: Nitrogen Dioxide and Nitric Oxide 13 Distributions of NO2 concentrations inside HENGH and CNHS homes are presented in Figure 5 14 and summary statistics are provided in Table 3. The distributions were not significantly different 15 based on the nonparametric Mann-Whitney test (p-value = 0.08) and the means of the log16 transformed data were not statistically different using the Student’s t-test (p-value = 0.15). This 17 occurred despite all HENGH homes having natural gas cooktops (compared to just 2% of CNHS 18 homes) and outdoor NO2 being higher in HENGH. The higher median indoor NO2 in HENGH 19 may be misleading as the CNHS median was in the group of data set as half of the quantitation 20 limit and the outdoor median for CNHS was lower (though uncertain for the sample as NO2 was 21 sampled outside of only a subset of homes). Differences in NO2 between HENGH and CNHS 22 homes were much smaller than those reported for homes with gas versus electric cooking in a recent study of mostly older and smaller California homes 5 23 . The highest weekly averaged NO2 24 measured in a HENGH home was below the California annual average standard of 30 ppb and 25 less than half of the U.S. annual air quality standard of 53 ppb. Figure S8 shows that for NO, 26 indoor concentrations were almost always higher than outdoors, as indoor emissions added to the

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 22
1 NO coming from outdoors. For NO2, deposition indoors resulted in indoor concentrations being 2 lower than outdoors in many homes.
3 3.11. Air Pollutant Concentrations: Carbon Dioxide as Indicator of Adequate Ventilation 4 Overall, time-averaged CO2 levels measured in HENGH and CNHS homes were similar, as presented in Table 3. The one substantive difference – at the 90th 5 percentile – aligns with 6 mechanical ventilation systems in HENGH homes more consistently providing outdoor air to 7 dilute occupant emissions of CO2.
8 Within HENGH homes, CO2 concentrations varied spatially (Figure 6). The highest time9 averaged concentrations were in the master bedroom and concentrations in other bedrooms were 10 higher than in the main indoor living space.
11 CO2 concentrations also varied in time, with the highest concentrations occurring overnight in 12 bedrooms. Figure 7 shows the distributions of average CO2 concentrations in each room, looking 13 only at data from midnight to 5 am, and SI Figure S9 presents overnight CO2 concentrations 14 measured in the main indoor location and master bedrooms of the same houses. These results 15 indicate that CO2 in HENGH bedrooms did not reach the levels that have been reported to affect sleep or next day alertness26, 27 16 .
17 3.12. Satisfaction and Discomfort with Indoor Environmental Conditions 18 Sixty-eight of the 70 HENGH study participants provided responses to survey questions about 19 their satisfaction with environmental conditions in the home. Responding to the question “To 20 what extent are you satisfied or dissatisfied with the indoor air quality in your home?”, 68% 21 (n=46) selected one of four levels indicating positive satisfaction, 24% (n=16) selected neutral, 22 and 9% (n=6) marked one of four levels indicating dissatisfaction. These results are very similar 23 to those obtained from 2765 respondents to the online survey of people living in California 24 homes built before ventilation standards were in place. That survey, conducted in 2014, was 25 open to occupants of California homes built since 2002; yet almost all respondents lived in

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 23
homes built before 2011 and located in the SoCalGas service territory of Southern California6 1 . In 2 the online survey, 69% indicated positive satisfaction, 21% were neutral, and 10% indicated 3 dissatisfaction with their IAQ. Among 68 field study respondents, 51% were satisfied with the 4 air quality outside of their homes, 17% were neutral and 32% were dissatisfied. These totals are 5 also similar to the online survey, for which 47% were satisfied, 27% were neutral and 26% were 6 dissatisfied with their outdoor air. When asked “How would rate you rate your home in 7 protecting you from outdoor air pollution?” 62% of responding field study participants were 8 satisfied, 31% were neutral and 7% were dissatisfied. The CNHS did not report results for IAQ 9 satisfaction and the survey reported by Piazza asked about “acceptability” of indoor air quality, 10 rather than “satisfaction”, which is not directly translatable. 11 The survey of HENGH participants – both field study and online – also asked about the 12 frequency of specific environmental discomforts, offering options of “never”, “few times a 13 year”, “few times a month”, “few times a week”, and “every day”. The CNHS study asked 14 participants if they experienced discomfort during the preceding week. Table 4 shows that 15 specific discomfort conditions were generally similar in the two studies, with the exception that 16 21% of HENGH participants reported not enough air movement compared to 12% of CNHS 17 participants experiencing the air as “too stagnant” in the week prior. The robustness of that 18 difference is unclear as 18% of the survey respondents from homes built around the same time as 19 those in the CNHS also expressed frequent dissatisfaction with air movement. 20 Survey responses from the field study were analyzed to evaluate if environmental satisfaction 21 differed in homes that had MV systems operating or not operating when the research team first 22 arrived to study homes. Results provided in Tables S32 to S34 indicate no statistically significant 23 associations with satisfaction for air quality, seasonal temperature, or other environmental 24 conditions (air movement, dryness or dampness, musty odors).

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 24
1 3.13. Comparison to Other Studies of Ventilation and IAQ in Recent Construction Homes 2 There have been few large field studies examining the impact of mechanical ventilation on IAQ 3 in recently constructed homes. The study that most directly addressed this topic examined 62 4 homes built in 2010-2012 to an Austrian efficiency standard that included general mechanical 5 ventilation with heat recovery (MVHR) and 61 homes constructed during the same years using normal building standards without mechanical ventilation28 6 . The study measured IAQ parameters 7 roughly 3 months and 1 year after occupancy and used interviews to collect data about health symptoms and perceptions of IAQ and comfort29 8 . The efficient homes with MVHR had lower 9 concentrations of total volatile organic compounds (TVOC), formaldehyde, saturated acyclic aliphatic aldehydes, CO2, and radon28 10 . While there were not significant differences in self11 reported overall health status or for most symptoms, occupants of the efficient, ventilated homes 12 rated their environmental quality higher by more frequently noting positive attributes (pleasant, 13 clean, fresh and fragrant) and less frequently perceiving negative attributes (stale, stuffy, stagnant, bad smelling or smoky)29 14 .

The effects of improving ventilation in existing airtight homes was reported by Lajoie et al.30 15 in a 16 study that added mechanical ventilation with heat or enthalpy recovery to 43 of 83 Quebec area 17 homes of asthmatic children that were verified to be under-ventilated. IAQ parameters and the 18 children’s respiratory health were monitored over two years. The homes with added mechanical 19 ventilation had several statistically significant and substantial (>25%) improvements including 20 higher outdoor air exchange and lower CO2, formaldehyde, styrene, limonene and mold spores; 21 but also had higher indoor NO2 and di(2-ethylhexyl) phthalate. 22 Several studies have reported on the installed performance of mechanical ventilation systems in 23 modern homes. A study of mechanical ventilation systems in 299 Dutch homes completed in 24 2006-2009 conducted visual inspections, measured ventilation rates per room and equipment noise, and asked occupants their perceptions of their indoor air quality31 25 . Issues identified in 26 many homes included ventilation rates below and noise levels above building code requirements,

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 25
1 blocked supply vents, and absence of required controls. Problems occurred during installations, maintenance and operations. A study in Belgium32 2 conducted mechanical ventilation system 3 diagnostics and measured carbon dioxide, temperature and humidity levels in 39 standard 4 construction homes built in 2007-2008 with wet room exhaust ventilation and trickle vent 5 supplies (and mean air leakage of 3 ACH50), 23 similarly tight (2 ACH50) low-energy homes 6 with MVHR, and 16 passive houses (0.5 ACH50) with MVHR. Installed equipment in many of 7 the homes did not achieve the required airflows at any setting and occupants generally operated 8 the systems at lower settings, leading to large differences between actual and design airflows. 9 Humidity and CO2 measurements showed some differences between groups of homes but none 10 indicated substantial problems. In a study of 29 homes in the U.S. state of Washington, which 11 has required mechanical ventilation for many years, researchers reported that most had systems that were set, or that could be set to comply with the standard33 12 . In many of the homes the MV 13 systems were not operating according to design standards when researchers first arrived. A study of mechanical ventilation systems installed in 21 homes in the U.S. state of Florida34 14 , which did 15 not require such systems at the time, found that only 12 were capable of operating and actual 16 airflows generally were well below design targets. These two U.S. studies reported problems 17 with installation (disconnected duct, blocked vent, poorly hung ducts, inoperable outdoor air 18 exhaust duct damper, ERV/HRV system installed backward) and operations and maintenance 19 (fan turned off, dirty filters, controller set to inadequate runtime fraction). 20 Among the air pollutants measured in HENGH, the most direct comparisons to prior U.S. studies 21 can be made for formaldehyde. HENGH homes had substantially lower formaldehyde than a 22 sample of homes constructed in the late 2000s with low-VOC flooring and paints along with mechanical ventilation; those homes had mean formaldehyde of 27 ppb (33 g m-3 23 ) at adjusted conditions of 23ºC, 43% RH, and 2.25 years old35 24 . In a study in the U.S. state of Arizona, 25 apartments that were renovated in 2011 with low-VOC materials and mechanical ventilation had 26 reported mean(SD) and median formaldehyde levels of 27(7) ppb and 26 ppb roughly 1 year

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 26
after renovations36 1 . These levels represented a decrease from pre-retrofit formaldehyde of 39(11) 2 ppb and 38 ppb (ibid). The higher concentrations measured in these studies relative to HENGH 3 could result from sampling occurring only during daytime hours in the summer season, a time at 4 which emissions are expected to be higher than concentrations measured over full diurnal cycles and varied seasons37 5 . The lower concentrations in HENGH homes could also result in part from 6 lower emissions resulting from the California air toxic control measure. 7 3.14. Limitations
8 The samples of homes included in the HENGH and CNHS studies may not accurately represent 9 the population of recently constructed homes in the state now or in the mid-2000s. Relative to 10 the general population of new home owners, HENGH households were biased toward higher 11 income and higher education and potentially also toward higher interest in IAQ (since they 12 volunteered to participate in the study). The impact of these biases is not known. 13 Even within the homes studied, the air quality measured in both HENGH and CNHS may not 14 accurately reflect average conditions. In the HENGH study, IAQ was measured while homes 15 were operated without natural ventilation (i.e., with occupants agreeing to keep windows and 16 doors closed) and with mechanical ventilation systems set to operate. This mode likely does not 17 represent conditions in newer California homes throughout the year, especially since we found 18 that general ventilation systems were not operating in 74% of the homes studied. This was not an 19 issue for CNHS because occupants were asked to use natural ventilation as normal. For both 20 studies, the act of participating could have changed occupant activities that impact indoor air 21 quality. Since CNHS sampling occurred over a single 24 h period, occupant routines may have 22 been impacted by modified schedules to accommodate sampling equipment installation, removal 23 and diagnostics on subsequent days. The processes of completing surveys and activity logs and 24 having monitoring equipment in the homes could have impacted behaviors in both studies. 25 Between study differences in recruitment, sample design and measurement methods also may 26 have impacted the relative results in HENGH and CNHS.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 27
1 For the HENGH study, ventilation rates were not directly measured as they were in the CNHS. 2 The ventilation estimated by combining calculated infiltration rates and measured mechanical 3 airflows in the HENGH study would be biased low in any homes with sustained opening of 4 doors and/or windows for natural ventilation.
5 4. Conclusions
6 Measurements were conducted in 70 single-family, detached homes constructed in 2011–2017 7 under California building standards that require mechanical ventilation and a separate regulation 8 that limits formaldehyde emissions from composite wood products. All homes had mechanical 9 ventilation equipment that was mostly or completely compliant with the requirements. With the 10 general mechanical systems operating and most homes not using any natural ventilation, indoor 11 air pollutant levels were generally lower than those measured in a prior study of otherwise 12 similar California homes built before the ventilation and material emission standards took effect. 13 The recently constructed homes had somewhat lower PM2.5, much lower formaldehyde, and 14 slightly higher NO2 despite having gas cooking burners whereas homes in the prior study had 15 electric cooking. IAQ satisfaction was also similar in the newer homes as compared to homes 16 built in years prior. These results indicate the success of standards that limit formaldehyde 17 emissions and require ventilation systems to maintain acceptable IAQ. 18

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 28
Table 1. Measured Air Quality Parameters1 1
Measurement
Device
ParametersAccuracy1 Res. Sampling
Locations
Met One ES-642
Photometer
PM2.5 ± 5% traceable standard with

0.6 um PSL
1-min Outdoor
Met One BT-645
Photometer
1-min Indoor: central
Extech SD-800
Infrared
CO2,
T,
RH
±40 ppm <1000; ±5%
>1000ppm; 2
±0.8°C
±4% below 70%; 4% of reading
+ 1% for 70–90% range
1-min Indoor: central,
master BR, other BR
Ogawa Passive
Samplers
NO2 and
NOX
Field validation3: 7 d rel. dev.:
3±2% NO2 at 11-37 ppb; 4±3%
NOX at 16-85 ppb; 10±9%
(NOX-NO2) at 4-56 ppb
1-week Outdoor;
Indoor: central
Aeroqual 500 Series
Electrochemical
NO2 ± 0.02 ppm within 0 to 0.2 ppm
range
1-min Indoor: central
GrayWolf FM-801
(Shinyei Multimode)
HCHO ± 4 ppb <40 ppb,
± 10% of reading ≥40 ppb
30-min Indoor: central,
master BR
SKC UMEx-100
Passive
HCHO ± 25%, exceeds OSHA
requirements
1-week Outdoor; Indoor:
central, master BR
Onset HOBO
UX100-011
Onset HOBO U23
Pro v2
T, RH ±0.21°C from 0° to 50°C
±2.5% from 10% to 90%; up to
±3.5% at 25°C including
hysteresis
1-min Indoor: central
(UX100-011);
Outdoor (U23);
1 2 Based on manufacturer specifications unless noted otherwise. Table S1 in Supporting Information provides some additional information. 3
2 Manufacturer indicates ± 40 ppm for CO2<1000 ppm; the cited value of ±50 ppm reflects our group’s experience (unpublished) with the monitors. 3 Field validation in California reported by Singer et al.38 4

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 29
Table 2. Selected House and Occupancy Characteristics1 1 Parameter HENGH CNHS
Year Built2 2011-2017 2002-2005
Monitoring 07/2016–04/2018 08/2006–03/2007
Age at Testing3
91% 3 years 90% 4.3 years
Floor Area (m2)
4 Mean
Median (10th–90th)
244
243 (146–339)
248
251 (160–339)
Density (m2/person)
Mean
Median (10th-90th)
88 77 (45–143)
90 80 (48–142)
Gas Cooking Burners
Cooktop / Oven 100% / 43% 2% / 27%
1Additional information in SI Tables S5-S15.2Table S5. 3Table S6. 4Table S7. 25Others had electric cooking. 3 Table 3. Time-averaged pollutant concentrations in California homes built 2011-2017 (HENGH, 4 current study) and 2002-2005 (CNHS, Offermann, 2009).

Location HCHO (ppb) PM2.5 g/m3
) NO2 (ppb) CO2 (ppm)
Statistic HENGH CNHS1 HENGH CNHS1 HENGH CNHS1 HENGH CNHS2 Indoor N=68 N=105 N=67 N=28 N=66 N=29 N=69 N=107
Mean 19.8 35.0 7.5 13.4 5.8 5.2 620 610
Median 18.2 29.3 4.8 10.5 4.5 1.6 608 564
10th–90th 13–28 11–70 1.6–16 6.0–31 1.1–12 1.4–12 481–770 405–890 Outdoor N=66 N=39
4 N=673 N=114 N=65 N=114 No data No data
Mean 2.2 1.8 9.3, 10.5 7.9 5.4 2.1
Median 2.3 1.7 6.8, 9.7 8.7 3.6 1.5
10th–90th 1.4–3.1 0.6–2.8

2.7–18.1,

5.3–16.7

5.0–10 0.1–11 1.4–1.7
1 From CNHS “all-home” sample frame dataset. 2 From Table 39 of Offermann (2009). 3 5 The first set of outdoor 6 values are from unadjusted, on-site photometer measurements over the full monitoring period at each home; the 7 second set are from air quality monitoring stations nearby to the homes and use only the 24-h data from complete days during each monitoring period.
4 8 The CNHS collected one outdoor sample per cluster of 2-3 homes in close 9 proximity. Outdoor formaldehyde collected at clusters for all 108 homes. Outdoor samples for PM2.5 and NO2 10 collected for clusters that included 28 homes total.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 30
1 Table 4. Discomfort rates reported by participants in California homes built with code-required 2 mechanical ventilation (HENGH), recent online survey of homes mostly built before dwelling unit 3 ventilation was required, and field study of homes built before ventilation was required (CNHS).

Parameter HENGH field
study (n=68)1
HENGH online
survey (n=2271)
1 CNHS2
Too hot Winter: 14%
Summer: 31%
Winter: 10%
Summer: 41%
19%
Too cold Winter: 29%
Summer: 4%
Winter: 20%
Summer: 9%
15%
Too dry 9% 11% 8%
Too damp (HENGH) / too humid
(CNHS)
1% 2% 2%
Too much air movement
(HENGH) / too drafty (CNHS)
1% 5% 0%
Too stagnant / not enough air
movement
21% 18% 12%
Too dusty Not asked Not asked 11%
Musty odor 1% 3% 13% in bathroom
1-3% other locations
1 When asked how often does the discomfort occurs, respondent selected “few times per week” or “daily”. 2 4 From 5 Table 44 of Offermann (2009), respondents reporting that the discomfort occurred during 3 weeks prior. For musty 6 odor, the CNHS asked if participants had “observed, seen or smelled mold” in the past week in various locations. 7

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 31
1 2 Figure 1. Locations of study homes.
3

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 32
1 2 Figure 2: One-week integrated formaldehyde measured with passive samples: Comparison of 3 concentrations in master bedroom and large, open common room (main) indoor locations 4 5 Figure 3: Time-Integrated formaldehyde concentrations measured in California homes built before 6 (CNHS) and after (HENGH) mechanical ventilation was required.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 33
1 2 Figure 4: Time-averaged PM2.5 concentrations measured in California homes built before (CNHS) 3 and after (HENGH) mechanical ventilation was required. 4 5 Figure 5: Time-integrated NO2 concentrations measured in California homes built before (CNHS) 6 and after (HENGH) mechanical ventilation was required. Most CNHS homes had electric cooking 7 and all HENGH homes had gas cooking burners.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 34
1 2 Figure 6: Time-average CO2 concentrations in indoor main living space and bedrooms. 3 4 Figure 7: Nighttime (midnight-5am) CO2 in indoor main living space and bedrooms 5

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 35
1 5. References
2 1. Piazza T, Lee R, Sherman M, Price P. Study of Ventilation Practices and Household 3 Characteristics in New California Homes. Final Report for Energy Commission Contract 4 500-02-023 and ARB Contract 03-026. CEC-500-2007-033; Sacramento, CA: California 5 Energy Commission and California Air Resources Board; June 2007, 2007. 6 2. Offermann FJ. Ventilation and Indoor Air Quality in New Homes. CEC-500-2009-085; 7 Sacramento, CA: California Energy Commission and California Air Resources Board; 2009. 8 3. Lawrence Berkeley National Lab. LBNL. Ventilate Right: Ventilation Guide for New and 9 Existing California Homes. https://homes.lbl.gov/ventilate-right/ashrae-standard-622 Last 10 Accessed:05-Oct-2019-
11 4. Logue JM, Klepeis NE, Lobscheid AB, Singer BC. Pollutant Exposures from Natural Gas 12 Cooking Burners: A Simulation-Based Assessment for Southern California. Environ Health 13 Perspect. 2014;122:43-50.
14 5. Mullen NA, Li J, Russell ML, Spears M, Less BD, Singer BC. Results of the California 15 Healthy Homes Indoor Air Quality Study of 2011-2013: impact of natural gas appliances on 16 air pollutant concentrations. Indoor Air. 2016;26:231-45. 17 6. Chan WR, Kim Y-S, Less BD, Singer BC, Walker IS. Ventilation and Indoor Air Quality in 18 New California Homes with Gas Appliances and Mechanical Ventilation. LBNL-2001200; 19 Berkeley CA: Lawrence Berkeley National Laboratory; 2019. 20 7. California Air Resources Board. CARB. Composite Wood Products Airborne Toxic Control 21 Measure. www.arb.ca.gov/toxics/compwood/compwood.htm Last Accessed:05-Oct-2019- 22 8. Chan WR, Kim Y-S, Singer BC, Walker IS, Sherman MH. Healthy Efficient New Gas 23 Homes (HENGH) Field Study Protocol. LBNL-1005819; Berkeley, CA: Lawrence Berkeley 24 National Lab; 2016.
25 9. Walker IS, Wray CP, Dickerhoff DJ, Sherman MH. Evaluation of flow hood measurements 26 for residential register flows. LBNL-47382; Berkeley CA: Lawrence Berkeley National 27 Laboratory; 2001.
28 10. Dacunto PJ, Cheng KC, Acevedo-Bolton V, Jiang RT, Klepeis NE, Repace JL, Ott WR, 29 Hildemann LM. Real-time particle monitor calibration factors and PM2.5 emission factors 30 for multiple indoor sources. Environmental Science-Processes & Impacts. 2013;15:1511- 31 1519.
32 11. Tryner J, Good N, Wilson A, Clark ML, Peel JL, Volckens J. Variation in gravimetric 33 correction factors for nephelometer-derived estimates of personal exposure to PM2.5. 34 Environ Pollut. 2019;250:251-261.
35 12. Singer BC, Delp WW. Response of consumer and research grade indoor air quality monitors 36 to residential sources of fine particles. Indoor Air. 2018;28:624-639. 37 13. Zhang J, Marto JP, Schwab JJ. Exploring the applicability and limitations of selected optical 38 scattering instruments for PM mass measurement. Atmos. Meas. Tech. 2018;11:2995-3005. 39 14. Wang XL, Chancellor G, Evenstad J, Farnsworth JE, Hase A, Olson GM, Sreenath A, 40 Agarwal JK. A Novel Optical Instrument for Estimating Size Segregated Aerosol Mass 41 Concentration in Real Time. Aerosol Sci Technol. 2009;43:939-950. 42 15. Carter EM, Jackson MC, Katz LE, Speitel GE. A coupled sensor-spectrophotometric device 43 for continuous measurement of formaldehyde in indoor environments. J Exposure Sci 44 Environ Epidemiol. 2014;24:305-310.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 36
1 16. Maruo YY, Yamada T, Nakamura J, Izumi K, Uchiyama M. Formaldehyde measurements in 2 residential indoor air using a developed sensor element in the Kanto area of Japan. Indoor 3 Air. 2010;20:486-493.
4 17. Offermann FJ, Hodgson AT. In Accurancy of Three Types of Formaldehyde Passive 5 Samplers, Indoor Air 2018, Philadelphia PA, 2018; International Society of Indoor Air 6 Quality Sciences: Philadelphia PA, 2018.
7 18. Matthews TG, Thompson CV, Wilson DL, Hawthorne AR, Mage D. Air velocities inside 8 domestic environments: An important parameter in the study of indoor air quality and 9 climate. Environ Int. 1989;15:545-550.
10 19. Chan WYR, Joh J, Sherman MH. Analysis of air leakage measurements of US houses. 11 Energ Buildings. 2013;66:616-625.
12 20. Salthammer T, Mentese S, Marutzky R. Formaldehyde in the Indoor Environment. Chem 13 Rev. 2010;110:2536-2572.
14 21. Allen RW, Adar SD, Avol E, Cohen M, Curl CL, Larson T, Liu LJS, Sheppard L, Kaufman 15 JD. Modeling the Residential Infiltration of Outdoor PM2.5 in the Multi-Ethnic Study of 16 Atherosclerosis and Air Pollution (MESA Air). Environ Health Perspect. 2012;120:824- 17 830.
18 22. Wallace LA, Mitchell H, O'Connor GT, Neas L, Lippmann M, Kattan M, Koenig J, Stout 19 JW, Vaughn BJ, Wallace D, Walter M, Adams K, Liu LJS. Particle concentrations in inner20 city homes of children with asthma: The effect of smoking, cooking, and outdoor pollution. 21 Environ Health Perspect. 2003;111:1265-1272.
22 23. Allen R, Larson T, Sheppard L, Wallace L, Liu LJS. Use of real-time light scattering data to 23 estimate the contribution of infiltrated and indoor-generated particles to indoor air. Environ 24 Sci Technol. 2003;37:3484-3492.
25 24. Meng QY, Spector D, Colome S, Turpin B. Determinants of indoor and personal exposure 26 to PM2.5 of indoor and outdoor origin during the RIOPA study. Atmos Environ. 27 2009;43:5750-5758.
28 25. Rodes CE, Lawless PA, Thornburg JW, Williams RW, Croghan CW. DEARS particulate 29 matter relationships for personal, indoor, outdoor, and central site settings for a general 30 population. Atmos Environ. 2010;44:1386-1399.
31 26. Mishra AK, van Ruitenbeek AM, Loomans M, Kort HSM. Window/door opening-mediated 32 bedroom ventilation and its impact on sleep quality of healthy, young adults. Indoor Air. 33 2018;28:339-351.
34 27. Strom-Tejsen P, Zukowska D, Wargocki P, Wyon DP. The effects of bedroom air quality on 35 sleep and next-day performance. Indoor Air. 2016;26:679-686. 36 28. Wallner P, Munoz U, Tappler P, Wanka A, Kundi M, Shelton JF, Hutter HP. Indoor 37 Environmental Quality in Mechanically Ventilated, Energy-Efficient Buildings vs. 38 Conventional Buildings. Int J Environ Res Public Health. 2015;12:14132-14147. 39 29. Wallner P, Tappler P, Munoz U, Damberger B, Wanka A, Kundi M, Hutter HP. Health and 40 Wellbeing of Occupants in Highly Energy Efficient Buildings: A Field Study. Int J Environ 41 Res Public Health. 2017;14.
42 30. Lajoie P, Aubin D, Gingras V, Daigneault P, Ducharme F, Gauvin D, Fugler D, Leclerc JM, 43 Won D, Courteau M, Gingras S, Heroux ME, Yang W, Schleibinger H. The IVAIRE project 44 - a randomized controlled study of the impact of ventilation on indoor air quality and the 45 respiratory symptoms of asthmatic children in single family homes. Indoor Air. 46 2015;25:582-597.

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-190-10-297-R2 04-April-2020 37
1 31. Balvers J, Bogers R, Jongeneel R, van Kamp I, Boerstra A, van Dijken F. Mechanical 2 ventilation in recently built Dutch homes: technical shortcomings, possibilities for 3 improvement, perceived indoor environment and health effects. Architectural Science 4 Review. 2012;55:4-14.
5 32. Laverge J, Delghust M, Janssens A. Carbon Dioxide Concentrations and Humidity Levels 6 Measured in Belgian Standard and Low Energy Dwellings with Common Ventilation 7 Strategies. International Journal of Ventilation. 2015;14:165-180. 8 33. Eklund K, Kunkle R, Banks A, Hales D. Pacific Northwest Residential Effectiveness Study - 9 FINAL REPORT NEEA Report #E15-015; Portland, OR: Prepared by Washington State 10 University Energy Program; 2015.
11 34. Sonne JK, Withers C, Vieira RK. Investigation of the effectiveness and failure rates of 12 whole-house mechanical ventilation systems in Florida. FSEC-CR-2002-15; Cocoa, FL:
13 June 1, 2015, 2015.
14 35. Hult EL, Willem H, Price PN, Hotchi T, Russell ML, Singer BC. Formaldehyde and 15 acetaldehyde exposure mitigation in US residences: in-home measurements of ventilation 16 control and source control. Indoor Air. 2015;25:523-535. 17 36. Frey SE, Destaillats H, Cohn S, Ahrentzen S, Fraser MP. The effects of an energy efficiency 18 retrofit on indoor air quality. Indoor Air. 2015;25:210-219. 19 37. Huangfu YB, Lima NM, O'Keeffe PT, Kirk WM, Lamb BK, Pressley SN, Lin BY, Cook 20 DJ, Walden V, Jobson BT. Diel variation of formaldehyde levels and other VOCs in homes 21 driven by temperature dependent infiltration and emission rates. Build Environ. 2019;159. 22 38. Singer BC, Hodgson AT, Hotchi T, Kim JJ. Passive measurement of nitrogen oxides to 23 assess traffic-related pollutant exposure for the East Bay Children's Respiratory Health 24 Study. Atmos Environ. 2004;38:393-403.
25

06/23/2026 Item No.18.

IAQ in Mechanically Ventilated U.S. Homes INA-19-10-297-R2 04-April-2020 SI-1

SUPPORTING INFORMATION
Indoor Air Quality in California Homes with Code-Required Mechanical Ventilation Brett C. Singer1, Wanyu R. Chan1, Yang-Seon Kim1,2, Francis J. Offermann3, Iain S. Walker1 1 Residential Buildings Systems Group and Indoor Environment Group, Lawrence Berkeley National Laboratory, Berkeley, California, USA
2 Wichita State University, Wichita, Kansas, USA
3 Indoor Environmental Engineering, San Francisco California, USA Contents
CONTENTS ......................................................................................................................................................... 1 LIST OF FIGURES................................................................................................................................................. 2 LIST OF TABLES................................................................................................................................................... 2 METHODS .......................................................................................................................................................... 4 RECRUITMENT AND SCREENING ........................................................................................................................................4 INFORMATION COLLECTED FOR HOUSE AND EQUIPMENT CHARACTERIZATION............................................................................4 SPECIFICATION OF AIR QUALITY MONITORING EQUIPMENT....................................................................................................5 LOCATIONS OF AMBIENT AIR QUALITY MONITORING STATIONS USED TO ESTIMATE OUTDOOR PM2.5 ...........................................8 QUALITY ASSURANCE PROCEDURES FOR AIR QUALITY MONITORS ...........................................................................................9 WEIGHING OF FILTERS FOR GRAVIMETRIC PM2.5 DETERMINATION........................................................................................10 PASSIVE SAMPLER PROCEDURES AND QUALITY ASSURANCE .................................................................................................10 POTENTIAL IMPACT OF LOW AIR SPEEDS ON PASSIVE SAMPLER DATA ....................................................................................12 ADJUSTMENTS TO FORMALDEHYDE DATA FROM FM-801 MONITOR.....................................................................................13 CALCULATION OF OUTDOOR AIR EXCHANGE RATE..............................................................................................................13 ESTIMATE OF POTENTIAL BIAS IN CALCULATED AIR INFILTRATION..........................................................................................14 RESULTS............................................................................................................................................................16 HOUSE CHARACTERISTICS ..............................................................................................................................................16 HOUSEHOLD DEMOGRAPHICS.........................................................................................................................................19 AIR TIGHTNESS ............................................................................................................................................................21 VENTILATION AND FILTRATION EQUIPMENT ......................................................................................................................22 GENERAL OCCUPANCY AND SOURCES – FROM SURVEY .......................................................................................................27 OCCUPANCY AND SOURCES DURING WEEK OF MONITORING ...............................................................................................27 AIR POLLUTANT CONCENTRATIONS: FORMALDEHYDE..........................................................................................................30 AIR POLLUTANT CONCENTRATIONS: PM2.5 .......................................................................................................................31 ANALYSIS OF REGULATORY AIR MONITORING DATA TO ESTIMATE PM2.5 OUTSIDE OF HENGH HOMES.......................................31 AIR POLLUTANT CONCENTRATIONS: NITROGEN DIOXIDE AND NITRIC OXIDE............................................................................34 AIR POLLUTANT CONCENTRATIONS: CO2..........................................................................................................................35 IEQ SATISFACTION BY VENTILATION SYSTEM OPERATION ....................................................................................................36 RECRUITMENT POSTCARD.................................................................................................................................38 DAILY ACTIVITY LOG..........................................................................................................................................39 OCCUPANT SURVEY...........................................................................................................................................40