CALIFORNIA 

ENERGY 

COMMISSION

VENTILATION AND INDOOR AIR

QUALITY IN NEW HOMES 

PIER

COLLABORATIVE 

REPORT

November 2009 

CEC-500-2009-085 

Prepared By: 

Francis J. Offermann PE CIH 

Principal Investigator 

Indoor Environmental Engineering 

1448 Pine Street 

Suite 103 

San Francisco, CA 94109 

California Energy Commission Contract 500-02-023 

California Air Resources Board Contract 04-310 

Prepared For: 

Public Interest Energy Research (PIER) 

California Energy Commission 

Marla Mueller 

Project Manager 

Linda Spiegel 

Program Area Lead 

Energy-Related Environmental Research

Ken Koyama 

Office Manager 

Energy Generation Research 

Thom Kelly, Ph.D. 

Deputy Director 

ENERGY RESEARCH AND DEVELOPMENT 

DIVISION 

Melissa Jones 

Executive Director 

and

California Air Resources Board 

Tom Phillips 

Contract Manager 

Research Division 

Peggy Jenkins

Manager 

Indoor Exposure Assessment Section 

Research Division

DISCLAIMER 

This report was prepared as a result of work sponsored by the Air Resources Board (ARB) and the California 

Energy Commission (Energy Commission). It does not necessarily represent the views of ARB, the Energy 

Commission, their employees, or the State of California. The mention of commercial products, their source, or 

their use in connection with reported material herein is not to be construed as actual or implied endorsement of 

such products. The ARB, the Energy Commission, the State of California, its employees, contractors, and 

subcontractors make no warranty, express or implied, and assume no legal liability for the information in this 

report; nor does any party represent that the use of this information will not infringe upon the privately owned 

rights. This report has not been approved or disapproved by the ARB or the Energy Commission, nor has the 

ARB or the Energy Commission passed upon the accuracy or adequacy of this information in this report. 

i 

Acknowledgments 

The research team thanks the homeowners and families that participated in this study. It also

thanks this study’s field staff and subcontractors: Teresa Woo of Indoor Environmental

Engineering for leading the Team 2 field work and data entry; Jonathan Robertson of Indoor

Environmental Engineering for leading the Team 3 field work and data entry; Shaun Trevino,

Josh McNeil, and Leo Ranier of Davis Energy Group for the Team 1 portions of the field work;

Allen Amaro, Jerry Kniffen, Joe Lima, Josh McConnell, and Demitri Wells of Amaro

Construction for assisting with the Team 2 and Team 3 portions of the field work; Corina Jump

and Richard Mountain of Itron Inc. for the home recruitment and scheduling of all field team

visits and database management and statistical analyses; Lisa Ramezzano of Indoor

Environmental Engineering for the field work logistics; Geoffrey Offermann of Indoor

Environmental Engineering for assistance in data analyses and document preparation; and Al

Hodgson and Raja Tannous of Berkeley Analytical Associates for the formaldehyde analyses,

Russell Dietz of Brookhaven National Laboratory for the perfluorocarbon tracer sample

analyses, Chester LabNet for the particulate matter (PM2.5) sample analyses, and DataChem for

the nitrogen dioxide sample analyses. In addition, the research team would like to thank Iain

Walker of Lawrence Berkeley National Laboratory for assisting with the duct leakage analyses

and Collin Olson of the Energy Conservatory for assisting with the garage‐home zone pressure

diagnostics.

Special thanks to Peggy Jenkins, Manager of the California Air Resources Board’s Indoor

Exposure Assessment Section, and Tom Phillips, California Air Resources Board Contract

Manager, for their advice and guidance throughout this research project.

The team also thanks and acknowledges the Expert Advisory Panel for their valuable advice;

Larry Palmiter of Ecotope; Jed Waldman of the California Department of Public Health; Lance

Wallace, Environmental Protection Agency (retired); and Bruce Wilcox, PE. Input from the

Expert Advisory Panel on the study protocol, Pilot Study report, and the draft final report was

considered by California Air Resources Board and California Energy Commission staff.

Finally, as the Principal Investigator of this research project, Francis J. Offermann would like to

personally acknowledge the inspiration, encouragement, and mentorship received in the past

from the following individuals who are no longer with us: Dr. Craig Hollowell and Dr. Joan

Daisey of the Lawrence Berkeley National Laboratory; Professor Ole Fanger of the Technical

University of Denmark; and Alfred and Estelle Stabel of Buffalo, New York.  

This report was submitted in fulfillment of ARB Agreement #04‐310 by Indoor Environmental

Engineering under the sponsorship of the California Air Resources Board and the California

Energy Commission.
ii 

Please cite this report as follows:  

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.
iii 

Preface 

The California Air Resources Board (ARB) carries out and funds research to reduce the health,

environmental, and economic impacts of indoor and outdoor air pollution in California. This

research involves four general program areas:

• Health and Welfare Effects

• Exposure Assessment

• Technology Advancement and Pollution Prevention

• Global Air Pollution

For more information about the ARB Research Program, please see ARB’s website at:

www.arb.ca.gov/research/research.htm, or contact ARB’s Research Division at (916) 445‐0753.

For more information about ARB’s Indoor Exposure Assessment Program please visit the

website at: www.arb.ca.gov/research/indoor/indoor.htm.

The California Energy Commission’s Public Interest Energy Research (PIER) Program supports

public interest energy research and development that will help improve the quality of life in

California by bringing environmentally safe, affordable, and reliable energy services and

products to the marketplace.

The PIER Program conducts public interest research, development, and demonstration (RD&D)

projects to benefit California.

The PIER Program strives to conduct the most promising public interest energy research by

partnering with RD&D entities, including individuals, businesses, utilities, and public or

private research institutions.

• PIER funding efforts are focused on the following RD&D program areas:

• Buildings End‐Use Energy Efficiency

• Energy Innovations Small Grants

• Energy‐Related Environmental Research

• Energy Systems Integration

• Environmentally Preferred Advanced Generation

• Industrial/Agricultural/Water End‐Use Energy Efficiency

• Renewable Energy Technologies

• Transportation

Ventilation and Indoor Air Quality in New Homes is the final report for project contract number

500‐02‐023, ARB contract number 04‐310, conducted by Indoor Environmental Engineering. The
iv 

information from this project contributes to PIER’s Energy‐Related Environmental Research

Program.

For more information about the PIER Program, please visit the Energy Commission’s website at

www.energy.ca.gov/research/ or contact the Energy Commission at 916‐654‐4878.
v 

Table of Contents 

Preface...............................................................................................................................................iii

Abstract ........................................................................................................................................... xv

Executive Summary......................................................................................................................... 1

1.0 Introduction ....................................................................................................................... 13

1.1 Project Study Objectives .............................................................................................. 16

1.2 Report Organization..................................................................................................... 17

2.0 Project Approach/Material and Methods ...................................................................... 19

2.1 Study Design ................................................................................................................. 19

2.2 Home Recruitment and Selection............................................................................... 20

2.3 Field Work Teams and Work Assignments .............................................................. 22

2.4 Home and Site Characteristics Collection................................................................. 23

2.5 Home Air Leakage Measurements............................................................................. 25

2.5.1 Forced Air Unit Heating/Cooling System Duct Leakage ............................... 25

2.5.2 Building Envelope Air Leakage Area ............................................................... 25

2.5.3   Home‐to‐Garage Air Leakage ............................................................................ 25

2.6 Window/Door and Mechanical Systems Usage ....................................................... 26

2.6.1 Occupant Use of Windows and Doors.............................................................. 26

2.6.2 Occupant Use of Mechanical Exhaust Systems ............................................... 26

2.6.3 Occupant Use of Mechanical Outdoor Air Systems ....................................... 27

2.6.4 Occupant Use of Nighttime Cooling Systems ................................................. 27

2.6.5 Occupant Use of Forced Air Heating/Cooling Systems (FAU) ..................... 28

2.7 Outdoor Air Ventilation Measurements ................................................................... 28

2.7.1 Mechanically Supplied Outdoor Airflow Rates .............................................. 28

2.7.2 Tracer Gas Measurements of Outdoor Air Exchange Rate............................ 29

2.8 Indoor Air Quality Measurements............................................................................. 31

2.8.1   Integrated Time Averaged IAQ Measurements (24‐hour)............................. 32

2.8.1.1 Volatile Organic Compounds.............................................................. 32 

2.8.1.2 Formaldehyde and Acetaldehyde ....................................................... 33 

2.8.1.3 Nitrogen Dioxide ................................................................................. 35 

2.8.1.4 Particulate Matter (PM2.5)..................................................................... 36 

2.8.2 Real‐Time IAQ Measurements........................................................................... 36

2.8.2.1 Carbon Monoxide ................................................................................ 36 

2.8.2.2 Carbon Dioxide.................................................................................... 37 

2.8.2.3 Temperature and Relative Humidity .................................................. 37 

2.9 Homeowner Source Activity....................................................................................... 38

2.10 Homeowner IAQ/Ventilation Perceptions and Decision Factors.......................... 39

2.11 Quality Assurance and Quality Control.................................................................... 39

2.12 Data Management and Analyses................................................................................ 40

3.0 Project Outcomes/Results and Discussion .................................................................... 47

3.1 Quality Assurance and Quality Control.................................................................... 47

3.2 Home Selection and Recruitment............................................................................... 50
vi 

3.3 Home and Site Characteristics Collection................................................................. 55

3.4 Home Air Leakage Measurements............................................................................. 57

3.4.1 Forced Air Heating/Cooling System Duct Leakage........................................ 57

3.4.2   Home Building Envelope Air Leakage Area.................................................... 58

3.4.3 Home‐to‐Garage Air Leakage ............................................................................ 58

3.5 Window/Door and Mechanical Systems Usage ....................................................... 60

3.5.1 Occupant Use of Windows and Doors for Ventilation................................... 61

3.5.2 Measured and Owner‐Estimated Window/Door Usage Comparison ......... 62

3.5.3 Occupant Use of Mechanical Exhaust Air Systems ........................................ 64

3.5.4 Occupant Use of Mechanical Outdoor Air Systems ....................................... 65

3.5.5 Occupant Use of Mechanical Nighttime Cooling Systems ............................ 66

3.5.6 Occupant Use of Forced Air Unit (FAU) Systems........................................... 67

3.6 Outdoor Air Ventilation Measurements ................................................................... 67

3.6.1 Mechanically Supplied Outdoor Airflow Rates .............................................. 67

3.6.2 Tracer Gas Measurements of Home Outdoor Air Exchange Rates .............. 72

3.7 Indoor Air Quality Measurements............................................................................. 73

3.7.1 Integrated Time Averaged IAQ Measurements (24‐hour)............................. 73

3.7.1.1 Volatile Organic Compounds Concentrations .................................... 73 

3.7.1.2 Formaldehyde and Acetaldehyde Concentrations.............................. 76 

3.7.1.3 Nitrogen Dioxide ................................................................................. 78 

3.7.1.4 Particulate Matter (PM2.5)..................................................................... 79 

3.7.2 Real‐Time IAQ Measurements........................................................................... 80

3.7.2.1 Carbon Monoxide (CO) ....................................................................... 80 

3.7.2.2 Carbon Dioxide (CO2).......................................................................... 81 

3.7.2.3 Temperature and Relative Humidity .................................................. 82 

3.7.3  Volatile Organic Compound Concentration Study Comparisons........................ 82

3.7.4  Volatile Organic Compound Proposition 65 Safe Harbor Levels......................... 83

3.8 Homeowner Source Activity Log............................................................................... 83

3.9 Homeowner Reported IAQ Related Perceptions and Observations..................... 84

3.10 Relationships Between Home and IAQ Characteristics.......................................... 85

3.10.1   Indoor Air Contaminant Emission Rates ..................................................... 85

3.10.2   Formaldehyde Emissions from Forced Air Units ....................................... 86

3.10.3   Multi‐day Home Measurement Comparisons................................................ 87

3.10.4   Multi‐Season Home Measurement Comparisons .......................................... 88

3.10.5   Group Comparisons ........................................................................................... 90

3.10.5.1 Formaldehyde and Acetaldehyde and Group Comparisons .............. 91 

3.10.5.2 Outdoor Air Exchange Rate and Window Usage Group

Comparisons........................................................................................ 92 

3.11 Formaldehyde and Acetaldehyde Concentration Correlations............................. 92

3.12 Incentives and Barriers that Influence People’s Use of Ventilation ...................... 95

3.13 Incentives and Barriers Related to People’s Purchases and Practices that  

             Improve IAQ ................................................................................................................. 97

3.14 Recent Developments Related to Codes, Regulations, and Guidelines................ 98
vii 

4.0   Conclusions and Recommendations ............................................................................ 206

4.1   Summary...................................................................................................................... 206

4.2   Conclusions ................................................................................................................. 207

4.3   Recommendations ...................................................................................................... 215

4.4 Benefits to California.................................................................................................. 218

5.0 References ........................................................................................................................ 220

6.0 Glossary of Terms, Abbreviations, and Symbols ....................................................... 226

Appendix A: Pilot Study Report with Recruitment Letter and Script

Appendix B: Volatile Organic Compound Analytical Method

Appendix C: “All Homes” Sample Frame List

Appendix D: Home‐Season Test List

Appendix E: Air Contaminant and Outdoor Air Exchange Rate PFT Measurements

Appendix F: Home and Mechanical Ventilation System Characteristics

Appendix G: Difficulties Encountered in the Field Study
viii 

List of Figures 

Figure 1. Quiet indoor air sampler for formaldehyde, VOCs, PM2.5, NO2, CO, CO2, 

temperature, and relative humidity, typically installed in a home living/dining room 

area for a 22–26 hour sampling period. ...............................................................................44 

Figure 2. Outdoor air sampler for formaldehyde, VOCs, PM2.5, NO2, CO, CO2, 

temperature, and relative humidity, with outdoor radiation/rain shield...............................45 

Figure 3. Locations of homes for the summer and winter 2006–2007 field sessions in 

Northern and Southern California......................................................................................102 

Figure 4. Forced air duct leakage cumulative frequency distribution - All Home Sample 

Frame. ................................................................................................................................103 

Figure 5. Building envelope air leakage cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................104 

Figure 6. Window and door opening cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................105 

Figure 7. Mechanical exhaust system usage cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................106 

Figure 8. Mechanical outdoor air system usage cumulative frequency distribution – All 

Home Sample Frame..........................................................................................................107 

Figure 9. Nighttime cooling system usage cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................108 

Figure 10. Forced air unit system usage – All Home Sample Frame. .......................................109 

Figure 11. ASHRAE 62.2-2004 Intermittent ventilation indoor air contaminant 

concentration plot...............................................................................................................110 

Figure 12. Outdoor air exchange rate PFT (24-hour) measurement cumulative frequency – 

All Home Sample Frame. ..................................................................................................111 

Figure 13. Benzene concentration cumulative frequency distribution – All Home Sample 

Frame. ................................................................................................................................112 

Figure 14. 1,4 Dichlorobenzene concentration cumulative frequency distribution –All 

Home Sample Frame..........................................................................................................113 

Figure 15. Ethylene glycol concentration cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................114 

Figure 16. n-Hexane concentration cumulative frequency distribution – All Home Sample 

Frame. ................................................................................................................................115 

Figure 17. Naphthalene concentration cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................116 

Figure 18. Phenol concentration cumulative frequency distribution – All Home Sample 

Frame. ................................................................................................................................117 

Figure 19. Styrene concentration cumulative frequency distribution – All Home Sample 

Frame. ................................................................................................................................118 
ix 

Figure 20. Tetrachloroethene concentration cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................119 

Figure 21. Toluene concentration cumulative frequency distribution – All Home Sample 

Frame. ................................................................................................................................120 

Figure 22. Trichloromethane (chloroform) cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................121 

Figure 23. Vinyl acetate concentration cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................122 

Figure 24. m,p-Xylene concentration cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................123 

Figure 25. o-Xylene concentration cumulative frequency distribution – All Home Sample 

Frame. ................................................................................................................................124 

Figure 26. Formaldehyde concentration cumulative frequency distribution – All Home 

Sample Frame. ...................................................................................................................125 

Figure 27. Acetaldehyde concentration frequency distribution – All Home Sample Frame.....126 

Figure 28. Formaldehyde indoor concentrations and outdoor air exchange rates. ....................127 

Figure 29. Cumulative frequency distribution of the log of formaldehyde concentration – 

All Homes Sample Frame..................................................................................................128 

Figure 30. Cumulative frequency distribution of the log of acetaldehyde concentration – 

All Homes Sample Frame..................................................................................................129 

Figure 31. Cumulative frequency distribution for the inverse of the air exchange rate – All 

Homes Sample Frame........................................................................................................130 

Figure 32. Cumulative frequency distribution of the square root of window usage – All 

Homes Sample Frame........................................................................................................131 

Figure 33. Cumulative frequency distribution for indoor temperature – All Homes Sample 

Frame. ................................................................................................................................132 

Figure 34. Cumulative frequency for the indoor relative humidity squared – All Homes 

Sample Frame. ...................................................................................................................133 

Figure 35. Cumulative frequency distribution for outdoor temperature – All Homes 

Sample Frame. ...................................................................................................................134 

Figure 36. Cumulative frequency distribution for outdoor relative humidity – All Homes 

Sample Frame. ...................................................................................................................135 

Figure 37. Cumulative frequency distribution for the log of the normalized composite 

wood loading – All Homes Sample Frame........................................................................136 

Figure 38. Cumulative frequency distribution for home age – All Homes Sample Frame. ......137 

Figure 39. Scatter plots of home age and indoor formaldehyde and acetaldehyde 

concentrations – All Homes Sample Frame.......................................................................138 

Figure 40. Scatter plots of composite wood loading and indoor formaldehyde and 

acetaldehyde concentrations – All Homes Sample Frame.................................................139 

Figure 41. Scatter plots of outdoor air exchange rates and indoor formaldehyde and 

acetaldehyde concentrations – All Homes Sample Frame.................................................140 
x 

Figure 42. Scatter plots of indoor temperature and indoor formaldehyde and acetaldehyde 

concentrations – All Homes Sample Frame.......................................................................141 

Figure 43. Scatter plots of indoor relative humidity and indoor formaldehyde and 

acetaldehyde concentrations – All Homes Sample Frame.................................................142 

Figure 44. Scatter plots of outdoor temperature and indoor formaldehyde and acetaldehyde 

concentrations – All Home Sample Frame. .......................................................................143 

Figure 45. Scatter plots of outdoor relative humidity and indoor formaldehyde and 

acetaldehyde concentrations – All Homes Sample Frame.................................................144 
xi 

List of Tables 

Table 1. Seasonal percentage of new California single-family detached homes reporting no 

use of windows for 24, 23, 22, and 21 hours per day. .........................................................17 

Table 2. Percentages of air contaminant and PFT field samples, blanks, and duplicates 

successfully collected and analyzed...................................................................................145 

Table 3. Summer-North field session field blank analyses for volatile organic compounds, 

including formaldehyde and acetaldehyde.........................................................................146 

Table 4. Summer-South field session field blank analyses for volatile organic compounds 

including formaldehyde and acetaldehyde.........................................................................147 

Table 5. Winter-North field session field blank analyses for volatile organic compounds 

including formaldehyde and acetaldehyde.........................................................................148 

Table 6. Winter-South field session field blank analyses for volatile organic compounds 

including formaldehyde and acetaldehyde.........................................................................149 

Table 7. Precision of volatile organic compound measurements over a 24-hour period...........150 

Table 8. Winter-North field session field blank analyses for nitrogen dioxide and PM2.5 

particulate matter. ..............................................................................................................151 

Table 9. Precision for carbon dioxide, carbon monoxide, nitrogen dioxide, and PM2.5

measurements over a 24-hour period.................................................................................152 

Table 10. Summer and field session field blank analyses for PFT measurements. ...................153 

Table 11. Precision of PFT outdoor air exchange rates measured over the 24-hour Test 

Day and the following two-week period............................................................................154 

Table 12. Comparison of PFT measurements in the first and second zones of the home. ........155 

Table 13. Home recruitment results for each region-season......................................................156 

Table 14. Home sample comparison for the field study to the UCB mail survey sample by 

geographical strata. ............................................................................................................157 

Table 15. Home characteristics-1. .............................................................................................158 

Table 16. Home characteristics-2. .............................................................................................159 

Table 17. Home characteristics-3. .............................................................................................160 

Table 18. Homeowner reported home characteristics, renovations, maintenance, and other 

IAQ related activities-1......................................................................................................161 

Table 19. Homeowner reported home characteristics, renovations, maintenance, and other 

IAQ related activities-2......................................................................................................162 

Table 20. Homeowner reported home characteristics, renovations, maintenance and other 

IAQ related activities-3......................................................................................................163 

Table 21. Mechanical outdoor air system types and controls....................................................164 

Table 22. Forced air unit (FAU) heating/cooling system duct leakage measurements. ............165 

Table 23. Building envelope air leakage measurements............................................................166 

Table 24. Home-to-garage air leakage measurements...............................................................167 
xii 

Table 25. Window and door opening usage during the 24-hour air testing day and the 

preceding one-week. ..........................................................................................................168 

Table 26. Percentage comparisons of actual measured home window/door usage and the 

homeowner’s estimated seasonal usage in the UCB mail survey......................................169 

Table 27. Differences between the actual measured home window/door usage and the 

homeowner’s estimated seasonal usage in the UCB mail survey......................................170 

Table 28. Mechanical system usage for the 24-hour Test Day period and the ratio of the 

Test Day usage to the week average usage........................................................................171 

Table 29. Mechanical outdoor air ventilation system characteristics and code requirements...172 

Table 30. PFT measurements of outdoor air exchange rates for the 24-hour Test Day and 

the following two-week period. .........................................................................................173 

Table 31. Comparison of outdoor air exchange rate PFT measurements to CBC 2001 

minimum code requirements..............................................................................................174 

Table 32. Percentage of samples with concentrations of volatile organic compounds 

greater than the method detection......................................................................................175 

Table 33. Concentrations of individual volatile organic compounds measured indoors over 

the 24-hour Test Day. ........................................................................................................176 

Table 34. Concentration of individual volatile organic compounds measured outdoors over 

the 24-hour Test Day. ........................................................................................................177 

Table 35. Maximum indoor concentrations of the volatile organic compounds comparison 

to indoor air contaminant guidelines..................................................................................178 

Table 36. Comparison of indoor concentrations of formaldehyde and acetaldehyde to 

indoor air contaminant guidelines......................................................................................179 

Table 37. Percentage of homes with indoor and concentrations of carbon monoxide, 

nitrogen dioxide, and PM2.5 particulate matter greater than the method detection limit. ..180 

Table 38. Concentrations of carbon monoxide, nitrogen dioxide and PM2.5 particulate 

matter measured indoor and outdoor over the 24-hour Test Day. .....................................181 

Table 39. Temperature, relative humidity, and carbon dioxide concentrations measured 

indoors and outdoors over the 24-hour Test Day...............................................................182 

Table 40. Comparison of volatile organic compound concentrations measured in new 

residences in this study and two other studies. ..................................................................183 

Table 41. Percentage of homes with concentrations exceeding California Proposition 65 

Safe Harbor Dose concentrations.......................................................................................184 

Table 42. Occupant cooking and cleaning source activities conducted during the 24-hour 

Test Day.............................................................................................................................185 

Table 43. Occupant special activities, garage and outdoor source activities conducted 

during the 24-hour Test Day..............................................................................................186 

Table 44. Homeowner reported IAQ related perceptions and observations..............................187 

Table 45. Indoor emission rates of volatile organic compounds over the 24-hour Test Day....188 

Table 46. Formaldehyde concentration and emission rates from FAU systems........................189 

Table 47. Multi-day home concentration and emission rates over three 24-hour periods for 

Home 033...........................................................................................................................190 
xiii 

Table 48. Multi-day home concentration and emission rates over three 24-hour periods for 

Home 041...........................................................................................................................191 

Table 49. Multi-day home concentration and emission rates over three 24-hour periods for 

Home 059...........................................................................................................................192 

Table 50. Multi-day home concentrations and emission rates for three 24-hour periods for 

Home 099...........................................................................................................................193 

Table 51. Multi-season home concentration and emission rates over 24-hour periods in 

three seasons for Home 005...............................................................................................194 

Table 52. Multi-season home concentration and emission rates over 24-hour periods in 

three seasons for Home 006...............................................................................................195 

Table 53. Multi-season home concentration and emission rates over 24-hour periods in 

three seasons for Home 013...............................................................................................196 

Table 54. Multi-season home concentration and emission rates over 24-hour periods in 

three seasons for Home 019...............................................................................................197 

Table 55. Normality test results for formaldehyde and acetaldehyde concentration, air 

exchange rate, indoor and outdoor temperature and relative humidity, composite 

wood loading, home age, and window usage. ...................................................................198 

Table 56. Group comparisons for formaldehyde and acetaldehyde concentrations. .................199 

Table 57. Group comparison for outdoor air exchange rates and window usage......................200 

Table 58. Correlations of indoor formaldehyde concentrations with home characteristics 

and with indoor and outdoor environmental conditions. ...................................................201 

Table 59. Correlation of indoor acetaldehyde concentrations with home characteristics and 

with indoor and outdoor environmental conditions...........................................................202 

Table 60. Homeowner reported mechanical ventilation system operation and choices-1.........203 

Table 61. Homeowner reported mechanical ventilation system operation and choices-2.........204 

Table 62. Homeowner reported IAQ related improvement choices..........................................205 
xiv 
xv 

Abstract 

Concerns have been raised regarding whether homeowners use windows, exhaust fans, and

other mechanical ventilation devices enough to remove indoor air contaminants and excess

moisture. In a multi‐season study of ventilation and indoor air quality of 108 new single‐family,

detached homes in California, window use, ventilation rates, and air contaminant

concentrations were measured. The median 24‐hour outdoor air exchange rate was 0.26 air

changes per hour; 67 percent of the homes were below the California building code requirement

of 0.35 air changes per hour; and 32 percent of the homes did not use their windows. Home‐to‐

garage pressure testing guidelines were exceeded in 65 percent of the homes. The median

indoor formaldehyde concentration was 36 micrograms per cubic meter (range of 4.8 to

136 micrograms per cubic meter). Nearly all homes had formaldehyde concentrations that

exceeded guidelines for cancer and chronic irritation, while 59 percent exceeded guidelines for

acute irritation. In conclusion, new single‐family detached homes in California are built

relatively airtight, can have very low outdoor air exchange rates, and can often exceed exposure

guidelines for air contaminants with indoor sources, such as formaldehyde and some other

volatile organic compounds. Mechanical ventilation systems are needed to provide a

dependable, continuous supply of outdoor air to new homes, and reductions of various indoor

formaldehyde sources are also needed.

Keywords: air contaminant exposure guidelines, air exchange rate, carbon monoxide, building

envelope tightness, exhaust fans, formaldehyde, garage air contaminants, indoor air

contaminant emission rates, indoor air contaminant sources, indoor air quality, mechanical

ventilation systems, natural ventilation, nitrogen dioxide, particulate matter, ventilation

standards, volatile organic compounds, windows. 
xvi 
1 

Executive Summary 

Introduction and Purpose

Concerns have been raised regarding whether homeowners use windows, doors, exhaust

fans, and other mechanical ventilation devices enough to remove indoor air contaminants

and excess moisture. Building practices and building standards for energy efficiency have

led to more tightly sealed homes that rely on occupants to open windows for ventilation.

However, there is very little information on current ventilation practices, indoor air

quality, or indoor air contaminant sources in homes. This study provides, for the first time,  

accurate and current statewide information on ventilation and indoor air quality in new

California homes.

A mail survey conducted in 2005 on occupants’ use of windows and mechanical ventilation

equipment in 1,515 new single‐family homes in California confirmed that many

homeowners never use their windows for ventilation. From this mail survey, a concern

emerged that the current California residential building code allowance for ventilation to

be provided merely through openable windows may not be sufficient to enable new homes

to receive adequate ventilation to control indoor air contaminants to acceptable levels.

As a follow‐up to the mail survey, a large field study was then conducted to measure

window and mechanical ventilation system use, outdoor air ventilation rates, sources and

concentrations of indoor air contaminants, and occupant perceptions. Data on indoor air

quality and household ventilation systems and practices were obtained from multiple

seasons and regions of the state. Measured levels of ventilation and indoor air quality were

compared to current guidelines and standards. These data will help characterize the full

range of indoor air contaminant exposure in such homes. Information on the use of

windows, fans, and central systems collected in this field study will help establish realistic

values for developing California standards for building energy efficiency.

The Energy Commission used these study results to revise the state’s 2008 Residential

Building Energy Efficiency standards to require mechanical ventilation to provide more

healthful homes in California. The study results will improve the California Air Resource

Board’s ability to identify current sources of indoor air contaminants, to assess

Californians’ current exposure to measured toxic air contaminants, and to recommend

effective strategies for reducing indoor air pollution.

Methods

The field study design involved recruitment of single‐family detached Californian homes

built between 2002 and 2004, using the University of California at Berkeley mail survey

database as well as some supplementary recruitment. The homes were occupied by owners

for at least one year before testing occurred, and homes with occupants who smoked

indoors were excluded. This field study involved 108 homes from Northern and Southern
2 

California, including a subset of 26 homes with mechanical outdoor‐air ventilation

systems. Home age ranged from 1.7 years to 5.5 years. The field teams measured home

ventilation and indoor contaminant source characteristics, including the amount of

composite wood, indoor contaminant concentrations, the residents’ ventilation practices,

indoor air quality perceptions, and decision factors regarding ventilation and indoor air

quality‐related actions. Measurements of indoor and outdoor air quality and ventilation

parameters were made in the summer and fall of 2007 and the winter of 2007–2008. Indoor

air concentrations of 22 volatile organic compounds, formaldehyde, acetaldehyde, PM2.5

particulate matter, nitrogen dioxide, carbon monoxide, carbon dioxide, temperature, and

relative humidity were measured over one 24‐hour period. The outdoor air ventilation

rates were determined concurrent with the air contaminant measurements using tracer gas

measurements. In addition, the field teams measured the building envelope air leakage,

garage‐to‐home air leakage, forced air unit duct leakage, window use, airflow rates, and

fan system use. Twenty of the 108 homes were tested in both the summer and winter

seasons; four homes were tested in the summer, fall, and winter; and four homes were

tested over multiple days, including weekends.

Results and Discussion

The following summarizes the results and provides some of the key discussion points for

each of the six study objectives.

Objective 1. Determine how residents use windows, doors, and mechanical ventilation

devices such as exhaust fans and central heating and air‐conditioning systems.

Occupant Use of Windows and Doors for Ventilation. In this field study, 32 percent of the

homes did not use their windows during the 24‐hour test day, and 15 percent of the homes

did not use their windows during the entire preceding week (Table E1). Most of the homes

with no window use were homes in the winter field session. The study concluded that a

substantial percentage of homeowners never open their windows, especially in the winter,

and confirms the seasonal results from the University of California at Berkeley mail survey

and the previous California Air Resources Board‐funded statewide survey of human

activity patterns. Results from the mail survey indicate that many homeowners never open

their windows or doors for ventilation as a result of their concerns for security/safety,

noise, dust, and odors.
3 

Table E1. Summary of window and door opening usage during the 24-hour Test Day and the 

preceding one week.

Number of 

Homes 

Tested 

Number of Homes with 

No Window/Door 

Usage 

Percentage of Homes 

with No Window/Door 

Usage 

(%) 

 

Test Day a 108 34 32 

 

Preceding Week b 108 16 15 

a) Test day usage was measured during the 24-hour air testing day. 

b) Preceding week usage was measured during the one week preceding the 24-hour air 

 testing day. 

Occupant Use of Mechanical Outdoor Air Systems. For the two types of mechanical outdoor

air systems encountered in the field study—ducted outdoor air systems and heat recovery

ventilator systems—the median test day use was 2.5 hours for the ducted outdoor air

systems (n=14) and 24 hours for heat recovery ventilator systems (n=8). These data indicate

that the ducted outdoor air systems, which typically are operated intermittently and in

conjunction with the forced air unit fan, operate for only a small portion of the day, while

the heat recovery ventilator systems are typically operated continuously. To ensure

adequate delivery of outdoor air to the home, ducted outdoor air systems should have a

fan cycler, so that even if the thermostat fan switch does not operate the forced air unit fan,

the fan is automatically operated for a minimum time. Few of the homes in this study with

operational ducted outdoor air systems (four of the 14 homes) had fan cyclers. Thus, to

ensure adequate and energy efficient delivery of outdoor air to the home, ducted outdoor

air systems should include a fan cycler with fan cycle times and outdoor airflow rates set to

provide sufficient outdoor air ventilation.

Occupant Use of Mechanical Nighttime Cooling Systems. For the two types of nighttime

cooling systems found in the field study—whole house fan systems and forced air unit

return air damper systems—the median test day use was 0.7 hours for whole house fan

systems and 5.3 hours for return air damper systems. Use of these systems was confined

primarily to the summer months, so the nighttime cooling systems were operated for

relatively few hours each day, with the return air damper systems having longer operating

times.

Occupant Use of Forced Air Unit Systems. The median test day use for forced air units was 1.1

hours; 32 percent of the homes had zero forced air unit use during the 24‐hour test day,

and 11 percent had zero use during the entire preceding week. This low operating time of

the forced air unit fan limits the effectiveness of ducted outdoor air systems, which depend

on the operation of the forced air unit fan, to deliver the required outdoor air.
4 

Objective 2. Measure and characterize indoor air quality, ventilation, and the potential

sources of indoor pollutants.

Forced Air Heating/Cooling System Duct Leakage. A total of 86 percent of the homes had duct

leakage exceeding the California Title 24 maximum of 6 percent, demonstrating that new

homes in California have relatively leaky ducts.

Home Building Envelope Air Leakage Area. The median ACH50 (air changes per hour at

50 pascals) for the homes in this study was 4.8 air changes per hour, which compares to a

median of 5.2 air changes per hour for a group of homes built since 1992 and 8.6 air

changes per hour for a group of homes built before 1987. New Californian homes are

generally being built tighter, but not exceptionally tight, like those found in colder climate

regions.  

Home‐to‐Garage Air Leakage. A total of 65 percent of the homes did not meet the American

Lung Association guideline for a home‐to‐garage negative pressure of at least  

‐49 pascals when the home is depressurized to ‐50 pascals with respect to the outdoors. In

the three‐home pilot study, tracer gas measurements indicated that between 4 percent and

11 percent of the garage sources entered the home. A substantial amount of air from

attached garages, which often contain air contaminant sources such as vehicle fuel, exhaust

fumes, gasoline‐powered lawn equipment, solvents, oils, paints, and pesticides, can enter

the home’s indoor air.  

Mechanically Supplied Outdoor Airflow Rates. Sixty‐four percent of ducted outdoor air

systems failed to meet the California Energy Commission’s new 2008 Building Energy

Efficiency Standards. The very low outdoor air exchange rates for the ducted outdoor air

systems resulted from a combination of low outdoor airflow rates and short operating

times. Heat recovery ventilator systems performed much better. All of the heat recovery

ventilator systems met the new 2008 Building Energy Efficiency Standards. These results

show that the heat recovery ventilator systems that we tested are a more effective outdoor

air supply strategy than the ducted outdoor air systems.

The performance of the ducted outdoor air systems is poor because these systems

(1) lacked controls (such as fan cyclers) to ensure adequate operating times of the forced air

unit fan, and (2) lacked proper sizing and balancing of the outdoor air duct to ensure

sufficient outdoor airflow rate into the system when the forced air unit fan was operated.  

In addition, the performance of intermittent mechanical outdoor air systems (such as

ducted outdoor air systems) is not equivalent to continuous systems (such as heat recovery

ventilator systems) with respect to controlling the short‐term exposures to indoor air

contaminants, especially if the cycle times are long (for example, greater than two hours).

The 2008 Building Energy Efficiency Standards, which were adopted after this study was

completed, require a minimum operation time of 1 hour every 12 hours. During extended
5 

outdoor air ventilation off‐times, intermittent ventilation systems allow for air

contaminants with indoor sources to increase substantially as compared to the increases

that would occur with a continuous ventilation system. For some indoor air contaminants,

such as those that cause irritation and/or odor, the effects are initiated by the immediate

exposure to the indoor concentration rather than prolonged exposure to a concentration

over a period of time. For such compounds, intermittent ventilation systems may not be

sufficient for reducing indoor concentrations to acceptable levels.

Tracer Gas Measurements of Home Outdoor Air Exchange Rates. The median 24‐hour outdoor

air exchange rate measurement was 0.26 air changes per hour, with a range of 0.09 air

changes per hour to 5.3 air changes per hour (Table E2). A total of 67 percent of the homes

had outdoor air exchange rates below the minimum California Building Code requirement

of 0.35 air changes per hour. 

 

Table E2. Summary comparison of outdoor air exchange rate measurements and CBC 2001 

minimum code requirements.

Number of 

Homes 

Tested 

Minimum 

Air 

Exchange 

Rate 

(ach) 

Median 

Air 

Exchange 

Rate 

(ach) 

Maximum 

Air 

Exchange 

Rate 

(ach) 

CBC Code

Requirement 

(ach)* 

Percentage 

of Homes 

Below CBC Code 

Requirement 

(%) 

24-Hour 

Measurement 

106 0.09 0.26 5.3 0.35 67 

 * 2001 California Building Code, Appendix Chapter 12, Interior Environment, Division 

1-Ventilation, Table A-12-A, Outdoor Air Requirements for Ventilation, Living Areas. Air 

changes per hour (California Building Code 2001). 

The relatively tight envelope construction, combined with the fact that many people never

open their windows for ventilation, resulted in many homes with low outdoor air

exchange rates.  

Indoor Air Contaminant Concentrations. The only indoor air contaminants that exceeded

recommended non‐cancer and non‐reproductive toxicity guidelines were formaldehyde

and PM2.5 particulate matter. For formaldehyde, 98 percent of the homes exceeded the 2008

Chronic and 8‐hour Reference Exposure Levels for irritant effects of 9 micrograms per

cubic meter, 59 percent exceeded the 2005 California Air Resources Board’s indoor air

guideline for irritant effects of 33 micrograms per cubic meter, and 28 percent exceeded the

2008 Acute Reference Exposure Levels for irritant effects of 55 micrograms per cubic meter

(Table E3). None of the homes exceeded the 2008 Reference Exposure Levels for

acetaldehyde. For PM2.5, only one home, with an indoor concentration of 36 micrograms

per cubic meter, exceeded the U.S. Environmental Protection Agency’s PM2.5 24‐hour

ambient air quality standard of 35 micrograms per cubic meter. 
6 

Table E3. Summary comparison of indoor concentrations of formaldehyde, acetaldehyde, 

and indoor air contaminant guidelines.

Compound Number 

of 

Homes 

Tested 

Minimum 

Concentration

(μg/m3) 

Median 

Concentration

(μg/m3) 

Maximum 

Concentration

(μg/m3) 

Indoor Air 

Guideline 

(μg/m3

) 

Percentage 

Above 

Indoor Air 

Guideline 

(%) 

2 a 100 

9 b 98 

9 c 98 

33 d 59 

Formaldehyde 105 4.8 36 136 

55 e

 28 

4.5 a 93 

140 b 0 

300 c 0 

Acetaldehyde 105 1.9 20 102 

470 e

 0 

a) Proposition 65 No Significant Risk Level for carcinogens (OEHHA 2008a). 

b) Office of Environmental Health Hazard Assessment Chronic Reference Exposure Levels, 

2008 (OEHHA 2008b). Adopted after study completed. 

c) OEHHA 8-hour Reference Exposure Levels, 2008 (OEHHA 2008b). Adopted after study 

completed. 

d) Indoor Air Quality Pollution in California (California Air Resources Board 2005). 

e) OEHHA Acute Reference Exposure Levels, 2008 (OEHHA 2008b). Adopted after study 

completed. 

Most new homes had indoor formaldehyde concentrations that exceeded recommended

guidelines.

Volatile Organic Compound Proposition 65 Safe Harbor Levels. For each of the seven

volatile organic compounds with No Significant Risk Levels for cancer, there were some

homes that exceeded the No Significant Risk Levels concentration indoors. As summarized

in Table E3 for formaldehyde and acetaldehyde, the percentages of homes exceeding the

No Significant Risk Levels concentration were 100 percent and 93 percent, respectively. For

the five other volatile organic compounds, the percentage of homes exceeding the No

Significant Risk Levels concentration ranged from 8 percent for trichloromethane

(chloroform) and tetrachloroethene to 63 percent for benzene.  

For the two volatile organic compounds with Maximum Allowable Dose Levels for

reproductive toxicity, only the benzene Maximum Allowable Dose Levels was exceeded.

A total of 20 percent of the homes had indoor benzene concentrations that exceeded the

calculated indoor Maximum Allowable Dose Levels concentration. Thus, a substantial

percentage of new homes have indoor concentrations that exceed recommended guidelines

for cancer and/or reproductive toxicity.
7 

Potential Sources of Indoor Air Contaminants. The primary source of the indoor

concentrations of formaldehyde and acetaldehyde, which were the two air contaminants

that most frequently exceeded recommended guidelines, is believed to be composite wood

products. While the research team was not able to determine the extent to which

formaldehyde‐based resins were used in the composite wood identified in the homes,

formaldehyde‐based resins are the most common resins used in the production of

composite wood products. The composite wood identified in these homes include

particleboard that was used in 99 percent of the kitchen and bathroom cabinetry, as well as

many pieces of furniture. Other sources of composite wood include plywood and oriented

strand board in walls, subfloors, and attics, and medium density fiberboard in baseboards,

window shades, interior doors, and window/door trims.

Potential sources of some volatile organic compounds were identified for homes with

elevated indoor volatile organic compound concentrations. The following potential sources

of indoor air contaminants are suggested from a comparison of the occupant activity logs

and house characteristics with the indoor contaminant concentrations and emission rates:

1,4‐dichlorobenzene and naphthalene from mothballs, d‐limonene from furniture polish

and cleaning chemicals, 2‐butoxyethanol from anti‐bacterial wipes, toluene from air

fresheners, and tetrachloroethene from dry cleaned clothes or drapes.

Objective 3. Determine occupant perceptions of, and satisfaction with, the indoor air

quality in their homes.

A total of 28 percent of the households reported experiencing one or more of nine physical

symptoms during the previous three weeks that they did not experience when they were

away from the home. The three most frequently reported symptoms were nose/sinus

congestion (19 percent), allergy symptoms (15 percent), and headache (13 percent). The

three most frequently reported thermal comfort perceptions were “too cold” (19 percent),

“too hot” (15 percent), and “too stagnant (not enough air movement)” (12 percent). Thus, a

substantial percentage of occupants of new homes report experiencing physical symptoms

or thermal discomfort.  

Objective 4. Examine the relationships among home ventilation characteristics, measured

and perceived indoor air quality, and house and household characteristics.

Statistical comparisons were conducted for indoor formaldehyde and acetaldehyde

concentrations, outdoor air exchange rates, and window usage. Formaldehyde and

acetaldehyde were selected for these analyses, as these were the two air contaminants that

most frequently exceeded recommended indoor concentration guidelines. Because of the

small number of homes in the sample groups and the important seasonal and house‐

specific differences, these comparisons should only be considered as suggestive of

differences. Multivariate analyses need to be done to further establish any differences

between the groups.
8 

Formaldehyde concentrations were found to be significantly higher in the following group

comparisons:

• Non‐mechanically ventilated Northern California homes had higher formaldehyde

concentrations than Southern California homes

• Ducted outdoor air homes had higher formaldehyde concentrations than homes

without mechanical outdoor air ventilation systems

• Ducted outdoor air homes had higher formaldehyde concentrations than heat

recovery ventilator homes

Acetaldehyde concentrations were found to be significantly higher in the following group

comparisons:

  

• Ducted outdoor air homes had higher acetaldehyde concentrations than homes

without mechanical outdoor air ventilation systems

• Ducted outdoor air homes had higher acetaldehyde concentrations than heat

recovery ventilator homes

Window usage was found to be significantly higher in the following group comparisons:

• Summer homes had higher window usage than winter homes

Outdoor air exchange rates were found to be significantly higher in the following group

comparisons:

• Heat recovery ventilator homes had higher outdoor air exchange rates than homes

without mechanical outdoor air ventilation systems

• Heat recovery ventilator homes had higher outdoor air exchange rates than ducted

outdoor air homes

Correlation analyses were also conducted for indoor formaldehyde and acetaldehyde

concentrations with six home characteristics and four environmental conditions. For both

formaldehyde and acetaldehyde concentrations, the outdoor air exchange rate was

determined to have a significant inverse correlation. For formaldehyde concentrations,

indoor air temperature was determined to have a significant correlation. These results

indicate that as outdoor air exchange rates decrease or the indoor temperate increases, the

indoor concentrations of formaldehyde increase.
9 

Objective 5. Identify the incentives and barriers that influence people’s use of windows,

doors, and mechanical ventilation devices for adequate air exchange.

Of the homeowners with mechanical outdoor air systems (that is, ducted outdoor air or

heat recovery ventilator systems, not nighttime cooling systems, evaporative cooling

systems, or window fans):

• 78 percent stated that the operation of the system was explained to them when they

bought or moved into the house

• 63 percent responded that they understood how the system works

• 83 percent stated that they felt that they understood how to operate the system

properly

A total of 91 percent stated they chose the system because it came with the house, and the

things they liked most about the system were: “Fresh air” (52 percent), “Quiet”

(48 percent), and “Reduced concern about indoor air quality” (26 percent). The things they

liked least about the system were: “Not effective” (32 percent), ”Too drafty” (26 percent),

and “Too noisy” (26 percent).

Objective 6. Identify the incentives and barriers related to people’s purchases and practices

that improve indoor air quality, such as the use of low‐emitting building materials and

improved air filters.

A total of 24 percent of the 105 respondents stated “none” in response to the question

“What special measures or choices have you or the builder taken to improve the quality of

the air in your home?” The four most frequent responses to improvements undertaken

were: “Hard flooring instead of carpeting” (33 percent), “Carbon monoxide alarm”

(28 percent), “High efficiency vacuum cleaner with special features such as filters to trap

more particles” (27 percent), and “Upgrade my central air filter” (25 percent).

Conclusions

The following summarizes the main conclusions from this study of new single‐family

homes built in California in 2002–2004.

1. Many homeowners never open their windows or doors, especially in the winter

months.

2. New homes in California are built relatively tight, such that outdoor air exchange

rates through the building envelope can be very low (e.g., 0.1 air changes per hour).
10 

3. In new homes with low outdoor air exchange rates, indoor concentrations of air

contaminants with indoor sources, such as formaldehyde and some other volatile

organic compounds, can become substantially elevated and exceed recommended

exposure guidelines.

4. Ducted outdoor air mechanical outdoor air ventilation systems generally did not

perform well as a result of the low outdoor airflow rates and short operating times.

A total of 64 percent of ducted outdoor air systems failed to meet the American

Society of Heating, Refrigerating and Air‐Conditioning Engineers 62.2‐2007

standard for residential ventilation, which is referenced in the Energy

Commission’s 2008 Building Energy Efficiency Standards.

5. Heat recovery ventilator mechanical outdoor air ventilation systems performed

much better than ducted outdoor air systems. All heat recovery ventilator systems

met the California Energy California’s new 2008 Building Energy Efficiency

Standards.

Recommendations

1. Consideration should be given to installing mechanical outdoor air ventilation

systems in new single‐family residences to provide a dependable and continuous

supply of outdoor air to the residence for the purpose of controlling indoor air

contaminants.  

2. Consideration should be given to regulating the emissions of air contaminants from

building materials, such as the 2007 California Air Resources Board regulation to

limit formaldehyde emissions from composite wood products.

  

3. Given the relatively high frequency of indoor formaldehyde concentrations that

exceeded recommended exposure guidelines, and the fact that formaldehyde is a

known human carcinogen, consideration should be given to conducting studies

focused on quantifying the emission rates of formaldehyde from all potential

indoor sources (such as building materials, furnishings, consumer products, and

others). Based on this research, regulations should be developed to reduce indoor

formaldehyde emissions.  

4. Outreach to public and professional groups should be increased regarding the need

to reduce indoor formaldehyde concentrations in existing homes by sealing

exposed composite wood surfaces, selecting low‐emission furniture, improving

outdoor air ventilation in the home, and controlling indoor humidity.

5. Multivariate analyses of the data collected in this study should be conducted to

further develop the understanding of the relationships between indoor air
11 

contaminant concentrations, indoor sources, ventilation, season, and other major

sources of variance.  

6. A statewide population‐weighted assessment from the data collected in this field

study should be performed to better understand the air contaminant source and

ventilation characteristics of new homes.

7. Additional studies of indoor air quality and ventilation with diurnal wind speed

and temperature swings should be conducted to examine the significance of

nighttime cooling by natural or mechanical means.  

8. Further studies in additional homes with mechanical outdoor air ventilation

systems should be conducted to confirm the findings identified in this study and

with consideration for other building factors. Both installation and field

performance of the mechanical outdoor air ventilation systems should be

evaluated.  

9. Revision of the intermittent ventilation effectiveness factors in the 2008 Building

Energy Efficiency Standards and the Energy Commission’s companion Residential

Compliance Manual should be considered, to provide intermittent ventilation that

results in indoor air quality that is comparable to that provided by continuous

ventilation systems.

10. Research should be conducted on exhaust‐only ventilation systems, which were not

encountered in this study but may be used widely in the future.

11. Home builders should be educated about the importance of conveying to

homeowners the need for outdoor air ventilation in homes, how the ventilation

systems operate, and the importance of designing systems that are easy for

homeowners to maintain. In addition, consider creating an easy‐to‐read short fact

sheet that can be distributed to the public regarding residential ventilation systems

and the importance of the operation and maintenance of these systems to indoor air

quality.

12. Research should be conducted to investigate residential exposures to ozone‐

initiated reaction products, such as formaldehyde and other aldehydes and

ultrafine particles, that are formed when ozone reacts with contaminants such as

d‐limonene, which is emitted by many air freshener and cleaning products as well

as some orange oil termite treatments. This project’s database contains important

information for such research, including d‐limonene concentrations, outdoor air

exchange rates, air cleaners that generate ozone, and formaldehyde and other

aldehyde concentrations.  
12 

Benefits to California

This was the first large field study of window use, outdoor air ventilation rates, and indoor

air contaminants in new California homes. The data from this study were immediately

useful for the California Energy Commission in guiding the development of building

design standards that require mechanical ventilation to protect indoor air quality and

comfort in California homes and for the California Air Resources Board to improve

exposure assessments of indoor and outdoor air contaminants. In particular, the Energy

Commission used the study results as a scientific basis to revise the State’s building energy

efficiency standards to provide more healthful, energy‐efficient homes in California. The

study results will also improve California Air Resources Board’s ability to identify current

sources of indoor air contaminants, to assess Californians’ current exposure to measured

toxic air contaminants, and to recommend effective strategies for reducing indoor air

pollution.
13 

1.0 Introduction 

Concerns have been raised about whether homeowners use windows, doors, exhaust fans,

and other mechanical ventilation devices enough to remove indoor air contaminants and

excess moisture. Building practices and building standards for energy efficiency have led

to more tightly sealed homes, and building codes have relied on occupants to open

windows for ventilation. However, there is very little information on current ventilation

practices, indoor air quality (IAQ), or indoor air contaminant sources in homes.

In 2005, the California Air Resources Board (ARB) prepared a comprehensive report on

indoor air quality in response to requirements of Assembly Bill 1173, Report to the California

Legislature–Indoor Air Pollution in California (California Air Resources Board 2005). This

report summarizes the best scientific information on indoor air pollution, including:

information on common indoor air contaminants and their sources; the potential health

impacts of indoor air contaminants and associated costs; existing regulations and practices;

and options for mitigation in schools, homes, and non‐industrial workplaces. This report

concludes that indoor air pollution causes substantial, avoidable illness and health

impacts–ranging from irritant effects to asthma, cancer, and premature death–and costs

Californians billions of dollars each year.  

Phillips et al. (1990) reported results of a statewide telephone survey of 1,780 Californians

conducted in 1987–1988 regarding the occupant’s use of mechanical and natural

ventilation. The authors reported that a sizable number of households only open

windows/doors for natural ventilation for a few minutes a day at most, especially during

the winter (25% never open windows/doors for ventilation). In addition, very few

households use exhaust fans. Based upon the results of this survey the authors conclude

that in homes where the occupants do not use windows/doors or mechanical systems for

ventilation, that these households may be susceptible to high concentrations of indoor air

contaminants.

In addition to the fact that many homeowners do not use windows/doors for ventilation,

the building envelope tightness in new Californian homes has been increasing, which

reduces the natural infiltration of outdoor air into residences. Wilson and Bell (2003),

report that construction practices have resulted in lower infiltration rates. The building

envelope air tightness as determined from blower door tests in a sample of 76 homes built

in California since November 2002 had a median ACH50 (i.e., air changes per hour at

50 pascals [Pa]) of 5.2, with a range of 2.3 to 8.7; while in a sample of 13 homes built before

1987, the median ACH50 was 8.6, with a range of 6.2 to 13.2. In addition, Chan et al. (2003)

report in an analyses of more than 70,000 measurements in the U.S. housing stock that

envelope leakage has been steadily decreasing. For conventional homes that are not

participants of a low‐income or an energy‐efficiency program and that have floor areas

between 1500 square feet (ft2) to 2000 ft2, the median normalized envelope leakage area has

decreased from 0.67 in homes built before 1950, to 0.49 for homes built between 1950 and
14 

1979, to 0.38 for homes built between 1980–1995, to 0.31 for homes built between 1995 and

2002.  

In recognition that many homeowners often do not use windows for outdoor air

ventilation and that residential building envelopes have evolved to be more airtight, the

State of Washington has, since 1991, required mechanical outdoor ventilation for

residences. A 1999 field study (Devine 1999) of 31 homes built since 1991 with mechanical

outdoor ventilation systems revealed that the technical details of the mechanical outdoor

air ventilation requirements were widely misunderstood. While all 31 homes evaluated

were equipped with at least some system components, less than half (15) met the

requirements either prescriptively or by performance.

Batterman et al. (2005) reported that attached garages may be important sources of air

contaminants in the home. In a study of 15 residential garages, the authors observed

elevated concentrations of volatile organic compounds in the garage air. The calculated

emission rates of 34 volatile organic compounds in the 15 garages, totaled 3.0 ± 4.1 grams

(g)/day and were dominated be gasoline‐related compounds (e.g., benzene, toluene, and

xylenes). Although the impact of the concentrations of volatile organic compounds (VOC)

in the garage air upon the indoor air concentrations of the residences was not assessed in

this study, the authors conclude that garages are potentially significant sources of VOC

into the air of residences.  

Hodgson and Levin (2003) reported the indoor concentrations of VOC in two studies

involving 20 new single‐family homes. The VOC concentrations with maximum

concentrations of 50 parts per billion (ppb) or more included formaldehyde, acetaldehyde,

hexanal, toluene, ethylene glycol, 1,2‐propanediol, 2‐propanaone, and alpha‐pinene.

Hodgson et al. (2000) reported in a study of new manufactured and site‐built homes that

formaldehyde is by far the most likely of the 12 VOCs evaluated to produce sensory

irritation effects. Phenol and acetic acid were also identified as relatively potent irritants.

Multiplying the relative irritancy for these three VOCs by the geometric mean indoor

concentration measured in the seven site‐built homes in this study results in acetic acid

contributing 17 times more times sensory irritation than phenol, and formaldehyde

contributing 419 time more. In addition to the sensory irritant effects of formaldehyde, in

2004, the World Health Organization designated formaldehyde as a known human

carcinogen (IARC 2004).

Hodgson et al. (2002) measured the emission rates of formaldehyde in a new, fully

furnished but unoccupied manufactured home. The materials with the highest percentage

of the total emission rates of formaldehyde were determined to be to the particleboard

cabinetry cases (36%) and the high density fiberboard passage doors (32%).
15 

To help better understand ventilation and the impact upon air quality in new Californian

homes, a mail survey of new single‐family detached homes was conducted to determine

occupant use of windows, barriers that inhibit their use, satisfaction with IAQ, and the

relationships between these factors (Price et al. 2007). This study, sponsored by the ARB

and the California Energy Commission (Energy Commission), was conducted by the

University of California, Berkeley (UCB) Survey Research Center. In December 2004 and

January 2005 a questionnaire was mailed to a stratified random sample of 4,972 single‐

family detached homes built in 2003. A total of 1,448 responses were received. An

additional sample of 230 homes was obtained from builders. These additional homes were

also mailed the questionnaire and were reported by the builders to have mechanical

ventilation systems. A total of 67 responses were received from this sample.

Table 1 (page 17) summarizes the percentage of homes responding to the questionnaire

that reported no use of windows for ventilation on a seasonal basis. The results are

presented for four categories of never‐used hours per day: 24‐hours/day (i.e., never

opened), 23 or more hours/day, 22 or more hours/day, and 21 or more hours/day;

corresponding to 0 hours, 1 or less hours, 2 or less hours, and 3 or less hours of window

usage per day. As can be seen in Table 1, a substantial percentage of homeowners, ranging

from 5.8% in the spring to 29% in the winter, report never using their windows. The

percentage of homeowners reporting 21 or more hours per day of no window usage

ranged from 12% in the spring to 47% in the winter.

The reasons reported most frequently as “very important” by the homeowners (i.e., 20% or

more of homeowners) for not opening their windows included: security/safety (80%),

maintain comfortable temperature (68%), keep out rain/snow (68%), save energy (61%),

keep out insects (52%), keep out dust (42%), too windy/drafty (45%), keep out noise (39%),

reduce air contaminants or odors from outdoors (36%), keep out pollen/allergens (35%),

privacy from neighbors (29%), and keep out woodsmoke (23%).

In July 2005 as a follow‐up to the UCB mail survey, a large indoor air quality field study

entitled Ventilation and Indoor Air Quality in New Homes, sponsored by the California Air

Resources Board and the California Energy Commission, was launched to assist in

answering some of the questions regarding ventilation and indoor air quality in new

single‐family detached homes.  

This field study involved 108 new single‐family homes from Northern and Southern

California, including a subset of 26 homes with mechanical outdoor‐air ventilation

systems. The field teams measured home ventilation and indoor contaminant source

characteristics, including the amount of composite wood associated with

cabinetry/furnishings and the finishes of floors, walls, and ceilings; indoor contaminant

concentrations; the residents’ ventilation practices; IAQ perceptions; and decision factors

regarding ventilation and IAQ‐related actions. Measurements of indoor and outdoor air

quality and ventilation parameters were made in the summer, fall, and winter. Indoor air
16 

concentrations of volatile organic compounds; aldehydes (including formaldehyde); PM2.5

particulate matter; nitrogen dioxide; carbon monoxide; carbon dioxide; temperature; and

relative humidity were measured over one 24‐hour period. The outdoor air ventilation

rates were determined concurrent with the air contaminant measurements using passive

perfluorocarbon tracer (PFT) gas measurements. In addition, the field teams measured the

building envelope air leakage, garage‐to‐home air leakage, forced air unit duct leakage,

window use, airflow rates, and fan system usage. Twenty of the 108 homes were tested in

both the summer and winter seasons, and four homes were tested in the summer, fall, and

winter. Four homes were tested over multiple days, including weekends.

This study provides, for the first time, statewide, accurate and current information on both

ventilation and IAQ in new California homes. Indoor air quality and household ventilation

practices were obtained from multiple seasons and regions of the state, which will help

characterize the full range of indoor air contaminant exposure in such homes. Measured

levels of ventilation and IAQ were compared to current guidelines and standards.

Information on the use of windows, fans, and central systems will help establish realistic

values for developing California building energy efficiency standards.  

The Energy Commission used the study results as a scientific basis to revise the state’s

building energy efficiency standards, in order to provide more healthful, energy‐efficient

homes in California. The study results will improve ARB’s ability to identify current

sources of indoor air contaminants, to assess Californians current exposure to measured

toxic air contaminants, and to recommend effective strategies for reducing indoor air

pollution.

1.1 Project Study Objectives 

This project has the following six specific study objectives:

1. Determine how residents use windows, doors, and mechanical ventilation devices such

as exhaust fans and central heating and air‐conditioning systems.

2. Measure and characterize IAQ, ventilation, and the potential sources of indoor

pollutants.

3. Determine occupant perceptions of, and satisfaction with, the IAQ in their homes.

4. Examine the relationships among home ventilation characteristics, measured and

perceived IAQ, and house and household characteristics.

5. Identify the incentives and barriers that influence people’s use of windows, doors, and

mechanical ventilation devices for adequate air exchange.
17 

6. Identify the incentives and barriers related to people’s purchases and practices that

improve IAQ, such as the use of low‐emitting building materials and improved air

filters.

1.2 Report Organization 

Section 2, Project Approach / Materials and Methods, describes the study design,

participant recruitment, and measurements methods for home characteristics, window and

mechanical ventilation system usage, outdoor air exchange rates, indoor air contaminants,

and occupant perceptions and decision factors.

Section 3, Project Outcomes / Results and Discussion, presents and discusses the results

associated with each of the study objectives.

Section 4, Conclusions and Recommendations, presents the research team’s conclusions

and recommendations.  

Because there are so many large tables and figures in this report, in order to not have

frequent and multiple page interruptions of the report text, the figures and tables have

been placed at the end of each section in which they are introduced. To help readers locate

the specific table or figure, the page number is included in the text of the report.

Table 1. Seasonal percentage of new California single-family detached homes reporting no 

use of windows for 24, 23, 22, and 21 hours per day. 

Percentage of Homes Surveyed Reporting No Use of Windows a

 

for the Indicated Number of Hours per Day 

(N = 1,334)

24 hours/day 23 or more 

hours/day 

22 or more 

hours/day 

21 or more 

hours/day 

Summer 7.5 9.1 12 14 

Fall 8.6 12 16 18 

Winter 29 36 45 47 

Spring 5.8 5.8 8.4 12 

a) Study of Ventilation Practices and Housing Characteristics in New California Homes (Price et al. 2007). 
18 
19 

2.0 Project Approach/Material and Methods 

2.1 Study Design 

 

This study’s design involved recruitment of 108 new Californian homes utilizing the UCB

mail survey database, although it was anticipated that some additional homes outside of

the UCB mail survey database would need to be recruited to fulfill the requirements of the

proposed study sample. Only single‐family detached homes built after January 2002 that

were owner‐occupied primary residences for at least one year were eligible for the field

study. Additionally, if occupants reported tobacco smoking inside the homes, they were

excluded from the field study. The intent was to have homes that were recently built under

the latest California building standards (i.e., 2001), including the California Building Code

(California Building Standards Commission 2001) and the California Title 24 Energy

Efficiency Standards (California Energy Commission 2001a and 2001b). The intent was also

to include occupants who would recollect their “new‐home experience” but had been in

the home long enough to be familiar with its operation across the year (four seasons).  

Our proposed home sample frame consisted of a total of 108 California new single‐family

detached homes, with a total of 54 homes from the South Coast (Los Angeles and San

Diego) region and 54 homes in the Central Valley / Delta (Sacramento) region. Our sample

frame also required for the 54 homes in each region to be divided into 27 homes for testing

in the winter field session and 27 homes for testing in the summer field session. In

addition, our sample frame required inclusion of a minimum of 20 mechanically ventilated

homes (i.e., homes with mechanically supplied outdoor air to the whole house) selected to

represent at least three major manufacturers of these type systems.

Additionally, our study plan required the following crossover/repeat testing of homes:

• 10 of the 54 homes in each region were selected for retesting during the alternate

season (summer or winter).  

• The 4 homes of the 5 seasonal repeat homes in Northern California were retested

during the fall swing season.  

• 2 of the 27 winter and 2 of the 27 summer homes in Northern California were

selected for testing on 2 additional consecutive 24‐hour periods, which include one

additional week day and one weekend day (i.e., Thursday, Friday, and Saturday).

Our study plan also required, to the extent there was sufficient sample in excess of those

required to fulfill the primary selection criteria, to select homes following secondary

selection criteria, which were requested by the ARB and Energy Commission. These

criteria were:
20 

• Match the 60/20/20 percentage mix from the UCB mail survey three strata: Rest‐of‐

State, Sacramento Delta, and Southern California Coastal

• Northern California Inland

o Use the Rest of the State stratum to identify the homes in the Central Valley

from Merced north

o Exclude homes in the Sacramento Delta Stratum  

o Exclude San Jose homes

• Northern California Delta

o Include the homes in the Sacramento Delta Stratum

  

o Exclude homes in the Bay Area  

• Southern California Inland

o Use the Rest of the State Stratum to identify homes in the areas from about

Lancaster south

o Exclude the Southern California Coastal Stratum homes

• Southern California Coastal

o If there are few homes available in this group, include some homes in the high

desert areas of Lancaster, Palmdale, areas east to Victorville, or in the Lake

Elsinore area. Verify that these areas meet the Energy Commission screening

criteria for nighttime ventilative cooling potential: Summer maximum

temperature of at least 90°

F and nighttime minimum temperature at least 30°F

lower.

o Exclude homes if less than two miles from the coast.

 

2.2 Home Recruitment and Selection 

To recruit the homes for this study, the database from the UCB (Price et al. 2007) mail

survey that was administered in 2004–2005 was utilized, along with supplemental listings

of new homes (i.e., built since 2002) in the same areas as homes already identified. The

UCB mail survey drew a random sample of 10,000 new single‐family homes from a listing
21 

by DataQuick, which had the best available records of this type. This list was stratified:

2,000 homes from the Sacramento Delta area, 2,000 from the Southern Coastal area, and

6,000 from the rest of the state. The first two strata were defined by zip code areas where

substantial nighttime cooling was expected in the summer due to coastal or delta wind

influence. About one‐half of the selected homes in each stratum were sent a recruitment

letter. Over 300 of those homes were ineligible, mostly because the residents had not lived

in the home at least nine months, the home was vacant, or the address was incorrect.  

In this stratified‐random sample by UCB survey, known as the Statewide Probability

Sample, a total of 4,648 eligible homes were contacted, and 1,448 of those homes completed

the mail questionnaire, for a 31% response rate. The participating homes from this sample

have a sample weight assigned to them to adjust for the different sampling rates and the

slightly different response rates for each stratum.  

The UCB Statewide Probability Sample appears to be fairly representative of new single‐

family homes in California. The survey response rate of 31% was very good for mail

surveys, which usually achieve a response rate of about 10%. As discussed by Price et al.

(2007), the ethnic composition of the households was similar to the California population

as a whole, except that the fraction of Asian households was a little larger than that for

California. As expected for recent homebuyers, the households had higher incomes and

household sizes compared to the general population.

In addition to recruiting the Statewide Probability Sample, the UCB mail survey recruited a

Supplementary Builders’ Sample of new homes reported by the builders to have outdoor

air mechanical ventilation systems. This sample listing consisted of homes built by a

Northern California building firm with homes mainly in the Sacramento Delta area, homes

built in Southern California as part of the U.S. Department of Energy (2007) Building

America program and homes identified by ARB staff. Out of 192 eligible homes from this

group, 67 completed the questionnaire, for a response rate of 35%.

For the present study, the research team tried to contact participants in the UCB mail

survey who had previously indicated their willingness to participate in a field study

involving measurements of ventilation and indoor air quality in their homes. Out of all the

completed questionnaires in the UCB survey (1,515), 965 respondents (66%) of the

respondents indicated such willingness. About one‐third (340) of these respondents were

located in Northern California, and two‐thirds (624) were located in Southern California. A

total of 126 respondents (107 in Northern California and 19 in Southern California) were

excluded from the study due to their location in areas with coastal influences (Bay Area in

Northern California; proximity to the coast in Southern California.).

Unfortunately the database did not contain telephone numbers for the 965 respondents; a

search by address returned phone numbers for 300 (32%) of them.
22 

Initial recruiting attempts failed to obtain the target sample sizes because of the limited

number of potential participants and the need to cluster homes geographically. Therefore,

in addition to the interested respondents to the UCB mail survey, supplemental DataQuick

listings of owners of new (2002 to 2004 vintage) single‐family detached homes from the

neighboring areas were purchased. This supplemental listing had 8,345 addresses,

homeowner names, and telephone numbers.

From this overall sample listing consisting of UCB sample homes and the supplemental

DataQuick sample, recruitment letters were mailed. A copy of the recruitment letter and

recruitment script is in the appendices of the Pilot Report, in Appendix A of this report.

The letters asked for homeowners interested in participating in the field study to call the

project participant recruiters’ toll‐free number. The letters also offered a $100 incentive in

addition to providing the indoor air quality and ventilation system testing to those who

participated in the field study. Calls were received from interested homeowners and the

calls were placed to those non‐responding homeowners for which telephone numbers

were available.

Upon making contact with the interested homeowners the research team administered a

recruitment script and collected information on the home, occupancy, and ventilation

systems and described the details of the three visits required by the field teams.

Researchers also collected information regarding the participants’ preferences for dates

and times of the three field visits with the understanding that the same time periods would

be required for each of the three field visits. These were:

• Time Period 1: 9 AM to 12 PM

• Time Period 2: 1 PM to 4 PM

• Time Period 3: 4 PM to 7 PM

The recruiters informed the homeowners that those who indicated flexibility in the field

visit dates and times would have a much higher probability of being selected.  

Upon completion of the administration of these recruiting scripts to interested

homeowners, the homes for the field study were selected based on the primary and

secondary sampling criteria discussed above. 

2.3 Field Work Teams and Work Assignments 

The fieldwork was divided amongst three field teams, each consisting of two field

technicians. All fieldwork was conducted according to the specific standard operating

procedures (SOPs) developed for each of the three field teams.  
23 

Field Team 1 installed PFT sources, installed data loggers on windows and fans, and

administered the Occupant Fan and Window Logs, the Indoor Contaminant Source

Activity Sheet, and the Occupant Questionnaire one week in advance of the field work

performed by Field Teams 2 and 3.  

Field Team 2 followed Field Team 1 by 7–10 days, to allow for the PFT sources to

equilibrate. Their duties included: the installation and start of the air contaminant

sampling equipment at an indoor and outdoor location, installation and start of the PFT

samplers, collecting information on home construction characteristics, and collecting an

inventory of indoor air contaminant sources.  

Field Team 3 followed Field Team 2 by 22–26 hours. This field team was responsible for the

removal of the air sampling equipment, the PFT samplers, window/door and fan logs and

loggers, collecting detailed information on building air leakage, duct air leakage, and

ventilation system airflow rates. 

2.4 Home and Site Characteristics Collection 

 

Characteristics of each home were collected using forms that were filled out by the field

team members during the home inspections. The forms used to record these data are the

Home Characteristics Form 1, PFT Form, Home Floor Plan Sketch or floor plan provided

by the homeowner, Home Characteristics Form 2, and Room Tally Form. The following list

describes the home characteristics that were collected in each home:

• General Characteristics

o number of occupants

o number of stories

o foundation type

o conditioned floor area, volume and envelope area

o area of openable windows and doors

• Mechanical Characteristics

o heating/cooling system: general description, location, filter type, duct

locations, airflow rates

o mechanically supplied outdoor air system: general description and airflow

rates

o exhaust fans: number, controls, and airflow rates
24 

o appliances: fuel type, venting, location

o other ventilation/conditioning equipment: general description and airflow

rates  

o air cleaning devices: type, manufacturer, and model

   

• Site Characteristics

o outdoor air contaminant sources (e.g., busy roadways, nearby gasoline

stations)

o site drainage conditions  

o site wind shielding

• Home Contaminant Source Characteristics

o vacuum system ‐ type and typical usage frequency

o number of occupants and pets  

o mechanical system fuels

o composite wood materials

o type of floor surface

o moisture staining/damage  

The conditioned floor area, envelope area, and air volume was calculated from on site

dimension measurements. Floor plans were obtained for each of the homes. Field Team 1

collected on‐site measurements of the home exterior dimensions, indoor ceiling heights,

and selected indoor wall dimensions. These dimensions were then used to calculate a scale

factor for the floor plans, and this scale factor was used to calculate the conditioned floor

areas, envelope areas, and air volumes on a room‐by‐room basis for the entire home.  

The amount of composite wood in each home was calculated as the combined sum of the

square feet associated with furniture/cabinetry and the finishes of floors, walls, and

ceilings. There were a substantial amount of composite wood products that were likely

present but could not be verified without damaging the surfaces. These included medium‐ 

density fiberboard baseboards, interior doors, window trim, window shades, and plywood

subflooring. In addition, data were not collected on whether the composite wood product

was covered with a laminate.
25 

2.5 Home Air Leakage Measurements 

2.5.1 Forced Air Unit Heating/Cooling System Duct Leakage 

Testing for forced air unit (FAU) duct leakage was conducted in accordance with ASTM

E1554‐03, Standard Test Method for Determining External Air Leakage of Air Distribution

Systems by Fan Pressurization (ASTM 2003a). The method uses a fan flow meter device

(i.e., DuctBlaster) attached to the return air grill, which measures the airflow required to

pressurize the ducts to 25 Pa while the supply ducts are sealed. The FAU system duct

leakage airflow was then divided by the total FAU return airflow to get the percent duct

leakage.

2.5.2 Building Envelope Air Leakage Area 

The building envelope air leakage area was determined by Field Team 3, using a

depressurization multipoint blower door test with automated pressure testing (APT)

instrumentation. Testing was conducted in accordance with ASTM E779‐99, Standard Test

Method for Determining Air Leakage by Fan Pressurization (ASTM 2003b). For this test the

homes were configured with all windows and exterior door closed, all interior doors open

(except doors to attached garages and hatches to attics), fireplace dampers closed, and all

exhaust fans off. The continuously operating mechanical outdoor air delivery fans (i.e., the

heat recovery ventilator systems [HRVs]) were left operating. Windy outdoor conditions

during testing of a few homes were such that a multipoint blower door test was not

possible. For these homes a single point depressurization blower door test was conducted

at 50 pascals of pressure.

2.5.3 Home-to-Garage Air Leakage 

Home‐to‐garage air leakage measurements were collected by Field Team 3 using two

methods to measure the potential air leakage between the home and the garage. The first

method consisted of using a blower door with APT instrumentation to conduct a zone

pressure diagnostic test of the garage‐to‐home connection. This test consists of conducting

two multi‐point blower door home depressurization tests as described above; one with the

home door to the garage closed and one with the door open. From these data the

equivalent leakage area (EqLA @10 Pa) in square inches was calculated between the garage

and the home and between the garage and outdoors. The second test method consisted of

measuring the differential pressure between the home and the garage while the home was

‐50 Pa with respect to outdoors. This test is recommended by the American Lung

Association in their Health Home Builder Guidelines (American Lung Association 2006).

When the home is depressurized to  ‐50 Pa with respect to outdoors, the home‐to‐garage

negative pressure must be at least  ‐49 Pa. It should be noted that the team contacted

members of the Technical Committee for information to determine the basis for this

guideline, and there are apparently no specific studies upon which it is based. Thus, it is

assumed that this guideline most likely represents the professional judgment of the
26 

Technical Committee with respect to a garage‐home coupling factor that is both relatively

low and achievable.

2.6 Window/Door and Mechanical Systems Usage 

 

The approach for measuring window/door and mechanical system usage applies a

combination of one‐time tests and weekly monitoring. Collection methods are summarized

in this section for the following ventilation parameters:

• windows and doors  

• mechanical exhaust fans and appliances

• forced air heating/cooling systems

The usage of select windows and doors, and operation of mechanical systems was

monitored for approximately one week by written logs and/or data logger instruments.

The amount of time that windows and doors were used and mechanical systems were

operated is reported in 24‐hour time periods counting back from the time that Field Team 3

entered the home and stopped the IAQ contaminant and PFT measurements.  

The following is a description of the methods that were used to collect data on each of the

ventilation parameters.

2.6.1 Occupant Use of Windows and Doors 

The homeowners were asked by Team 1 which windows and doors, if any, they use for

ventilation. Written logs and a writing utensil were placed on the glass or panel, near

where the window or door was opened. The homeowners used these logs to record the

time, duration, and distance of the window or door opening. The windows or doors that

were verified as never being used were not equipped with window written logs.

Homeowners were also asked to identify the two windows or doors that were most

frequently used for ventilation. Magnetic state loggers were taped to these two windows or

doors to record the time and duration that the window or door was opened.

Measurements of all window and door maximum opening areas in the home were

collected by Team 1. The opening width and height were measured using a tape measure.

2.6.2 Occupant Use of Mechanical Exhaust Systems 

Homeowners were asked by Team 1 which exhaust fans they use for ventilation. Data

loggers or written logs were deployed for all exhaust fans that would be used and all

exhausting appliances (i.e., dryers).

  
27 

For bathroom or laundry room exhaust fans, ac‐field data loggers were placed above the

exhaust grille in the vicinity of the fan motor for the two fans that the homeowners

identified as used the most. For these exhaust fans with data loggers, no written logs were

installed. For any additional exhaust fans, beyond the two equipped with data loggers,

written logs and a writing utensil were placed near the fan switch/timer for the

homeowners to log the usage. For bathroom and laundry room exhaust fans that are meant

to run on a continuous basis, such as HRVs, the homeowner was questioned by Team 1

about usage and for those HRVs that were reported to operate intermittently, either a

written log or an ac‐field data logger was installed.  

For clothes dryer exhaust appliances, an ac‐field data logger was hooked directly onto the

power cord of the dryer using a zip‐tie, and electrical tape if needed, or an ac‐field sensor

was clamped to the power cord and plugged directly into the data logger.  

For kitchen range hood exhaust fans, written logs and a writing utensil were placed on the

wall or microwave near the fan switch for the homeowners to log the usage and fan speed.  

All bathroom and laundry room exhaust fan airflow rates were determined using a

balometer flow hood. Where the exhaust duct was accessible along the exterior wall of the

building, kitchen range hood exhaust fan airflow rates were determined using a balometer

flow hood. For those homes where the exhaust duct was not accessible, the average air

speed was measured at the hood air filters and the filter dimensions were collected using a

tape measure.

Where the exhaust duct was accessible along the exterior wall of the building the dryer

exhaust airflow rate was determined using a balometer flow hood. While onsite the

number of bends (e.g., 900, 450) and the length of the ductwork were estimated and the

dryer make and model information was collected. For homes where the exhaust duct was

not accessible, these characteristics were used to calculate the estimated dryer exhaust

airflow rate using the flow rate specifications from the manufacturer.  

2.6.3 Occupant Use of Mechanical Outdoor Air Systems 

There were two types of systems encountered in the field study, ducted outdoor air (DOA)

systems and heat recovery ventilator systems (HRV). The DOA systems are also sometimes

called central fan integrated systems (CFI). The usages of the DOA systems, which are

integrated with the FAU systems, were monitored as described below for the FAU

systems. The usages of the HRV systems, which were either manually operated or

operated off a timer, were recorded by the occupant on a log sheet. Typically the HRV

systems operated continuously 24 hours per day.

2.6.4 Occupant Use of Nighttime Cooling Systems 

There were two types of nighttime cooling systems encountered in the field study: whole

house fan (WHF) systems and FAU return air damper (RAD) systems. The WHF systems
28 

consist of a large fan installed in the ceiling that draws outdoor air in by exhausting air

from the home into the attic and subsequently to the outdoors through the attic vents. The

usage of the WHF systems was monitored in a similar fashion to the FAU systems. The

RAD systems have an automatic motorized damper integrated with the FAU return air

duct that switches the air drawn into the FAU between the home air (i.e., from the central

return air grille) and the outdoor air (i.e., from an outdoor air intake on the roof). The

usage of the RAD systems was monitored using a relay and state logger combination.

Magnetic tape or a zip‐tie was used to secure the data logger with relay to the damper

control and the lead wires were fastened with alligator clips to the damper 24 volts‐direct

current (VDC) motor wiring connections.  

2.6.5 Occupant Use of Forced Air Heating/Cooling Systems (FAU) 

The research team used ac‐field data loggers to measure the FAU heating/cooling system

operation. The data loggers were installed directly on the electrical wire for the fan with a

zip‐tie, and electrical tape if needed, for all FAUs in each home. The access panel to the

furnace was removed in all cases to reach the electrical board for the forced air

heating/cooling system. Airflow rates were measured at the return grill(s) using a

balometer flow hood equipped with a 2 x 2‐foot or 2 x 4‐foot capture hood. The flow rate

for those homes with a single fan dual zoned system with two fan speeds were measured

with both thermostats in the ”fan‐on” position, therefore, the highest fan flow rate was

collected.  

2.7 Outdoor Air Ventilation Measurements 

2.7.1 Mechanically Supplied Outdoor Airflow Rates 

Two different types of mechanical outdoor air systems were encountered in this field

study: ducted outdoor air to the return side of the FAU (DOA systems) and heat recovery

ventilators (HRV systems). In addition, there were other mechanical systems that provided

outdoor air ventilation, directly or indirectly by exhaust, such as nighttime ventilation

cooling systems (e.g., WHF, RAD), bathroom and kitchen exhaust fans, evaporative

coolers, and window fans.

Ducted Outdoor Air Systems

There were two types of DOA systems encountered in the field study: those with manual

dampers and those with automatic dampers and fan cyclers. Operation of the DOA

systems with manual dampers is paired with operation of the FAU, so the usage was

collected by the ac‐field logger that monitored the FAU fan operation. The DOA systems

with automatic dampers and fan cyclers were monitored using a relay and state logger

combination. A magnetic tape or zip‐tie was used to secure the data logger with relay to

the damper control and lead wires were fastened with alligator clips to the damper 24

VDC motor wiring connections. The approach used to calculate the airflow rates of DOA

systems was to measure the average air speed through the outdoor air duct with a
29 

velometer while the FAU is operating and then to determine the duct dimensions with a

tape measure.  

Heat Recovery Ventilators

Heat recovery ventilators are two‐fan systems; typically one fan/duct system exhausts air

from bathrooms and laundry/utility rooms to the outdoors, and another fan/duct system

supplies outdoor air to the living space. The exhaust and outdoor air streams are ducted

through an air‐to‐air heat exchanger so that the outdoor air is warmed by the exhaust air

during the heating season and cooled by the exhaust air during the cooling season. The

HRVs were typically operated continuously, and were therefore not monitored with either

a data logger or written log. The homeowner was questioned by Team 1 about usage, and

for those HRVs that were reported to be operated intermittently, either a written log or an

ac‐field data logger was installed using a zip‐tie or tape to secure the data logger. The

approach used to measure the airflow rates of HRVs was a balometer flow hood. The HRV

outdoor airflow rates were measured at the single outdoor air supply air diffuser.

There were two types of nighttime cooling ventilation systems encountered in the field

study: WHF systems and FAU RAD systems. The approach used to measure the airflow

rates of the RAD systems was a balometer flow hood at the return air grill. The approach

used to measure the airflow rates of the WHF systems was to measure the average air

speed over the air intake in the home with a hot wire anemometer and multiply the air

speed by the exhaust intake dimensions. This approach was used for the WHF systems

rather than the balometer flow hood, because of the much higher airflow rates associated

with the WHF systems.

There was also one home with a window fan consisting of a portable fan system that is

inserted directly into window and one home with an evaporative cooling (EC) system. The

EC system was separate from the FAU system and consisted of a roof mounted fan system

that pulled outdoor air through evaporative cooling pads and delivered the air to a central

supply air grille. The window fan system usage was monitored using written logs and the

EC system usage was measured as described for the WHF systems. The airflow rates of the

window fan system and the EC system were measured as described for the WHF systems. 

2.7.2 Tracer Gas Measurements of Outdoor Air Exchange Rate 

The outdoor air exchange rate in all the homes was measured with a tracer gas technique

during the 24‐hour air contaminant measurements and in a selection of homes for two‐ 

week period. This technique uses a passive constant injection of perfluorocarbon tracer

(PFT). The tracer gas sources were placed by Field Team 1 at locations in each home

approximately one week in advance of the tracer gas sampling, to allow for the emission

rates of the sources to equilibrate. The number of sources and placement locations were

determined for each home based on room volumes and layout to approximate a uniform

indoor concentration. Since the emission rates from the PFT sources are temperature

dependent, an air temperature data logger was deployed, located at the heating/cooling
30 

system thermostat, to log the air temperature at 15‐minute intervals. These temperature

data were then input into an equation of the emission rate as a function of time that was

supplied by Brookhaven National Laboratory, the supplier of the PFT sources, to calculate

the temperature‐corrected PFT emission rates. The PFT used for these tests was

perfluoromethylcyclohexane (PMCH).  

The PFT samplers used for these tests were capillary adsorption tube samplers (CATS).

These are small passive samplers that were co‐located at the indoor air contaminant

measurement site (e.g., family/living room) and were deployed by Field Team 2. The

outdoor air exchange rate was calculated as described in ASTM E741 (ASTM 2000). For the

24‐hour measurements, the samplers were collected by Field Team 3, but for the two‐week

measurements the samplers were collected by the homeowner, and returned by mail. A

total of 25 homes had two‐week PFT measurements.  

The calculated method detection limit (MDL) in terms of air changes per hour of outdoor

air and from the analyses of variance among the duplicate samples was 0.016 air changes

per hour (ach).  

In three 2‐story homes, during the Winter North field session, additional CATS samplers

were deployed in locations other than the air contaminant measurement site on the second

floor (e.g., master bedroom, second floor bonus room) to evaluate the tracer gas

concentration uniformity. In two of these three homes, a 24‐hour measurement was

collected during the same time as the CATS sampler at the air contaminant measurement

site, and in one of these three homes a two‐week measurement was collected during the

same time as the CATS sampler at the air measurement contaminant site.

Since the blower door measurements conducted by Field Team 3 the day after the

deployment of the PFT samplers by Field Team 2 would have a substantial and atypical

impact on the home ventilation rate, the long‐term PFT samplers were capped when we

shut down the indoor air sampler before the blower door tests. The homeowners were then

asked if they would uncap the long‐term PFT sampler 48 hours later. Each of the

homeowners was called to confirm that the samplers were uncapped, and then the

homeowner collected the long‐term PFT samplers, PFT sources, and temperature data

logger approximately two weeks later. The homeowner used two mailing containers to

return the CATs sampler and PFT sources separately at least a day apart.

The forms used to record these data were the House Dimensions/PFT Form, the Logger

Form, the PFT Form, and the Air Sampling Tube Return Instructions. The home floor plan

was also used by Team 1 to depict the locations of the PFT sources to assist Field Team 3 in

retrieving the PFT sources and CAT samplers.
31 

2.8 Indoor Air Quality Measurements 

The following is a summary of the indoor air quality parameters that were measured in

each home, with the exception of nitrogen dioxide and particulate matter (PM2.5), which

were only measured in 31 homes of the Winter North field session.

• Integrated Time Averaged IAQ Measurements

o Volatile Organic Compounds (VOCs)

o Formaldehyde and Acetaldehyde

o Nitrogen Dioxide

o Particulate Matter (PM2.5)

• Real‐Time IAQ Measurements

o Carbon Monoxide

o Carbon Dioxide

o Temperature and Humidity

These IAQ parameters were measured for 22–26 hour period at one indoor location in the

family/living room area of each of the homes. In addition, these IAQ parameters were also

measured over the same time period at one outdoor location, in the backyard, for each

cluster of two to three homes. The homes in each cluster were all within two miles of each

other, with the exception of one cluster in the Summer North field session. This cluster had

one home in Brentwood, which was 6.4 miles from the other two homes in Discovery Bay.

Duplicate air samples were randomly selected to fulfill the 10% quality assurance and

quality control requirement. The airflow rates for the integrated air samples were

measured at the beginning and end of the sampling period using calibrated rotometers.

Special air samplers were developed to collect the integrated and real‐time air contaminant

concentrations. Figure 1 (page 44) is a photograph of the air sampler at an indoor site and

Figure 2 (page 45) is a photograph of the air sampler at an outdoor site with the outdoor

radiation/rain shield. For the integrated air samples, this air sampler consisted of a pair of

air sampling pumps contained in an acoustically shielded fiberglass lock box mounted to a

tripod. The study used SKC AirCheck 2000 air sampling pumps, which include an internal

flow sensor that provides automatic electronic airflow control, such that the sample airflow

rate is maintained within ± 5%, and 115 volts‐alternating current (VAC) battery eliminators

to allow operation over the proposed 24‐hour sampling periods. One of these pumps

provided the air sampling flow rate for the PM2.5 air sampler. The second pump, through

the use of a four‐port manifold with low‐flow control valves, provided the air sampling

flow rate for the VOCs, nitrogen dioxide, and formaldehyde/acetaldehyde air samplers.  
32 

A power on‐time meter provided a measurement of the time that 110 VAC power was

supplied to the air sampler so that if there was a power interruption during the air

sampling period the duration of the interruption would be known. The air sampling

pumps automatically restart upon restoration of the power following a power interruption.

In addition, a power cord restraint cover was installed at the connection of the power cord

to the power receptacle to guard against inadvertent disconnection of the power cord plug

from the receptacle.  

For the real‐time IAQ measurements, a TSI IAQ‐Calc indoor air quality meter was

mounted on the tripod next to the integrated air sampler manifold. The AC adaptor for the

TSI IAQ‐Calc was connected to a source of AC power inside of the fiberglass lock box. In

addition, the TSI IAQ‐Calc contained a parallel battery pack power supply that allows the

instrument to continue operation upon a power interruption.  

For the outdoor air sampler, a special rain/radiation shield was fabricated from galvanized

sheet metal to enclose and protect the air samplers from rain and solar radiation. This

rain/radiation shield has screened and louvered vents on two sides to allow circulation of

outdoor air within the enclosed area.

The following is a detailed description of the air sampling and analytical techniques for

each of the IAQ parameters. 

2.8.1 Integrated Time Averaged IAQ Measurements (24-hour) 

2.8.1.1 Volatile Organic Compounds 

Volatile organic compounds other than formaldehyde and acetaldehyde were measured

using methods based on U.S. EPA Method TO‐17, ”Determination of Volatile Organic

Compounds in Ambient Air Using Active Sampling onto Sorbent Tubes“ (EPA 1999). This

method involves drawing air at a constant rate with a pump through a multi‐sorbent tube

(i.e., Berkeley Analytical Associates sorbent tubes). The multi‐sorbent tube consisted of a  

3.5‐inch (89‐millimeter [mm]) long by 1⁄4‐inch (6.4‐mm) outside diameter (OD) passivated

stainless steel tube packed with two sorbent materials. The sorbent materials were

270 milligram (mg) Tenax TATM 60/80 mesh backed up by 100 mg Carbosieve S‐IIITM 60/80

mesh. The samples were split 1:5 to prevent overloading of the analytical instrumentation

and thermally desorbed and analyzed by gas chromatograph/mass spectrometry. The

calculated MMDL from the analyses of variance among the replicate samples was between

2 and 5 nanograms (ng) for most compounds. Details of the analytical method and

derivation of the method mass detection limit are summarized in Appendix B.  

Samples were collected over a 24‐hour period at a flow rate of approximately 10 cubic

centimeters per minute (cc/min), which provided a method concentration detection limit of

0.1 μg/m3 to 0.4 μg/m3 for most compounds. Two samples were collected at each indoor

and outdoor air sample location and one of each sample pair was submitted for analyses

while the companion sampler was submitted as a backup sample.
33 

Laboratory results for each sampler were corrected using the average of the field blanks for

each batch of samplers that was submitted to the lab for analyses. For field blanks where

the concentration was below the method detection limit of the instrumentation, a value

equal to one‐half the method detection limit concentration was used to calculate the

average of the field blanks.

A total of 20 volatile organic compounds were selected by the ARB for quantification.

These compounds were selected to include those with known indoor sources, those of

known or suspected health concerns in indoor environments, and those with relevance to

ARB programs.

2.8.1.2 Formaldehyde and Acetaldehyde 

Formaldehyde and acetaldehyde concentrations were measured according to ASTM

Standard D5197‐03 (ASTM 2003c). This method involves drawing air at a constant rate

with a pump through a solid sorbent cartridge (i.e., Waters Associates Sep‐PAK silica gel

impregnated with dinitrophenylhydrazine, DNPH). In addition, since ozone is known to

interfere with this sample analyses, an ozone scrubber was installed directly upstream of

the solid sorbent cartridge. This scrubber consists of a solid sorbent cartridge filled with

granular potassium iodide (i.e., Waters Associates Sep‐PAK Ozone Scrubber).

Additionally, a scrubber (i.e., Anasorb CSC, coconut charcoal sorbent tube) was placed

downstream of the sampler to scrub the emissions of residual acetonitrile released by the

DNPH sample cartridge. The calculated MMDL from the analyses of variance among the

replicate samples was 9 ng for both formaldehyde and acetaldehyde. Details of the

analytical method and derivation of the MMDL are summarized in Appendix B.

Samples were collected over a 24‐hour period at a flow rate of approximately 20 cc/min,

which provided a concentration MDL of 0.3  μg/m3 for formaldehyde and acetaldehyde.

This concentration MDL is well below the California Environmental Protection

Agency/Office of Environmental Health Hazard Assessment (Cal/EPA OEHHA) Chronic

Inhalation Reference Exposure Levels (RELs) of 3 μg/m3 for formaldehyde and 9 μg/m3 for

acetaldehyde (OEHHA 2003) and well below the ARB Indoor Air Quality Guideline of

33 μg/m3 for formaldehyde (California Air Resources Board 2005).  

Laboratory results for each sampler were corrected using the average of the field blanks for

each batch of samplers that was submitted to the lab for analyses. For field blanks where

the concentration was below the method detection limit a value equal to one‐half the

method detection limit concentration was used to calculate the average of the field blanks.

Measurements of the emission rates of formaldehyde from the FAU in three homes were

also made. The impetus for these measurements, were some preliminary measurements

conducted during warm months in some Arizona homes with FAUs located in attics

(Davis 2004). In this study the investigator concluded that that the fiberglass inside of the
34 

FAUs may be contributing to increased indoor concentrations of formaldehyde. Indeed the

FAUs in the homes of this study contain a substantial amount of fiberglass soundliner,

which may contain formaldehyde resins, and thus these materials may become substantial

emitters of formaldehyde gas, especially when the materials are warm.  

Measurements of emission rates were made by simultaneously measuring the

concentration of formaldehyde in the supply and return air of the FAU as well as the attic

air, where the FAUs were located, over a 30‐minute period at a sample flow rate of

approximately 950 cc/min. During these measurements the FAU fans were operated

without cooling or heating. The supply air concentrations were measured at a supply air

diffuser by inserting the sample inlet directly into the supply air diffuser. The return air

concentrations were measured by inserting the sample inlet directly into the return air

inlet. The attic air concentrations were measured in the attic at a location close to the attic

access hatch, which was kept closed except to set the air sampler into the attic. The

emission rates were calculated according to Equation 1 as the difference between the

concentrations in the supply and return air streams times the FAU airflow rate.

Efau = (Csa – Cra) Qfau   (EQ 1)

where:

Efau   = emission rate from FAU (μg/h)

Csa   = concentration in the FAU supply air at the supply air diffuser (μg/m3)

Cra   = concentration in the FAU return air at the return air inlet (μg/m3)

Qfau   = airflow rate of the FAU (m3/h)

This calculation assumes that the concentration of formaldehyde measured at the supply

air diffuser represented the average concentration of the supply air delivered to the home

and that the concentration measured at the return air inlet represented the average

concentration of the return air leaving the home. While the latter is considered to be a

reasonably good assumption, the assumption of uniform concentrations at all of the supply

air diffusers is likely not nearly as good an assumption.  

The emission rate of formaldehyde from the FAU was also compared to the total emission

rate of formaldehyde into the home indoor air. The total home emission rate was

calculated according to Equation 2 as the difference between the concentrations in the

indoor air and the outdoor air times the outdoor air ventilation (calculated from the air

exchange rate as determined by the PFT measurements and the home indoor air volume).

Ehome = (Ci – Co) λ pft V   (EQ 2)
35 

where:

Ehome   = total home indoor emission rate from FAU (μg/h)

Ci   = concentration in the indoor air (μg/m3)

C0   = concentration in the outdoor air (μg/m3)

λ pft   = home outdoor air exchange rate determined from PFT measurement (h‐1)  

V   = home indoor air volume (m3)  

This calculation assumes that the concentration of formaldehyde measured at the living

room/dining room sampling location represented the average home indoor air

concentration.

In addition to these FAU formaldehyde emission rate measurements, the air temperature

and relative humidity in the attic air was also measured.

2.8.1.3 Nitrogen Dioxide 

Nitrogen dioxide (NO2) was measured following National Institute for Occupational Safety

and Health (NIOSH) Method 6014 (NIOSH 1994a). This method involves drawing air at a

constant rate with a pump through a two‐stage solid‐sorbent tube (i.e., SKC 226‐40‐02

molecular sieve impregnated with triethanolamine). The samplers were extracted and

analyzed using spectrophotometry at a wavelength of 540 nanometers (nm). Both the front

tube section and the back tube section were analyzed separately to verify that there was no

significant breakthrough. The laboratory mass reporting limit of 0.8 μg was used for the

MMDL.

Samples were collected over a 24‐hour period at a flow rate of approximately 100 cc/min,

which provided a concentration MDL of 5.7 μg/m3. This concentration MDL is well below

both the U. S. Environmental Protection Agency National Ambient Air Quality Standards

(EPA NAAQS) (EPA 1990) standard of 100 μg/m3 for an annual exposure, as well as the

ARB Indoor Air Quality Guidelines (California Air Resources Board 2005) of 150 μg/m3 for

a 24‐hour exposure.  

Laboratory results for each sampler were corrected using the average of the field blanks for

each batch of samplers that was submitted to the lab for analyses. For field blanks where

the concentration was below the minimum mass reporting limit of the laboratory, a value

of 0 μg was used to calculate the average of the field blanks.
36 

2.8.1.4 Particulate Matter (PM2.5) 

Particulate matter (PM2.5) was collected using gravimetric analyses according to NIOSH

500 (NIOSH 1994b). This method involves drawing air at a constant rate with a pump

through a PM2.5‐size selective inlet (i.e., SKC 761‐203 Personal Environmental Monitor)

containing a 37 mm PTFE (i.e., Teflon) filter with a 2.0 μm pore size (i.e., SKC – 225‐1709).

Prior to and after sampling, the filters were equilibrated in a climate‐controlled weighing

room and analyzed gravimetrically. For the MMDL the research team used a MMDL of

5 μg, which is five times the 1 μg sensitivity of the microbalance.

Samples were collected over a 24‐hour period at a flow rate of 2 liters per minute (L/min),

which represents the design flow rate of the PM2.5 impactor and provided a concentration

MDL of 1.8  μg/m3. This concentration MDL is well below both the EPA NAAQS (EPA

2007) ambient air quality standard of 35 μg/m3 and the ARB Indoor Air Quality Guidelines

(California Air Resources Board 2005) of 65 μg/m3 for 24‐hour exposures.  

Laboratory results for each sampler were corrected using the average mass change of the

field blanks for each batch of samplers that was submitted to the lab for analyses. For field

blanks where the mass change was below the minimum MMDL of 5  μg, the actual

reported mass change was used to calculate the average of the field blanks.

2.8.2 Real-Time IAQ Measurements 

2.8.2.1 Carbon Monoxide 

Carbon monoxide was measured with real‐time instrumentation following EPA method  

IP‐3A (EPA 1989) using an electrochemical sensor. We used a TSI IAQ‐Calc meter, which

incorporates a passive diffusive sample element and has built in data logging capabilities.

The data logger was programmed to record carbon monoxide concentrations at one‐

minute intervals. The sensor has an accuracy of ± 3% or ± 3 parts per million (ppm),

whichever is greater, a precision of ± 2% of reading, a resolution of 1 ppm, and a range of

0–500 ppm.

The concentration MDL was determined to be 0.8 ppm from analysis of the variance of the

eight IAQ‐calc instruments used for this field study. The eight instruments were co‐located

in a well‐mixed test chamber with CO concentrations of 1 ppm to 2 ppm and the average

of 60 one‐minute consecutive measurements was used to determine the variance. The

concentration MDL was calculated as the product of the standard deviation of the eight

60‐minute average concentrations and the t‐test value for a 95% confidence level  

(i.e., t =1.98, p = 0.05, df = 7).  

This concentration MDL is well below the ARB Indoor Air Quality Guideline (California

Air Resources Board 2005) of 9 ppm for 8‐hour exposures. The instrument was calibrated

immediately prior to the start of sampling and checked following the sampling period,

using zero and span (34 ppm) certified calibration gases. The sample data logged over the
37 

24‐hour period was corrected using the pre‐ and post‐calibration curves and assuming that

any changes in the calibrations occurred in a linear manner over time.  

Prior to the commencement of the main field study and following a review of the Pilot

Study data it was determined that the carbon monoxide sensors had a positive interference

with water vapor of 2–4 ppm. This occurs only in outdoor air samples during periods of

high relative humidity (i.e., greater than 75% and typically during rain events). No

attempts have been made to correct these data, nor has any data been deleted where this

effect appears to be occurring. 

2.8.2.2 Carbon Dioxide 

Carbon dioxide was measured with real‐time instrumentation following EPA method

IP‐3A (EPA 1989) using non‐dispersive infrared spectrophotometry (NDIR). A TSI IAQ‐

Calc meter, which incorporates a passive diffusive sample element and has built‐in data

logging capabilities, was used. The data logger was programmed to record carbon dioxide

concentrations at one‐minute intervals. The sensor has an accuracy of ± 3% or ± 50 ppm,

whichever is greater; a resolution of 1 ppm; and a range of 0–5,000 ppm.

The concentration MDL was determined to be 24 ppm from analysis of the variance of the

eight IAQ‐calc instruments used for this field study. The eight instruments were co‐located

in a well‐mixed test chamber with CO concentrations of 540 ppm to 570 ppm, and the

average of 60 one‐minute consecutive measurements was used to determine the variance.

The concentration MDL was calculated as the product of the standard deviation of the

eight 60‐minute average concentrations and the t‐test value for a 95% confidence level (i.e.,

t =1.98, p = 0.05, df = 7).

This concentration MDL is well below both the ASHRAE (ASHRAE 2004b) body odor

standard of 700 ppm over the outdoor concentration, which for typical outdoor

concentrations of 350 to 450 ppm represents an indoor concentration of 1,050 to 1,150 ppm.

The instrument was calibrated immediately prior to the start of sampling, and checked

following the sampling period, using zero and span (1,035 ppm) certified calibration gases.

The sample data logged over the 24‐hour period was corrected using the pre‐  and post‐

calibrations curves and assuming that any changes in the calibrations occurred in a linear

manner over time.

2.8.2.3 Temperature and Relative Humidity 

Temperature and relative humidity were measured with real‐time instrumentation using a

thermistor sensor for air temperature and a thin‐film capacitive sensor for relative

humidity. A TSI IAQ‐Calc meter, which has built in data‐logging capabilities, was used.

The data logger was programmed to record temperature and relative humidity at one‐

minute intervals. The temperature sensor has an accuracy of 1°

F, a resolution of 0.1°F, and a

range of 32°

F–122°F. Prior to the field effort, the instruments’ temperature sensors were

compared to a certified mercury thermometer and the sample data logged over the 24‐hour
38 

period was corrected using a single point correction. The relative humidity (RH) sensor has

an accuracy of 3% RH, a resolution of 0.1% RH, and a range of 5%–95% RH. Prior to the

field effort, the instruments’ relative humidity sensors were compared with a laboratory

probe that was calibrated with salt solutions according to ASTM E104‐02 (ASTM 2002). The

sample data points logged over the 24‐hour period were corrected using a single point

correction.

Meteorological data for the specific site of sampling were obtained from the nearest

weather station listed by the National Climatic Data Center. The data included hourly

wind speed and outdoor‐air dry bulb temperature. Three weather stations were used for

the northern California sites. The Sacramento Mather Airport was chosen; it is 13 miles

northeast from the Elk Grove site, 12 miles northeast from the Sacramento site, 7 miles

northwest from the Rancho Murieta site, 9 miles southwest from the El Dorado Hills site,

and 10 miles southwest from the Folsom site. The second was the Stockton Metropolitan

Airport, which is 23 miles east from the Brentwood sites, 18 miles east from the Discovery

Bay sites, and 8 miles northwest from the Manteca sites. Finally the Auburn Municipal

Airport was chosen for the Lincoln sites, which is 18 miles to the northeast.  

Five weather stations were used for the Southern California sites. First was the Van Nuys

Airport, which is 18 miles southeast of the Valencia sites, 15 miles southeast of the Santa

Clarita sites, and 21 miles southeast from the Castaic sites. Second chosen was the Marine

Corps Air Station‐Miramar, which is 8 miles southeast from the San Diego sites and 6 miles

southeast from San Marcos sites. Third chosen was the Naval Auxiliary Landing‐Imperial

Beach that is 5 miles southwest from the Chula Vista sites. Next, the Palmdale Regional

Airport was chosen, which is 6 miles northeast of the Palmdale sites. Finally, the Riverside

Municipal Airport was used, which is 13 miles southwest and northwest from the Fontana

and Riverside sites, respectively.

2.9 Homeowner Source Activity 

Homeowner activities potentially related to release of contaminants into the indoor air

were recorded by the homeowner during the 24‐hour IAQ measurement period using an

indoor Source Activity Log, which was administered by Team 1 and collected by Team 3.

The homeowner was asked to record the activity start times, duration, and type (e.g.,

cooking, cleaning, candle burning, dinner parties, barbecuing, leaf blowing, grass cutting)

starting at 7:00 PM on the day before the 24‐hour IAQ measurements and ending when

Team 3 retrieved the forms. This results in up to a 48‐hour time period when the

homeowner recorded their source activities, with the first 12–20 hours being practice and

which Team 2 checked, and the last 28–36 hours being the time period during which the  

24‐hour IAQ measurements were be collected for input into the database.
39 

2.10 Homeowner IAQ/Ventilation Perceptions and Decision 

Factors 

Perceptions regarding IAQ and ventilation were collected using the Occupant

Questionnaire that was be administered to the homeowner by Team 1 and collected by

Team 3. The Occupant Questionnaire was adapted from the UCB mail survey study. This

questionnaire collected information regarding the homeowners’ perception of activities

that may affect IAQ in the home. Also included were key decision factors regarding home

ventilation and purchasing ventilating equipment, building materials, air cleaners, and

other products and materials that affect IAQ. The requested recall period was three weeks

and the homeowners were instructed to complete the questionnaire following the start of

the indoor air quality measurements by Team 3.

2.11 Quality Assurance and Quality Control 

The October 10, 2005, Quality Assurance/Quality Control Plan (QA/QC Plan) was

followed. The goal was to successfully collect and analyze a minimum of 98% of all field

samples. For each of the integrated air contaminant measurements, VOCs, NO2,

formaldehyde/acetaldehyde, PM2.5, and the PFT measurements the goal was to successfully

collect and analyze a total of 10% field blanks and 10% field duplicates. In addition, for the

PFT measurements the research team used three of the 10% duplicate samples for samples

in a second zone of the home (i.e., the primary measurement zone was the living/dining

room on the first floors and the second zone location was a second floor bedroom). The

purpose of these two zone PFT measurements was to provide some data on the variation

in the PFT indoor concentration, as the calculations of outdoor air exchange measurements

from this measurement method assume that the indoor concentration of PFT is uniform

through the home. In accordance with the QA/QC plan, the PFT sources and PFT samplers

were stored and shipped separately to the field site.

Details of the QA/QC for the laboratory analyses of the VOCs, including formaldehyde

and acetaldehyde, are discussed in Appendix B.

The QA/QC for the laboratory analyses of NO2 and PM2.5 were performed as described in

the NIOSH Manual of Analytical Methods (NIOSH 1994a and 1994b).

For each VOC, an MDL was established based upon the variance observed in duplicate

samples. The MDL was calculated to have greater than a 95% confidence that the measured

value is greater than zero. This was calculated as the product of the standard deviation of

the duplicate samples and the student’s t‐value t0.095. For nitrogen dioxide, the laboratory

mass reporting limit for the MDL was used, and for PM2.5 an MDL equal to five times the

sensitivity of the microbalance was used.
40 

The flow rates for all integrated air samples utilizing sampling media (i.e., VOCs,

aldehydes, nitrogen dioxide, and PM2.5), were measured before and after the designated

sample interval using rotometers, which were calibrated with a primary standard bubble

meter or frictionless piston meter at the start of each sample season.  

For the real‐time measurements of carbon monoxide and carbon dioxide, these instruments

were calibrated in the field at the start and end of each 24‐hour sampling period utilizing

certified bottled calibration gasses. Temperature sensors were calibrated with a NIST‐

certified mercury thermometer, and relative humidity sensors were calibrated with salt

solutions at the start of each sample season.  

Airflow rate devices (e.g., flow hoods) were calibrated using orifice plates at the start of

each sample season. Pressure transducers for the building and duct leakage measurement

devices (e.g., blower door and duct blaster) were calibrated with a primary standard

micromanometer at the start of each sample season.

  

To assess the precision of the measurements of both the air contaminants and PFT

measurements of outdoor air exchange rates, the 10% side‐by‐side duplicate samples were

used. Then both the absolute precision and relative precision of each sample pair were

calculated and summary statistics were prepared. The absolute precision was calculated as

the absolute difference of the results of the sample pair. The relative precision was

calculated as the relative standard deviation of the results of the sample pair. The relative

precision is the more useful metric for assessing the precision, however, where the

measured values are very low this calculation can result in inflated relative precision

values. Thus in the case of high relative precision calculations it is useful to look at the

absolute precisions. Low relative precisions always indicate good measurement precision.

High relative precisions are only indicative of poor measurement precision if the absolute

precision is also high.

2.12 Data Management and Analyses 

For this study spreadsheets were created in Excel for all of the field data sheets contained

in the SOPs that are detailed in our October 10, 2005, Quality Assurance/Quality Control

Plan (QA/QC Plan). Hard copies of these field data sheets were taken into the field and

used to record the data. The data on these hard copy field data sheets were then entered

into identical electronic copy field data sheets. These Excel sheets contain all of the

calibrations and calculations for converting the collected field data into the various

ventilation and indoor air quality parameters. A minimum of 10% of each set of Excel field

data sheets were compared with the corresponding hard copy field sheet for accuracy. If

errors were identified, they were corrected and then another 10% of those data were

checked in other field sheets. This process continued until no errors were found. In

addition, the range of values was inspected for each variable, and for each variable that

was unusually low or high the data sheets were inspected for errors, any errors observed
41 

were corrected, and then another 10% of those data were checked in other field sheets. This

process continued until no errors were found. If a particular piece of data was found to be

unusually low or high, and no error could be identified, then that piece of data was

deleted.  

A similar check of data in the ACCESS/SAS databases was conducted after the data were

imported from the Excel data sheets. For each variable a 10% data check was conducted,

and data that was incorrect was corrected, as described for the Excel datasheets.  

  

Unless specified otherwise, the results and associated population statistics are based upon

the “All Home” sample frame of 108 homes, which is summarized in Appendix C. The

complete list of all home season‐region tests is summarized in Appendix D. The “All

Home” sample frame was constructed to provide a sample base for producing the

population statistics without having a home represented more than once and to provide a

balance between the North and South regions and the summer and winter seasons. The fall

swing season tests were excluded from this sample frame. The 10 seasonal repeat North

homes and 10 seasonal repeat South homes were randomly selected and evenly split into

the summer and winter field sessions. The first test day contaminant concentration and

outdoor air exchange rate data were selected for the four multi‐day test homes.

Appendix E contains for each home the following data; the results of the indoor and

outdoor air contaminant measurements, the indoor and outdoor temperature and relative

humidity measurements, and the outdoor air exchange rate PFT measurements.

Appendix F contains for each home the following data; home characteristics, including

building envelope air leakage and duct leakage measurements, window usage, mechanical

and outdoor air exhaust air exchange rate measurements, and characteristics of the

mechanical outdoor air ventilation systems.  

The indoor emission rates of VOCs were calculated according to Equation 3, as the

difference between the concentrations in the indoor air and the outdoor air times the

outdoor air exchange rate (as determined by the PFT measurements).

Ev = (Ci – Co) λ pft   (EQ 3)

where:

Ev   = total volume specific indoor emission rate into home (μg/m3‐h)

Ci   = concentration in the indoor air (μg/m3)

C0   = concentration in the outdoor air (μg/m3)

λ pft   = home outdoor air exchange rate determined from PFT measurement (h‐1)  
42 

This calculation assumes that the penetration factor of VOCs in the outdoor air that is

infiltrating through the building envelope was 1.0 and that there was no removal of VOCs

from the indoor air unrelated to the outdoor air exchange rate (e.g., surface

deposition/surface reaction, indoor air reactions, air filtration). The research team feels that

these are relatively valid assumptions for the VOCs reported here. In addition, this

calculation assumes that that the concentration of VOCs measured at the living room/

dining room sampling location represented the average home indoor air concentration.

No emission rates were calculated for homes where both the indoor and outdoor

concentrations were less than the method detection limit concentration. For homes where

either the indoor or outdoor concentration was below the method detection limit

concentration, the calculation was performed utilizing a concentration of one half the MDL

concentration.  

It is important to note these emission rates are different than the home emission rates of

formaldehyde that were described in Section 2.8.1.2 and calculated according to

Equation 2. Those emission rate calculations are total emission rates of formaldehyde into

the home indoor air and are expressed in units of micrograms per hour (μg/h). The

emission rates described above, and calculated according to Equation 3, are the volume‐

specific emission rates that are the emission rates normalized by the indoor air volume of

the home. These volume‐specific emission rates are useful when comparing emission rates

between different homes, since larger homes have larger areas from which indoor air

contaminants can be emitted.

Several group comparisons for indoor air contaminants, outdoor air exchange rates, and

window usage were also performed. These group comparisons included North versus

South homes, summer versus. winter repeat homes, and homes with and without

mechanical outdoor air ventilation systems. For these comparisons, t‐tests were used to test

the hypothesis that there is no difference between the mean values of two different sample

populations. A two‐tailed t‐test was used for two samples with unequal variance to

determine the probability that the mean of the two sample groups were not different for

the comparisons of North versus South homes and homes with and without mechanical

outdoor air ventilation systems. For the comparison of summer versus winter repeat

homes, a paired t‐test was used. For each of these comparisons the probability that the

difference between the means was not different was calculated. If the probability of no

difference was less than 0.05, then the difference between the means was deemed

significant.  

Because t‐tests require that sample populations be normally distributed, the Kolmogorov‐

Smirnov (K‐S) statistic, as programmed in the SAS Univariate procedure, was used to test

whether the distributions of variables being compared were normal. The Kolmogorov‐

Smirnov null hypothesis is that the distribution is normal. If the K‐S statistic returned a
43 

result with a probability of less than 0.05, then the distribution was determined to not be

normal. If the sample population was determined to not be normal, then a transformation

was applied to the sample, beginning with a log transformation. If the log transformation

did not produce normal data then other transformations were tried, including inverse,

squared, and square root transformations until a transformation that was normal was

identified.

Correlation analyses between selected indoor air contaminants and house characteristics

and environmental factors were also prepared. For these analyses the Pearson correlation

method was used to test for the strength and direction of a linear relationship between

pairs of variables. Because these analyses require that sample populations be normally

distributed, the data were normalized as described above. The research team also prepared

Spearman correlation analyses, which do not require the sample populations be normally

distributed.
Figure 1. Quiet indoor air sampler for formaldehyde, VOCs, PM2.5, NO2, CO, CO2, temperature, and relativ

humidity, typically installed in a home living/dining room area for a 22

–26 hour sampling period. 

44
Figure 2. Outdoor air sampler for formaldehyde, VOCs, PM2.5, NO2, CO, CO2, temperature, and relative hu

with outdoor radiation/rain shield.

45
46 
47 

3.0 Project Outcomes/Results and Discussion 

3.1 Quality Assurance and Quality Control 

Table 2 (page 145) contains a summary of the percentages of air contaminant and PFT field

samples, blanks, and duplicates that were successfully collected and analyzed along with

the goals in the QA/QC plan.  

With respect to the percentage of field samples successfully collected and analyzed, the

study’s goal of a minimum of 98% was met, with the exception of the

formaldehyde/acetaldehyde samples, where the percentage successfully collected and

analyzed was 96%.

With respect to the percentage of field sample blanks successfully collected and analyzed,

the goal of a minimum of 10% of the total field samples successfully collected and analyzed

(i.e., less field blanks and duplicates) was met.

With respect to the percentage of field sample duplicates successfully collected and

analyzed, the study’s goal of a minimum of 10% of the total field samples successfully

collected and analyzed (i.e., less field blanks and duplicates) was met, with the exception of

the formaldehyde/acetaldehyde and carbon monoxide samples, where the percentages

successfully collected and analyzed were 9%.

Details on the sample and/or analyses failures can be found in Appendix G Difficulties

Encountered in the Field, which summarizes the difficulties encountered during the study,

followed by the corrective action that was taken. For the population statistics discussed in

this section, unless otherwise noted, the following samples were deleted: those that had

shortened sample periods (thus not representative of the standard 24‐hour samples), those

with failed analytical analyses, or those that yielded unrealistic data.  

The results of the sample blank analyses for VOCs, including formaldehyde and

acetaldehyde, are summarized separately in Tables 3, 4, 5, and 6 (pages 146–149) for the

Summer‐North, Summer‐South, Winter‐North, and Winter‐South field sessions

respectively. The average field blank masses were calculated separately for each field

sessions and subtracted from the field sample masses for that field session. If the mass of a

field blank was below the method mass detection limit (MMDL) then a value of one half of

the MMDL was used to calculate the average field blank mass.  

For the 18 VOC blank samples, just six of the 20 compounds analyzed had masses

exceeding the MMDL; phenol (6 samples), styrene (3 samples), hexanal (2 samples),  

d‐limonene (1 sample), 1,2,4 trimethylbenzene (1 sample), and naphthalene (1 sample). The

compound with most field blank concentrations exceeding the MMDL, phenol, had field

blank mass concentrations that ranged from 3.3 ng to 24 ng, with an average of 7.9 ng
48 

(MMDL 2.8 ng). The ratio of the average field blank mass to the MMDL for phenol was less

than 1.0 for all field sessions except for the Summer South field session, where the ratio

was 3.1. The only other compounds with ratios of the average field blank mass to the

MMDL that exceeded 1.0 were styrene (with a ratio of 1.5 for the Summer South field

session) and hexanal (with a ratio of 1.4 for the Winter South field session).

For the 19 aldehyde blank samples, 10 had masses exceeding the MMDL for acetaldehyde

and 5 had masses exceeding the MMDL for formaldehyde. For acetaldehyde, the field

blank mass concentrations ranged from 9.4 ng to 49 ng with an average of 20 ng (MMDL

9.0 ng). The ratio of the average field blank mass to the MMDL for acetaldehyde ranged

from 1.1 for the Winter North field session to 2.1 for the Summer North field session and

was less than 1.0 in the Winter South field session. For formaldehyde, the field blank mass

concentrations ranged from 10 ng to 22 ng, with an average of 15 ng (MMDL 9.0 ng). The

ratio of the average field blank mass to the MMDL for formaldehyde was less than 1.0 in

each of the field sessions.

The results of the VOC sample duplicate analyses, including formaldehyde and

acetaldehyde, are summarized in Table 7 (page 150). The mean absolute precision ranged

from 0.003  μg/m3 for 1,4‐dichlorobenxene to 4.0  μg/m3 for formaldehyde. The mean

relative precision ranged from 0.01 for 1,4‐dichlorobenzene to 0.27 for styrene.  

The results of the sample blank analyses for nitrogen dioxide and PM2.5 particulate matter

are summarized in Table 8 (page 151). For these two air contaminans, which were only

sampled during the Winter North field session, the samples were analyzed in three

batches; one for each of the three weeks of the field session. For the nitrogen dioxide field

blanks, if the field blank mass was below the MMDL of 0.8 μg, a mass of zero was used to

calculate the average of the field blanks. For PM2.5, the average mass of the field blanks was

calculated directly from the measured masses of the field blanks. There were a total of five

field blanks each for nitrogen dioxide and PM2.5 particulate matter. The five nitrogen

dioxide field blanks were all below the MMDL for an average field blank mass of zero for

each of the three sample weeks. The five PM2.5 particulate matter field blanks ranged from  

‐1 to ‐3 μg, with an average field blank mass of ‐2 μg for Week 1 and Week 2 and ‐3 μg for

week 3.

The results of the carbon monoxide, carbon dioxide, nitrogen dioxide, and PM2.5 particulate

matter sample pair duplicate analyses are summarized in Table 9 (page 152). The mean

absolute precision for nitrogen dioxide was 0.2 μg/m3 and the mean relative precision was

0.02. The mean absolute precision for PM2.5 particulate matter was 2.0 μg/m3, and the mean

relative precision was 0.11. The mean absolute precision for carbon monoxide was 0.6 ppm

and the mean relative precision was 0.53. The mean absolute precision for carbon dioxide

was 16 ppm and the mean relative precision was 0.02.
49 

The results of the sample blank analyses for the PFT samples for the outdoor air exchange

rate measurements are summarized in Table 10 (page 153). The PFT samples were

analyzed in three batches, Summer‐1, for the first 12 homes of the Summer‐North field

session, Summer‐2, for the remainder of the Summer‐North homes and all of the Summer‐

South homes, and Winter, for all of the Winter‐North and Winter‐South homes. There were

a total of 16 field blanks analyzed. The percentage of field blank to field samples ranged

from 6% to 11% for the three laboratory analyses sessions. More field blank samples were

added to the Winter field session when it was determined that more were required to meet

the 10% required by the QA/QC plan.

A total of 13 of the 16 field blanks were above the Method Volume Detection Limit

(MVDL) of 0.001 picoliters (pL), and ranged from 0.009 pL to 0.043 pL. The impact of the

variance in the field blank analyses is minimal, since the amount of tracer that the samplers

collect is so much larger than contained in the blanks. This is especially true for homes

with low outdoor air exchange rates.

For example, Home 025 had an outdoor air exchange rate of 0.35 ach based upon the

6.356 pL of tracer collected by the sampler less the average of 0.017 pL for that batch of

field sample blanks. If it is assumed that the true amount of tracer in the sample prior to

sampling ranges from 0 pL to the maximum observed field blank amount of 0.043 pL, the

calculated outdoor air exchange rate ranges differ by less than 0.2%. For homes with very

high air exchange rates, and consequently less tracer collected by the sampler, the impact

of the blank correction to the analyses can be more substantial. For example, Home 014 had

an outdoor air exchange rate of 5.3 ach based upon the 0.347 pL of tracer collected by the

sampler less the average of 0.013 pL for that batch of field sample blanks.  

If it is assumed that the true amount of tracer in the sample prior to sampling  

ranges from 0 pL to the maximum observed field blank amount of 0.043 pL, the  

calculated outdoor air exchange rate ranges differ by about 8%  

(e.g., 5.1–5.9 ach).

The results of the PFT outdoor air exchange rate measurement sample pair duplicate

analyses are summarized in Table 11 (page 154). The mean absolute precision for the

24‐hour measurements was 0.01 ach, and the mean relative precision was 0.02. The mean

absolute precision for the two‐week measurements was 0.01 ach, and the mean relative

precision was 0.01.

The research team also compared the PFT measurements of outdoor air exchange rates in

three 2‐story homes where the outdoor air exchange rate was measured at two locations;

one in the usual first floor living/dining room area and one at a second location on the

second floor. The purpose of these two zone PFT measurements was to provide some data

on the variation in the PFT indoor concentration, because the calculations of outdoor air

exchange measurements from this measurement method assume that the indoor

concentration of PFT is uniform through the home. The results of these measurements are
50 

presented in Table 12 (page 155), along with the number of hours that the FAU operated

and the square foot‐hours (ft2‐hrs) of window opening. The absolute precision of the two

PFT measurements ranged from 0.01 ach in Home 019 and Home 099 to 0.06 ach in Home

116. The relative precision of the two PFT measurements ranged from 0.05 in Home 099 to

0.22 in Home 116.  

While the research team only had two‐zone measurements in three homes, these

measurements indicated that the differences between the two PFT measurements were

relatively small and that the air in the homes was well mixed. Home 116, which had the

highest difference in the two PFT measurements, had no operation hours of the FAU and

50.5 ft2‐hrs of window usage, both of which are factors that are not conducive to good

mixing of the indoor air. Thus, even in this home with factors not conducive to good

mixing of the indoor air, the difference between the 2 PFT measurements of outdoor air

exchange was moderate (i.e., 0.22 ach versus 0.16 ach).

3.2 Home Selection and Recruitment 

The home recruitment response rate for each region‐season is summarized in Table 13

(page 156). For the summer field session, a total 1,358 recruitment letters were mailed to

new single‐family detached homes in Northern California, of which 340 were to UCB

mailer respondents and 1,018 were to additional sample. Researchers mailed 1,408

recruitment letters to new single‐family detached homes in Southern California, of which

329 were to UCB mailer respondents and 1,079 were to an additional sample. The

percentage of homeowners sent recruitment letters that called to say they were interested

in participating in the field study ranged from 3% to 7% for the summer and winter

recruitment sessions.

Clusters were then established for those homes based on their relative distance, and on

which of the three inspection times each home noted as being required or preferred.

Homes were clustered into groups of 2–3 homes with one outdoor air sampling location

for each cluster.  

Recruitment was begun in geographic areas where the most calls from homeowners

interested in participating in the field study had been received. Efforts were also made to

reach out by telephone to homeowners in the same areas who had not called in to express

interest, favoring UCB mailer respondents over the additional sample. Four percent of both

the UCB respondents and additional sample who had received the mailers refused to

participate. One percent of the UCB respondents and less than 1% of additional sample

who had received mailers were disqualified (renters, smokers, home built before 2002).

Due to the geographical constraints of the study and the location of some homes, a few

willing homeowners could not be included in the study (5% of the mailers to UCB

respondents and 2% of the mailers to the additional sample). Due to scheduling constraints
51 

some homeowners had time conflicts and could not participate (1% of the mailers to UCB

respondents and 2% of the mailers to the additional sample).

Overall, 827 phone calls were made to 471 homes in Northern California to recruit 32

homes (25.8 calls per recruited home). The research team made 429 phone calls to 201

homes in Southern California to recruit 31 homes (13.8 calls per recruited home).

Between August 7 and August 25, 2006, field measurements were scheduled for a total of

32 Northern California homes, our target for the three‐week Summer North field session.

Of these, 17 (53%) were UCB mailer respondents and 15 were from the additional sample.

Week 1 consisted of 11 homes: 9 in Brentwood and 2 in Discovery Bay; Week 2 consisted of

12 homes: 9 in Elk Grove and 3 in Sacramento; and Week 3 consisted of 9 homes: 3 in Elk

Grove, 4 in Manteca, and 2 in Rancho Murrieta.  

There were a total of 18 mechanically ventilated homes in the 32‐home sample, including

4 with nighttime ventilation cooling systems.  

Between September 5 and September 22, 2006, field measurements were scheduled for a

total of 31 homes—one home short of the 32‐home target for the three‐week Summer South

field session. Of these, 17 (55%) were UCB mailer respondents and 14 were additional

sample. Week 1 consisted of 12 homes: 3 in Valencia, 3 in Castaic, 3 in Santa Clarita, and 3

in Canyon Country; Week 2 consisted of 8 homes: 2 in Chula Vista, 4 in San Diego, and 2 in

San Marcos; Week 3 consisted of 11 homes: 2 in Castaic, 3 in Santa Clarita, and 6 in

Palmdale.  

There were a total of 4 mechanically ventilated homes in the 31‐home sample, including

1 with a nighttime ventilation cooling system and one with an evaporative cooling system.  

The fall swing season study targeted the re‐testing of four naturally ventilated homes in

Northern California. Recruitment letters were mailed to the 15 of the 32 Summer

participants Northern California who had naturally ventilated homes, and they were asked

to participate in a new series of tests in the fall swing season. Ten homeowners (67% of the

mailers) replied that they were interested in participating. One homeowner was not

interested, one homeowner was not able to participate within the timeframe suggested,

and three never replied and could not be contacted by telephone.

On October 16 and 17, 2006, field measurements were scheduled in two clusters: 2 in

Discovery Bay and 2 in Brentwood. One home in Discovery Bay and one home in

Brentwood were UCB mailer respondents.

The inter Study targeted re‐testing of 10 homes each in Northern and Southern California.

A total 1,500 recruitment letters were mailed to new single‐family detached homes in

Northern California, of which 177 were to UCB mailer respondents and 1,323 were to an
52 

additional sample. The research team mailed 1,486 recruitment letters to new single‐family

detached homes in Southern California, of which 313 were to the UCB mailer sample and

1,173 were to the additional sample. Each of these mailers included all the participants

from the Summer season. Again, homeowners were asked to call back if they were willing

to participate in the study. A total of 71 Northern California homeowners (5% of the

mailer) and 62 Southern California homeowners (4% of the mailer) called in to state they

were interested in the study.

Recruitment started in geographic areas from which most calls from homeowners

interested in participating in the study had been received. The research team also reached

out by telephone to homeowners in the same areas who had not called in to express

interest, favoring UCB mailer respondents over the additional sample. Less than 1% of the

UCB respondents and 1% of the additional sample who were contacted by phone refused

to participate. Less than 1% of both the UCB respondents and of the additional sample who

had received mailers were disqualified (e.g., renters, smokers, home vintage before 2002).

Due to the geographical constraints of the study and the location of some homes, a few

willing homeowners could not be included in the study (3% of the mailers to UCB

respondents and less than 1% of the mailers to additional sample). Due to scheduling

constraints some willing homeowners had conflicts and could not participate (1% of the

mailers to both UCB respondents and to the additional sample).

Overall, 385 phone calls were made to 264 homes in Southern California to recruit 33

homes (11.6 calls per recruited home). The research team made 158 phone calls to 73 homes

in Northern California to recruit 33 homes (4.8 calls per recruited home). Two factors

contributed to the higher success rate in the winter recruitment: 10 homes in each region

were repeat participants and due to the geographic constraints of the study, the location of

the 10 repeat homes dictated the location of the other homes that had to be recruited.

Consequently, the effort of recruiting and scheduling 24 additional homes in the North and

23 additional homes in the South was much reduced as compared to the Summer

recruitment.

Between January 16 and February 1, 2007, field measurements were scheduled for a total of

33 homes in Southern California—one more than the 32‐home target for the three‐week

Winter South field session. Of these, 12 (36%) were UCB mailer respondents and 21 were

additional sample. Of the 33 homes, 10 had also participated in the Summer Study (8 UCB

mailer respondents and 2 additional sample). Week 1 consisted of 11 homes: 5 in Santa

Clarita, 3 in Valencia, and 3 in Castaic; Week 2 consisted of 11 homes: 5 in San Marcos, 3 in

Chula Vista, and 3 in San Diego; Week 3 consisted of 11 homes: 8 in Fontana, and 3 in

Riverside.  

There were a total of four mechanically ventilated homes in the 33‐home sample, including

two with nighttime ventilation cooling systems.  
53 

Between February 12 and March 1, 2007, field measurements were scheduled for a total of

32 Northern California homes, our target for the three‐week Winter North field session. Of

these, 10 (31%) were UCB respondents and 22 were from the additional sample. Of the 32

homes, 10 homes were previous Summer participants (6 UCB mailer respondents and 4

from the additional sample). Three of the 10 repeat homes were fall participants as well.

Week 1 consisted of 12 homes: 6 in Elk Grove and 6 in Sacramento; Week 2 consisted of 12

homes: 3 in Discovery Bay, 3 in Stockton and 6 in Brentwood; and Week 3 consisted of 10

homes: 5 in El Dorado Hills, 3 in Lincoln and Lincoln Hills, and 2 in Folsom.  

There were a total of 17 mechanically ventilated homes in the 32‐home sample, including

5 with nighttime ventilation cooling systems.  

The following is the breakdown of the recruited sample set. No‐mechanical outdoor air

homes are defined as those homes without either a mechanical outdoor air supply system

or a nighttime cooling system.

Summer‐North

32 homes

18 mechanical outdoor air (including 4 with nighttime ventilation cooling systems)

14 non‐mechanical outdoor air

1 multi‐day home (Thursday‐Friday, Friday‐Saturday, Saturday‐Sunday)

Summer‐South

31 homes

4 mechanical outdoor air (including 1 with a nighttime ventilation cooling system)

28 non‐mechanical outdoor air

1 multi‐day home (Thursday–Friday, Friday–Saturday, Saturday–Sunday)

Winter‐North

32 homes

17 mechanical outdoor air (including 5 with nighttime ventilation cooling systems)

15 non‐mechanical outdoor air

1 multi‐day home (Thursday–Friday, Friday–Saturday, Saturday–Sunday)

10 seasonal repeats from Summer (i.e., 22 new homes)

Winter‐South

33 homes

4 mechanical outdoor air (including 1 with a nighttime ventilation cooling system)

29 non‐mechanical outdoor air

1 multi‐day home (Thursday–Friday, Friday–Saturday, Saturday–Sunday)

10 seasonal repeats from Summer (i.e., 23 new homes)
54 

Figure 3 (page 102) is a map of the State of California, depicting the locations of homes for

the summer and winter 2006–2007 field sessions in Northern and Southern California.

A total of 58 (44%) of the 132 home tests, including seasonal repeat tests, were recruited

from the UCB mail survey. Excluding seasonal repeats, a total of 42 (39%) of the 108 homes

were recruited from the UCB mail survey.  

As can be seen from Table 13, the Summer recruitment substantially depleted the potential

participants from the UCB mail survey, and while 53% and 55% of the Summer homes

were recruited from the UCB mail survey for the North and South regions respectively,

only 36% and 31% were recruited from the Winter North and South regions, respectively.

Thus, the study met the primary selection criteria of 54 homes in the North, 54 homes in

the South, a minimum of 20 homes with mechanical outdoor air systems, 20 seasonal

crossover homes, and 4 multi‐day homes.  

With respect to the secondary selection criteria requested by the ARB and Energy

Commission, the study was constrained by the lack of sufficient excess sample, as well as

the geographical constraints required for clustering of homes, to completely fulfill all of

these requirements. Homes were excluded in the San Jose and San Francisco Bay areas. In

addition, 6 homes in Palmdale were recruited for the high desert area, and for the ARB

concurrent acrylonitrile air testing, 3 homes were recruited from Chula Vista. The research

team was not able to completely avoid selecting homes in the Southern California Coastal

areas, and so included 7 homes in the San Diego area and 4 homes in the San Marcos area.  

With respect to the secondary selection criteria of matching the sample percentages from

the UCB mail survey, Table 14 (page 157) presents this comparison for the three

geographical strata in the UCB mail survey: Sacramento/Delta, Southern California

Coastal, and Rest‐of‐State. While the field sample is in relatively close agreement to the

UCB mail survey sample for the percentage of homes in the Southern California

geographical strata, 16% and 21% respectively, the percentage of homes in the field study

is over‐represented in the Sacramento/Delta region (i.e., 39% and 21%, respectively) and

under‐represented in the Rest‐of‐State region (i.e., 45% and 58%, respectively). One of the

reasons it was difficult to more closely achieve a match of the geographical strata

distributions between the field study and UCB mail survey study was that the study plan

required 50% of the homes to be in the North and 50% in the South, while the UCB mail

survey contained only 28% in the North and 72% in the South.

Although the UCB mail survey sample, upon which the sample selection was largely but

not entirely based, was a stratified random sample, the results in this study have not been

weighted to adjust for that stratification or other selection factors. 
55 

3.3 Home and Site Characteristics Collection 

The home and site characteristics were collected on‐site by the field teams and reported by

occupants on questionnaires. The data collected for these characteristics are summarized in

Tables 15, 16, 17, 18, 19, 20, and 21 (pages 158–164).

The 108 homes recruited for the summer, fall and winter field sessions were primarily from

track developments by production builders, were built in 2002 or later, and have been

owner‐occupied for at least one year. As summarized in Table 15, the median age of the

homes was 3.4 years, with a range of 1.7 years to 5.5 years. The median square footage was

2,703 square feet (ft2), with a range of 1,283 ft2 to 5,064 ft2. The total median composite

wood loading was 925 ft2, with a minimum of 263 ft2 and a maximum of 2,925 ft2. Most of

the composite wood came from furniture and cabinetry, with none from wall or ceiling

finishes and only one home with 979 ft2 of a floor finish made from composite wood.  

As summarized in Table 16, a total of 97% of the homes had slab‐on‐grade foundations and

99% had attached garages. A total of 60% of the homes had attached garages with living

spaces above the garage, which is a configuration with a stronger potential for transport of

garage air contaminants into the home indoor air than attached garages without living

spaces located above.  

A total of 99% of the homes had attics. The exterior envelope was typically stucco. All

homes had FAU heating systems, 94% of which, also had cooling capabilities, and all but

one, which was located in the garage, were located in the attic. The kitchen cooking ranges

consisted of 2% gas ranges and 98% electric ranges. A total of 85% of the cooking ranges

had exhaust fans ducted to outdoors. The kitchen ovens consisted of 27% gas ovens and

73% electric ovens. Only 2% of the ovens had exhaust fans ducted to outdoors. The clothes

dryers consisted of 76% gas dryers and 24% electric dryers, with 98% with exhaust ducted

to outdoors and 11% with exhaust leaks. All of the FAUs were gas‐fired heaters; there were

no homes with electric heat. All of the FAU t‐stats had the fan switch set in the auto

position, which operates the fan only when the t‐stat calls for heating or cooling. The water

heaters consisted of 98% gas heaters and 2% electric heaters. There were no window air

conditioning units. There were a total of 61% homes with decorative gas log fireplaces that

were vented to the outdoors and a total of 31% sealed combustion fireplaces vented to the

outdoors. There were no unvented gas log fireplaces. The field team inspectors reported an

odor upon entry to the home in 27% of the homes.

As summarized in Table 17, the primary kitchen cabinetry consisted of 97% with

composite wood with laminate, 2% composite wood with no laminate, and 1% solid wood

cabinetry. The primary bathroom cabinetry consisted of 99% with composite wood with

laminate, 1% composite wood with no laminate, and none with solid wood cabinetry. The

overall cleanliness of the homes, was rated by the field team inspectors as “Very Clean” in

72% of the homes, and the overall home clutter was rated as “No Clutter” in 49% of the
56 

homes and “Some Clutter” in 41% of the homes. Outdoor contaminant sources within

500 feet of the home, were observed by the field team in 55% of the homes. The three

outdoor sources most frequently encountered were gas station at 13% of the homes, and

restaurants or open field crops at 8% of the homes  

As summarized in Table 18, a total of 73% of the homes reported having two adults living

in the home, with 8% having just one adult and 1% having 5 adults. A total of 46% of the

homes reported having no children under 18 living in the home, with 25% having two

children and 1% having 5 children. Only 3% of the homeowners reported having one or

more occupants that smoke in the home, and as per our recruitment criteria these smokers

reported that they do not smoke in the home. A total of 56% of the homes reported having

pets that live in the home, and 57% of the homeowners reported wearing shoes in the

home. A total of 16% of the homeowners reported cloths or drapes that had been dry‐

cleaned within the last week prior to the air testing date.

As summarized in Table 19, homeowners reported that within the last 6 months (3 months

for homes with seasonal repeat tests), a number of potentially air contaminant‐generating

indoor activities. The three activities reported most frequently were: pesticide applications

in 42% of the homes, painting in 32% of the homes, and new furniture installed in 22% of

the homes. No homeowners reported and fire/smoke damage, and 6% reported mold or

moisture damage.

The homeowners reported use of portable air cleaners in 17% of the homes. This

percentage compares to approximately 15% of California homeowners reporting that they

used a portable air cleaner, as determined from the statewide probability sample in the

UCB mail survey (Price et al. 2007). In a telephone survey of 2,019 California households,

approximately 14% reported they either owned or used a portable air cleaner in the past

five years (Piazza et al. 2007).

The homeowners also reported use of plug‐in air fresheners in 33% of the homes, candles

in 58% of the homes, incense in 11% of the homes, and mothballs in 7% of the homes. A

total of 28% of the homeowners reported activities associated with hobbies and crafts in

their homes. With respect to storage of materials in the home or garage that are potential

sources of indoor air contaminants, homeowners reported storage of various products with

a frequency of 61% of the homes for latex products to 100% of the homes for cleaning

supplies. A total of 92% of the homeowners reported storing motor vehicles in the garage.  

As summarized in Table 20, a total of 13% of the homeowners reported vacuuming the

carpets and rugs in the most heavily used rooms “twice per week or more often”, while 5%

reported vacuuming “less than every 3–4 weeks.” In addition, 37% of the homeowners

reported steam cleaning of carpets, 16% reported professional dry cleaning, and 63%

reported spot cleaning or dry cleaning by the homeowner. With respect to problems

encountered in the home since they began occupancy the most frequently reported
57 

conditions were: wall or window leaks in 13% of the homes, plumbing leaks in 10% of the

homes, other unpleasant odors in 7% of the homes, and other moisture problems in 7% of

the homes.  

The types of mechanical outdoor air systems and controls observed in the field study are

summarized in Table 21. There were a total of 36 of the 108 homes (33%) with one or more

type of mechanical outdoor air systems. These included 17 homes (16%), with only a DOA

system, 12 homes (11%) with nighttime cooling systems (i.e., either whole house fans,

WHF, or FAU return air damper (RAD) systems, 6 homes (6%) with only an HRV system,

5 homes (4%) with multiple mechanical outdoor air systems, and one home (1%) with an

evaporative cooling system. There were a total of 40 mechanical outdoor air ventilation

systems in the 36 homes with these type systems, with DOA systems comprising 43% and

HRV systems comprising 23%.  

The type of damper controls included 30% manual, typically found with some DOA

systems, 33% automatic, typically found with some DOA and the RAD systems, 13%

gravity, typically found with the WHF systems, and 25% no damper, typically found with

the HRV systems.  

The type of operation control types included: 45% controlled with the FAU thermostat,

typically found with the DOA and RAD systems; 33% controlled with an on/off switch,

typically found with HRV systems; 18% with an FAU fan cycler, typically found with some

DOA systems; and 5% controlled by a timer, typically found with some HRV systems. The

location of the controls were in the home (i.e., accessible) in 75% of the homes, and in the

attic (inaccessible) in 25% of the homes, typically found with HRV systems.

3.4 Home Air Leakage Measurements 

3.4.1 Forced Air Heating/Cooling System Duct Leakage 

The forced air heating/cooling (FAU) system duct leakage area, as calculated from the duct

pressurization tests, is expressed as the percent of the total forced air heating/cooling

system flowrate and is summarized in Table 22 (page 165). Figure 4 (page 103) is the

cumulative frequency distribution of the measured FAU duct leakage percentage. These

measurements are compared to the California Title 24 (California Energy Commission

2001a) requirement of 6%. The home FAU system leakage had a median of 10% that

ranged from 1.9% to 73%. A total of 116 of the 138 systems (86%) had percentages

exceeding the California Title 24 maximum of 6%. The median ratio of the measured duct

leakage percentage to the maximum 6% requirement, for those homes exceeding 6% duct

leakage, was 1.7.

There were a total of 8 homes with duct leakage percentages exceeding 28%, which

represents 2.8 times the median of 10%. Four of these nine homes had mechanical outdoor

air ventilation systems integrated into the FAU system and included one DOA systems
58 

and three RAD systems. The additional ducting associated with these systems is believed

to contribute to the higher duct leakage. In particular, the RAD systems, which were tested

with the return air/outdoor air damper set for 100% return air, are likely to have some air

leakage to the outdoors during this test.

3.4.2 Home Building Envelope Air Leakage Area 

The building envelope air leakage variables and envelope air leakage area, as calculated

from the building envelope depressurization tests, are summarized in Table 23 (page 166).

The building envelope air leakage is expressed in terms of both ACH50 and specific leakage

area (SLA). Figure 5 (page 104) is the cumulative frequency distribution of the measured

building envelope air leakage. The median effective leakage area (ELA) was 104 square

inches (in2) and ranged from 56 in2 to 261 in2. The median 24‐hour average wind speed was

5.7 miles per hour (mph) and ranged from 1.4 mph to 16 mph. The median 24‐hour

average indoor–outdoor temperature difference was 5.3°

F, and ranged from ‐2.3°F to 14°F.  

The median ACH50 was 4.8, and ranged from 2.8 to 8.4. The median SLA was 2.9, and

ranged from 1.4 to 5.6. A total of 64 homes (60%) had SLA values less than 3.0, for which

the California Title 24 Alternative Calculation Method (ACM) Manual (California Energy

Commission 2001b) requires mechanical outdoor ventilation of 0.047 cubic feet per minute

per square foot (cfm/ft2). This requirement only applies to those builders taking credit for

building a home with an SLA less than 3.0. It is unknown if any of the homes in this study

were built taking a credit for an SLA less than 3.0. There was also one home with an SLA

value of less than 1.5, for which California Title 24 additionally requires that the

mechanical ventilation outdoor ventilation be sufficient to maintain an indoor air pressure

with respect to the outdoors that is greater than ‐5 pascals with all continuous ventilation

systems operating.

The median ACH50 of 4.8 in this study compares to the median of 5.2 in a study of

76 homes built in California since November 2002, and a median of 8.6 in a sample of 13

homes built before 1987 (Wilson and Bell 2003).

There were four homes that had ACH50 values exceeding 7.0, which represents 1.5 times

the median of 4.8. Three of these four homes did not have a mechanical outdoor air

ventilation system and one had an HRV system. Thus, the higher envelope leakage in three

of these four homes cannot be attributed to penetrations associated with the mechanical

outdoor air ventilation system.

3.4.3 Home-to-Garage Air Leakage 

The results of the zone pressure measurements of the garage‐to‐home connection are

summarized in Table 24 (page 167). The home‐to‐garage leakage areas (EqLA @ 10 Pa, in2)

had a median of 16 in2 and ranged from 0 in2 to 97 in2. There are no guidelines for garage‐

to‐home air leakage areas. The ratio of the home‐to‐garage leakage to the total leakage area

of the home‐to‐outdoors and the garage‐to‐outdoors was also calculated, and is expressed
59 

as a percentage. This percentage had a median of 4.9% and ranged from 0% to 18%. Also

measured was the home‐to‐garage pressure with the home‐to‐outdoor air pressure held at

‐50 Pa. The median home‐to‐garage pressure was ‐49 Pa and ranged from ‐34 Pa to ‐55 Pa.

A total of 70 homes (65%) did not meet the American Lung Association guideline for a

home‐to‐garage negative pressure of at least  ‐49 Pa when the home is depressurized to

‐50 Pa (American Lung Association 2006).  

One other garage‐to‐home metric that was calculated is the ”coupling factor.” This is

calculated as the ratio of the garage‐to‐outdoor differential pressure to the home‐to‐

outdoor differential pressure. A coupling factor equal to 0 indicates no garage‐to‐home

coupling and a coupling factor of 1.0 indicates total coupling of the garage to the home.

The median coupling factor was 0.03, and ranged from 0 to 0.26.

During the Pilot Study that preceded this field study we also conducted a limited number

of tracer gas tests of garage air entering the home. Appendix A contains a complete copy of

the Pilot Study report.

In the pilot study, the transport of garage air contaminants into the indoor air of the home

was measured with a tracer gas technique during the 24‐hour air contaminant

measurements and during a subsequent two‐week period. This technique uses a passive

constant injection PFT. The tracer gas sources were placed by Field Team 1 at locations in

the garage, approximately one week in advance of the tracer gas sampling, to allow for the

emission rates of the sources to equilibrate. A total of two sources were placed at a central

location in the garage. Since the emission rates from the PFT sources are temperature

dependent, an air temperature data logger was deployed in the garage to log the air

temperature at 15‐minute intervals. These temperature data were then input into an

equation of the emission rate as a function of time that was supplied by Brookhaven

National Laboratory, the supplier of the PFT sources, to calculate the temperature

corrected PFT emission rates. The PFT used for these tests, para‐

perfluorodimethylcyclohexane (p‐PDCH), was a different PFT than that used to measure

the outdoor air exchange rate of the home. The same PFT samplers that were used to

measure the outdoor air exchange rate of the home were used to sample the garage‐located

PFT entering the home.  

The percent of the garage air contaminant sources entering the home was determined from

the ratio of the calculated source of garage PFT entering the home to the calculated source

of garage PFT emitted into the garage. The emission rate of garage PFT entering the home

was calculated from the average concentration of the PFT in the home (determined from

the laboratory analysis of the indoor PFT sampler) multiplied by the outdoor airflow rate

entering the home (determined from the tracer gas measurements of the outdoor air

exchange rate and the indoor air volume of the home). For the emission rate of garage PFT

into the garage, the temperature‐corrected calculation of the garage PFT emission rates
60 

were used. This calculation assumes perfect mixing of the indoor home air and a zero

concentration of the PFTs in the outdoor air.

The calculation of the percentage of garage emissions entering the home was calculated

according to Equation (4):

Eh/g = (Ci‐pdch ) λ pft V 100 / Eg‐pdch (EQ 4)

where:

Eh/g   = percentage of garage emissions entering home (%)

Ci‐pdch   = concentration of PDCH garage tracer in the home indoor air (nL/m3)

λ pft   = home outdoor air exchange rate determined from PFT measurement (h‐1)  

V   = home indoor air volume (m3)  

Eg‐pdch   = emission of PDCH garage tracer into garage (nL/h)    

This calculation assumes that the concentration of PDCH tracer measured at the living

room/dining room sampling location represented the average home indoor air

concentration and that the PDCH sources in the garage represented the sources of other air

contaminants in the garage.

For the 24‐hour measurement period, the percentage of the garage sources entering the

home ranged from 2.6% (1.9% duplicate) for Home P1, to 9.8% for Home P3, to 10.1%

(11.9% duplicate) for Home P2. For the two‐week measurement period, the percentage of

the garage sources entering the home ranged from 4.0% for Home P1, to 7.2% for Home P2,

to 11.3% (11.4% duplicate) for Home P3. The garage‐to‐home air leakage ratios were 3% for

Home P1, 2% for Home P2, and 1% for Home P3, which compares to the median of 4.9%

observed in this study. The home‐to‐garage pressure, with the home‐to‐outdoor air

pressures held at ‐50 Pa, were ‐49.1 Pa for Home P1, ‐49.4 for Home P2, and ‐49.8 for Home

P3.

Thus, a substantial amount of garage air, along with the contaminants released by sources

in the garage (e.g., vehicle fuel and exhaust fumes, gasoline‐powered lawn equipment,

solvents, oils, paints, pesticides) enters the indoor air of the home. 

3.5 Window/Door and Mechanical Systems Usage 

The following fulfills the requirements results of Study Objective 1: Determine how

residents use windows, doors, and mechanical ventilation devices, such as exhaust fans

and central heating and air‐conditioning systems.
61 

3.5.1 Occupant Use of Windows and Doors for Ventilation 

The window/door usage in square foot‐hours (ft2‐hrs; the product of the opening area and

the amount of time open) is reported for both the Test Day usage and Week Average

usage. If a one square foot opening (i.e., a 4‐inch opening of a typical double‐hung

window) is kept open for an entire day, then the calculated window opening is 24 ft2‐hrs.

General population statistics are summarized in Table 25 (page 168). Figure 6 (page 105) is

the cumulative frequency distribution of window door opening recorded during both the

24‐hour air testing day and preceding one‐week period.

The median Test Day usage was 46 ft2‐hrs, with a range of 0 ft2‐hrs to 2,448 ft2‐hrs. The

Week Average usage had a median of 70 ft2‐hrs, with a range of 0 ft2‐hrs to 1,260 ft2‐hrs.

The homes with zero window usage for both the Test Day and Week Average included

multiple homes from the Summer and Winter field sessions and from both the North and

South Regions. The maximum usage for both the Test Day and Week Average usage were

both Summer field‐session homes, with one being in the North and one in the South.  

As an indicator of how well the usage during the Test Day compared to the usage during

the previous week, the Test Day/Week Average usage ratio was calculated. This ratio had a

median of 1.0, with a range of 0 to 7.0. The minimum of 0 was from multiple homes, which

had no usage on the Test Day but did have usage during the previous week. The

maximum of 7.0 was from a home in the Winter‐South field session, where the Week

Average usage was 22.5 ft2‐hrs and the Test Day usage was 3.2 ft2‐hrs.

The number of homes that had no window/door usage for the Test Day and for the

preceding week was also reported. A total of 34 of the 108 homes (32%) of the homes did

not use their windows during the 24‐hour Test Day, and 16 of the 108 homes (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. A total 29 of the 34 for the

homes with no window usage during the Test Day were in the winter field session, which

represents 53% of the homes in that session (N=55). All 16 of the homes with no window

usage during the preceding week were in the winter field session, which represents 9.4% of

the homes in that session.  

As an indicator of how well the occupants logged their window/door usage on the written

forms, the actual window/door usage measured with data loggers was compared with the

data from the occupant written logs. Log/Logger ratio numbers less than 1 indicate that the

window/door opening activity time‐period was under‐estimated on the written logs by the

occupants. Log/Logger ratio numbers greater than 1 indicate that the Window/Door

opening activity time period was over‐estimated on the written logs by the occupants.

The Log/Logger ratio had a median of 1.0, with a range of 0.04 to 74. Note that an

unusually large Log/Logger ratio may result when a Log value is divided by a very small
62 

Logger value. Two homes had Log/Logger ratios that were unusually high. Home 008,

with a Log/Logger ratio of 74, and Home 071, with a Log/Logger ratio of 24. Both these

homes were from the Summer field session, with one being in the North and one in the

South.  

The usage of the garage door to the home, in hours of open time, is reported for use as an

indicator of communication between the garage, a potential source area for indoor air

contaminants such as automobiles, chemicals, solvents, etc., and the home. General

population statistics, for both the Test Day usage, Week Average usage, and the Test

Day/Week Average usage ratio are summarized in Table 25.

The median Test Day usage was 0.06 hrs, with a range of 0.003 hrs to 6.2 hrs. The median

Week Average usage was 0.07 hrs, with a range of 0.004 hrs to 8.0 hrs. As an indicator of

how well the usage during the Test Day compared to the usage during the previous week,

the Test Day/Week Average usage ratio was calculated. The ratio had a median of 0.85,

with a range of 0.01 to 6.1.

3.5.2 Measured and Owner-Estimated Window/Door Usage Comparison 

For the participants in the UCB mail survey, the measured usage in the field session (i.e.,

occupant written logs) was compared with the homeowner’s self‐reported estimates of

usage in the mail survey, to provide some information on the accuracy of that reporting.

There were two sets of questions regarding window usage in the UCB mail survey.

Questions 10–25 asked for each season what the average number of hours was that

windows or doors were open more than one inch for four home areas and three time

periods. The four areas were: kitchen, bedrooms, bathrooms (including laundry room and

utility rooms), and other rooms. The three periods of time were daytime (6 AM to 6 PM),

evening (6 PM–11 PM), and nighttime (11 PM–6 AM). The question is problematic for us to

compare to the data that were collected for actual usage, as it is unknown how many

windows in the UCB mail survey data were open in each room and time period, or if the

hours listed as open for windows in a time period represent separate, concurrent, or

overlapping hours. For these reasons a comparison of the data in this study to Questions

10–25 has not been included.

Questions 28–31 asked for each season, how many hours out of a 24‐hour day, on average,

did your house have no ventilation, or low, medium, or high ventilation as defined below:

• No ventilation: All windows and doors closed.

• Low: One or two windows or doors open just a crack (up to one inch).

• Medium: Several windows or doors open at least a crack, or one or two windows

open partway (at least several inches).

• High: Some windows or doors fully open, or several windows or doors open part‐

way, or almost all windows or doors open at least a crack.
63 

As this question includes information on both the hours of window/door opening, and the

number and extent of the opening, it is possible to calculate a range of reported

window/door openings as square foot‐hours, which then be compared to the actual

measured usage. For this calculation, a range for the opening area in square feet for each of

the Low‐, Medium‐, and High‐usage categories described above was prepared. The

opening area ranges, which were selected for the usage categories in square feet, are listed

below:

• No ventilation: 0 ft2

• Low: 0.1 ft2 to 0.5 ft2

• Medium: 1.0 ft2 to 3 ft2

• High: 5 ft2 to 15 ft2, or greater

A total of 33 homes in our field study were also present in the UCB mail survey. Of the 33

homes, 7 did not have usable responses on their Occupant Questionnaire. Many of the

remaining 26 homes were repeat homes so a total of 48 home‐inspection dates had data

from the Homeowner Questionnaire that were compared to the estimated window usage

ranges collected by the UCB mail survey. To do this calculation, the research team

collected the hours of usage for each season‐usage category from the UCB mail survey,

Question 28–30, and multiplied it by the above opening area high and low ranges for the

reported usage category. This gives a low and high range of usage for each UCB mail

survey home‐season that was compared to the measured usage in the field study for that

home‐season.  

Q31 was not used, as there were no spring tests in the field study. As was done in the UCB

mail survey analyses, the researchers deleted from these analyses any homes where the

reported total usage hours exceeds 24 hours or where the reported usage hours are all

blank (these are posted as 99 in the UCB database). For those homes where there is at least

one non‐blank entry to the usage hour questions, it was assumed that the blanks are zero.

Percent comparisons and the population statistics of the measured versus estimated

Window/Door usage are summarized in Tables 26 and 27 (pages 169 and 170).

The percentage of homes with zero measured usage and zero estimated usage was 15%.

The percentage of homes with measured usage within the estimated usage range was 15%.

The percentage of homes with measured usage higher than the high end of the range

estimated usage was 52%. The percentage of homes with measured usage lower than the

low end of the range estimated usage was 8.3%. Thus a total of just 30% of the home‐

seasonal comparisons had actual measured usage that agreed with the estimated usage

reported in the UCB mail survey, with measured usage higher than the estimated usage

comprising most of the disagreements  
64 

The research team also evaluated the magnitude of the window/door usage disagreements

in Table 27. Homes that had actual measured usage but zero estimated usage had a median

of 3.1 ft2‐hrs that ranged from 0.3 ft2‐hrs to 153 ft2‐hrs. The median ratio of the actual

measured week average usage to the high end estimated usage in homes with higher

actual usage than estimated usage was 3.1. The median ratio of the actual measured week

average usage to the low end estimated usage in homes with lower actual usage than

estimated usage was 0.04.

3.5.3 Occupant Use of Mechanical Exhaust Air Systems

The occupant use of mechanical exhaust air systems is reported in hours for the 24‐hour

Test Day usage. General population statistics are summarized in Table 28 (page 171).

Figure 7 (page 106) is a cumulative frequency plot of the usge of the mechanical exhaust

systems.

The median Test Day usage was 0 hrs for kitchen exhaust fans, 0.05 hours for bathroom

exhaust fans, and 0.3 hours for other exhaust fans (i.e., clothes dryer, laundry/utility room).

As an indicator of how well the usage during our Test Day compared to the usage during

the previous week, the Test Day/Week Average usage ratio was calculated. The median

ratio was 1.0 for kitchen and bathroom exhaust fans and 0.9 for other exhaust fans.

There was one home, 055, with an unusually high usage of Other Exhaust (i.e., dryer,

laundry) of 17.1 hours. In this home, the laundry room fan was operated for 14.2 hours and

the clothes dryer was operated for a total of 2.8 hours.  

In the 2005 UCB mail survey on occupants’ use of windows and mechanical ventilation

equipment in 1,515 new homes in California (Price et al. 2007), 17% of the owners report

they rarely use the bathroom exhaust fans, and 13% say they never use the fans. In this

study, based upon the electronic logging of the two most used bathroom fans, 47% never

used the fans during the 24‐hour Test Day, and 27% never used the fans during the entire

preceding week. Thus, the percentage of homes in this study reporting no usage of the

bathroom exhaust fans from electronic logging of fan operation is notably higher than

percentage of homes reporting no usage in the UCB mail survey.  

In the 2005 UCB mail survey, 11% of the owners say they rarely use the kitchen range

exhaust fan and 2% say they never use the fan. In this study, based upon the occupant

written logs, 54% never used the fan during the one week preceding our 24‐hour Test Day,

and 78% never used the fan during the 24‐hour Test Day. Thus, the percentage of homes in

this study reporting no usage of the kitchen range exhaust fan from their written occupant

logs is notably higher than the percentage of homes reporting no usage in the UCB

mail survey. 
65 

3.5.4 Occupant Use of Mechanical Outdoor Air Systems

Three of the 17 homes with DOA systems (Home 001, Home 011, and Home 119) had the

mechanical outdoor air systems disabled (i.e., outdoor air damper closed). The

homeowners of Home 022, which had an HRV system, complained that the system

brought in hot air in the summer and cold air in the winter, and thus they kept the system

off the entire week except for 0.09 hours on Day 3. The analyses of the usage reported

below excludes these four disabled systems.

The occupant use of mechanical outdoor air systems is reported in hours for the 24‐hour

Test Day usage. General population statistics are summarized in Table 28 for the two types

of systems encountered in the field study: ducted outdoor air (DOA) systems and heat

recovery ventilator systems (HRV). Figure 8 (page 107) is a cumulative frequency plot of

the usage of the mechanical outdoor air systems.

The median Test Day usage was 2.5 hours for DOA systems and 24 hours for HRV

systems. Note that five homes with HRV systems were operated continuously for 24 hours.

As an indicator of how well the usage during the Test Day compared to the usage during

the previous week, the Test Day/Week Average usage ratio was calculated. The median

ratio was 1.1 and 1.0 for the DOA and HRV systems, respectively.  

These data indicate that the DOA systems, which typically are operated intermittently and

in conjunction with the operation of the FAU, operate for only a small portion of the day,

while the HRV systems are typically operated continuously.

The low fractional on‐times for the DOA systems are the result of the FAU fan control,

which typically was controlled by the FAU thermostat fan switch and was always set in

the “auto” position, and thus the fan only operated when the thermostat called for heating

or cooling.  

To ensure adequate delivery of outdoor air to the home, DOA systems should have a fan

cycler, so that even if the thermostat fan switch does not operate the fan, the fan is

operated for a minimum percentage of time. In addition, some of these fan cyclers have

controls for a damper in the outdoor air duct so that this damper can be opened only for

those times that outdoor air is desired. Typically these fan cyclers are set up to provide

outdoor air one‐third of each hour with an outdoor airflow rate that is three times higher

than that required for continuous operation, and thus provide an average outdoor airflow

rate over the hour that is equivalent to the flow rate of a continuous system.  

Of the 17 homes with DOA systems only six had fan cyclers, four of which had automatic

damper controls in the outdoor air duct. Of the 14 homes with operational DOA systems,

only four had fan cyclers, three of which had automatic damper controls in the outdoor air

duct. Measurements of the minimum percent operation time that these four fan cyclers

provided (e.g., the percentage of on‐time during the night when the thermostat was set
66 

back and only the fan cycler was causing the FAU fan to operate) indicated the following:

one FAU fan was never turned on, one was on for 10 minutes for each 90‐minute cycle (i.e.,

0.11 fractional on‐time), one was on for 10 minutes for each 30‐minute cycle (i.e., 0.33

fractional on‐time), and one FAU fan ran continuously, but the outdoor air damper opened

55 minutes for each 75‐minute cycle (i.e., 0.73 fractional on‐time).

ASHRAE 62.2‐2004 (ASHRAE 2004a) requires that intermittently operated residential

outdoor air mechanical ventilation systems operate at least 1 hour out of every 12 hours

(i.e., a minimum fractional on‐time of 0.083). Thus, three of the four DOA systems with fan

cyclers met the ASHRAE 62.2‐2004 minimum fractional on‐time requirement. The 10

operational DOA systems, which did not have fan cyclers and were operated by the

thermostat fan switch in the “auto” mode, do not meet the ASHRAE 62.2‐2004 minimum

fractional on‐time requirement.  

It is important to note that while the thermostat fan switch could be set to the “on”

position, and thus overcome the low operational times of some of these DOA systems, this

would not be a very energy efficient means of providing outdoor air to the home. The FAU

fan system is a large fan designed to provide the large supply airflow rates required for

heating or cooling the air in the home, and operating the FAU fan continuously would be a

large and costly consumption of electricity. The flow rates of outdoor air required for

ventilating homes is just a fraction (e.g., 5%–10%) of the total supply airflow rate delivered

by the FAU fan. Thus, to ensure adequate and energy‐efficient delivery of outdoor air to

the home, DOA systems should include a fan cycler with fan cycle times and outdoor

airflow rates set to provide the sufficient outdoor air ventilation.

Note that intermittently operated mechanical outdoor systems do not provide indoor air

quality that is equivalent to that provided by continuous mechanical outdoor air systems.

The concentrations of indoor air contaminants with indoor sources can increase

substantially during the off periods of intermittent systems, especially for those systems

with long cycle times (e.g., 12 hours), which may result in the occupants experiencing

odors or irritation.  

3.5.5 Occupant Use of Mechanical Nighttime Cooling Systems

The occupant use of mechanical nighttime cooling systems is reported in hours for the  

24‐hour Test Day usage. General population statistics are summarized in Table 28 for the

two types of nighttime cooling systems encountered in the field study: whole house fan

(WHF) systems and FAU return air damper (RAD) systems. Figure 9 (page 108) is a

cumulative frequency plot of the usage of the mechanical nighttime cooling systems.

The median Test Day usage was 0.7 hours for WHF systems and 5.3 hours for RAD

systems. As an indicator of how well the usage during the Test Day compared to the usage

during the previous week, the Test Day/Week Average usage ratio was calculated. The

median ratio was 0.7 for WHF fans and 1.0 for RAD systems.
67 

Note that there were five homes where there was zero usage of the nighttime cooling

system. These included three RAD systems in the winter field session and two WHF

systems—one in the summer and one in the winter field sessions. Thus, the zero usage for

four of these homes is consistent with the fact that the homes were in the winter field

session where nighttime cooling would not be expected to be used.

These data indicate that the RAD systems encountered in this field study were operated for

more hours each day than the WHF systems encountered.

3.5.6 Occupant Use of Forced Air Unit (FAU) Systems 

The occupant use of mechanical FAU) heating/cooling systems is reported in hours for the

24‐hour Test Day usage. For homes with multiple FAUs, data were summarized here for

only FAU#1, which typically served the downstairs living/dining area. General population

statistics are summarized in Table 28. Figure 10 (page 109) is a cumulative frequency plot

of the FAU systems’ usage.

The median Test Day usage for FAUs was 1.1 hours. A total of 32% of the homes had zero

FAU usage during the 24‐hour Test Day and 11% had zero usage during the preceding

week. As an indicator of how well the usage during the Test Day compared to the usage

during the previous week, the Test Day/Week Average usage ratio was calculated. The

median ratio was 0.9.  

These data indicate that the FAU systems encountered in this field study were operated for

relatively few hours each day.

3.6 Outdoor Air Ventilation Measurements 

This section fulfills the ventilation requirements, stated in Study Objective 2, Measure and

characterize IAQ, ventilation, and the potential sources of indoor air contaminants.

3.6.1 Mechanically Supplied Outdoor Airflow Rates 

The mechanically provided outdoor airflow rates for DOA and HRV systems are reported

for the systems on the Test Day in units of air changes per hour (ach) and cubic feet per

minute (cfm), along with the percent operation time. General population statistics and

comparison to the ASHRAE 62.2‐2004 requirement (ASHRAE 2004a) and the California

Title 24 Alternative Calculation Method (ACM)‐2001 code requirement (California Energy

Commission 2001b) are summarized in Table 29 (page 172). The analyses of the outdoor

airflow rates reported below excludes the four disabled mechanical outdoor air systems.

The ASHRAE 62.2‐2004 requirement for mechanically provided outdoor air ventilation is

calculated according to Equation 5 as follows:  
68 

Qr = (0.01 cfm/ft2) Afloor ) + 7.5 cfm (Nbr +1) (EQ 5)

where:

Qr   = required continuous mechanical outdoor airflow rate (cfm)

Afloor = floor area (ft2)

Nbr = number of bedrooms

The California Title 24 ACM‐2001 code requirement for mechanically provided outdoor air

ventilation is calculated according to Equation 6 as:  

Qr = (0.047 cfm/ft2) Afloor (EQ 6)

For the 14 operational DOA systems, the median 24‐hour average outdoor airflow rate, in

units of ach, was 0.01 ach with a minimum of 0.002 ach and a maximum of 0.08 ach. The

median 24‐hour average percent operation time was 10%, with a minimum of 0.6% and a

maximum of 74%. The median outdoor airflow rate when the system was operational was

38 cfm, with a minimum of 8.8 cfm and a maximum of 355 cfm.  

A total of 64% of DOA systems had outdoor airflow rates that failed to meet the ASHRAE

62.2‐2004 guideline, and 86% failed to meet the California Building Code (CBC) 2001

requirements. Note that this comparison was made using the outdoor airflow rate that was

measured when the system was operating, and assuming the system was operated

continuously and not with the actual time averaged outdoor airflow rates corrected for

ventilation effectiveness, as prescribed by ASHRAE 62.2‐2004.

The very low outdoor air exchange rates for the DOA systems were a result of the

combination of low outdoor airflow rates and low fractional on‐times.  

The low outdoor airflow rates were the result of the connection location of the outdoor air

duct, which typically has a diameter of five or six inches. The most common connection of

the outdoor air duct is to a sheet metal box just above the hallway return air inlet grille,

which contains the air filter. As this air filter is typically low efficiency and has a low

pressure drop, there is little negative air pressure at the outdoor air intake location to draw

in outdoor air. The few systems that had the outdoor air connection located further

downstream of the return air ducting (e.g., just before or at the fan box) had much higher

airflow rates.  

The low fractional on‐times are the result of the FAU fan control, which typically was

controlled by the FAU thermostat fan switch and was always set in the “auto” position,

and thus the fan only operated when the thermostat called for heating or cooling. As was
69 

previously discussed in Section 3.5.4, “Occupant Use of Mechanical Outdoor Air Systems,”

only 4 of the 14 operational DOA systems had fan cyclers, which could be set up to ensure

that the homes received adequate delivery of outdoor air.

ASHRAE 62.2‐2004 (ASHRAE 2004a) requires that intermittently operated residential

outdoor air mechanical ventilation systems operate at least 1 hour out of every 12 hours.

The outdoor air ventilation rate for intermittently operated systems, Qf must be increased

according to Equation 7 by a factor equal to one divided by the product of the fractional

on‐time and the ventilation effectiveness:  

Qf = Qr / (ε x f)   (EQ 7)

where:

Qf   = required intermittent mechanical outdoor airflow rate (cfm)

Qr = required continuous outdoor airflow rate – see Equation 5 (cfm)

ε   = ventilation effectiveness factor for intermittent ventilation

f = fractional on‐time of intermittent ventilation system

The ventilation effectiveness is determined by the fractional on‐time, f, according to the

following ranges of fractional on‐times:

• 0.33 (f < 0.35)

• 0.50 (0.35 ≤ f < 0.60)  

• 0.75 (0.60 ≤ f < 0.80)

• 1.0 (f ≥ 0.80)

In addition, if the system runs at least once every three hours then the ventilation

effectiveness can be assumed to be 1.0.

The fan cycler in Home 021 operated the fan 10 minutes out of every 30 minutes, which is a

fractional on‐time of 0.33. The ventilation effectiveness for this fractional on‐time is 0.33.

Thus, the required increase in the outdoor airflow rate is one divided by the product of the

fractional on‐time of 0.33 and the ventilation effectiveness of 0.33, or an increase of 9.2

times the requirement for a continuously operated ventilation system. The ASHRAE  

62.2‐2004 requirement for this house, based on the square footage of the home and the

number of bedrooms, is 57 cfm of outdoor air delivered continuously, or based upon the

fractional on‐time of the fan controller, 57 cfm times 9.2, or 524 cfm. The flowrate of
70 

outdoor air measured in this system was just 44 cfm, which is less than the continuous

flow rate requirement and just 8% of the intermittent flow rate requirement.

The fan cycler in Home 099 operated the outdoor air damper 55 minutes out of every

75 minutes, which is a fractional on‐time of 0.73. For some reason the FAU ran

continuously in this home even though the thermostat fan switch was set for “auto.” The

ventilation effectiveness for this fractional on‐time is 0.75. Thus, the required increase in

the outdoor airflow rate is one divided by the product of the fractional on‐time of 0.73 and

the ventilation effectiveness of 0.75, or an increase of 1.8 times the requirement for a

continuously operated ventilation system. The ASHRAE 62.2‐2004 requirement for this

house, based on the square footage of the home and the number of bedrooms, is 79 cfm of

outdoor air delivered continuously, or based upon the fractional on‐time of the fan

controller, 79 cfm times 1.8, or 144 cfm. The flowrate of outdoor air measured in this

system was just 10 cfm, which is less than the continuous flow rate requirement and just

7% of the intermittent flow rate requirement.

The fan cycler in Home 118 operated the fan 10 minutes out of every 90 minutes, which is a

fractional on‐time of 0.11. The ventilation effectiveness for this fractional on‐time is 0.33.

Thus the required increase in the outdoor airflow rate is one divided by the product of the

fractional on‐time of 0.11 and the ventilation effectiveness of 0.33, or an increase of 27.5

times the requirement for a continuously operated ventilation system. The ASHRAE  

62.2‐2004 requirement for this house, based on the square footage of the home and the

number of bedrooms, is 38 cfm of outdoor air delivered continuously, or based upon the

fractional on‐time of the fan controller, 38 cfm times 27.5, or 1,047 cfm. The flowrate of

outdoor air measured in this system was just 31 cfm, which is less than the continuous

flow rate requirement and just 3% of the intermittent flow rate requirement.

The fan cycler in Home 102 did not operate the fan at all, The thermostat did operate the

fan for 1.63 hours, however ASHRAE 62.2‐2004 does not allow for intermittent operation of

a mechanical outdoor air system with a thermostat and without a fan cycler because this

will not ensure adequate outdoor air delivery to the home during mild weather periods

when the thermostat may not turn on the FAU fan. Similarly the 10 other homes with

operational DOA systems that did not have fan cyclers do not meet the ASHRAE 62.2‐2004

requirements for intermittent operation of a mechanical outdoor air system.

Note that intermittent mechanical outdoor air systems, such as DOA systems, cannot

perform equivalently to continuous systems such as HRV systems with respect to

controlling the short‐term exposures to indoor air contaminants, especially if the cycle

times are long (e.g., greater than two hours). During extended outdoor air ventilation off‐

times, intermittent ventilation systems allow for air contaminants with indoor sources to

increase substantially as compared to the increases that would occur with a continuous

ventilation system. For some indoor air contaminants, such as those that cause irritation
71 

and/or odor, the effects are initiated by the immediate exposure to the indoor

concentration rather than the exposure to a concentration over a period of time.  

In addition, the increased outdoor air ventilation as required by ASHRAE 62.2‐2004 for

intermittent ventilation systems does not always provide equivalent long‐term average

indoor concentrations, especially for systems with long cycle times (e.g., 12 hours). The

long‐term average concentrations for air contaminants with indoor sources can be

substantially higher in homes with intermittent ventilation systems, which is important for

health effects such as cancer and cardiovascular disease.

To examine the equivalence of continuous and intermittent ventilation, a constant emission

indoor air contaminant source of 1,000 μg/h was modeled in a home ventilated according

to ASHRAE 62.2‐2004 ventilation rates. A well‐mixed single‐zone computer model was

used to simulate the indoor air contaminant concentrations for a 4‐bedroom home with a

1,500 ft2 floor area, 8‐ft ceiling height, and a 12,000‐cubic foot (ft3) indoor air volume. The

simulation used one‐minute time steps for a 24‐hour period with the initial concentration

set to equal the concentration at the end of the 24‐hour simulation and assumed a zero air

contaminant concentration in the outdoor air. The outdoor air ventilation rate for a

continuous ventilation system as prescribed by ASHRAE 62.2‐2004 is 52 cfm for this home.

In addition, the research team included an infiltration rate of outdoor air into the home

equal to the ASHRAE 62.2.‐2004 infiltration default credit of 2 cfm/100 ft2.

For the intermittent ventilation system the research team used a cycle time of 12 hours and

a fractional on‐time of 0.10, which according to ASHRAE 62.2‐2004 has a ventilation

effectiveness factor of 0.33.  

Figure 11 (page 110) is a plot of the modeled indoor air contaminated concentrations for

continuous and intermittent ventilation systems. The average 24‐hour indoor air

contaminant concentration was 9.3 μg/m3 for the intermittent ventilation system, which is

29% higher than the 7.2  μg/m3 average concentration for the continuous system. In

addition, the maximum indoor air contaminant concentration was 15.9  μg/m3 for the

intermittent ventilation system, which is 220% higher than the 7.2  μg/m3 maximum

concentration for the continuous system.

For the analyses of the HRV systems, Home 022 was excluded because the homeowner had

turned the system off for the 24‐hour Test Day as well as for all but 0.9 hours of the

preceding week. For the 8 operational HRV systems, the median 24‐hour average outdoor

airflow rate, was 0.30 ach with a minimum of 0.12 ach and a maximum of 0.47 ach. The

median 24‐hour average percent operation time was 100%, with a minimum of 32% and a

maximum of 100%. The median outdoor airflow rate when the system was operational, in

units of cfm, was 128 cfm, with a minimum of 66 cfm and a maximum of 159 cfm.  
72 

None of the HRV systems failed to meet the ASHRAE 62.2‐2004 guideline, and 22% failed

to meet the CBC 2001 requirements. The two homes that failed to meet the CBC 2001

requirement were the result of low outdoor airflow rates and not low operating times.

These results show that, as encountered in this field study, HRV systems are a more

effective outdoor air supply strategy than the DOA systems.

3.6.2 Tracer Gas Measurements of Home Outdoor Air Exchange Rates 

The air changes per hour (ach) in the homes are reported over the 24‐hour Test Day and

the two‐week measurement period. General population statistics are summarized in Table

30 (page 173). Figure 12 (page 111) is a cumulaive frequency plot of the24-hour outdoor

air exchange rate measurements.

The median 24‐hour measurement was 0.26 ach, with a range of 0.09 ach to 5.3 ach. The

median two‐week measurement was 0.24 ach, with a range of 0.11 ach to 2.3 ach. As an

indicator of how well the 24‐ hour Test Day ach compared with the two‐week period ach,

the absolute and relative difference between the 24‐hour versus two‐week period

measurements was calculated for the all homes with both measurements (i.e., not just those

homes in the All Home sample frame). The median absolute difference was 0.07 ach, with a

range of 0.001 to 5.1. The median relative standard deviation was 0.19, with a range of 0.01

to 1.1 (Table 30, page 173).

The 24‐hour Test Day measurements were compared to the CBC code requirement of  

0.35 ach and then the outdoor air exchange rate/CBC 2001 minimum code requirement

ratio for homes that were below the code requirement was calculated. There were 72

homes (67%) with outdoor air exchange rates below the minimum code requirement of

0.35 ach. General population statistics for these homes are summarized in Table 31 (page

174). The media ratio was 0.58, with a range of 0.25 to 1.00.  

There were eight homes with outdoor air exchange rates exceeding 1.25 ach, which is 4.8

times the median of 0.26 ach. Of these eight homes, seven were homes in the Summer Field

session, with six of these homes having relatively high window usage of between 421 and

1306 ft2‐hrs. In addition, four of these eight homes had mechanical outdoor air ventilation

systems, including two HRV, one WHF, and one DOA.  

On the other end of the spectrum there were eight homes with outdoor air exchange rates

less than 0.12 ach, which is less than half of the median of 0.26 ach. Of these eight homes,

seven were homes in the winter field session, with six of these homes having zero window

usage. In addition, four of these eight homes had operating mechanical outdoor air

ventilation systems, all of which were DOA systems.  

There were two homes where the outdoor air exchange rate was substantially less than the

measured mechanical outdoor air ventilation rates.
73 

The 24‐hour average mechanical outdoor air exchange rate for Home 034 was 3.7 ach,

whereas the PFT 24‐hour measured outdoor air exchange rate was 0.59 ach. The FAU did

not operate at all during this period and the whole house exhaust fan operated for

11.3 hours. There was a lot of window opening, 457 ft2‐hrs, of which 72% was located on

the second floor, where the inlet to the whole house exhaust fan was located. As the PFT

air sampler was on the first floor and the whole‐house exhaust fan was exhausting air on

the second floor with most of the open windows, the airflow into the exhaust fan was

mostly from the second floor open windows creating a two‐zone situation, with lower

ventilation rates on the first floor where the PFT sampler was located.

The 24‐hour average mechanical outdoor air exchange rate for Home 044 was 2.2 ach,

whereas the PFT 24‐hour measured outdoor air exchange rate was 0.86 ach. The FAU did

not operate at all during this period and the whole‐house exhaust fan operated for

4.8 hours. There was also a window fan blowing outdoor air into the second floor for

18.5 hrs. There was a lot of window opening, 301 ft2‐hrs, of which 34% was located on the

second floor, where the inlet to the whole house exhaust fan was located. As the PFT air

sampler was on the first floor and the whole house exhaust fan was exhausting air on the

second floor with most of the open windows, the airflow into the exhaust fan was mostly

from the second floor open windows, creating a two‐zone situation, with lower ventilation

rates on the first floor where the PFT sampler was located.

It is important to note that the ventilation inefficiencies caused by poor mixing of the

indoor air, such as in these two homes, has the most impact in homes where the outdoor

air exchange rates are high (e.g., greater than 2 ach); in homes with lower outdoor air

exchange rates (e.g., less than 0.5 ach) there is much less of an impact. This is because in

homes with low outdoor air exchange rates, the air has a longer residence time in the

home, which allows for more mixing of the indoor air to occur from mechanically and

thermally induced airflows.

3.7 Indoor Air Quality Measurements 

This section fulfills the indoor air quality requirements stated in Study Objective 2,

Measure and characterize indoor air quality (IAQ) ventilation, and the potential sources of

indoor air contaminants.

3.7.1 Integrated Time Averaged IAQ Measurements (24-hour) 

3.7.1.1 Volatile Organic Compounds Concentrations 

Table 32 (page 175) contains the analytical method mass detection limit, MDL mass, the

typical air sample method detection limit concentration, MDL concentration, the indoor air

contaminant concentration guidelines, the ratio of the MDL concentration to the indoor air

contaminant concentration guidelines, and the percentage of samples with concentrations

above the MDL concentration for volatile organic compounds.
74 

The primary selection of an indoor air contaminant concentration guideline for VOCs for

this project was the California Air Resources Board Indoor Air Pollution in California,

Table 4.1 ARB Indoor Air Quality Guidelines, July 2005 (California Air Resources Board

2005). The second basis for selection, for those compounds without ARB indoor air

guidelines, is the California Office of Environmental Health Hazard Assessment Chronic

RELs (OEHHA 2003). The final basis of selection, for those compounds with neither ARB

indoor guidelines or OEHHA Chronic RELs, is 2.5% of the occupational standard. This

recommendation is based upon the different exposure periods (40‐hour week for an

industrial worker versus 168‐hour per week for a full‐time occupant) and to provide a

safety factor of ten for more sensitive populations (Nielsen 1997).

The ratio of the MDL concentration to the indoor air contaminant concentration guidelines

ranged from 4E‐5 (0.00004) for 2‐butoxyethanol and n‐hexane to 2E‐2 (0.02) for

naphthalene.

The percentage of homes with indoor concentrations exceeding the MDL concentration

ranged from 0% for caprolactam to 100% for phenol and toluene. The percentage of

outdoor air samples with concentrations exceeding the MDL concentration ranged from

0% for ethylene glycol, 1‐methyl‐2‐pyrrolidinone, trichloromethane, and vinyl acetate to

98% for phenol.

The indoor concentrations of VOCs are summarized in Table 33 (page 176). Figures 13–25

(pages 112–124) are cumulative frequency plots of the indoor and outdoor concentrations

of the 15 VOCs that have Chronic RELs (OEHHA 2003). The median indoor concentrations

ranged from 0.1  μg/m3 for caprolactam and 1,4‐dichlorobenzene to 11  μg/m3 for

d‐limonene and alpha‐pinene. The maximum indoor concentrations ranged from 0.1 μg/m3

for caprolactam to 219 μg/m3 for 1,4‐ dichlorobenzene.  

The outdoor concentrations of VOCs are summarized in Table 34 (page 177). The median

outdoor concentrations ranged from 0.1  μg/m3 for 2‐butoxyethanol, caprolactam,

1,4‐dichlorobenzene, naphthalene, alpha‐pinene, and styrene to 1.2 μg/m3 for toluene. The

maximum outdoor concentrations ranged from 0.2  μg/m3 for 1‐methyl‐2‐pyrroldinone,

naphthalene, trichloromethane, and vinyl acetate, to 6.3 μg/m3 for toluene.

The maximum indoor concentrations of VOCs are compared to the indoor air contaminant

guidelines in Table 35 (page 178). None of the indoor concentrations of the 20 VOCs

exceeded the indoor air contaminant guidelines. The ratio of the maximum indoor

concentration and indoor air contaminant guideline ranged from less than 0.0001 for

caprolactam to 0.646 for tetrachloroethene. There were several homes where the indoor

concentrations were substantially higher than the median (i.e., 25 times or more higher).  
75 

Homes 097 and 022 both had indoor concentrations of 1,4‐dichlorobenzene that were

between 1,600 and 2,200 times higher than the median of 0.1  μg/m3 (i.e., 161  μg/m3 in

Home 022 and 219 μg/m3 in Home 097). The outdoor air exchange rates in these two homes

were not unusually low—0.64 ach in Home 097 and 0.41 ach in Home 022. Thus, an indoor

source of 1,4‐dichlorobenzene appears to be the primary cause of these elevated

concentrations. An examination of the potential indoor sources in these two homes

indicates that mothballs, a known source of this chemical, is the likely source. There were a

total of seven homes where the homeowners reported the use of mothballs, including the

two homes cited above. Two of the other five homes where use of mothballs was reported

also had indoor concentrations that were relatively high in comparison to the median;

Home 094 with concentrations 760 times higher (i.e., 75.6  μg/m3) and Home 071 with

concentrations 335 times higher (i.e., 33.5 μg/m3).

Home 112 had indoor concentrations of naphthalene that was 25 times higher than the

median of 0.2 μg/m3. The outdoor air exchange rate in this home was also not unusually

low, 0.31 ach. Thus, an indoor source of naphthalene appears to be the primary cause of

the elevated concentration. An examination of the potential indoor sources in this home

indicates that mothballs, a known source of this chemical, is also the likely source. In the

United States naphthalene is no longer used to make mothballs; instead  

1,4‐dichlorobenzene is used. However, people still have these mothballs stored at home or

bring them into the United States from abroad.

Home 074 had indoor concentrations of styrene that were 75 times higher than the median

of 0.9  μg/m3. The outdoor air exchange rate in this home was relatively low, 0.17 ach,

which contributed to the elevated indoor concentration. An examination of the potential

indoor sources in this home did not reveal any indoor sources. While a potential indoor

source of styrene is polystyrene, no unusual amount of this material was observed in the

home. It is possible that polystyrene materials may be used in construction of this home

that are not visible, such as structural insulated panels (SIPs), which often contain

polystyrene,

Home 075 had indoor concentrations of tetrachloroethene that was 15 times higher than

the median of 0.2 μg/m3. The outdoor air exchange rate in this home was relatively low,  

0.25 ach, which contributed to the elevated indoor concentration. An examination of the

potential indoor sources in this home indicates that dry cleaned clothes or drapes, a known

source of this chemical, is the likely source. The homeowner reported that clothes or

drapes had been dry‐cleaned within the last week.

Home 120 had indoor concentrations of trichloromethane (chloroform) that was 60 times

higher than the median of 0.2  μg/m3. The outdoor air exchange rate in this home was

relatively low, 0.12 ach, which contributed to the elevated indoor concentration. An

examination of the potential indoor sources in this home indicates that use of chlorinated

water, a known source of this chemical, is the likely source. The homeowner reported
76 

showering or bathing, warming/boiling water, and use of the clothes washer during the  

24‐hour air sampling Test Day.

Unlike the other homes in this study, which at most had one or two volatile organic

compounds with concentrations substantially higher than the median, Home 108 had five

compounds with elevated concentrations; benzene at 11 times the median, n‐hexane at 26

times the median, toluene at 12 times the median, m, p‐xylene at 14 times the median, and

0‐xylene at 17 times the median. The outdoor air exchange rate in this home was relatively

low, 0.24 ach, which contributed to the elevated indoor concentrations. Potential sources of

these compounds include paints, caulking, and solvents. The homeowner reported

painting and caulking of the exterior of the front door and the purchase of two new leather

recliners within the last six months, and spot cleaning or dry cleaning of the carpet within

the last two months.

  

3.7.1.2 Formaldehyde and Acetaldehyde Concentrations 

Table 32 (page 175) contains the analytical method mass detection limit (MDL mass), the

typical air sample method detection limit concentration (MDL concentration), the indoor

air contaminant concentration guidelines, the ratio of the MDL concentration to the indoor

air contaminant concentration guidelines, and the percentage of samples with

concentrations above the MDL concentration for formaldehyde and acetaldehyde.

The selections of indoor air contaminant concentration guidelines for formaldehyde and

acetaldehyde for this project were the California Air Resources Board, Indoor Air Pollution

in California, Table 4.1 ARB Indoor Air Quality Guidelines, July 2005 (California Air

Resources Board 2005) and the California Office of Environmental Health Hazard

Assessment Chronic RELs (OEHHA 2003) and Acute RELs (OEHHA 2000). For

formaldehyde, the OEHHA Chronic REL (OEHHA 2003) of 3 μg/m3 and the OEHHA

Acute REL (OEHHA 2000) of 94 μg/m3 was included, in addition to the ARB Indoor Air

Guideline of 33 μg/m3. For acetaldehyde, the OEHHA Chronic REL of 9 μg/m3 (OEHHA

2003) was included.  

The ratio of the MDL concentration to the indoor air contaminant concentration guidelines

ranged from 9E‐3 (0.009) for formaldehyde (ARB Indoor Air Guideline of 33 μg/m3) to 3E‐2

(0.03) for acetaldehyde (OEHHA Chronic REL of 9 μg/m3).

The percentage of homes with indoor concentrations exceeding the MDL concentration

was 100% for both formaldehyde and acetaldehyde. The percentage of outdoor air samples

with concentrations exceeding the MDL concentration was 97% for both formaldehyde and

acetaldehyde.

The indoor concentrations of formaldehyde and acetaldehyde are compared to the indoor

air contaminant guidelines in Table 36 (page 179). Figures 26 and 27 (pages 125 and 126)
77 

are cumulative frequency plots of the indoor and outdoor concentrations of acetaldehyde

and formaldehyde.  

The median indoor concentration of formaldehyde was 36 μg/m3, with a range of 4.8 μg/m3

to 136 μg/m3.  

For formaldehyde, all of the homes exceeded the Chronic REL of 3 μg/m3, 59% exceeded

the ARB Indoor Air Guideline of 33 μg/m3, and a total of 6.7% exceeded the OEHHA Acute

REL of 94 μg/m3.

For those homes exceeding the indoor formaldehyde guidelines, the ratio of the indoor

concentrations to the indoor air contaminant guidelines were also calculated. The median

ratio was 12, with a range of 1.6 to 45 for the Chronic REL of 3 μg/m3; 1.5, with a range of

1.0 to 4.1 for the ARB indoor air guideline of 33 μg/m3; and 1.2, with a range of 1.0 to 1.4 for

the OEHHA Acute REL of 94 μg/m3.  

The median indoor concentration of acetaldehyde was 20 μg/m3, with a range of 1.9 μg/m3

to 102 μg/m3. The median indoor concentration of acetaldehyde was 20 μg/m3, with a range

of 1.9 μg/m3 to 102 μg/m3.

For acetaldehyde a total of 82% of the 105 homes exceeded the OEHHA Chronic REL of  

9 μg/m3. For homes exceeding the indoor acetaldehyde guidelines, the ratio of the indoor

concentrations to the indoor air contaminant guidelines was also calculated. The median

ratio was 2.5, with a range of 1.2 to 11.

Figure 28 (page 127) compares the indoor formaldehyde concentrations and the outdoor

air exchange rates in 84 homes without mechanical outdoor air ventilation systems and in

38 homes with working mechanical outdoor air ventilation systems (i.e., 17 pure DOA, 6

pure HRV, and 15 other and mixed mechanical outdoor air systems). Also included in

Figure 28 are the median ASHRAE 62.2‐2004 (ASHRAE 2004a) and California Title 24

ACM (California Energy Commission 2001b) recommendations for mechanical outdoor air

ventilation as calculated for the specific homes in this study. The ASHRAE 62.2‐2004

median calculated rate was 0.15 ach, while the California Title 24 ACM median calculated

rate was 0.30 ach.

Note that ASHRAE 62.2‐2004 assumes that natural infiltration will add to the mechanically

supplied outdoor air exchange rate a total of 2 cfm/100 ft2, or 0.15 ach, assuming an 8 ft

ceiling height. However, if the indoor‐outdoor temperature difference and wind speed are

low, the natural infiltration rates can be much less than 0.15 ach. For a two‐story home

with a building envelope leakage equal to the median of the sample of homes in this study

(i.e., ACH50 of 4.8 or SLA of 2.9), the natural infiltration rate for an indoor‐outdoor

temperature difference of 2°

F and a wind speed of 2 mph, is just 0.08 ach. This is calculated

according to the ASHRAE Basic Model (ASHRAE 2005). Furthermore, if the mechanical
78 

outdoor air ventilation system is not a balanced system, such as the DOA systems in this

study, then the natural infiltration rates can be substantially muted when the system is

operating. For those systems equipped with fan cyclers set to operate the system for 33%

operation time, the added natural infiltration is reduced from 0.08 ach to 0.06 ach, as

calculated according to the ASHRAE‐recommended calculation for combining infiltration

and mechanical ventilation outdoor rates (ASHRAE 2005). If an unbalanced system is set

up to run at a low continuous rate, then the added natural infiltration rate can be reduced

from 0.08 ach to less than 0.01 ach.

Figure 28 also includes the California Air Resources Board recommended maximum

indoor 8‐hour formaldehyde exposure guideline of 33  μg/m3 (California Air Resources

Board 2005). This guideline was developed to protect sensitive subgroups of the

population to non‐cancer irritant effects. In 2004, the World Health Organization

designated formaldehyde as a known human carcinogen (IARC 2004).  

As can be seen in Figure 28, there are few homes with outdoor air exchange rates of at least

0.5 ach that had indoor concentrations of formaldehyde above the recommended

maximum indoor concentration of 33 μg/m3; just 5 of 122 homes, or 4%, of the homes. For

homes with outdoor air exchange rates of at least 0.30 ach (i.e., the median mechanical rate

recommended by California Title 24 ACM for the homes in this study), a total of 14 of 38

homes, or 37%, had indoor concentrations of formaldehyde above 33  μg/m3. For homes

with outdoor air exchange rates of at least 0.15 ach (i.e., the median mechanical rate

recommended by ASHRAE 62.2‐2004 for the homes in this study), a total of 32 of 57 homes,

or 56%, had indoor concentrations of formaldehyde above 33 μg/m3.  

If we look separately at the number of homes with indoor formaldehyde concentrations

exceeding the 33 μg/m3 guideline, we find that 55% (46 of 84) of homes without mechanical

outdoor air ventilation systems, 100% (i.e., 17 of 17) of homes with DOA systems, and 50%

(i.e., 3 of 6) homes with HRV systems exceeded this guideline. Note that one of the three

HRV system homes with elevated indoor formaldehyde concentrations was only operated

32% of the time via a manual switch by the homeowner.

3.7.1.3 Nitrogen Dioxide 

Table 37 (page 180) contains the analytical method mass detection limit (MDL mass), the

typical air sample method detection limit concentration (MDL concentration), the indoor

air contaminant concentration guidelines, the ratio of the MDL concentration to the indoor

air contaminant concentration guidelines, and the percentage of homes with indoor and

outdoor concentrations above the MDL concentration.  

The California Air Resources Board 24‐hour guideline of 150 μg/m3 (California Air

Resources Board 2005) was selected as an indoor air contaminant concentration guideline

for nitrogen dioxide.
79 

The MDL concentration of 5.7 μg/m3 was determined by dividing the MDL mass of 0.8 μg

with the typical air sample volume (i.e., 140 L). The ratio of the MDL concentration to the

indoor air contaminant concentration guideline is 0.04.

The percentage of the homes (i.e., Winter‐North homes only) with indoor concentrations

exceeding the MDL concentration was 48%. The percentage of the outdoor air samples

with concentrations exceeding the MDL concentration was 9%.

The indoor and outdoor concentrations of nitrogen dioxide are summarized in Table 38

(page 181). The median indoor concentration was 3.1 μg/m3, with a range of 2.6 μg/m3 to

50 μg/m3. The median outdoor concentration was 2.9 μg/m3, with a range of 2.7 μg/m3 to

14 μg/m3.

None of the indoor or outdoor nitrogen dioxide concentrations exceeded the 150  μg/m3

guideline.

In addition, none of the homes exceeded the California Air Resources Board annual

ambient air quality standard of 56 μg/m3 for outdoor air. (California Air Resources Board

2007a).

  

3.7.1.4 Particulate Matter (PM2.5) 

Table 37 (page 180) contains the analytical method mass detection limit (MDL mass), the

typical air sample method detection limit concentration (MDL concentration), the indoor

air contaminant concentration guidelines, the ratio of the MDL concentration to the indoor

air contaminant concentration guidelines, and the percentage of homes with indoor and

outdoor concentrations above the MDL concentration.  

The California Air Resources Board 24‐hour guideline of 65 μg/m3 was selected as the

indoor air contaminant concentration guideline for PM2.5 (California Air Resources Board

2005).

The MDL concentration of 1.8 μg/m3 was determined by dividing the MDL mass of 5 μg

with the typical air sample volume (i.e., 2.8 m3). The ratio of the MDL concentration to the

indoor air contaminant concentration guideline is 0.03.

The percentage of the homes (i.e., Winter‐North homes only) with indoor concentrations

exceeding the MDL concentration was 100%. The percentage of the outdoor air samples

with concentrations exceeding the MDL concentration was 100%.

The indoor concentrations of PM2.5 are summarized in Table 38 (page 181). The median

indoor concentration was 11  μg/m3, with a range of 3.8  μg/m3 to 36  μg/m3. The median

outdoor concentration was 8.7 μg/m3, with a range of 4.3 μg/m3 to 12 μg/m3.
80 

None of the indoor or outdoor concentrations of PM2.5 particulate matter exceeded the

65 μg/m3 ARB 24‐hour average indoor air guideline.

The EPA recently established a lower PM2.5 24‐hour requirement of 35 μg/m3 (EPA 2007)

for outdoor air. Only one of the homes exceeded this concentration—Home 116, which had

an indoor concentration of 36  μg/m3. The outdoor concentration was 8.9  μg/m3, which

indicates a substantial indoor source of PM2.5 particulate matter in this home.

The Occupant Source Activity Log was examined to see if there were any activities that

might have contributed to the elevated indoor concentrations of PM2.5. The only substantial

activity was 180 minutes of baking. While there was a fireplace and candles in the living

room where the air sampler was located, the occupant did not report any usage of the

fireplace or any candle burning. The occupancy of this home was relatively high and

included two adults, two children under 18 years old, two dogs, two hamsters, and one

goldfish. Contributing to the elevated indoor concentration of PM2.5 is the relatively low

outdoor air exchange rate of 0.22 ach.

3.7.2 Real-Time IAQ Measurements 

3.7.2.1 Carbon Monoxide (CO) 

Table 37 (page 180) contains the method detection limit concentration, the indoor air

contaminant concentration guidelines, the ratio of the MDL concentration to the indoor air

contaminant concentration guidelines, and the percentage of homes with indoor and

outdoor concentrations above the MDL concentration.

For indoor air contaminant concentration guidelines for carbon monoxide, the California

Air Resources Board 8‐hour guideline of 9 ppm and the 1‐hour guideline of 20 ppm

(California Air Resources Board 2005) was selected. There is no 24‐hour exposure guideline

for carbon monoxide.

The ratio of the MDL concentration to the indoor air contaminant concentration guideline

is 0.09.

The percentage of the homes with indoor concentrations exceeding the MDL concentration

was 100%. The percentage of the outdoor air samples with concentrations exceeding the

MDL concentration was 100%.

The indoor concentrations of carbon monoxide are summarized in Table 38 (page 181). The

median maximum 8‐hour average indoor concentration was 1.1 ppm, with a range of  

0.4 ppm to 3.7 ppm. The median maximum 8‐hour average outdoor concentration was

1.9 ppm, with a range of 0.4 ppm to 4.4 ppm.
81 

The median maximum 1‐hour average indoor concentration was 1.6 ppm, with a range of

0.4 ppm to 6.8 ppm. The median maximum 8‐hour average outdoor concentration was  

2.4 ppm, with a range of 0.4 ppm to 4.9 ppm.

None of the indoor or outdoor concentrations of carbon monoxide exceeded either the  

9 ppm 8‐hour guideline or the 20 ppm 1‐hour guideline.

  

3.7.2.2 Carbon Dioxide (CO2) 

The indoor and outdoor concentrations of carbon dioxide are summarized in Table 39

(page 182). The median indoor conentration was 564 ppm,with a range of 334 ppm to  

1,108 ppm. The median outdoor concentration was 323 ppm, with a range of 258 ppm to

369 ppm.

Note that measurements of the outdoor concentration of carbon dioxide less than  

375 ppm are indicative of a measurement error, as the atmospheric concentration of carbon

dioxide measured at the Mauna Loa Observatory in Hawaii in 2006–2007 ranged from  

375–385 ppm. These measurements are not influenced by urban sources of atmospheric

carbon dioxide, such as vehicle and industrial combustion exhaust fumes, and thus

represent the minimum concentration of carbon dioxide in outdoor air.

The carbon dioxide sensors used, TSI IAQ‐Calcs, are non‐dispersive infrared

spectrophotometers and were calibrated with certified calibration gasses before and after

each 24‐hour sampling period. It was first thought that changes in the outdoor air

temperature might be causing this error. To test this hypothesis, the research team

calibrated the instrument at room air temperature and then measured the instrument’s

response to 1,035 ppm calibration gas with the instrument and the calibration gas at 70°

F

and then at 41°

F. The response of the instrument decreased by 230 ppm (22%) at the 41°F

temperature.

A review of the minute‐by‐minute concentrations of outdoor carbon dioxide

concentrations and the outdoor air temperature from homes with very low outdoor air

24‐hour average concentrations (e.g., 260 ppm) suggest that the response of the sensor

decreases with the outdoor air temperature.

The impact of relative humidity on the response of the sensor was also examined. The

instrument was calibrated at room air temperature and the research team measured its

response to 1,035 ppm calibration gas directly from the compressed gas cylinder to the

sensor, and then with the calibration gas passed through a series of water filled bubblers

and then to the sensor. The relative humidity of the calibration gas was 1.6% directly from

the compressed gas cylinder and 87% after passing through the bubblers. The response of

the sensor to the 1,025 ppm calibration gas decreased by 40 ppm (3.8%) at 87% relative

humidity.
82 

Thus, it appears that the major error associated with the outdoor carbon dioxide

measurements is associated with outdoor air temperature changes. No attempt has been

made to correct these data, nor have any data where this effect appears to be occurring

been deleted.

It is not anticipated that this type of error is associated with the indoor air measurements

since there are not large changes in the indoor air temperatures as there are with outdoor

air temperatures.

3.7.2.3 Temperature and Relative Humidity 

The indoor and outdoor air temperatures and relative humidities are summarized in Table

39 (page 182). The median indoor air temperature was 72.3°

F, with a range of 62.7°F to  

82.8°

F. The median outdoor air temperature was 63.8°F, with a range of 44.9°F to 82.4°F. The

median indoor air relative humidity was 45.2%, with a range of 19.5% to 63.5%. The

median outdoor air relative humidity was 57.9%, with a range of 25.1% to 93.3%.

3.7.3 Volatile Organic Compound Concentration Study Comparisons 

Table 40 (page 183) compares the concentrations of VOCs measured in this study to those

measured in two other studies in new homes as summarized by Hodgson and Levin

(2003). In the Hodgson and Levin paper they present the geometric mean and the

maximum concentrations observed in six experimental low‐emitting homes and three

conventional homes built in Denver, Colorado in 1992–1993 and four manufactured homes

and seven site‐built homes built in the east and southeast United State in 1997–1998. The

measurements of VOCs were made within the first six moths after the homes were

completed. The four manufactured homes were unoccupied but furnished, and the seven

site‐built homes were unoccupied and unfurnished, but finished, including cabinetry and

carpeting. One of the four manufactured homes had a DOA outdoor air ventilation system

with a fan cycler. One of the seven site‐built homes had a DOA outdoor air ventilation

system with a fan cycler, and one home had an HRV system. The six experimental homes

and three conventional homes were tested both during pre‐occupancy period without

furnishings and a post‐occupancy period with furnishings. Each of six experimental homes

had continuous outdoor air ventilation systems, of which three were HRVs.  

The outdoor air exchange rates were lower in the new homes in this study, with a

geometric mean outdoor air exchange rate of 0.31 ach and a geometric mean outdoor air

exchange rate of 0.44 ach for the 20 new homes in the other studies.  

There were 13 VOCs measured in this study that were all measured in the two other

studies. For comparison purposes, Table 40 presents the ratio of the geometric mean

concentrations observed in this study with the geometric mean concentration in the two

other studies. A total of 7 of the 13 compounds had a ratio of the geometric mean

concentrations between 0.5 and 2, with 8 of the 13 having ratios greater than 1.0. There
83 

were two compounds in this study with a ratio of more than 2: benzene (4.4) and

trichloromethane (4.0).

There were also two compounds with a ratio of less than 0.5: alpha‐pinene (0.4) and

ethylene glycol (0.1).

Also included in Table 40 is a comparison of the maximum concentrations in this study

and the other two studies. A total of 12 of the 13 compounds had a ratio of maximum

concentrations exceeding 1.0. There were 8 compounds in this study with a ratio of more

than 2: trichloromethane (24), 2‐butoxyethanol (15), d‐limonene (13), m, p – xylene (5.5),

o‐xylene (4.5), benzene (2.5), acetaldehyde (2.4), and formaldehyde (2.2).

There was also one compound with a ratio of less than 0.5: ethylene glycol (0.2).

3.7.4 Volatile Organic Compound Proposition 65 Safe Harbor Levels 

Table 41 (page 184) presents the percentage of homes with indoor concentrations that

exceed the California Proposition 65 Safe Harbor Levels (OEHHA 2008a). Table 41 contains

the calculated indoor concentrations associated with the No Significant Risk Levels (NSRL)

for carcinogens and the Maximum Allowable Dose Levels (MADL) for chemicals causing

reproductive toxicity. These calculated indoor concentrations assume a continuous 24‐hour

exposure with a total daily inhaled air volume of 20 m3 and 100% absorption by the

respiratory system. The NSRL is the daily intake level calculated to result in one excess

case of cancer in an exposed population of 100,000. The MADL is the level at which

reproductive toxicity would have no observable effect, assuming exposure at 1,000 times

that level.

Of the 22 volatile organic compounds measured in this study, there were eight with

California Proposition 65 Safe Harbor Levels. For each of the seven VOCs with NSRLs,

there were some homes that exceeded the calculated indoor NSRL concentration. The

percentage of homes exceeding the calculated indoor NSRL concentration ranged from 8%

for trichloromethane (chloroform) and tetrachloroethene to 93% for acetaldehyde and

100% for formaldehyde.  

For the two volatile organic compounds with MADLs, benzene and toluene, there were

homes that exceeded the calculated indoor MADL concentration only for benzene. The

percentage of homes exceeding the calculated indoor MADL concentration for benzene

was 20%.  

3.8 Homeowner Source Activity Log 

This section fulfills the potential sources requirements stated in Study Objective 2, Measure

and characterize indoor air quality (IAQ), ventilation, and the potential sources of indoor
84 

air contaminants. Other potential sources have previously been summarized in the Home

and Site Characteristic Collection Section.

The indoor source activities were reported by the occupants for the 24‐hour Test Day and

are summarized in Tables 42 and 43 (page 185 and 186).

The cooking and cleaning activities logged by the homeowner during the 24‐hour Test Day

are summarized in Table 42. The median total cooking activity time was 35 minutes, and

ranged from a minimum of 0.3 minutes to a maximum of 295 minutes. The median cooking

activity times with the three highest times were: baking (45 minutes), warming/boiling

water soup etc. (20 minutes), and broiling (19 minutes). The median total cleaning activity

time was 83 minutes, and ranged from a minimum of 1 minute to a maximum of  

800 minutes. The median cleaning activity times with the three highest times were:

dishwasher (68 minutes), use of clothes washer (59 minutes), and vacuuming (25 minutes).

The special, garage, and outdoor source activities logged by the homeowner during the  

24‐hour Test Day are summarized in Table 43. The median total special activity time was

30 minutes, and ranged from a minimum of 0.3 minutes to a maximum of 1,440 minutes.

The median special activity times with the three highest times, other than “nobody at

home” were: candle burning (165 minutes), gas‐burning fireplace (140 minutes), and other

activities that produce dust, smoke, or fumes (140 minutes). The median total garage

activity time was 1,037 minutes and ranged from a minimum of 0.3 minutes to a maximum

of 3,480 minutes. This maximum of 3,480 minutes reflects the storage of multiple cars in the

garage. The median vehicle operated in the garage time was 2 minutes, and ranged from a

minimum of 0.2 minutes to a maximum of 10 minutes. The median total outdoor activity

time was 29 minutes, with a minimum of 1 minute and a maximum of 360 minutes. The

median outdoor activity times with the three highest times were: painting (55 minutes),

use of gasoline‐powered equipment (25 minutes), and smoking outdoors (25 minutes).

3.9 Homeowner Reported IAQ Related Perceptions and 

Observations 

This section fulfills requirements stated in Study Objective 3, Determine occupant

perceptions of, and satisfaction with, the IAQ in their homes.

The homeowner self‐reported perceptions and satisfaction with the IAQ in their homes are

summarized in Table 44 (page 187) for the three-week recall period. In the Occupant

Questionnaire there were a total of nine physical symptom questions where the occupants

were asked “During the past three weeks have you experienced any of the following

physical symptoms when in your home that you do not experience when you are away

from the home?”. A total of 30 of the 108 homeowners (28%) reported experiencing one or

more of the nine physical symptoms. The three most frequently reported symptoms were

nose/sinus congestion (19%), allergy symptoms (15%), and headache (13%).
85 

This Occupant Questionnaire also included a total of seven home comfort questions where

the occupants were asked “During the past week, please indicate if you have noticed a

significant period when your home has experienced each of the conditions listed below.”

The three most frequently reported conditions were “too cold” (19%), “too hot” (15%), and

“too stagnant (not enough air movement)” (12%).

In the 2005 UCB mail survey of new homes in California (Price et al. 2007), 60% of the

homeowners in the summer reported at least one thermal comfort problem and 58%

reported the same in the winter. Those results are notably higher than the results in this

field study: 38% in the winter and 43% in the summer. The UCB mail survey also reported

that thermal comfort problems were higher in the summer in the winter (i.e., 60% and 58%,

respectively) than in the spring and fall swing seasons (i.e., 24% and 29%, respectively).  

Also included were three questions regarding mold or mildew. “During the past week,

please indicate if you have noticed, seen, or smelled mold or mildew in the following

locations?”. The most frequently reported location where the homeowners report mold or

mildew was the bathroom, which was reported by 13% of the occupants. Other locations

were also reported by between 0.9% and 2.8% of the occupants.

In the 2005 UCB mail survey (Price et al. 2007), homeowners were asked if they “noticed,

saw or smelled mold or mildew” in the bathroom during the different seasons. The

percentage of homeowners reporting mold or mildew in the bathroom ranged from 4% in

the spring to 7% in the winter. The percentage of homeowners reporting mold in other

locations (i.e., basement/crawlspace, walls or ceilings, carpets, or closets), ranged from 0%

to 1% across the four seasons.

Thus, a higher percentage of the homeowners in this study reported observing mold in the

bathroom (i.e., 13% in this study and 4%–7% in the UCB mail survey).

3.10 Relationships Between Home and IAQ Characteristics 

This section fulfills the requirements stated in Study Objective 4, Examine the relationships

among home ventilation characteristics, measured and perceived IAQ, and house and

household characteristics. Note that because of the low number of homeowners reporting

IAQ related perceptions and observations, there are insufficient data to prepare statistically

meaningful correlations with home and IAQ characteristics.  

3.10.1 Indoor Air Contaminant Emission Rates 

The indoor emission rates of VOCs were calculated as the product of the indoor

concentration minus the outdoor concentration and the outdoor air exchange rate. This

calculation assumes that the penetration factor of VOCs in the outdoor air that is

infiltrating through the building envelope was 1.0 and that there was no removal of VOCs
86 

from the indoor air unrelated to the outdoor air exchange rate (e.g., surface

deposition/surface reaction, indoor air reactions, air filtration). These are relatively valid

assumptions for the VOCs reported here.

Emission rates for PM2.5 and NO2 were not calculated, because these air contaminants can

have significant removal mechanisms unrelated to the outdoor air exchange rate (e.g.,

surface deposition/surface reaction, indoor air reactions, air filtration). The emission rates

for CO were also not calculated, because of the substantial uncertainty in the outdoor air

concentrations caused by high outdoor humidity levels.

Table 45 (page 188) contains the calculated indoor emission rates of volatile organic

compounds. The median indoor emission rates ranged from ‐0.03 μg/m3‐h for caprolactam

to 11 μg/m3‐h for formaldehyde. The six highest maximum emission rates observed were:

139  μg/m3‐h for 1,4‐dichlorobenzene, 65  μg/m3‐h formaldehyde, 44  μg/m3‐h for ethylene

glycol, 32  μg/m3‐h for 2‐butoxyethanol, 24  μg/m3‐h for toluene, and 20  μg/m3‐h for

acetaldehyde and d‐limonene.

The results of these indoor emission rate calculations for VOCs will used in the discussion

of the variability observed in the multi‐day and multi‐season measurements.  

3.10.2 Formaldehyde Emissions from Forced Air Units 

Table 46 (page 189) contains the formaldehyde emission rate measurements from the FAUs

in two Northern California homes: 017 and 120. The FAU formaldehyde emissions for

Home 017 were measured in both the summer and winter. The FAU formaldehyde

emissions for Home 120 were measured in just the winter. The FAU formaldehyde

emissions were measured in a second summer session home, 033; however, a failure in the

sample collection resulted in these data being lost.

The FAU emission rate of formaldehyde in Home 017 in the summer was 3,423 μg/h. This

emission rate represents 21% of the total home emission rate as determined from the

indoor and outdoor formaldehyde concentration measurements and the PFT measure of

the outdoor air exchange rate. The FAU emission rate of formaldehyde in Home 017 in the

winter was  ‐3,381  μg/h, which is  ‐56% of the total home emission rate. The negative

emission rate measured in the winter is believed to be primarily the result of duct leakage

associated with the return side of the FAU and the formaldehyde concentration in the attic

air, which was lower than the concentration in the return air. The measured duct leakage

for the FAU in this home was 4.8%. If the majority of this duct leakage were to be on the

return side of the system (e.g., the fan cabinet panel), then leakage of the attic air, which

has a much lower formaldehyde concentration than the return air (i.e., 2.0  μg/m3 in the

attic air and 15.3  μg/m3 in the return air) into the return air could explain much of the

lower formaldehyde concentration in the supply air, and hence the negative FAU emission

rate. Also, the lower attic temperature (i.e., 67.0°

F in the winter and 88.1°F in the summer) is

expected to reduce the formaldehyde emissions from the fiberglass soundliner into the
87 

FAU airstream and the formaldehyde emissions from materials in the attic (e.g., composite

wood materials) into the attic air.

The FAU emission rate of formaldehyde in Home 120 in the winter was ‐7,681 μg/h, which

is  ‐151% of the total home emission rate. The reasons for the negative emission rates are

believed to be similar to those for the Home 017 winter emission rate measurements. The

measured duct leakage of the FAU in this home was 5.7%. The supply air concentration

was also measured at a second location in this home. The supply air concentration at this

second location was substantially lower (i.e., 65.7 μg/m3 compared to 70.0 μg/m3). Thus, the

assumption in the emission rate calculation of perfect mixing of the air entering the FAU

from the return air and from attic air entering through return air duct leaks does not

appear to be a good assumption. Thus, the calculated emission rates of formaldehyde from

the FAUs have a substantial amount of uncertainty. It does appear that in the summer,

when attic temperatures can become elevated, that the FAU can transport formaldehyde

into the home from either emissions of formaldehyde from fiberglass soundliner directly

into the FAU airstream or from leakage of attic air with elevated formaldehyde

concentrations into the return air of the FAU.  

3.10.3 Multi-day Home Measurement Comparisons 

The outdoor air exchange rate and indoor and outdoor VOC and aldehyde concentrations

were measured in a total of four homes on three consecutive 24‐hour periods: Thursday–

Friday, Friday–Saturday, and Saturday–Sunday. The purpose of these multi‐day

consecutive measurements was to evaluate the day‐to‐day variations, including weekday

and weekends. The four multi‐day home measurements included one home in each

season‐region: Home 033 (Summer‐North), Home 041 (Winter‐South), Home 059

(Summer‐South), and Home 099 (Winter‐North). These four homes were each non‐

mechanically ventilated homes. Tables 47–50 (pages 190–193) contain the indoor and

outdoor concentrations of VOCs, the outdoor air exchange rate, the indoor emission rates,

and the absolute and relative variation in the emission rates. Note that the outdoor air

contaminant measurements were only measured on the first day, Thursday–Friday, and

thus to calculate the emission rates this measurement of the outdoor air contaminant

concentrations were used to compute the indoor air contaminant emission rates for Days 2

and 3. Also, the PFT measurement for Day 1 in Home 099 was lost due to a lab error and

thus there are no emission rates calculated for Day 1.

The variations in the indoor concentrations are expected to be largely the result of the

variations in the outdoor air exchange rate and the emission rates of indoor sources,

especially those sources that are not continuous, such as those related to intermittent

activities such as cleaning, cooking, air fresheners, etc.  

The relative standard deviations of the outdoor air exchange rates were 0.04 for Home 041,

0.05 for Home 099, 0.28 for Home 059, and 0.38 for Home 033, with an average of 0.19 for

the four homes. The average relative standard deviation of the indoor air contaminant
88 

concentrations were 0.12 for Home 099, 0.30 for Home 041, 0.44 for Home 059, and 0.50 for

Home 033, with an average of 0.34 for the four homes. Thus, as the variation in the outdoor

air exchange rates increased, so did the variation in the indoor air contaminant

concentrations.

The average absolute variation of the indoor air contaminant emission rates were

0.6 μg/m3‐h for Home 099, 0.9  μg/m3‐h for Home 033, 1.0  μg/m3‐h for Home 041, and

2.5 μg/m3‐h for Home 059, with an average of 1.3 μg/m3‐h for the four homes.

By comparing the variations of the indoor air contaminant emission rates with the source

activity logs prepared by the homeowners, it is possible to develop hypotheses as to the

identity of the indoor sources. For each home the research team looked at the indoor air

contaminant emission rates with substantial variations (i.e., more than 2 μg/m3‐h absolute

variation and with more than a 0.50 relative standard deviation) and examined the

occupant source activity logs to see if there were any sources that might explain the

variation in the emission rates.

For Home 033, d‐limonene was the VOC with the most substantial variation in the indoor

emission rate, as defined above, with emission rates of 2.2 μg/m3‐h on Thursday–Friday,

1.8 μg/m3‐h on Friday–Saturday, and 4.9 μg/m3‐h on Saturday–Sunday. An examination of

the source activity logs did not reveal and activities that might explain this increase. Note

that d‐limonene is often found in deodorizers and household cleaning chemicals.  

For Home 041, 2‐butoxyethanol was the VOC with the most substantial variation in the

indoor emission rate, with emission rates of 5.8 μg/m3‐h on Thursday–Friday, 0.8 μg/m3‐h

on Friday–Saturday, and 0.6 μg/m3‐h on Saturday–Sunday. An examination of the source

activity logs indicated that on Thursday–Friday, and not on the other two days, there was

20 minutes of sweeping/dusting with anti‐bacterial wipes, which is a potential source of

2‐butoxyethanol, a common ingredient in cleaning chemicals.

For Home 059, hexanal was the VOC with the most substantial variation in the indoor

emission rate, with emission rates of 4.7 μg/m3‐h on Thursday–Friday and 5.8 μg/m3‐h on

Friday–Saturday, and 1.2  μg/m3‐h on Saturday–Sunday. An examination of the source

activity logs did not reveal any activities that might explain this variation.  

For Home 099, there were no volatile organic compounds with substantial variations in the

indoor emission rates.

3.10.4 Multi-Season Home Measurement Comparisons 

The outdoor air exchange rate and indoor and outdoor air contaminant concentrations

were measured in a total of four homes for three 24‐hour periods, during three different

seasons; summer, fall, and winter. The purpose of these multi‐season measurements was to

evaluate the season‐to‐season variations. The four multi‐season home measurements
89 

included four homes in the North region; Home 005, Home 006, Home 013, and Home 019.

These four homes were each non‐mechanically ventilated homes. Tables 51–54 (pages 194–

197) contain the indoor and outdoor concentrations of VOCs, the outdoor air exchange

rate, the indoor emission rates, and the absolute and relative variation in the emission

rates. Note that for Home 013, the homeowners were unable to participate in the winter

field session, thus there are only measurements for two seasons, summer and fall. Also, the

PFT measurement for Day 1 in Home 019 resulted in an unrealistically low air exchange

rate (i.e., 0.03 ach) and thus was deleted as an unreliable measurement. For this reason

there are no emission rates calculated for Day 1 in Home 019.

As with the multi‐day homes, the variations in the indoor concentrations of these multi‐

season homes are expected to be largely the result of the variations in the outdoor air

exchange rate and the emission rates of indoor sources, especially those sources that are

not continuous, such as those related to intermittent activities such as cleaning, cooking, air

fresheners, etc. The variations in the outdoor air exchange rates, and thus the indoor air

contaminant concentrations, are expected to be higher for the multi‐season homes than the

multi‐day homes, with outdoor air exchange rates being lower and the indoor air

contaminant concentrations higher in the winter season when windows are more often

kept closed.

The relative standard deviations of the outdoor air exchange rate were 0.34 for Home 005,

0.64 for Home 019, 0.75 for Home 006, and 0.95 for Home 013, with an average of 0.67 for

the four homes. The average relative standard deviation of the indoor air contaminant

concentrations were 0.45 for Home 006, 0.52 for Home 013, 0.59 for Home 005, and 0.82 for

Home 019, with an average of 0.60 for the four homes.  

Thus, the variations of both the outdoor air exchange rate and indoor air contaminant

concentrations were much higher for these multi‐season homes then for the multi‐day

homes. The average relative standard deviation of the outdoor air exchange rates was 3.5

times higher for the multi‐season homes, and the average relative standard deviation of the

indoor air contaminant concentrations was 1.8 times higher.

The average absolute variation of the indoor air contaminant emission rates were  

0.50  μg/m3‐h for Home 019, 1.5  μg/m3‐h for Home 006, 4.1  μg/m3‐h for Home 013, and  

6.3 μg/m3‐h for Home 005, with an average of 3.1 μg/m3‐h for the four homes, which is 2.6

times higher that the average of 1.2 μg/m3‐h for the four multi‐day homes.

Thus, the larger variations in the indoor air contaminant concentrations in the multi‐season

homes appears to be the combination of larger variations in the outdoor air exchange rates

and the indoor air contaminant emission rates.

For each home the research team looked at the indoor air contaminant emission rates with

substantial variations (i.e., more than 2 μg/m3‐h absolute variation and with more than a
90 

0.50 relative standard deviation) and examined the occupant source activity logs to see if

there were any sources that might explain the variation in the emission rates.

For Home 005, 1,4‐dichlorobenzene, was the VOC with the most substantial variation in

the indoor emission rate, with emission rates of 72 μg/m3‐h in the summer, 1.9 μg/m3‐h in

the fall, and 0.8 μg/m3‐h in the winter. An examination of the source activity logs did not

reveal any activities that might explain this increase. Note that 1,4‐dichlorobenzene is often

found in mothballs, although the homeowners did not report in the Occupant

Questionnaire any use of mothballs.  

For Home 006, d‐limonene was the VOC with the most substantial variation in the indoor

emission rate, with emission rates of 1.6  μg/m3‐h in the summer,  

0.9 μg/m3‐h in the fall, and 4.1 μg/m3‐h in the winter. An examination of the source activity

logs indicated that the occupants used furniture polish for 15 minutes and cleaning

chemicals for 30 minutes during the winter field session but not in either the summer or

fall field sessions. Note that d‐limonene is often found in deodorizers and household

cleaning chemicals.  

For Home 013, toluene was the VOC with the most substantial variation in the indoor

emission rate, with emission rates of 18 μg/m3‐h in the summer, and 50 μg/m3‐h in the fall.

An examination of the source activity logs indicated that the occupants used two plug‐in

air fresheners for 24 hours during the fall field session but not in the summer field session.

Note that toluene is found in some air fresheners.  

For Home 019, there were no VOCs with substantial variations in the indoor emission

rates.

3.10.5 Group Comparisons 

Group comparisons were prepared for indoor formaldehyde and acetaldehyde

concentrations, outdoor air exchanges rates, and window usage. Formaldehyde and

acetaldehyde were selected for these analyses, as these were two air contaminants that

most frequently exceeded recommended indoor concentration guidelines. Note that

because of the small number of homes in the sample groups, these comparisons should

only be considered as suggestive of differences. Multivariate analyses need to be done to

further establish any differences between the groups.  

The group comparisons consisted of homes in the North versus South regions, homes in

summer versus winter seasons, and homes without mechanical outdoor air systems versus

homes with either pure DOA or pure HRV outdoor air ventilation systems. For the

seasonal group comparison the research team used the 19 seasonal repeat homes with

formaldehyde and acetaldehyde measurements (one of the 20 seasonal repeat homes did

not have a formaldehyde or acetaldehyde measurement as a result of a sampler failure).
91 

Homes with nighttime cooling systems, evaporative coolers, and window fans were

excluded from these analyses.  

According to the K‐S statistic analyses, the distributions of indoor formaldehyde and

acetaldehyde concentrations, outdoor air exchange rates, and window usage were found to

be not normally distributed. The K‐S statistic was repeated with several functions applied

to the distributions. If the K‐S statistic returned a result with a probability greater than 0.05,

then the distribution was determined to be normal. The formaldehyde and acetaldehyde

concentrations were found to be lognormal; the inverse of the outdoor air exchange rate

was found to be normal; and the square root of window opening, where different than

zero, was found to be normal. The results of these analyses are summarized in Table 55

(page 198), along with the probability that the distribution is normal. Figures 29–32 (pages

128–131) present the cumulative frequency plots of the normalized data.

3.10.5.1 Formaldehyde and Acetaldehyde and Group Comparisons 

Table 56 (page 199) contains the group analyses for indoor formaldehyde and acetaldehyde

concentrations. For the t‐test comparisons of differences in the group mean concentrations

the research team used the normalized data; the log of the indoor formaldehyde

concentrations and the log of the indoor acetaldehyde concentrations. If the probability of

no difference was less than 0.05, then the means were considered to be different. Note that

the number of homes with HRV systems in these group comparisons was very small (i.e.,

n=4), and thus only very large differences in the group means can be identified.  

North‐South Homes. For this comparison only those homes without mechanical outdoor

air ventilation systems were compared. The mean log of the indoor formaldehyde

concentration was found to be significantly higher in North homes than in South homes  

(p = 0.001). The mean log of the indoor acetaldehyde concentration was not found to be

significantly different in North homes and South homes.

Summer‐Winter Homes. The mean log of the indoor formaldehyde acetaldehyde

concentrations were not found to be significantly different in summer homes and winter

homes.

Homes With and Without Mechanical Outdoor Air Ventilation Systems. The mean log of

the indoor formaldehyde and acetaldehyde concentrations were found to be significantly

higher in homes with DOA mechanical outdoor air systems than in non‐mechanically

ventilated homes (p=0.0001 and p=0.005 respectively). The mean log of the indoor

formaldehyde and acetaldehyde concentrations were not found to be significantly different

in homes with HRV mechanical outdoor air systems and in non‐mechanically ventilated

homes. The low number of HRVs (i.e., n=4) precluded identifying the substantially lower

mean indoor log concentrations of formaldehyde and acetaldehyde in the HRV homes as

being statistically significant.
92 

Homes With DOA and HRV Outdoor Air Ventilation. The mean log of the concentration of

formaldehyde and acetaldehyde was found to be significantly higher in homes with DOA

mechanical outdoor air systems than in homes with HRV mechanical outdoor air systems

(p=0.05 and p=0.02 respectively). 

3.10.5.2 Outdoor Air Exchange Rate and Window Usage Group Comparisons 

Table 57 (page 200) contains the group analyses for outdoor air exchange rates and

window usage. The outdoor air exchange rate consisted of the 24‐hour PFT measurement

and the window usage consisted of the 24‐hour log of the ft2‐hrs of window/door usage.

For the t‐test comparisons of differences in the group mean outdoor air exchange rates and

window usage the research team used the normalized data; inverse air changes per hour

and the square root of the window usage. If the probability of no difference was less than

0.05, then the means were considered to be different.  

North‐South Homes. For this comparison only those homes without mechanical outdoor

air ventilation systems were compared. The mean inverse of the outdoor air exchange rate

and the mean square root of the window usage was found to not be significantly different

in North homes and South homes.

Summer‐Winter Homes. The mean inverse of the outdoor air exchange rate was found to

not be significantly different in summer homes and winter homes. The mean square root of

the window usage was found to be significantly higher in summer homes than in winter

homes (p=0.02).

Homes With and Without Mechanical Outdoor Air Ventilation Systems. The mean inverse

of the outdoor air exchange rate was found to not be significantly different in DOA

mechanical outdoor air systems and non‐mechanically ventilated homes. The mean inverse

of the outdoor air exchange rate was found to be significantly higher in homes with HRV

mechanical outdoor air systems than in non‐mechanically ventilated homes (p = 0.002). The

mean square root of the window usage was found to not be significantly different in either

DOA or HRV mechanical outdoor air systems when compared to the non‐mechanically

ventilated homes.

Homes With DOA and HRV Outdoor Air Ventilation Systems. The mean inverse of the

outdoor air exchange rate was found to be significantly lower in HRV than DOA

mechanical outdoor air systems (p=0.008). The mean square root of the window usage was

found to not be significantly different in HRV and DOA mechanical outdoor air systems.

3.11 Formaldehyde and Acetaldehyde Concentration Correlations 

Correlation analyses were prepared for indoor formaldehyde and acetaldehyde

concentrations with home characteristics and indoor and outdoor environmental

conditions. Formaldehyde and acetaldehyde were selected for these analyses, because
93 

these were the two air contaminants that most frequently exceeded recommended indoor

concentration guidelines.  

The six home characteristics included:

• home age (years)

• composite wood loading (ft2 per 1,000 ft3 of indoor air volume)  

• new cabinetry (within six months)

• new furniture (within six months)

• air fresheners (presence or absence)

• outdoor air exchange rate (ach)

The four environmental conditions included:

• indoor air temperature (oF)

• indoor relative humidity (%)

• outdoor air temperature (oF)

• outdoor relative humidity (%)

The composite wood loading includes the total composite wood area in square feet

observed to be associated with cabinetry/furniture and the finishes of walls, ceilings, and

floors divided by the indoor air volume (i.e., ft2 of composite wood per 1,000 ft3 of indoor

air volume).

The research team prepared both Pearson correlations for those variables that could be

normalized as well as Spearman correlations, which do not require the sample populations

be normally distributed.

Outdoor air temperature and relative humidity, indoor air temperature, and home age

data were found to be normally distributed. As previously discussed, according to the K‐S

statistic analyses, the distributions of indoor formaldehyde and acetaldehyde

concentrations, outdoor air exchange rates, window usage, composite wood loading, and

indoor air relative humidity were found to be not normally distributed. The K‐S statistic

was repeated with several functions applied to the distributions. The formaldehyde and

acetaldehyde concentrations were found to be lognormal; the inverse of the outdoor air

exchange rate (i.e., outdoor air residence time) was found to be normal; and the square root

of window opening, where different than zero, was found to be normal. The log of the

composite wood loading was found to be log normal, and the indoor air relative humidity
94 

squared was found to be log normal. The results of these analyses are summarized in Table

55 (page 198) along with the probability that the distribution is normal. Figures 33–38

(pages 132–137) present the cumulative freuency of the normlized data.

Tables 58 and 59 (pages 201 and 202) contain the correlations for formaldehyde and

acetaldehyde concentrations, respectively, with the six home characteristics and four

environmental conditions. If the probability of no correlation was less the 0.05, then a

correlation was concluded to possibly exist. Note that since these are bivariate analyses, the

establishment of a possible correlation between two variables does not indicate that there is

a causal relationship. Other factors may be determined to be equally or more important

when analyzed together in a multivariate analyses, which is beyond the scope of this

study, but is recommended for future analyses.  

Figures 39–45 (pages 138–144) are scatter plots of the indoor formaldehyde and

acetaldehyde concentrations and the three continuous home characteristic variables, home

age, composite wood loading, and outdoor air exchange rate, and the four environmental

conditions.  

For both formaldehyde and acetaldehyde concentrations, one home characteristic—

outdoor air exchange rate—was determined by both the Pearson and Spearman correlation

analyses to have a statistically significant correlation. This correlation was relatively

strong, with probabilities of no correlation less than 0.0001, as determined by both Pearson

and Spearman correlation analyses. The correlation coefficients indicate that indoor

formaldehyde concentrations correlate negatively with the outdoor air exchange rates (i.e.,

as outdoor air exchange rates increase the indoor concentrations of formaldehyde

decrease). Note since the Pearson correlation coefficient uses the normalized inverse

outdoor air exchange rate (i.e., the outdoor air residence time), the positive correlation

coefficients represents a negative correlation with outdoor air exchange rate.

For formaldehyde concentrations, one environmental condition, indoor air temperature,

was determined by both the Pearson and Spearman correlation analyses to have a

statistically significant correlation. The correlation coefficients indicate that indoor

formaldehyde concentrations correlate positively with the indoor air temperature (i.e., as

indoor air temperatures increase, the indoor concentrations of formaldehyde increase).

Not as expected, both the Pearson and Spearman correlations produced negative

correlations for composite wood loading and acetaldehyde indoor concentrations, and no

significant correlation for composite wood loading and formaldehyde indoor

concentrations, despite the knowledge that composite wood is an indoor emitter of both

formaldehyde and acetaldehyde. This may be the result of incompleteness of the recovery

of this variable in the field from the visible inspection by the field team. Composite wood

could not always be accurately identified because of coverings by laminate or paint. In

addition, the inspectors only estimated the square footage of composite wood from
95 

furniture and cabinetry. Other substantial amounts of composite wood loading that are

common in many of these homes, but are difficult to quantify in the limited time available

to the inspectors, include plywood and oriented strand board (OSB) in walls, subfloors,

and attics and medium density fiberboard in baseboards, window shades, interior doors,

and window and door trims. Also, the inspectors estimated the areas of composite wood

without separately distinguishing those areas that were exposed and those areas that were

covered with laminate.

The variance introduced by the impact of outdoor air exchange rates upon the indoor

concentrations of formaldehyde and acetaldehyde may also be contributing to the lack of

an observed significant positive correlation between composite wood loading and the

indoor concentrations of formaldehyde and acetaldehyde.

3.12 Incentives and Barriers that Influence People’s Use of 

Ventilation 

This section fulfills the requirements stated in Study Objective 5, Identify the incentives

and barriers that influence people’s use of windows, doors, and mechanical ventilation

devices for adequate air exchange.

The Occupant Questionnaire on mechanical ventilation systems focused exclusively on the

mechanical outdoor air ventilation systems. Tables 60 and 61 (pages 203 and 204)

summarize the responses to these questions from homes with either a DOA or HRV

mechanical outdoor air system and with completed responses to questions, excluding

those with only nighttime cooling systems (e.g., WHF, RAD), evaporative cooling systems,

or window fans. The total of 26 homes with mechanical outdoor air systems included 17

DOA systems and 9 HRV systems.

A total of 78% stated that the operation of the system was explained to them when they

bought or moved into the house. In addition, 63% responded that they understood how the

system works, and 83% stated that they understood how to operate the system properly.  

With respect to questions how they typically operate the system, 32% reported continuous

operation in the summer, 36% in the fall, 18% in the winter, and 27% in the spring.  

With respect to the question of “Why did you choose the system?,” 91% of the respondents

replied that the system “came with the house.”  

With respect to the question of “What do you like about the system?,” the three most

frequent responses were, “Fresh air” (52%), “Quiet” (48%), and “Reduced concern about

indoor air quality” (26%).  
96 

The written descriptions accompanying the “Other” reasons that the homeowners did like

about the mechanical outdoor air systems, along with the system type and Home ID, were:

• “I can shut off one of the 2 zones for economy.” (DOA‐2 systems, Home 043)

• “House does not feel/smell stuff or that it has been closed.” (DOA, Home 102)

• “Clears moisture from baths and laundry.” (HRV, Home 104)

With respect to the question “What don’t you like about the system ?,” the four most

frequent responses were, “Not effective” (32%), “Too drafty” (26%), “Too noisy” (26%),

and “Other” (26%).

The written descriptions accompanying the “Not effective” and “Other” reasons that the

homeowners did not like about the mechanical outdoor air systems, along with the system

type and Home ID, were:

• “Needs to turn on with HVAC system, not every 45 mins. Automatically.” (DOA,

Home 001)

• “Need to go into attic to clean the filter.” (HRV, Home 017)

• “Unit is difficult to reach, expensive yearly maintenance service.” (HRV, Home 018)

• “House is always stuffy, cannot feel fresh air, not able to shut off, always running if

air/heater is off.” (DOA, Home 021)

• “Never understood how to use it.” (DOA, Home 021)

• “Brings in hot air in the summer and cold air in the winter.” (HRV, Home 022)

• “One zone does not shut off when it reaches its program.” (DOA‐2 systems, Home

043)

• “It is on a 90 min automatic cycle. It brings in hot air in summer, cold air in winter,

air w/smoke in it & air during aerial spraying for West Nile viruses.” (DOA, Home

102).

• “Dust seems to still get on the table tops.” (HRV, Home 104)

• “It does not heat & cool the house evenly. Half the house is fairly comfortable and

the other half is not.” (DOA, Home 109)
97 

With respect to the question of “Please list any additional problems or provide additional

comments you have on the system,” the following are the written descriptions, along with

the system type and Home ID:

• “The thermostat works when it wants to not when he wants it to, itʹs like it has a

mind of its own. They already replaced it once and it didnʹt fix the problem.”

(DOA, Home 008)

• “I have no idea how the system works. The only controls that I am aware of are for

heating and cooling.” (DOA, Home 011)

• “Should be able to clean filters more easily, especially since this is a senior

development. More reason clean filters.” (HRV, Home 017).

• “Not able to shut off system, never feel fresh air coming from outside, always

hot/stuffy in house; cooler outside.” (DOA, Home 021)

• “It needs to have a switch where the home owner can shut it off.” (DOA, Home

102).

• “Colder type air comes out of the vents during the winter along with the heated air,

thereby making it uncomfortable if you are positioned near the vents? Opposite in

the summer.” (DOA, Home 109)

• “Did not know one of my ducts was closed.” (DOA, Home 110).

3.13 Incentives and Barriers Related to People’s Purchases and 

Practices that Improve IAQ 

This section fulfills the requirements stated in Study Objective 6, Identify the incentives

and barriers related to people’s purchases and practices that improve IAQ, such as the use

of low‐emitting building materials and improved air filters.

The Occupant Questionnaire contained a number of questions focused upon home IAQ

related improvement choices. Table 62 (page 205) summarizes the responses to these

questions. A total of 24% of the 105 respondents to this question stated “none” in response

to the question “What special measures or choices have you or the builder taken to

improve the quality of the air in your home?”.  

The four most frequent responses to improvements undertaken were: “Hard flooring

instead of carpeting” (33%), “Carbon monoxide alarm” (28%), “High efficiency vacuum

cleaner with special features such as filters to trap more particles” (27%), and “Upgrade my

central air filter” (25%).
98 

With respect to the question of “Other” Home IAQ Improvements, the following are the

written descriptions, along with the Home ID:

• “Ceramic tile and linoleum to replace all but bedroom carpeting.” (Home 002).

• “Hard flooring in kitchen entryway & part of hallway.” (Home 015).

• “24‐hr fans: 2 bathrooms/utility room to prevent mold.” (Home 016).

• “Smartvent.” (Home 018).

• “Smartvent.” (Home 019).

• “All bath fans are on 60‐min. timers; whole house fan on 12‐hr. timer.” (Home 034).

• “Changed original air filter.” (Home 048).

• “Methane gas mitigation system ‐ builder installed.” (Home 054).  

• “Living Air portable cleaner system, Orek, Sharper Image air cleaners.” (Home

069).

• “Master cool evap cooler for fresh air.” (Home 070).

• “Switched to crystal (dustless) cat litter.” (Home 077).

• “We usually open windows and keep them open. During the last week its been

cold so weʹve not done so as usual.” (Home 079).

• “Whole house fan.” (Home 088).

• “Hard flooring in downstairs.” (Home 092)

• “Air purifiers in bedrooms (4).” (Home 105).

• “Cleaning supplies natural/nontoxic, plant in most rooms.” (Home 121).

3.14 Recent Developments Related to Codes, Regulations, and 

Guidelines 

Recently there have been several changes to codes, regulations, and guidelines that are

noteworthy with respect to the data collected in this study.
99 

The OEHHA RELs for formaldehyde and acetaldehyde were revised in December 2008

(OEHHA 2008b). These revisions reflect scientific knowledge and techniques developed

since the previous guidelines were prepared, and in particular, explicitly include

consideration of possible differential effects on the health of infants, children and other

sensitive subpopulations. In addition to the previously defined Acute and Chronic RELs,

the revisions include establishment of 8‐hour RELs.  

For formaldehyde, the Acute REL was reduced from 94  μg/m3 to 55  μg/m3. The interim  

8‐hour REL was reduced from 33 μg/m3 to 9 μg/m3 and is no longer an interim standard.

The Chronic REL was increased from 3 μg/m3 to 9 μg/m3.

For formaldehyde, the percentage of homes exceeding the Acute REL increases from 6.7%

to 28% for the new REL. The percentage of homes exceeding the 8‐hour REL increases from

59% to 98%. The percentage of homes exceeding the Chronic REL decreases from 100% to

98%.

For acetaldehyde, the Acute REL, for which previously there was no established level, was

set at 470 μg/m3, the 8‐hour REL, for which previously there was no established level, was

set at 300 μg/m3, and the Chronic REL was increased from 9 μg/m3 to 140 μg/m3.

For acetaldehyde the percentage of homes exceeding the Chronic REL decreases from 82%

to 0% for the new higher exposure levels, and 0% of the homes exceed the new 8‐hour REL

and the new Chronic REL.

In April 2007, the California Air Resources Board adopted an airborne toxics control

measure (ATCM) to reduce formaldehyde emissions from composite wood products

including hardwood plywood (HWPW), particleboard (PB), medium density fiberboard

(MDF), and also furniture and other finished products made with these wood products

(California Air Resources Board 2007b). This ATCM established the most stringent,

production‐based, formaldehyde standards in the world. ARBʹs evaluation of

formaldehyde exposure in California found that one of the major sources is from

inhalation of formaldehyde emitted by composite wood products containing urea‐

formaldehyde resin. Much of this HWPW, PB, and MDF is used to make furniture,

cabinets, shelving, countertops, flooring and moldings.

This ATCM was approved by the Office of Administrative Law on April 18, 2008

(California Code of Regulations 2008). The Phase 1 implementation date is scheduled for

January 1, 2009. A Phase 2 set of lower emissions rates is scheduled for implementation

January 1, 2010, for hardwood plywood with veneer core and January 1, 2011, for

particleboard and medium density fiberboard.
100 

The California Energy Commission (2008a) adopted the 2008 Building Energy Efficiency

Standards on April 23, 2008, and these standards become effective August 1, 2009. The new

2008 standards require all low‐rise residential buildings to have a mechanical outdoor air

ventilation system. The mechanical outdoor air ventilation system requirements in the new

2008 standard are an adoption of ASHRAE Standard 62.2‐2007, with the exception that use

of openable windows for outdoor ventilation in place of mechanical outdoor air

ventilation, while permitted by ASHRAE, is not an acceptable option. The ASHRAE

mechanical outdoor air ventilation rates discussed in this report, ASHRAE 62.2‐2004, are

identical to the ASHRAE 62.2‐2007 (ASHRAE 2007) rates and the new California 2008

Building Energy Efficiency Standards.

In addition, the new 2008 California Title 24 Alternative Calculation Method (ACM)

Manual (California Energy Commission 2008b) no longer requires mechanical outdoor

ventilation of 0.047 cfm/ft2 in homes that builders are taking credit for building a home

with an SLA less than 3.0. The new 2008 Building Energy Efficiency Standards now require

that all homes, regardless of the SLA, have mechanical outdoor air ventilation.

ASHRAE published addenda to ASHRAE Standard 62.2‐2007 in 2008 (ASHRAE 2008).

These 2008 addenda included Addendum b, which provides changes to Table 4.2,

“Ventilation Effectiveness for Intermittent Fans.” This addendum also changed the

requirement that intermittent mechanical outdoor air systems operate a minimum of

1 hour every 12 hours to a minimum operation of once per 24 hours and a minimum

fractional on‐time of 0.10. The new California 2008 Building Energy Efficiency Standards,

which cites ASHRAE 62.2‐2007, do not include this addendum.  

For the three DOA systems in this study with operational fan cyclers, the new

Addendum b ventilation effectiveness factors result in decreased outdoor airflow rate

requirements. The measured outdoor airflow rates in these three homes were all still well

below the requirements, as calculated according to the new Addendum b. Previously these

three homes had mechanical outdoor airflow rates that were just 3%, 7%, and 8% of the

intermittent flow rate requirements, and using the calculations in Addendum b the

mechanical outdoor airflow rates are 9%, 10%, and 26% of the intermittent flow rate

requirements.  

Ventilation rates and indoor air contaminant concentrations were re‐calculated using the

new Addendum b ventilation effectiveness factors for intermittent ventilation systems and

the modeling scenario utilized in Section 3.6.1. The ventilation effectiveness factor was

increased by Addendum b from 0.33 to 0.65. This resulted in a reduction of the required

outdoor airflow rate for intermittent mechanical systems, and further increases in the

indoor air contaminant concentrations. The 24‐hour average indoor concentration was 34%

higher than that with a continuous system, up from the 29% higher concentration with the

pre‐Addendum b ventilation effectiveness factor. The maximum air contaminant

concentration was 222% higher than that with a continuous system, up from the 220%
101 

higher concentration with the pre‐Addendum b ventilation effectiveness factor. Thus, for

the modeling scenario examined, the new Addendum b ventilation effectiveness factor

resulted in 4% higher 24‐hour average indoor air contaminant concentrations and similar

(i.e., less than 1% higher) maximum concentrations.   

The intent of the changes to the intermittent ventilation effectiveness factors in

Addendum b was to correct these factors such that the resulting 24‐hour time‐weighted

average indoor contaminant concentrations are equivalent to those for a continuously

operated ventilation system. However, as the analyses above indicate, the Addendum b

intermittent ventilation effectiveness factors provided higher 24‐hour time‐weighted

average indoor contaminant concentrations. The ASHRAE 62.2 Standards Committee has

acknowledged this error with the Addendum b intermittent ventilation effectiveness

factors and is currently pursuing a correction.
102 

Figure 3. Locations of homes for the summer and winter 2006–2007 field sessions in Northern 

and Southern California. 
Figure 4. Forced air duct leakage cumulative frequency distribution - All Home Sample Fram

Forced Air Unit Duct Leakage Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 7

Forced Air Unit Duct Leakage (%)

Cumulative Frequency (%)

N=138

Median (50%) Forced Air Unit Duct Leakage = 10%

86% of homes exceed the CBC 2005 requirement of < 6% leakage.

103
 Building Envelope Air Leakage Cumulative Frequency Distribution 

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 1 2 3 4 5 6 7 8 9

Building Envelope Leakage 

Cumulative Frequency (%)

ACH50, N=106SLA, N=107

Median (50%) SLA = 2.9 Median (50%) ACH50 = 4.8

Figure 5. Building envelope air leakage cumulative frequency distribution – All Home Sample Fr

104
Window/Door Opening Cumulative Frequency Distribution 

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 

Window/Door Opening (ft2-hrs)

Cumulative Frequency (%)

Test Day Average, N=108Test Week Average, N=108

Median (50%) Window/Door Opening = 46 ft2-hrs for 

the 24 hr Test Day average and 70 ft2-hrs for the Test 

Week average.

Figure 6. Window and door opening cumulative frequency distribution – All Home Sample Fram

105
Mechanical Exhaust System Usage Cumulative Frequency Distribution 

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 2 4 6 8 10 12 14 1

Mechanical Exhaust System Usage (hrs)

Cumulative Frequency (%)

Kitchen Exhaust, N=108Bathroom Exhaust, N=105Other Exhaust (i.e. clothes dryer, laundry, utility), N=1

Median (50%) = 0.0, 0.05, and 0.3 hrs for kitchen, bathroom, and other exhaust usage repsectively.

Figure 7. Mechanical exhaust system usage cumulative frequency distribution – All Home Sample F

106usage, respectively.
Mechanical Outdoor Air System Usage Cumulative Frequency Distribution 

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 2 4 6 8 10 12 14 16 18 20 22 24 

Mechanical Outdoor Air System Usage (hrs)

Cumulative Frequency (%)

DOA Ventilation Systems, N=1HRV Systems, N=8

Median (50%) = 2.5 and 24 hrs for DOA and HRV system usage repsectively.

5 homes have 24 hour usage

Figure 8. Mechanical outdoor air system usage cumulative frequency distribution – All Home Sample 

107

usage, respectively.
Nighttime Cooling System Usage Cumulative Frequency Distribution 

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 2 4 6 8 10 12 14 16 

Nighttime Cooling System Usage (hrs)

Cumulative Frequency (%)

Whole House Fan Systems, N=5FAU with Return Air Damper Systems, N=6

Median (50%) = 0.7 and 5.3 hrs usage foand FAU with Return Air Damper repsectiv

3 FAU with Return Air Samper System homes had zero usage and 2 Whole House Fan homes had zero usage.

Figure 9. Nighttime cooling system usage cumulative frequency distribution – All Home Sample Fr

108 , respect
Forced Air Unit System Usage Cumulative Frequency Distribution 

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 2 4 6 8 10 12 14 16 18 20 22 24 

Forced Air Unit System Usage (hrs)

Cumulative Frequency (%)

Forced Air Unit, N=108

Median (50%) = 1.1 hrs for forced air unit system usage 

Figure 10. Forced air unit system usage – All Home Sample Frame. 

109
Figure 11. ASHRAE 62.2-2004 Intermittent ventilation indoor air contaminant concentration pl

110

than

than
Outdoor Air Exchange Rate PFT (24-hour) Measurement Cumulative Frequency Distrib

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 

Outdoor Air Exchange Rate (ach)

Cumulative Frequency (%)

N=106

Median (50%) Outdoor Air Exchange Rate = 0.26 ach

67% of homes are below the CBC Code Requirement of 0.35 ach

Figure 12. Outdoor air exchange rate PFT (24-hour) measurement cumulative frequency – All Home Sam

111
Benzene Concentration Cumulative Frequency Distribution 

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 2 4 6 8 10 12 14 16 18 

Benzene Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=107Outdoor, N=40

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 60 μg/m3 

Median (50%) Indoor Concentration = 1.1 μg/m363% of indoor and 28% of outdoor samples above theProposition 65 Cancer NSRL of 0.7 μg/m3 

20% of indoor and 0% of outdoor samples above theProposition 65 Reproductive Toxicity MADL of 2.5 μg/m3 

Figure 13. Benzene concentration cumulative frequency distribution – All Home Sample Fram

112
1,4 Dichlorobenzene Concentration Cumulative Frequency Distribution 

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 50 100 150 200 

1,4 Dichlorobenzene Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=107Outdoor, N=40

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 800 μg/m

Median (50%) Indoor Concentration = 0.1 μg/m312% of indoor and 0% of outdoor samples above theProposition 65 Cancer NSRL of 1.0 μg/m3 

Figure 14. 1,4 Dichlorobenzene concentration cumulative frequency distribution –All Home Sample 

113
Ethylene Glycol Concentration Cumulative Frequency Distribution 

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 20 40 60 80 100 120 14

Ethylene Glycol Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=10Outdoor, N=4

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 400 μg/m3 

Median (50%) Indoor Concentration = 3.2 μg/m3

Figure 15. Ethylene glycol concentration cumulative frequency distribution – All Home Sample Fr

114
n-Hexane Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 3

n-Hexane Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=107Outdoor, N=40

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 7,000 μg/m3 

Median (50%) Indoor Concentration = 0.8 μg/m3

Figure 16. n-Hexane concentration cumulative frequency distribution – All Home Sample Fram

115
Naphthalene Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 1 2 3 4 5 6 7 8 9

Naphthalene Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=107Outdoor, N=40

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 9 μg/m3 

Median (50%) Indoor Concentration = 0.2 μg/

m3

27% of indoor and 0% of outdoor samples above theProposition 65 Cancer NSRL of 0.3 μg/m3 

Figure 17. Naphthalene concentration cumulative frequency distribution – All Home Sample Fra

116
Phenol Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0123456

Phenol Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, NOutdoor, 

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 200 μg/m3 

Median (50%) Indoor Concentration = 1.7 μg/m3

Figure 18. Phenol concentration cumulative frequency distribution – All Home Sample Frame

117
Styrene Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 5 10 15 20 25 30 35 40 45 50 55 60 

Styrene Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=107Outdoor, N=40

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 900 μg/m3 

Median (50%) Indoor Concentration = 0.9 μg/m3

Figure 19. Styrene concentration cumulative frequency distribution – All Home Sample Fram

118
Tetrachloroethene Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 5 10 15 20 25 30 35 

Tetrachloroethene Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=107Outdoor, N=40

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 35 μg/m3 

Median (50%) Indoor Concentration = 0.2 μg/m38% of indoor and 0% of outdoor samples above theProposition 65 Cancer NSRL of 0.7 μg/m3 

Figure 20. Tetrachloroethene concentration cumulative frequency distribution – All Home Sample F

119
Toluene Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 20 40 60 80 100 120 14

Toluene Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=10Outdoor, N=4

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 300 μg/m3 

Median (50%) Indoor Concentration = 8.5 μg/m3 0% of indoor and 0% of outdoor samples above the

Proposition 65 Reproductive Toxicity MADL of 350 μg/m

Figure 21. Toluene concentration cumulative frequency distribution – All Home Sample Fram

120
Trichloromethane (Chloroform) Concentration Cumulative Frequency Distributio

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 1 2 3 4 5 6 7 8 9 10 11 

Trichloromethane (Chloroform) Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=107Outdoor, N=40

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 300 μg/m3 

Median (50%) Indoor Concentration = 0.2 μg/m3

8% of indoor and 0% of outdoor samples above theProposition 65 Cancer NSRL of 2.0 μg/m3 

Figure 22. Trichloromethane (chloroform) cumulative frequency distribution – All Home Sample F

121
Vinyl Acetate Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0.0 0.1 0.2 0.3 0.4 

Vinyl acetate Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=107Outdoor, N=40

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 200 μg/m3 

Median (50%) Indoor Concentration = 0.2 μg/m3

Figure 23. Vinyl acetate concentration cumulative frequency distribution – All Home Sample Fra

122
m,p-Xylene Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 5 10 15 20 25 30 35 40 45 50 55 60 

m,p-Xylene Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=107Outdoor, N=40

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 700 μg/m3 

Median (50%) Indoor Concentration = 4.2 μg/m3

Figure 24. m,p-Xylene concentration cumulative frequency distribution – All Home Sample Fram

123
o-Xylene Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 2 4 6 8 10 12 14 16 18 20 

o-Xylene Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=107Outdoor, N=40

0% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 700 μg/m3 

Median (50%) Indoor Concentration = 1.2 μg/m3

Figure 25. o-Xylene concentration cumulative frequency distribution – All Home Sample Fram

124
Formaldehyde Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 10 20 30 40 50 60 70 80 90 100 110 120 130 

Formaldehyde Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=105Outdoor, N=39

100% of indoor and 21% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 3 μg/m3 (2.4 ppb) 

6% of indoor and 0% of outdoor samples above the OEHHA Acute Reference Exposure Level of 94 μg/m3 (77 ppb)

60% of indoor and 0% of outdoor samples above the CARB IAQ Guideline of 33 μg/m3 (27 ppb)

Median (50%) Indoor Concentration = 36 μg/m3 (29.2 ppb)

Figure 26. Formaldehyde concentration cumulative frequency distribution – All Home Sample Fr

125
Acetaldehyde Concentration Cumulative Frequency Distribution

All Home Sample Frame

0%

10%20%30%40%50%60%70%80%90%

100%

0 10 20 30 40 50 60 70 80 90 100 110 120 130 

Acetaldehyde Concentration (μg/m3

)

Cumulative Frequency (%)

Indoor, N=105Outdoor, N=39

82% of indoor and 0% of outdoor samples above theOEHHA Chronic Reference Exposure Level of 9 μg/m3 Median (50%) Indoor Concentration = 20 μg/m3

Figure 27. Acetaldehyde concentration frequency distribution – All Home Sample Frame. 

126
Figure 28. Formaldehyde indoor concentrations and outdoor air exchange rates. 

127

Mechanical
Cumulative Frequency for the Log of Formaldehyde Concentration 

All Homes Sample Frame

0

102030405060708090

100

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 

Log of Formaldehyde Concentration (μg/m3)

Cumulative Frequency (%)

Figure 29. Cumulative frequency distribution of the log of formaldehyde concentration – All Homes Sam

128
Cumulative Frequency for the Log of Acetaldehyde Concentration 

All Homes Sample Frame

0

102030405060708090

100

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 

Log of Acetaldehyde Concentration (μg/m3

)

Cumulative Frequency (%)

Figure 30. Cumulative frequency distribution of the log of acetaldehyde concentration – All Homes Sam

129
Cumulative Frequency Distribution for the Inverse of the Air Exchange R

All Homes Sample Frame 

0

102030405060708090

100

0 1 2 3 4 5 6 7 8 9 10 1

Inverse of the Air Exchange Rate (hrs)

Cumulative Frequency (%)

Figure 31. Cumulative frequency distribution for the inverse of the air exchange rate – All Homes Samp

130
Cumulative Frequency Distribution for the Square Root of Window Usag

All Homes Sample Frame

0

102030405060708090

100

0 5 10 15 20 25 30 35 40 45 

Square Root of Window Usage (ft2-hrs)

Cumulative Frequency (%)

Figure 32. Cumulative frequency distribution of the square root of window usage – All Homes Sample 

131
Cumulative Frequency Distribution for Indoor Temperature 

All Homes Sample Frame

0

102030405060708090

100

50 55 60 65 70 75 

Indoor Temperature (oF)

Cumulative Frequency (%)

Figure 33. Cumulative frequency distribution for indoor temperature – All Homes Sample Fram

132
Cumulative Frequency Distribution for the Indoor Relative Humidity Squ

All Homes Sample Frame

0

102030405060708090

100

0 500 1000 1500 2000 2500 3000 3500 

Indoor Relative Humidity (%) Squared

Cumulative Frequency (%)

Figure 34. Cumulative frequency for the indoor relative humidity squared – All Homes Sample Fr

133
Cumulative Frequency Distribution for Outdoor Temperature 

All Homes Sample Frame

0

102030405060708090

100

40 45 50 55 60 65 70 75 

Outdoor Temperature (oF) 

Cumulative Frequency (%)

Figure 35. Cumulative frequency distribution for outdoor temperature – All Homes Sample Fra

134
Cumulative Frequency Distribution for Outdoor Relative Humidity 

All Homes Sample Frame

0

102030405060708090

100

20 30 40 50 60 70 

Oudoor Relative Humidity (%)

Cumulative Frequency (%)

Figure 36. Cumulative frequency distribution for outdoor relative humidity – All Homes Sample F

135
Cumulative Frequency Distribution for the 

Log of the Normalized Composite Wood Loading

All Homes Sample Frame

0

102030405060708090

100

2 2.5 3 3.5 4 4.5 

Log of Home Air Volume Normalized Composite Wood Loading (ft2/1000 ft3)

Cumulative Frequency (%)

Figure 37. Cumulative frequency distribution for the log of the normalized composite wood loading – All Hom

136
Cumulative Frequency Distribution for Home Age 

All Homes Sample Frame

0

102030405060708090

100

012345

Home Age (years)

Cumulative Frequency (%)

Figure 38. Cumulative frequency distribution for home age – All Homes Sample Frame. 

137
138 

 

Scatter Plot of Home Age and Indoor Formaldehyde Concentrations 

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

1.522.533.544.555.5 6

Home age (yrs)

Indoor Concentration (μg/m3

)

Scatter Plot of Home Age and Indoor Acetaldehyde Concentration 

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

1.522.533.544.555.5 6

Home age (yrs)

Indoor Concentration (μg/m3

)

Figure 39. Scatter plots of home age and indoor formaldehyde and acetaldehyde concentrations – All 

Homes Sample Frame. 
139 

Scatter Plot of Composite Wood Loading and Indoor Formaldehyde 

Concentrations 

All Homes Sample Frame

0

20

40

60

80

100

120

140

0 20 40 60 80 100

Composite Wood Loading (ft2 of composite wood per 1,000 ft3

 indoor air volume)

Indoor Concentration (μg/m3

)

 

Scatter Plot of Composite Wood Loading and Indoor Acetaldehyde 

Concentrations 

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

0 20 40 60 80 100

Composite Wood Loading (ft2

 of composite wood per 1,000 ft3 indoor air volume)

Indoor Concentration (μg/m3

)

Figure 40. Scatter plots of composite wood loading and indoor formaldehyde and acetaldehyde 

concentrations – All Homes Sample Frame. 
140 

Scatter Plot of Outdoor Air Exchange Rates and Indoor Formaldehyde 

Concentrations 

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Outdoor Air Exchange Rate (1/hr)

Indoor Concentration (μg/m3

)

Scatter Plot of Outdoor Air Exchange Rates and Indoor Acetaldehyde 

Concentrations 

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Outdoor Air Exchange Rate (1/hr)

Indoor Concentration (μg/m3

)

Figure 41. Scatter plots of outdoor air exchange rates and indoor formaldehyde and 

acetaldehyde concentrations – All Homes Sample Frame. 
141 

Scatter Plot of Indoor Temperature and Indoor Formaldehyde 

Concentrations 

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

60 65 70 75 80 85

Indoor Temperature (o

F) .

Indoor Concentration (μg/m3

)

Scatter Plot of Indoor Temperature and Indoor Acetaldehyde

Concentrations

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

60 65 70 75 80 85

Indoor Temperature (oF)

Indoor Concentration (μg/m3)

All Homes Sample Frame

Figure 42. Scatter plots of indoor temperature and indoor formaldehyde and acetaldehyde 

concentrations – All Homes Sample Frame. 
142 

Scatter Plot of Indoor Relative Humidity and Indoor

Formaldehyde Concentrations

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

10 20 30 40 50 60 70

Indoor Relative Humidity (%)

Indoor Concentrations (μg/m3

)

 

Scatter Plot of Indoor Relative Humidity and Indoor

Acetaldehyde Concentrations

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

10 20 30 40 50 60 70

Indoor Relative Humidity (%)

Indoor Concentration (μg/m3

)

Figure 43. Scatter plots of indoor relative humidity and indoor formaldehyde and acetaldehyde 

concentrations – All Homes Sample Frame. 
143 

 

Scatter Plot of Outdoor Temperature and Indoor Formaldehyde

Concentrations 

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

40 45 50 55 60 65 70 75 80 85

Outdoor Temperature (o

F)

Indoor Concentration (μg/m3

)

 

Scatter Plot of Outdoor Temperature and Indoor Acetaldehyde

Concentrations 

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

40 45 50 55 60 65 70 75 80 85

Outdoor Temperature (oF) .

Indoor Concentration (μg/m3

)

Figure 44. Scatter plots of outdoor temperature and indoor formaldehyde and acetaldehyde 

concentrations – All Home Sample Frame. 
144 

Scatter Plot of Outdoor Relative Humidity and Indoor

Formaldehyde Concentrations 

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

20 30 40 50 60 70 80 90 100

Outdoor Relative Humidity (%)

Indoor Concentration (μg/m3

)

Scatter Plot of Outdoor Relative Humidity and Indoor Acetaldehyde

Concentrations 

All Homes Sample Frame

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

20 30 40 50 60 70 80 90 100

Outdoor Relative Humidity (%)

Indoor Concentration (μg/m3

)

Figure 45. Scatter plots of outdoor relative humidity and indoor formaldehyde and acetaldehyde 

concentrations – All Homes Sample Frame. 
Table 2. Percentages of air contaminant and PFT field samples, blanks, and duplicates successfully collected and a

Percentages of Air Contaminant and PFT 

Field Samples, Blanks, and Duplicates Successfully Collected and Analyzed

Field 

Samples 

Deployed 

Field Samples a

Successfully 

Collected and Analyzed 

(%) 

Field Sample Blanks b

Successfully 

Collected and Analyzed 

(%) 

Field Samp

Succ

Collected 

Volatile Organic Compounds 208 99 10 Formaldehyde/Acetaldehyde 221 96 10 Particulate Matter – PM2.5 44 98 12 Nitrogen Dioxide 45 100 12 Carbon Monoxide 206 98 NA PFT CATS Samplers 167 99 11 QA/QC Goal 98 10 

 a) Percentage of total number of samples excluding field sample blanks that were successfully collected and analyzed.  b) Percentage of field sample blanks successfully collected and analyzed – based upon total successfully collected and 

samples less duplicate and blank samples. 

 c) Percentage of field sample duplicates successfully collected and analyzed – based upon total successfully collected 

samples less duplicate and blank samples. 

145 
Table 3. Summer-North field session field blank analyses for volatile organic compounds, including formaldehyd

and acetaldehyde. 

Summer-North Field Session Field Blank Analyses (ng) 

Compound Method Mass 

Detection Limit 

Sample ID 

006-vb-080806 

Sample ID 

021-vb-081606 

Sample ID 

033-vb-082406 

Av

S

 Mass a Mass a Mass a Acetaldehyde 9 MDL MDL 49 Benzene 3.5 MDL MDL MDL 2-Butoxyethanol 1.9 MDL MDL MDL Caprolactam 3.4 MDL MDL MDL 1,4-Dichlorobenzene 2.9 MDL MDL MDL Ethylene glycol 16 MDL MDL MDL Formaldehyde 9 MDL MDL 17 Hexanal 1.4 MDL MDL MDL n-Hexane 4.2 MDL MDL MDL d-Limonene 4.2 MDL MDL MDL 1-Methyl-2-pyrrolidinone 6.0 MDL MDL MDL Naphthalene 2.0 MDL MDL MDL Phenol 2.8 3.7 MDL MDL alpha-Pinene 3.0 MDL MDL MDL Styrene 3.1 MDL MDL MDL Tetrachloroethene 4.7 MDL MDL MDL Toluene 4.9 MDL MDL MDL Trichloromethane 4.9 MDL MDL MDL 1,2,4-Trimethylbenzene 3.3 MDL MDL MDL Vinyl acetate 5.6 MDL MDL MDL m, p-Xylene 3.8 MDL MDL MDL o-Xylene 3.2 MDL MDL MDL 

a) Blanks with a mass below the method mass detection limit are designated as “MDL” and were assigned a value 

method mass detection limit for calculating the average field blank sample mass. 

 146 
Table 4. Summer-South field session field blank analyses for volatile organic compounds including formaldehyde 

and acetaldehyde. 

Summer-South Field Session Field Blank Analyses (ng) 

Compound Method Mass 

Detection Limit 

Sample ID 

046-vb-090806 

Sample ID 

055-vb-091406 

Sample ID 

067-vb-092006 

A

S

 Mass a Mass a Mass a Acetaldehyde 9 MDL 12.7 35 Benzene 3.5 MDL MDL MDL 2-Butoxyethanol 1.9 MDL MDL MDL Caprolactam 3.4 MDL MDL MDL 1,4-Dichlorobenzene 2.9 MDL MDL MDL Ethylene glycol 16 MDL MDL MDL Formaldehyde 9 MDL 15.9 MDL Hexanal 1.4 MDL MDL MDL n-Hexane 4.2 MDL MDL MDL d-Limonene 4.2 MDL MDL MDL 1-Methyl-2-pyrrolidinone 6.0 MDL MDL MDL Naphthalene 2.0 MDL MDL 3.2 Phenol 2.8 MDL MDL 24 alpha-Pinene 3.0 MDL MDL MDL Styrene 3.1 MDL MDL 11 Tetrachloroethene 4.7 MDL MDL MDL Toluene 4.9 MDL MDL MDL Trichloromethane 4.9 MDL MDL MDL 1,2,4-Trimethylbenzene 3.3 MDL MDL 4.2 Vinyl acetate 5.6 MDL MDL MDL m, p-Xylene 3.8 MDL MDL MDL o-Xylene 3.2 MDL MDL MDL 

a) Blanks with a mass below the method mass detection limit are designated as “MDL” and were assigned a valu

method mass detection limit for calculating the average field blank sample mass. 

147
Table 5. Winter-North field session field blank analyses for volatile organic compounds including formaldehyde and 

Winter-North Field Session Field Blank Method Mass Detection Limit (ng) 

Compound Method 

Mass 

Detection 

Limit 

Sample ID 

025-vb022107 

Sample ID 

101-vb022207 

Sample ID 

108-vb092006 

Sample ID 

002-vb030207 

Sample ID 

114-vb030607 

Sample ID 

117-vb030707 

Sample 

121-vb

03080

 Mass a Mass a Mass a Mass a Mass a Mass a Mass Acetaldehyde 9 11 15 MDL 22 9.4 MDL MBenzene 3.5 MDL MDL MDL MDL MDL MDL M2-Butoxyethanol 1.9 MDL MDL MDL MDL MDL MDL MCaprolactam 3.4 MDL MDL MDL MDL MDL MDL M1,4-Dichlorobenzene 2.9 MDL MDL MDL MDL MDL MDL MEthylene glycol 16 MDL MDL MDL MDL MDL MDL MFormaldehyde 9 10 MDL MDL MDL MDL MDL 11 Hexanal 1.4 MDL MDL MDL MDL 3.1 MDL Mn-Hexane 4.2 MDL MDL MDL MDL MDL MDL Md-Limonene 4.2 MDL MDL MDL MDL MDL MDL M1-Methyl-2-pyrrolidinone 6.0 MDL MDL MDL MDL MDL MDL MNaphthalene 2.0 MDL MDL MDL MDL MDL MDL MPhenol 2.8 3.9 5.2 MDL MDL MDL MDL Malpha-Pinene 3.0 MDL MDL MDL MDL MDL MDL MStyrene 3.1 MDL MDL MDL MDL MDL MDL MTetrachloroethene 4.7 MDL MDL MDL MDL MDL MDL MToluene 4.9 MDL MDL MDL MDL MDL MDL MTrichloromethane 4.9 MDL MDL MDL MDL MDL MDL M1,2,4-Trimethylbenzene 3.3 MDL MDL MDL MDL MDL MDL MVinyl acetate 5.6 MDL MDL MDL MDL MDL MDL Mm,p-Xylene 3.8 MDL MDL MDL MDL MDL MDL Mo-Xylene 3.2 MDL MDL MDL MDL MDL MDL M

a) Blanks with a mass below the method mass detection limit are designated as “MDL” and were assigned a value of o

detection limit for calculating the average field blank sample mass. 

b) na: Sample 119-fb-030707 is an additional formaldehyde and acetaldehyde blank, no additional volatile organic com

148
Table 6. Winter-South field session field blank analyses for volatile organic compounds including formaldehyde a

Winter-South Field Session Field Blank Analyses (ng) 

Compound Method Mass 

Detection 

Limit 

Sample ID 

039-vb012407 

Sample ID 

058-vb013107 

Sample ID 

080-vb013007 

Sample ID 

088-vb020507 

Sample ID 

091-vb030607 

 Mass a Mass a Mass a Mass a Mass a Acetaldehyde 9 MDL 9.4 MDL 11 MBenzene 3.5 MDL MDL MDL MDL M2-Butoxyethanol 1.9 MDL MDL MDL MDL MCaprolactam 3.4 MDL MDL MDL MDL M1,4-Dichlorobenzene 2.9 MDL MDL MDL MDL MEthylene glycol 16 MDL MDL MDL MDL MFormaldehyde 9 MDL MDL MDL 22 MHexanal 1.4 MDL MDL 6.8 MDL Mn-Hexane 4.2 MDL MDL MDL MDL Md-Limonene 4.2 MDL MDL 9.2 MDL M1-Methyl-2-pyrrolidinone 6.0 MDL MDL MDL MDL MNaphthalene 2.0 MDL MDL MDL MDL MPhenol 2.8 MDL MDL 4.5 3.3 Malpha-Pinene 3.0 MDL MDL MDL MDL MStyrene 3.1 4.2 MDL 4.0 MDL MTetrachloroethene 4.7 MDL MDL MDL MDL MToluene 4.9 MDL MDL MDL MDL MTrichloromethane 4.9 MDL MDL MDL MDL M1,2,4-Trimethylbenzene 3.3 MDL MDL MDL MDL MVinyl acetate 5.6 MDL MDL MDL MDL Mm,p-Xylene 3.8 MDL MDL MDL MDL Mo-Xylene 3.2 MDL MDL MDL MDL M

a) Blanks with a mass below the method mass detection limit are designated as “MDL” and were assigned a valu

method mass detection limit for calculating the average field blank sample mass. 

149
Table 7. Precision of volatile organic compound measurements over a 24-hour period. 

Precision of Volatile Organic Compounds Concentrations (μg/m3) 

 Absolute Precision a Relative PrCompound N Min Max Mean Standard 

Deviation 

Relative 

Standard 

Deviation 

Min Max Mean 

Acetaldehyde 17 0.1 7.2 1.7 2.2 1.3 0.01 0.33 0.12 Benzene 13 0.01 0.9 0.2 0.3 1.4 0.01 0.11 0.05 2-Butoxyethanol 12 1E-4 8.4 1.3 2.3 1.7 3E-4 1.03 0.19 Caprolactam 0 na na na na na na na na 1,4-Dichlorobenzene 1 0.003 0.003 0.003 - - 0.01 0.01 0.01 Ethylene glycol 6 0.4 8.1 3 2.9 0.9 0.07 0.35 0.15 Formaldehyde 17 0.05 18 4.0 5.0 1.2 0.01 0.37 0.11 Hexanal 13 0.002 2.9 0.7 0.7 1.0 3E-4 0.17 0.06 n-Hexane 13 0.01 1.1 0.3 0.3 1.0 0.01 0.40 0.10 d-Limonene 13 0.03 3.7 1.1 1.1 1.0 0.003 0.27 0.07 1-Methyl-2-pyrrolidinone 4 0.01 0.1 0.1 0.03 0.6 0.01 0.08 0.06 Naphthalene 15 0.002 0.1 0.02 0.03 1.2 0.003 0.17 0.06 Phenol 18 0.02 0.7 0.2 0.1 0.7 0.01 0.60 0.16 alpha-Pinene 13 0.004 2.4 1.0 1.0 1.0 0.001 0.09 0.04 Styrene 15 0.001 1.2 0.3 0.3 1.1 2E-4 0.67 0.27 Tetrachloroethene 4 5E-4 0.1 0.04 0.04 0.8 5E-4 0.12 0.06 Toluene 18 0.02 3 0.7 0.8 1.2 0.01 0.24 0.06 Trichloromethane 6 0.02 0.3 0.1 0.1 1.0 0.02 0.15 0.08 1,2,4-Trimethylbenzene 16 0.00 0.8 0.2 0.2 1.3 0.00 0.37 0.08 Vinyl acetate 0 na na na na na na na na m,p-Xylene 17 0.01 2.9 0.5 0.8 1.5 5E-4 0.37 0.07 o-Xylene 15 0.01 0.8 0.2 0.3 1.4 0.002 0.36 0.07 

a) Absolute precision is the absolute difference between the results of the sample pair. b) Relative precision is the relative standard deviation of the results of the sample pair. 

150
151 

Table 8. Winter-North field session field blank analyses for nitrogen dioxide and PM2.5 

particulate matter. 

Winter-North Field Session Field Blank Analyses (μg) 

Week Sample ID 

(Nitrogen Dioxide) 

Method Mass 

Detection 

Limit 

NO2 

a

mass 

Sample ID 

(PM2.5 Particulate Matter) 

Method Mass 

Detection Limit 

PM2.5

a

mass 

1 025-NB-022107 0.8 MDL 025-PB-022107 1 -3 

1 101-NB-022207 0.8 MDL 101-PB-022207 1 -1 

 Week 1 Average 

Blank Sample Mass 

 

0.0 

Week 1 Average Blank 

Sample Mass 

 

-2 

2 002-NB-030107 0.8 MDL 002-PB-030107 1 -1 

2 108-NB-022807 0.8 MDL 108-PB-022807 1 -3 

 Week 2 Average 

Blank Sample Mass 

 

0.0 

Week 2 Average Blank 

Sample Mass 

 

-2 

3 114-NB-030607 0.8 MDL 114-PB-030607 1 -3 

 Week 3 Average 

Blank Sample Mass 

 

0.0 

Week 3 Average Blank 

Sample Mass 

 

-3 

a) Nitrogen dioxide blanks with a mass below the method mass detection limit are designated as “MDL” and 

were assigned a value of zero for calculating the average field blank sample mass. The average mass for the 

PM2.5 field blanks was calculated directly from the measured masses of the field blanks. 
152 

Table 9. Precision for carbon dioxide, carbon monoxide, nitrogen dioxide, and PM2.5

measurements over a 24-hour period. 

 Precision Of Carbon Dioxide, Carbon Monoxide, Nitrogen Dioxide, and PM2.5 Measurements 

Absolute Precision a Relative Precision b 

Compound N Min Max Mean Standard 

Deviation 

Relative 

Standard 

Deviation 

Min Max Mean Standard 

Deviation 

Relative 

Standard 

Deviation

Carbon Dioxide 

(ppm) 17 1.7 69 16 17 1.1 0.01 0.15 0.02 0.04 1.46 

Carbon 

Monoxide 

(ppm) 17 0.0 1.5 0.6 0.5 0.8 0.01 1.39 0.53 0.50 0.93 

Nitrogen Dioxide 

(μg/m3

) 4 0.2 0.3 0.2 0.1 0.4 0.01 0.03 0.02 0.01 0.25 

Particulate 

Matter PM2.5 

(μg/m3) 4 0.6 3.4 2.0 1.2 0.6 0.04 0.28 0.11 0.11 0.99 

a) Absolute precision is the absolute difference between the results of the sample pair. 

b) Relative precision is the relative standard deviation of the results of the sample pair. 
153 

Table 10. Summer and field session field blank analyses for PFT measurements. 

Summer and Winter Field Session Field Blank Analyses (pL) 

Group Method Volume 

Detection Limit 

Sample ID Blank Volume (pL) d 

Summer –1 a 0.001 006-tb-080806 0.021 

 

Summer-1 Blank 

Average Volume 0.021 

Summer –2 b 0.001 067-TB-092006 MDL

Summer -2 0.001 055-TB-091406 MDL

Summer -2 0.001 046-TB-090806 0.022 

Summer -2 0.001 033-TB-082406 MDL

Summer -2 0.001 021-TB-081606 0.043 

 

Summer-2 Blank 

Volume Average 0.013 

Winter c 0.001 002-tb-030107 0.014 

Winter 0.001 025-tb-022107 0.024 

Winter 0.001 039-tb-012407 0.022 

Winter 0.001 058-tb-013107 0.010 

Winter 0.001 080-tb-013007 0.010 

Winter 0.001 088-tb-020507 0.029 

Winter 0.001 091-tb-020607 0.019 

Winter 0.001 101-tb-022207 0.009 

Winter 0.001 108-tb-022807 0.009 

Winter 0.001 114-tb-030607 0.028 

 

Winter Blank 

Volume Average 0.017 

a) Summer-1: This blank sample was used with the first 12 home of the Summer-North field 

session. 

b) Summer-2: These blank samples were used with homes 13–72 of the Summer-North and 

Summer-South field sessions. 

c) Winter: These blank samples were used with all of Winter homes, Winter-North and WinterSouth field sessions. 

d) Blanks with a volume below the method volume detection limit are designated as “MDL” and 

were assigned a value of one half the method volume detection limit for calculating the 

average field blank sample volume. 
154 

Table 11. Precision of PFT outdoor air exchange rates measured over the 24-hour Test Day and the following 

two-week period. 

Precision of PFT Outdoor Exchange Rate Measurement 

Absolute Precision (ach)a Relative Precision (ach) b 

N Min Max Mean Standard 

Deviation 

Relative 

Standard 

Deviation

Min Max Mean Standard 

Deviation 

Relative 

Standard 

Deviation

24-Hour 

Measurement 11 0.002 0.03 0.01 0.01 0.76 0.003 0.05 0.02 0.01 0.60 

2-Week 

Measurement 4 0.002 0.02 0.01 0.01 0.87 0.01 0.01 0.01 0.005 0.42 

a) Absolute precision is the absolute difference between the results of the sample pair. 

b) Relative precision is the relative standard deviation of the results of the sample pair. 
155 

Table 12. Comparison of PFT measurements in the first and second zones of the home. 

PFT Measurements in Two Zones 

 

PFT Sample #1 PFT Sample #2 Difference

Home 

ID Season 

FAU 

Hours 

On

Window 

ft2

/hrs

Sample 

Period Location ACH Location ACH 

Absolute b 

(ach) 

Relative c

019 Winter 5.5 0 24 hr 1st Floor 

Family 

Room 

0.11 2nd Floor 

 Loft 

0.10 0.01 0.07 

099 Winter na a na a 2 week 1st Floor 

Family 

Room 

0.15 2nd Floor 

Master 

Bed 

0.14 0.01 0.05 

116 Winter 0 50.5 24 hr 1st Floor 

Family 

Room 

0.22 

 

2nd Floor 

Bonus 

Room 

0.16 0.06 0.22 

a) na: No data were collected over the two-week period. 

b) Absolute precision is the absolute difference between the results of the sample pair. 

c) Relative precision is the relative standard deviation of the results of the sample pair. 
Table 13. Home recruitment results for each region-season. 

Home Recruitment Results

Summer 

North 

Summer 

South 

Fall 

North 

Winter 

South 

Winter 

North 

Homes that received mailer 1,358 1,408 15 1,486 1,500 Homes from UCB Mail Survey 25% 23% 53% 21% 12% Called to express interest in study 95 41 10 62 71 Interest rate 7% 3% 67% 4% 5% Homes contacted by phone 471 201 10 264 73 Disconnected phone number 20 4 0 18 0 Not qualified for study 18 3 0 3 2 Refused/hung up/not interested 81 18 0 31 4 Wrong address 3 8 0 7 22 Language barrier 4 2 0 2 0 Homes recruited 32 31 4 33 32 Homes recruited with mechanical outdoor a

air ventilation systems 18 4 0 4 17 

Homes recruited from UCB Mail Survey 53% 55% 50% 36% 31% Recruitment rate for mailers 2% 2% 27% 2% 2% Recruitment rate for calls 7% 15% 40% 13% 44% 

a) Includes homes with nighttime ventilation cooling systems. Note: Not all homes that received a mailer also received a phone call. The number of homes recruited in the wintehomes recruited for a seasonal repeat test in both the North and South regions and the four homes recruited for th

repeats from the summer session. Total homes recruited was 108 with 24 seasonal repeat recruits. 

156
Table 14. Home sample comparison for the field study to the UCB mail survey sample by geographical strata. 

Comparison of Field Study Sample to UCB Mail Survey Sample a

UCB Mail Survey 

Total Homes 

UCB Mail Survey 

% of Total 

Field Study 

Total Homes 

Fie

% 

Sacramento/Delta Region 177 21 42 Southern California Coastal 175 21 17 Rest-of-State 489 58 49 Total 841 100 108 

a) Total homes and percentage of total homes for the UCB mail survey sample three geographical strata and those 

this field study. 

157
Table 15. Home characteristics-1. 

Home Characteristic Variables 

Variable N a Mean Standard

Dev. 

Geometric 

Mean 

Geometric 

Std. Dev. 

Min 10% 25% 50% 7

Age of House (years) 105 3.5 0.8 2.2 12 1.7 2.4 3.0 3.4 Area (ft2) 108 2,669 742 2,566 1.3 1,283 1,718 2,166 2,703 3Volume (ft3) 108 24,343 7,484 23,240 1.4 10,667 16,010 19,063 23,355 28Openable Window Area/Floor Area 108 0.06 0.01 0.06 1.2 0.03 0.05 0.06 0.06 0Garage Outdoor Air Venting (ft2) 93 0.6 0.7 - - 0.0 0.0 0.0 0.7 Possible Fungal Growth (ft2) 107 0.01 0.1 - - 0.0 0.0 0.0 0.0 Moisture Staining (ft2) 107 0.2 0.9 - - 0.0 0.0 0.0 0.0 Interior Finish Materials (ft2) Floor - vinyl & linoleum 107 141 194 - - 0.0 0.0 0.0 42 Floor - stone & ceramic tile 107 393 342 - - 0.0 0.0 82 349 Floor - real wood 107 174 308 - - 0.0 0.0 0.0 0.0 Floor - concrete & brick 107 6.5 65 - - 0.0 0.0 0.0 0.0 Floor – rug 107 40 66 - - 0.0 0.0 0.0 0.0 Floor - carpet 107 1,326 511 996 7.9 210 695 975 1,311 1Floor - composite wood 107 39 167 - - 0.0 0.0 0.0 0.0 Wall - composite wood 107 0.0 0.0 - - 0.0 0.0 0.0 0.0 Ceiling - composite wood 107 0.0 0.0 - - 0.0 0.0 0.0 0.0 Furniture/cabinetry composite wood 107 990 512 721 7.7 263 422 607 898 1Total composite wood 107 1,030 532 746 7.8 263 422 615 925 1 a) The number of homes with completed data. 

158
159 

Table 16. Home characteristics-2. 

Home Characteristic Variables 

Variable 

 N a % Variable N a

 % 

Number of Stories Range(s) 

 - 1 Story 108 34 - Gas fuel 108 2 

 - 2 Story 108 66 - Electric fuel 108 98 

Number of Bedrooms - Range exhaust ducted outdoor 108 85 

 - 2 Bedrooms 108 8 Oven(s) 

 - 3 Bedrooms 108 20 - Gas fuel 108 27 

 - 4 Bedrooms 108 46 - Electric fuel 108 73 

 - 5 Bedrooms 108 19 - Oven exhaust ducted outdoor 108 2 

 - 6 Bedrooms 108 6 Clothes Dryer 

Number of Bath and Toilette Rooms - Gas Fuel 103 76 

 - 2 Rooms 108 26 - Electric Fuel 103 24 

 - 3 Rooms 108 55 - Exhaust ducted outdoor 103 98 

 - 4 Rooms 108 14 - Exhaust Leaks 103 11 

 - 5 Rooms 108 6 FAU System 

Attic Present 107 99 - Gas fuel 81 100 

Garage Present 108 100 - Electric fuel 81 0 

 - Attached 108 99 - T-Stat fan mode – Auto 99 100 

 - Detached 108 1 - T-Stat fan mode – On 99 0 

 - Attached door 108 99 Water Heater 

 - Weather-stripped attached door 108 100 - Gas fuel 106 98 

 - Self closing attached door 108 98 - Electric fuel 106 2 

 - Outdoor air venting 108 97 Portable Air Cleaners Present 101 14 

 - Used for vehicle parking 108 92 Window Fan Present 108 4 

 - Living space above 108 60 Window Air Conditioner Present 108 0 

 - Solvent smell 108 7 - Has Outdoor Air Supply 108 0 

 - Moisture staining 108 2 Odor Upon Entry 108 27 

 - Musty smell 108 9 

HEPA Filtered Vacuum Cleaner 

Present 108 39 

Foundation Type Air Fresheners Present 99 20 

 - Slab 107 97 Fireplaces Present 107 85 

 - Crawlspace 107 1 - Decorative gas log vented 108 61 

 - Basement 107 1 - Sealed combustion vented 108 31 

 - Unvented gas logs 107 0 

a) Number of homes with completed data. 
160 

Table 17. Home characteristics-3. 

Home Characteristic Variables 

Variable 

N a % 

Variable 

N a % 

Primary Kitchen Cabinetry Overall Home Clutter 

 - Composite wood - no interior laminate 108 2 - 1 No clutter 108 49 

 - Composite wood - interior laminate 108 97 - 2 Some clutter 108 41 

 - Solid wood 108 1 - 3 Moderately cluttered 108 8 

 - Metal 108 0 - 4 Very cluttered 108 2 

Bathroom Cabinetry Outdoor Contaminant Sources b 

 - Composite wood - no interior laminate 108 1 - Busy street or freeway 108 7 

 - Composite wood - interior laminate 108 99 - Construction or road work 108 3 

 - Solid wood 108 0 - Dirt or gravel road 108 7 

 - metal 108 0 - Restaurant 108 8 

Overall Cleanliness - Industrial activity 108 4 

 - 1 Very clean 108 72 - Open field or crops 108 8 

 - 2 A bit dirty 108 26 - Gas station 108 13 

 - 3 Moderately dirty 108 1 - Dry cleaners 108 5 

 - 4 Very dirty 108 1 - Bus or truck activity 108 0 

 - No sources 108 45 

a) Number of homes with completed data. 

b) Outdoor sources within 500 feet. 
161 

Table 18. Homeowner reported home characteristics, renovations, maintenance, and other IAQ 

related activities-1. 

Home Characteristics, Renovations, Maintenance and 

Other IAQ Related Activities 

Variable Na % 

How many adults live in the home 

 - 1 108 8 

 - 2 108 73 

 - 3 108 14 

 - 4 108 4 

 - 5 108 1 

How many children under 18 live in the home 

 - 0 108 46 

 - 1 108 17 

 - 2 108 25 

 - 3 108 8 

 - 4 108 3 

 - 5 108 1 

How many occupants who live in the home are smokers b

 

 - 0 107 97 

 - 1 107 2 

 - 2 107 0 

 - 3 107 1 

Do pets live in the home? 106 56 

Are shoes worn in the home? 108 57 

Are there cloths or drapes that have been dry-cleaned within the 

last week 104 16 

a) Number of homes with completed data. 

b) Homes that reported occupants that smoke inside the home were excluded from this study, 

thus the occupants who live in the home and smoke are ones that report only smoking 

outside of the home. 
162 

Table 19. Homeowner reported home characteristics, renovations, maintenance, and other IAQ related 

activities-2. 

Home Characteristics, Renovations, Maintenance 

and Other IAQ Related Activities 

Variable N a % 

Have there been any of the following in the home within the past 6 months: 

(Note: 3 months for repeat) 

Painting 108 32 

Caulking 107 12 

Carpet installation 108 7 

New cabinetry 105 3 

New furniture 106 22 

Other 82 10 

Duct cleaning 107 1 

Duct sealing 105 1 

Pesticide applications 104 42 

Fire/smoke damage 108 0 

Mold or moisture remediation 107 6 

Are any of the following used in the home: 

Portable air cleaners 103 17 

Vacuum cleaners 107 100 

Window fans 102 6 

Window air conditioners 103 3 

Plug-in air fresheners 102 33 

Candles 101 58 

Incense 101 11 

Mothballs 101 7 

Hobbies and crafts 95 28 

Are any of the following stored in your home or garage: 

Paints, varnishes, paint thinners 107 94 

Kerosene, gasoline, propane, lighter fluid, self lighting charcoal 106 70 

Pesticides, insecticides, lawn/garden chemicals 108 89 

Cleaning supplies, e.g., bleach, detergents 108 100 

Latex products 105 61 

Are motor vehicles stored in the garage: 108 92 

 a) Number of homes with completed data. 
163 

Table 20. Homeowner reported home characteristics, renovations, maintenance and other IAQ related 

activities-3. 

Home Characteristics, Renovations, Maintenance and 

Other IAQ Related Activities 

Variable N a % 

How often are the carpets and rugs in the most heavily used rooms vacuumed: 

Twice per week or more often 108 13 

About once per week 108 45 

About every two weeks 108 26 

About every 3 to 4 weeks 108 11 

Less often 108 5 

What methods, other than sweeping or vacuuming, have been used in the 

home to clean the carpets? 

Steam cleaning 92 37 

Professionally dry cleaned 92 16 

Spot cleaned or dry cleaned by homeowner 92 63 

Since you have lived in this home, has it had any of the following conditions? 

Significant condensation on windows or other indoor surfaces 108 4 

Roof leaks 108 4 

Plumbing leaks 108 10 

Wall or window leaks 108 13 

Flooding 108 3 

Poor site drainage 108 6 

Bothersome carpet odors 108 2 

Bothersome cabinetry odors 108 6 

Other unpleasant odors 108 7 

Other moisture problems 108 7 

 a) Number of homes with completed data. 
164 

Table 21. Mechanical outdoor air system types and controls. 

Mechanical Outdoor Air System Types And Control Variables 

Variable N a % 

Homes with one or more Mechanical Outdoor Air Systems 108 33 

Homes with Multiple Mechanical Outdoor Air Systems 108 4 

Homes with only a Ducted Outdoor Air Systems (DOA) 108 16 

Homes with only a Heat Recovery Ventilator Systems (HRV) 108 6 

Homes with Nighttime Cooling Systems (WHF or RAD) 108 11 

Homes with Evaporative Cooling Systems 108 1 

System Characteristics: 

System Type N b % 

• FAU with Ducted Outdoor Air (DOA) 40 43 

• Heat Recovery Ventilator (HRV) 40 23 

• Nighttime Cooling FAU Return Air Damper (RAD) 40 15 

• Nighttime Cooling Whole House Fan (WHF) 40 13 

• Evaporative Cooler (EC) 40 3 

• Window Fan (WF) 40 3 

Damper Type 

• Manual 40 30 

• Automatic 40 33 

• Gravity 40 13 

• No damper 40 25 

Operation Control Type 

• With the FAU Thermostat 40 45 

• On/Off Switch 40 33 

• FAU Fan Cycler 40 18 

• Timer 40 5 

Control Location 

• Home 40 75 

• Attic 40 25 

 a) N represents the number of homes with complete data. 

 b) N represents the total number of mechanical outdoor air systems. 
Table 22. Forced air unit (FAU) heating/cooling system duct leakage measurements. 

Forced Air Unit Heating/Cooling System Duct Leakage 

Variable N Mean Standard 

Dev. 

Geometric 

Mean 

Geometric 

Std. Dev. 

Min 10% 25% 50% 

FAU Duct a, b Leakage (%) 

138 11.9 8.7 6.5 21.1 1.9 5.2 7.4 10 

FAU Duct Leakage c

Ratio 119 2.2 1.5 0.1 1051 1.0 1.2 1.5 1.7 

% Homes Fail to Meet CBC Requirement 

CBC – 200

Requiremen

FAU Duct Leakage 138 86 < 6% 

a) Measured by sealing all supply registers and pressurizing the FAU system to 25 pascals at the return air grille. b) Measured duct leakage flowrate / total system flow rate, multiplied by 100 (%). c) Measured duct leakage percentage/6% for homes with duct leakage exceeding 6%. 

165
Table 23. Building envelope air leakage measurements. 

Building Envelope Air Leakage 

Variable N Mean Standard 

Dev. 

Geometric 

Mean 

Geometric 

Std. Dev. 

Min 10% 25% 50% 

Average Wind a

Speed (mph) 108 5.8 2.8 5.2 1.7 1.4 2.3 3.9 5.7 

Indoor/Outdoor Temperature Difference (0F) 108 5.4 3.9 - - -2.3 0.3 2.2 5.3 Effective Leakage b

Area (in2) 106 110 36 68 23 56 72 85 104 

SLA c 107 2.9 0.7 2.0 14 1.4 2.1 2.5 2.9 ACH50 d (ach) 106 4.9 0.9 4.0 6.9 2.8 3.8 4.3 4.8 

a) Collected from local weather station data and averaged over the 24-hour Test Day. b) Calculated from a multi-point depressurization (0–50 pascals) test using a blower door. 

c) SLA calculated by ELA/ft2 of floor area x 69.44. 

d) Measured while the home is depressurized to 50 pascals using a blower door. 

166
Table 24. Home-to-garage air leakage measurements. 

Home-to-Garage Air Leakage Measurements 

Variable N Mean Standard 

Dev. 

Geometric 

Mean 

Geometric 

Std. Dev. 

Min 10% 25% 50% 75

Home-to-Garage Leakage a

Area EqLA (in2) 105 22 19 6.3 94 0 6.4 11 16 2

Garage-to-Outdoor Leakage a Area EqLA (in2) 105 191 135 82 51 38 62 107 156. 2Home-to-Garage Pressure b

(pascals) 107 -48 -2.9 -39 -8.5 -34 -44 -47 -49 -

Coupling Factor b, c 107 0.05 0.05 - - 0 0 0.01 0.03 0Leakage Ratio d (%) 105 5.5 3.5 - - 0 1.9 3.1 4.9 7

a) Calculated from two multi-point depressurization tests (0–50 pascals), one with the home-garage door closed a

open. Leakage areas are calculated using a reference pressure of 10 pascals. 

b) Measured with the home depressurized to 50 pascals to outdoor air. c) Calculated from garage-to-outdoor differential pressure / home-to-outdoor differential pressure, 0= no couplingd) Calculated from home-to-garage leakage area / (home-to-outdoor leakage area + garage-to-outdoor leakage a

areas are calculated using a reference pressure of 10 pascals. 

167
Table 25. Window and door opening usage during the 24-hour air testing day and the preceding one-week. 

Window and Door Usage for the 24-Hour Test Day and the Preceding One-Week 

 N Mean Standard 

Dev. 

Geometric 

Mean 

Geometric 

Standard 

Dev. 

Min 10% 25% 50

Windows/Doors Test Day 24 hr Usage a (ft2-hrs) 108 209 366 - - 0 0 0 4Week Average Usage b (ft2-hrs) 108 186 268 - - 0 0 4.5 7Test Day / Week Average Usage Ratio 108 1.1 1.0 - - 0 0 0.4 1Log/Logger Ratio Week Average 136 1.7 6.6 0.9 2.3 0.04 0.5 0.9 1Garage Door Test Day 24 hr Usage a (ft2-hrs) 105 0.31 0.9 0.07 4.4 0.003 0.02 0.03 0.Week Average Usage b (ft2-hrs) 105 0.39 1.1 0.10 4.3 0.004 0.02 0.04 0.Test Day / Week Average Usage Ratio 105 1.1 1.0 0.8 2.7 0.01 0.22 0.52 0.No Window/Door Usage N Number of Homes with No Window/Door Usage % No WinTest Day a 108 34 Preceding Week b 108 16 

a) Test day usage: is measured during the 24-hour air testing day. b) Preceding week usage: measured during the one-week usage preceding the 24-hour Test Day. 

168
169 

Table 26. Percentage comparisons of actual measured home window/door usage and 

the homeowner’s estimated seasonal usage in the UCB mail survey. 

Percentage Comparisons of Measured and Estimated Window/Door Usage 

Home-Dates a N Percentage of 

Homes 

(%) 

Zero measured usage and 

zero estimated usage 48 7 15 

Measured usage and zero 

estimated 48 5 10 

Measured usage within b

estimated usage range 48 7 15 

Measured usage higher c

than high end estimated 

usage 48 25 52 

Measured usage lower d

than low end estimated 

usage 48 4 8.3 

a) Home-Dates: Total of 48 home seasonal measurement dates in 26 homes. 

b) The actual measured week average usage is within the range of the homeowner estimated 

usage from the UCB mail survey for that season and homes with non-zero usage. 

c) The actual measured week average usage is larger than the high end of the homeowner 

estimated usage from the UCB mail survey for that season. 

d) The actual measured week average usage is lower than the low end of the homeowner 

estimated usage from the UCB mail survey for that season. 
170 

Table 27. Differences between the actual measured home window/door usage and the homeowner’s estimated 

seasonal usage in the UCB mail survey. 

Differences Between Measured and Estimated Window/Door Usage 

Compound N Mean Standard 

Deviation 

Geometric 

Mean 

Geometric 

Standard 

Deviation 

Min 10% 25% 50% 75% 90% Max 

Measured 

usage in 

homes with 

zero 

estimated 

usage 

(ft2

-hrs) 5 33 67 4.4 10.5 0.3 0.3 1.1 3.1 9.6 153 153 

Measured a

usage 

above high 

end 

estimated 

usage ratio 25 48 209 4.1 4.7 1.0 1.2 1.5 3.1 6.3 18 1,050

Measured b

usage 

below low end 

estimated 

usage ratio 4 0.2 0.2 - - 0.0 0.0 0.02 0.04 0.3 0.5 0.5 

a) Ratio of the actual measured week average usage to the high end estimated usage in homes with higher actual 

usage than estimated usage for that season. 

b) Ratio of the actual measured week average usage to the low end estimated usage in homes with lower actual 

usage than estimated usage for that season. 
Table 28. Mechanical system usage for the 24-hour Test Day period and the ratio of the Test Day usage to the w

Mechanical System Usage (hours) 

Variable N Mean Standard 

Dev. 

Geometric 

Mean 

Geometric 

Std. Dev. 

Min 10% 25% 50% 7

Test Day Usage aKitchen Exhaust 108 0.2 0.5 - - 0 0 0 0 Bathroom Exhaust 105 0.7 1.4 - - 0 0 0 0.05 Other Exhaust (i.e., dryer, laundry) 108 1.2 2.2 - - 0 0 0 0.3 Ducted Outdoor Air (DOA) 14 4.3 4.8 2.2 3.9 0.1 0.4 1.5 2.5 Heat Recovery Ventilator (HRV) 8 21 6.1 20 1.5 7.8 13 22 24 Whole House Fan (WHF) 5 3.4 4.9 - - 0 0 0 0.7 FAU with Return Air Damper (RAD) 6 6.5 7.3 - - 0 0 0 5.3 1Forced Air Unit #1 108 3.2 5.6 - - 0 0 0 1.1 Test Day/Week Average b

Usage Ratio 

Kitchen Exhaust 108 1.4 1.9 - - 0 0 0.5 1.0 Bathroom Exhaust 105 1.4 1.9 - - 0 0 0.3 1.0 Other Exhaust (i.e., dryer, laundry) 108 1.3 1.6 - - 0 0 0 0.9 Ducted Outdoor Air (DOA) 14 1.7 1.8 1.0 3.1 0.09 0.13 0.9 1.1 Heat Recovery Ventilator (HRV) 8 1.0 0.04 1.0 1.0 0.9 1.0 1.0 1.0 Whole House Fan (WHF) 5 0.6 0.4 - - 0 0 0.5 0.7 FAU with Return Air Damper (RAD) 6 1.0 0.1 1.0 1.1 0.9 0.9 1.0 1.0 Forced Air Unit #1 108 1.2 1.5 - - 0 0 0.1 0.9  a) Hours of usage during the 24-hour Test Day period.  b) Ratio of the hours of usage during the 24-hour Test Day to the average 24-hour usage measured during the previo

171
Table 29. Mechanical outdoor air ventilation system characteristics and code requirements. 

Outdoor Air Exchange Rate Code Requirement Variables 

Variable N Min 10% 25% 50% 75% 90% Max % Homes Fail d

ASHRAE 62.2 

2004 Guidelines 

Ducted Outdoor Air Systems (DOA) a  - 24 hr average outdoor airflow rate (ach) b 14 0.002 0.002 0.002 0.01 0.03 0.07 0.08  - 24 hr average fan ON time (%) b 14 0.6 1.6 6.4 10 25 35 74  - Outdoor airflow rate (cfm) 14 8.8 14 27 38 51 68 355 Title 24 ACM - 2001 requirements (cfm) 14 60 64 79 90 102 152 172 ASHRAE 62.2 guidelines (cfm) 14 35 36 40 49 55 75 82 

64 

Heat Recovery Ventilators, (HRV) c  - 24 hr average outdoor airflow rate (ach) b 8 0.12 0.17 0.22 0.30 0.44 0.45 0.47  - 24 hr average fan ON time (%) b 8 32 55 90 100 100 100 100  - Outdoor airflow rate (cfm) 8 66 83 113 128 150 155 159 Title 24 ACM - 2001 requirements (cfm) 8 81 83 93 107 116 124 134 ASHRAE 62.2 guidelines (cfm) 8 40 45 50 54 61 64 66 

0 

a) DOA systems not disabled during the 24-hour Test Day. b) Mechanically provided outdoor air exchange rate measured during the 24-hour Test Day. c) HRV systems not disabled during the 24-hour Test Day. d) ASHRAE 62.2-2004 requirement: 0.01 cfm/ft2 floor area + 15 cfm times (#bedrooms +1) 

e) California Title 24 ACM-2001 requirement: 0.047 cfm/ft2 floor area for homes built with an intended envelope air tig

than 3.0. 

172
Table 30. PFT measurements of outdoor air exchange rates for the 24-hour Test Day and the following two-week p

PFT Measurement of Outdoor Air Exchange Rates 

N Mean Standard 

Deviation 

Geometric 

Mean 

Geometric 

Std. Dev. 

Min 10% 25% 50% 75% 90% 

24-Hour Measurement (ach) 107 b 0.48 0.78 0.31 2.24 0.09 0.13 0.18 0.26 0.45 0.85 2-Week Measurement (ach) 21 b 0.45 0.54 0.31 2.23 0.11 0.14 0.19 0.24 0.42 0.83 24-Hour vs. 2-Week  - Absolute difference c 

35 b 

0.49 1.13 0.08 6.99 0.001 0.01 0.03 0.07 0.30 1.7 

 - Relative Difference d 

35 b 

0.32 0.31 0.16 3.92 0.01 0.02 0.06 0.19 0.58 0.84 

a) 2001 California Building Code (CBC), Appendix Chapter 12, Interior Environment, Division 1-Ventilation, Table A-

requirements for Ventilation, Living Areas. 

b) 107 homes, in the All Homes Sample Frame, with 24-hour PFT measurements. 21 homes in the All Homes Samp

2-week measurements and 35 homes for all homes tested with both 24-hour and 2-week measurements. 

c) Absolute difference is calculated as the absolute difference between the 24-hour and two-week samples. d) Relative difference is calculated as the relative standard deviation of a 24-hour and two-week samples. 

173
Table 31. Comparison of outdoor air exchange rate PFT measurements to CBC 2001 minimum code requirements

Comparison of Outdoor Exchange Rate PFT Measurements to CBC 2001 Minimum Code Requir

Ratio of outdoor air exchange rate to CBC 2001 minimum codes requirements 

for homes below code requirements 

N Mean Standard 

Deviation 

Geometric 

Mean 

Geometric 

Standard 

Deviation 

Min 10% 25% 50% 75% 90% Max % 

Re

24-Hour 

Measurement 

(ach) 

72 0.61 0.21 0.57 1.5 0.25 0.31 0.46 0.58 0.75 0.92 1.0 

a) 2001 California Building Code (CBC), Appendix Chapter 12, Interior Environment, Division 1-Ventilation, Table A-12

Requirements for Ventilation, Living Areas. 

174
Table 32. Percentage of samples with concentrations of volatile organic compounds greater than the method dete

limit concentration. 

Percent of Samples with Concentrations of Volatile Organic Compounds 

Greater than the Method Detection Limit Concentration 

Compound N 

Indoor/ 

Outdoor 

MDL Mass a 

(ng) 

MDL 

Concentration b

(ug/m3) 

Indoor Air 

Guideline 

 (ug/m3) 

Ratio of MDL 

Concentration 

to Guideline 

%> MDL 

Concentratio

Indoor Air 

Acetaldehyde 105/ 39 9.0 0.30 9c 3E-2 100 Benzene 107/ 40 3.5 0.25 60c 4E-3 73 2-Butoxyethanol 107/ 40 1.9 0.13 3,000d 4E-5 86 Caprolactam 107/ 40 3.4 0.24 500d 5E-4 0 1,4-Dichlorobenzene 107/ 40 2.9 0.21 800c 3E-4 29 Ethylene glycol 107/ 40 16.4 1.17 400c 3E-3 56 Formaldehyde 105/ 39 9.0 0.30 33e 9E-3 100 Hexanal 107/ 40 1.4 0.10 na na 99 n-Hexane 107/ 40 4.2 0.30 7,000c 4E-5 80 d-Limonene 107/ 40 4.2 0.30 na na 93 1-Methyl-2-pyrrolidinone 107/ 40 6.0 0.43 2,000d 2E-4 13 Naphthalene 107/ 40 2.0 0.14 9c 2E-2 82 Phenol 107/ 40 2.8 0.20 200c 1E-3 100 alpha-Pinene 107/ 40 3.0 0.22 2,800d 1E-4 99 Styrene 107/ 40 3.1 0.22 900c 2E-4 93 Tetrachloroethene 107/ 40 4.7 0.33 35c 1E-2 27 Toluene 107/ 40 4.9 0.35 300c 1E-3 100 Trichloromethane 107/ 40 4.9 0.35 300c 1E-3 42 1,2,4-Trimethylbenzene 107/ 40 3.3 0.24 3,125d 1E-4 87 Vinyl acetate 107/ 40 5.6 0.40 200c 2E-3 2 m,p-Xylene 107/ 40 3.8 0.27 700c 4E-4 97 o-Xylene 107/ 40 3.2 0.23 700c 3E-4 91 

a) MDL mass = Method mass detection limit for GS/MS VOC analysis and HPLC formaldehyde and acetaldehyde b) MDL concentration = Method concentration detection limit for typical air sample volumes; 14 L for VOCs and 30 

acetaldehyde. 

c) OEHHA Chronic Reference Exposure Levels (OEHHA 2003). d) 1/40th of the 8-hour occupational health guideline in μg/m3 (e.g., Cal/OSHA PELs, ACGIH TLVs, DFG MAKs). 

e) Formaldehyde – California Air Resources Board Indoor Air Quality Guideline, 2005. na = no available guideline

175
Table 33. Concentrations of individual volatile organic compounds measured indoors over the 24-hour Test Day. 

Indoor Concentrations of Volatile Organic Compounds (μg/m3) 

Compound N Mean Standard

Dev. 

Geometric 

Mean 

Geometric 

Std. Dev. 

Min 10% 25% 50% 75% 

Acetaldehyde 105 25 20 19 2.3 1.9 6.3 12 20 32 Benzene 107 1.6 2.2 0.8 3.8 0.1 0.1 0.1 1.1 2.0 2-Butoxyethanol 107 7.3 19 2.0 6.0 0.1 0.2 0.9 2.8 6.0 Caprolactam 107 0.1 0.01 0.1 1.2 0.1 0.1 0.1 0.1 0.1 1,4-Dichlorobenzene 107 5.2 27 0.2 5.0 0.1 0.1 0.1 0.1 0.2 Ethylene glycol 107 12 20 3.2 5.6 0.5 0.6 0.6 3.2 16 Formaldehyde 105 43 27 36 1.9 4.8 14 25 36 58 Hexanal 107 10 7.9 7.0 2.7 0.1 2.3 4.1 7.6 14 n-Hexane 107 2.3 3.9 0.9 3.8 0.1 0.2 0.3 0.8 2.5 d-Limonene 107 18 25 7.6 5.0 0.1 0.9 3.5 11 21 1-Methyl-2-pyrrolidinone 

107 

0.4 0.8 0.3 1.7 0.2 0.2 0.2 0.2 0.2 

Naphthalene 107 0.3 0.5 0.2 2.3 0.1 0.1 0.1 0.2 0.3 Phenol 107 2.0 1.3 1.6 2.0 0.2 0.6 1.1 1.7 2.6 alpha-Pinene 107 15 13 9.3 3.3 0.1 1.9 6.6 11 20 Styrene 107 1.8 6.0 0.9 2.8 0.1 0.2 0.6 0.9 1.8 Tetrachloroethene 107 0.6 2.3 0.3 2.4 0.1 0.2 0.2 0.2 0.3 Toluene 107 17 22 9.5 2.9 0.3 3.0 4.8 8.5 18 Trichloromethane 107 0.7 1.4 0.4 2.8 0.1 0.2 0.2 0.2 0.7 1,2,4-Trimethylbenzene 107 1.8 2.0 1.0 3.2 0.1 0.1 0.6 1.1 2.3 Vinyl acetate 107 0.2 0.02 0.2 0.2 0.1 0.2 0.2 0.2 0.2 m,p-Xylene 107 7.1 8.4 4.2 3.1 0.1 1.4 2.3 4.2 9.2 o-Xylene 107 2.1 2.7 1.1 3.3 0.1 0.1 0.6 1.2 2.7 

a) OEHHA Chronic Reference Exposure Levels (OEHHA 2003). b) 1/40th of the 8-hour occupational health guideline in μg/m3 (e.g., Cal/OSHA PELs, ACGIH TLVs, DFG MAKs). 

c) Formaldehyde – California Air Resources Board Indoor Air Quality Guideline, 2005. na = no available guideline. 

176
Table 34. Concentration of individual volatile organic compounds measured outdoors over the 24-hour Test Day. 

Outdoor Concentrations of Volatile Organic Compounds (μg/m3) 

Compound N Mean Standard 

Deviation 

Geometric 

Mean 

Geometric 

Std. Dev. 

Min 10% 25% 50% 75% 9

Acetaldehyde 39 2.1 1.4 1.5 2.6 0.2 0.3 1.0 2.2 3.3 4Benzene 40 0.5 0.5 0.3 2.6 0.1 0.1 0.1 0.3 0.7 12-Butoxyethanol 40 0.1 0.2 0.1 1.9 0.1 0.1 0.1 0.1 0.1 0Caprolactam 40 0.1 0.04 0.1 1.2 0.1 0.1 0.1 0.1 0.1 01,4-Dichlorobenzene 40 0.1 0.1 0.1 1.3 0.1 0.1 0.1 0.1 0.1 0Ethylene glycol 40 0.6 0.03 0.6 1.1 0.5 0.6 0.6 0.6 0.6 0Formaldehyde 39 2.2 1.4 1.8 2.1 0.2 0.7 1.2 2.1 2.9 3Hexanal 40 0.2 0.2 0.2 2.7 0.1 0.1 0.1 0.2 0.4 0n-Hexane 40 0.3 0.3 0.2 2 0.1 0.2 0.2 0.2 0.3 0d-Limonene 40 0.2 0.2 0.2 1.7 0.1 0.1 0.2 0.2 0.2 01-Methyl-2-pyrrolidinone 40 0.2 0.01 0.2 1.1 0.2 0.2 0.2 0.2 0.2 0Naphthalene 40 0.1 0.03 0.1 1.4 0.1 0.1 0.1 0.1 0.1 0Phenol 40 0.6 0.3 0.5 2.1 0.02 0.2 0.4 0.5 0.7 0alpha-Pinene 40 0.1 0.04 0.1 1.2 0.1 0.1 0.1 0.1 0.1 0Styrene 40 0.2 0.2 0.1 1.8 0.03 0.1 0.1 0.1 0.2 0Tetrachloroethene 40 0.2 0.1 0.2 1.3 0.1 0.2 0.2 0.2 0.2 0Toluene 40 1.7 1.4 1.2 2.6 0.2 0.2 0.8 1.2 2.2 4Trichloromethane 40 0.2 0.01 0.2 1.1 0.2 0.2 0.2 0.2 0.2 01,2,4-Trimethylbenzene 40 0.4 0.3 0.3 2.2 0.1 0.1 0.1 0.2 0.6 0Vinyl acetate 40 0.2 0.01 0.2 1.1 0.2 0.2 0.2 0.2 0.2 0m,p-Xylene 40 1.2 0.9 0.9 2.5 0.1 0.2 0.5 1.0 2.0 2o-Xylene 40 0.3 0.3 0.2 2.2 0.1 0.1 0.1 0.2 0.5 0

a) OEHHA Chronic Reference Exposure Levels (OEHHA 2003). b) 1/40th of the 8-hour occupational health guideline in μg/m3 (e.g., Cal/OSHA PELs, ACGIH TLVs, DFG MAKs). 

c) Formaldehyde – California Air Resources Board Indoor Air Quality Guideline, 2005. na = no available guideline. 

177
178 

Table 35. Maximum indoor concentrations of the volatile organic compounds comparison to 

indoor air contaminant guidelines. 

Maximum Indoor Concentrations of Volatile Organic Compounds 

Comparison to the Indoor Guidelines (μg/m3) 

Compound Maximum Concentration

(μg/m3) 

Indoor Guideline 

(μg/m3) 

Maximum 

Concentration to 

Indoor Guideline Ratio 

Tetrachloroethene 22.6 35 a 0.646 

Naphthalene 4.9 9 a 0.544 

Toluene 115.2 300 a 0.384 

Ethylene glycol 119.5 400 a 0.299 

1,4-Dichlorobenzene 219 800 a 0.274 

Benzene 15.1 60 a 0.252 

m,p-Xylene 60.3 700 a 0.086 

Styrene 62 900 a 0.069 

2-Butoxyethanol 179.7 3,000 b 0.060 

Trichloromethane 11.8 300 a 0.039 

Phenol 6.5 200 a 0.033 

o-Xylene 19.9 700 a 0.028 

alpha-Pinene 65.1 2,800 b 0.023 

1,2,4-Trimethylbenzene 13.2 3,125 b 0.004 

1-Methyl-2-pyrrolidinone 8.3 2,000 b 0.004 

n-Hexane 24 7,000 a 0.003 

Vinyl acetate 0.3 200 a 0.002 

Caprolactam 0.1 500 b <0.0001 

Hexanal 35.1 na na 

d-Limonene 152.3 na na 

a) OEHHA Chronic Reference Exposure Levels (OEHHA 2003). 

b) 1/40th of the 8-hour occupational health guideline in μg/m3

 (e.g., Cal/OSHA PELs, ACGIH 

TLVs, DFG MAKs). na = no available guideline. 
Table 36. Comparison of indoor concentrations of formaldehyde and acetaldehyde to indoor air contaminant guide

Comparison of Indoor Concentrations of Formaldehyde and Acetaldehyde to Indoor Air Contamina

Compound N Mean Standard 

Deviation 

Geometric 

Mean 

Geometric 

Standard 

Deviation 

Min 10% 25% 50% 75% 90% M

Acetaldehyde Chronic Reference Exposure Level 86 3.3 2.2 2.8 1.8 1.2 1.4 1.7 2.5 4.0 6.5 Formaldehyde 

Chronic Reference Exposure Level 105 15 9.2 12 1.9 1.6 4.8 8.2 12 19 29 

ARB Indoor Air Guideline 62 1.8 0.8 1.7 1.5 1.0 1.1 1.2 1.5 2.1 2.9 Acute Reference Exposure Level 7 1.2 0.2 1.2 1.1 1.0 1.0 1.1 1.2 1.3 1.4 

a) Ratio of indoor concentration to indoor air contaminant guidelines for homes exceeding the guideline. b) OEHHA Chronic Reference Exposure Levels (OEHHA 2003). c) Formaldehyde – California Air Resources Board Indoor Air Quality Guideline, 2005; OEHHA Interim 8-hour Refere

d) OEHHA Acute Reference Exposure Levels (OEHHA 2000). 

179
Table 37. Percentage of homes with indoor and concentrations of carbon monoxide, nitrogen dioxide, and PM2.5 pa

matter greater than the method detection limit. 

Percent of Concentrations of Carbon Monoxide, Nitrogen Dioxide, and PM2.5 Particulate Matter 

Greater than the Method Detection Limit (μg/m

3) 

Compound N 

Indoor/ 

Outdoor 

MDL Mass a

(μg) 

MDL b

Concentration 

Indoor c

Guideline 

Ratio of 

MDL/Guideline 

% > MDL for 

Indoor Air 

Carbon Monoxide (ppm) 107/ 40 na 0.8 9 0.09 100 Nitrogen Dioxide (μg/m3) 29/ 11 0.8 5.7 150 0.04 48 PM2.5 Particulate 

Matter (μg/m3) 29/ 11 5 1.8 65 0.03 100 

a) MDL Mass = Method mass detection limit for nitrogen dioxide spectrophotometer analysis and PM2.5 particulate m

gravimetrical analysis. Not applicable for real-time carbon monoxide measurements. 

b) MDL Concentration = Method detection limit for a typical volume; NO2 = 0.14 m3 and PM2.5 = 2.8 m3; CO MDL con

determined from analyses of the variance of the average concentration from 8 co-located IAQ-Calc instruments. 

c) California Air Resources Board Indoor Air Quality Guideline, 2005: Carbon monoxide (8-hr), Nitrogen dioxide (24-

Particulate matter (24 hr). 

180
Table 38. Concentrations of carbon monoxide, nitrogen dioxide and PM2.5 particulate matter measured indoor and o

the 24-hour Test Day. 

Concentrations of Carbon Monoxide, Nitrogen Dioxide and PM2.5 Particulate Matter

Compound N Mean Standard 

Deviation

Geometric 

Mean 

Geometric 

Standard 

Deviation 

Min 10% 25% 50% 75% 9

Indoor Carbon Monoxide (ppm) - 24-hour average 105 0.9 0.6 0.8 1.9 0.4 0.4 0.4 0.8 1.4  - 8 hour average maximum 105 1.2 0.7 0.7 7.4 0.4 0.4 0.4 1.1 1.8  - 1 hour average maximum 105 1.6 1.1 1.0 7.8 0.4 0.4 0.4 1.6 2.3 Nitrogen Dioxide (μg/m3

) 29 9.8 11 6.2 2.5 2.6 2.7 2.8 3.1 13 

Particulate Matter PM2.5  (μg/m3

) 28 13 9.0 11 1.8 3.8 6.0 8.2 11 14 

Outdoor Carbon Monoxide (ppm)- 24-hour average 39 1.4 0.9 1.1 2.2 0.4 0.4 0.4 1.2 2.1 - 8 hour average maximum 39 1.9 1.2 1.5 2.3 0.4 0.4 0.4 1.9 2.7 - 1 hour average maximum 39 2.3 1.2 1.9 2.1 0.4 0.4 1.3 2.4 3.2 Nitrogen Dioxide (μg/m3

) 11 3.9 3.4 3.4 1.6 2.7 2.7 2.8 2.9 3.1 

Particulate Matter PM2.5 

(μg/m3

) 11 7.9 2.5 7.5 1.4 4.3 5.0 5.3 8.7 9.5 

a) California Air Resources Board Indoor Air Quality Guidelines, 2005: Carbon monoxide (1-hr and 8-hr), Nitrogen diox

Particulate Matter (24-hr). There is no 24-hour exposure guideline for carbon monoxide. 

181
Table 39. Temperature, relative humidity, and carbon dioxide concentrations measured indoors and outdoors over 

24-hour Test Day. 

Temperature, Relative Humidity and Carbon Dioxide Concentrations

Compound N Mean Standard 

Deviation 

Geometric 

Mean 

Geometric 

Standard 

Dev. 

Min 10% 25% 50% 7

Indoor Carbon Dioxide (ppm) a

 - 24-hour average 107 610 177 587 1.3 334 405 469 564 7

Temperature (°F)  - 24-hour average 103 72.4 5.0 72.2 1.1 62.7 65.7 68.1 72.3 7Relative Humidity (%)  - 24-hour average 103 43.4 9.6 42.2 1.3 19.5 29.7 37.5 45.2 4Outdoor Carbon Dioxide (ppm) b

 - 24-hour average 39 326 23 325 1.1 258 298 315 323 3

Temperature (°F)  - 24-hour average 39 62.4 10.4 61.6 1.2 44.9 48.1 52.5 63.8 7Relative Humidity (%)  - 24-hour average 39 57.0 18.6 53.8 1.4 25.1 31.7 39.2 57.9 7

a) Carbon dioxide concentration guideline; ASHRAE 62.1-2004, 700 ppm greater than outdoors – for acceptable body b) There appears to be a temperature induced error associated with the outdoor carbon dioxide measurements that re

measured concentration being substantially lower than the true concentration. 

182
Table 40. Comparison of volatile organic compound concentrations measured in new residences in this study and 

two other studies. 

 Comparison of Indoor Concentrations of Volatile Organic Compounds in New Homes

This Study a

GM Mean 

Other Studies b

GM Mean Ratio c

This Study a

Maximum

Other Studie

Maximum 

Acetaldehyde 19 14 1.4 102 43 Benzene 2.2 0.5 4.4 15 6.1 2-Butoxyethanol 2 2.9 0.7 180 12 Ethylene glycol 3.2 48 0.1 120 490 Formaldehyde 36 32 1.1 136 62 Hexanal 7 15 0.5 35 36 d-Limonene 7.6 4.3 1.8 152 12 Phenol 1.6 1.8 0.9 6.5 5.8 alpha-Pinene 9.3 23 0.4 65 60 Toluene 9.5 8.5 1.1 115 68 Trichloromethane 0.4 0.1 4.0 12 0.5 m,p-Xylene 4.2 2.1 2.0 60 11 o-Xylene 1.1 0.6 1.8 20 4.4 

a) Geometric mean and maximum indoor concentrations in the new Californian homes in this study (n=107 except 

formaldehyde and acetaldehyde with n=105) 

b) Geometric mean and maximum concentrations of 20 new homes in two other studies as reported in Volatile Org

Compounds in Indoor Air: A Review of Concentrations Measured Since 1990 (Hodgson and Levin 2003). 6 expelow-emitting and 3 conventional homes, Denver, Colorado, 1992

–1993, and 4 manufactured and 7 site-built hom

southeast United States, 1997

–1998. 

c) Ratio of geometric mean in this study to geometric mean in two other studies. d) Ratio of maximum in this study to maximum in two other studies. 

183
Table 41. Percentage of homes with concentrations exceeding California Proposition 65 Safe Harbor 

Dose concentrations. 

California Proposition 65 Safe Harbor Dose Indoor Concentrations a

Compound Number of 

Home 

Measurements

NSRL 

Concentration 

(μg/m3) 

Percentage of Homes 

Exceeding the NSRL 

Concentration 

(%) 

MADL 

Concentration

(μg/m3) 

Percentage of 

Exceeding the 

Concentra

(%) 

Acetaldehyde 105 4.5 93 NA Benzene 107 0.7 63 2.5 20 1,4-Dichlorobenzene 107 1.0 12 NA Formaldehyde 105 2.0 100 NA Naphthalene 107 0.3 27 NA Tetrachloroethene 107 0.7 8 NA Toluene 107 NA NA 350 0 Trichloromethane 107 2.0 8 NA 

a) California Proposition 65 Safe Harbor Dose indoor concentrations calculated from the No Significant Risk Le

(NSRL) for carcinogens and the Maximum Allowable Dose Level (MADL) assuming continuous 24-hour expwith a total daily inhaled air volume of 20 m3 and 100% absorption by the respiratory system. 

NA = no available Safe Harbor Dose. 

184
Table 42. Occupant cooking and cleaning source activities conducted during the 24-hour Test Day. 

Cooking and Cleaning Source Activities (minutes) 

Activity

N Mean Standard 

Deviation

Geometric 

Mean

Geometric 

Std. Dev.

min 10% 25% 50% 75

Toasting 50 6.4 5.2 4.9 2.1 1 2

3

5

8 

Frying or Sautéing 36 24 25 16 2.7 1 5 10 17 3Baking 33 46 34 36 2.0 10 15 21 45 6Broiling 11 39 45 22 3.2

5

6

6 19 6

Warming/Boiling Water Soup, etc. 47 30 30 19 2.6

3

6

8 20 3

Microwave 79 6.7 6.1 4.1 3.1 0.2 1 2

4 1

Other 

8 22 19 17 2.3

4

4 11 16 3

Total Cooking Activities 97 52 56 29 3.5 0.3

5 16 35 6

Cooking 

Activities

Vacuuming 16 49 76 25 3.0

7

9 10 25 4

Sweeping or Dusting 16 24 33 13 3.1

3

3

6 12 2

Use of Dishwasher 38 76 51 56 2.7

2 20 40 68 9

Use of Clothes Washer 44 95 88 69 2.2 15 30 41 59 11Use of Furniture Polish 

5 27 36 16 3.0

5

5 10 10 2

Use of cleaning chemicals 24 21 39

9 3.5 1 2

5 10 1

Other 1 10 - 10 - 10 10 10 10 1

Cleaning Activities

Total Cleaning Activities 74 120 126 66 3.8 1 10 45 83 15

185
Table 43. Occupant special activities, garage and outdoor source activities conducted during the 24-hour Test Day. 

Occupant Special, Garage, and Outdoor Source Activities (minutes)

Activity N Mean Standard 

Deviation 

Geometric 

Mean 

Geometric 

Std. Dev. 

Min 10% 25% 50

Gas burning fireplace 1 140 - 140 - 140 140 140 14Candle burning 4 203 108 185 1.6 120 120 135 16Painting 1 28 - 28 - 28 28 28 2Pesticide application 3 482 829 24 35 2 2 2 5 Nail polish application or removal 3 3.3 1.5 3.1 1.6 2 2 2 3 Aerosol air fresheners 6 0.6 0.5 0.3 4.8 0.0 0.0 0.1 0.Aerosol personal care products 24 1.9 4.0 0.7 4.0 0.0 0.1 0.4 1 Showering or bathing 80 33 18 28 1.8 5 13 20 3Large party/dinner gatherings 3 90 52 76 2.2 30 30 30 12Nobody at home 44 347 255 251 2.5 10 90 150 30Other activities: dust, smoke, or fumes 3 28 18 24 2.2 10 10 10 3Total Special Activities – excluding “nobody at home” 84 65 169 32 2.9 0.3 13 20 3

Occupant 

Special 

Activities 

Vehicle operated in garage  (vehicle-minutes) 39 2.7 2.2 1.9 2.5 0.2 0.5 1.0 2.Vehicle storage in garage (vehicle-minutes) 62 1,338 767 994 3.0 5.0 360 730 1,4Total Vehicle Activities 72 1,134 860 381 12.3 0.3 3 447 1,0

Garage 

Activities 

Use of gasoline powered equipment 4 31 20 27 1.8 15 15 18 2Painting 1 55 - 55 - 55 55 55 5Barbecuing 8 32 18 28 1.7 15 15 20 2Smoking outdoors 7 78 106 36 4.0 5 5 14 2Other activities: dust, smoke, or fumes 1 1.0 - 1.0 - 1 1 1 1 

Outdoor 

Activities 

Total Outdoor Activities 18 53 81 28 3.5 1 5 19 2

186
187 

Table 44. Homeowner reported IAQ related perceptions and observations. 

Homeowner Reported IAQ Related Perceptions and Observations

Variable N a % 

During the past three weeks have you experienced any of the following physical 

symptoms when in your home that you do not experience when you are away from the 

home? 

One or more of the symptoms below 108 28 

Eye irritation 108 11 

Nose/sinus congestion 108 19 

Nose irritation 108 12 

Allergy symptoms 108 15 

Headache 108 13 

Skin irritation 108 5.6 

Difficulty concentrating 108 6.5 

Asthma symptoms 108 4.6 

Other 108 3.7 

During the past week, please indicate if you have noticed a significant period when your 

home has experienced each of the conditions listed below. 

Too hot 108 19 

Too cold 108 15 

Too dry 108 8.3 

Too humid 108 1.9 

Too drafty 108 0.0 

Too stagnant (not enough air movement) 108 12 

Too dusty 108 11 

During the past week, please indicate if you have noticed, seen, or smelled mold or 

mildew in the following locations? 

Bathrooms 108 13 

Basement or crawlspace 108 0.9 

Walls or ceilings 108 1.9 

Carpets 108 0.9 

Closets 108 0.9 

Cabinetry 108 1.9 

Other 108 2.8 

Has anyone in your household had a medical diagnosis of any of the following? 

Allergies 108 36 

Asthma 108 16 

Chemical sensitivity 108 3.7 

Other activity-limiting conditions 108 4.6 

a) Number of homes with completed questionnaires. 
Table 45. Indoor emission rates of volatile organic compounds over the 24-hour Test Day. 

Indoor Emission Rates of Volatile Organic Compounds (μg/m3-h) a

Compound N Mean Standard 

Deviation 

Geometric 

Mean 

Geometric 

Standard 

Deviation 

Min 10% 25% 50% 75% 

Acetaldehyde 99 5.7 3.2 4.9 1.8 1.2 2.1 3.7 5.3 7.0 Benzene 77 0.4 0.6 - - -0.4 0.01 0.06 0.2 0.5 2-Butoxyethanol 91 2.0 3.7 1.0 3.5 0.03 0.2 0.4 0.9 2.4 Caprolactam 3 -0.03 0.02 - - -0.06 -0.06 -0.06 -0.03 -0.01 1,4-Dichlorobenzene 35 7.4 26 - - -0.3 -0.09 0.01 0.1 0.6 Ethylene glycol 59 6.7 8.5 3.7 3.4 0.05 1.0 1.8 3.9 7.8 Formaldehyde 99 13 10 10 2.0 2.3 4.0 5.8 11 16 Hexanal 105 2.5 1.4 2.1 1.8 0.4 0.9 1.5 2.2 3.3 n-Hexane 87 0.6 1.1 - - -0.2 0.02 0.1 0.2 0.5 d-Limonene 100 3.9 4.1 - - -4.2 0.6 1.4 2.6 4.8 1-Methyl-2-pyrrolidinone 13 0.3 0.5 0.1 5.2 0.00 0.02 0.07 0.1 0.4 Naphthalene 87 0.07 0.2 - - -0.01 0.01 0.01 0.03 0.06 Phenol 105 0.4 0.5 - - -0.5 0.02 0.1 0.3 0.5 alpha-Pinene 104 3.6 2.2 2.9 2.3 0.01 1.3 2.2 2.9 4.5 Styrene 99 0.4 1.1 - - -0.4 0.07 0.2 0.2 0.4 Tetrachloroethene 31 0.4 1.0 - - -0.05 -0.02 0.01 0.06 0.2 Toluene 105 3.7 4.7 - - -1.2 0.7 1.3 2.1 4.1 Trichloromethane 44 0.3 0.3 0.1 4.0 0.00 0.02 0.09 0.2 0.3 1,2,4-Trimethylbenzene 92 0.4 0.5 - - -0.1 0.07 0.1 0.2 0.5 Vinyl acetate 2 0.01 0.00 0.01 1.1 0.01 0.01 0.01 0.01 0.01 m,p-Xylene 104 1.6 2.3 - - -0.4 0.2 0.4 0.9 2.0 o-Xylene 96 0.5 0.8 - - -0.2 0.03 0.1 0.2 0.6 

a) Emission rates calculated as the difference between the indoor and outdoor concentrations, multiplied by the outdoo

rate. No emission rate was calculated when both the indoor and outdoor concentrations were below the MDL conceonly the indoor or outdoor concentration was below the MDL concentration, then the emission rate was calculated uconcentration equal to one-half the MDL concentration. 

188
Table 46. Formaldehyde concentration and emission rates from FAU systems. 

Formaldehyde Emission Rates from Forced Air Units (FAU) 

 Attic Formaldehyde 

Concentrations 

(μg/m3) 

Formaldehyde 

Emission Ratea

(μg/h) 

Home 

ID 

Season Temperature 

(°F) 

Relative 

Humidity 

(%) 

FAU 

Flowrate 

(m3/h) 

Supply 

Air 

Return 

Air 

Attic 

Air 

FAU Home FAU 

Percent of 

Home 

017 Summer 88.1 41.3 2,106 10.2 8.6 9.2 3,423 16,028 21 017 Winter 67.0 48.0 2,106 13.7 15.3 2.0 -3,381 6,018 -56 120 Winter 64.5 56.3 1,885 70.0 74.1 10.4 -7,681 5,093 -151 120 Winter 64.5 56.3 1,885 65.7 b 74.1 10.4 -15,656 5,093 -307 

 a) The FAU emission rate is calculated as the difference between the concentrations measured at the supply 

air diffuser and the return air inlet multiplied by the forced air handling unit return airflow rate. The home emission rate is calculated as the difference between the indoor air and outdoor air concentrations times the home outdoor airflow rate as determined from the PFT measurement and the home indoor air volume. 

b) Second supply air concentration measurement. 

189
Table 47. Multi-day home concentration and emission rates over three 24-hour periods for Home 033. 

Home 033 Multi-Day (Summer-North)

 Concentration 

(μg/m3) 

Emission Rates d 

(μg/m3-h) 

Day 1 Indoor a Day 2 Indoor a Day 3 Indoor a Day 1 Outdoor Day 1 Day 2 Day 3 

Compound ACH = 0.23 ACH = 0.29 ACH = 0.13 Acetaldehyde 75 55 109 3.2 17 15 13 Benzene 0.3 0.1 1.4 0.1c 0.1 0.01 0.2 2-Butoxyethanol 2.9 2.5 5.7 0.1c 0.7 0.7 0.7 Caprolactam 0.1 c 0.1 c 0.1 c 0.1c nab na na 1,4-Dichlorobenzene 0.1 c 0.1 c 0.1 c 0.1c na na na Ethylene glycol 0.5 0.6 0.6 0.6c na na na Formaldehyde 58 50 64 2.3 13 14 7.8 Hexanal 13 12 21 0.2 3.1 3.4 2.7 n-Hexane 1.0 0.8 3.0 0.2c 0.2 0.2 0.4 d-Limonene 9.4 6.4 39 0.2c 2.2 1.8 4.9 1-Methyl-2-pyrrolidinone 0.2 c 0.2 c 0.2 c 0.2c na na na Naphthalene 0.1 0.1 0.2 0.1c 0.01 0.01 0.01 Phenol 1.8 1.8 2.4 0.4 0.3 0.4 0.3 alpha-Pinene 16 11 26 0.1c 3.7 3.3 3.3 Styrene 0.9 0.2 0.8 0.1c 0.2 0.03 0.1 Tetrachloroethene 0.2 c 0.2 c 0.3 0.2c na na 0.01 Toluene 9.8 8.1 17 0.2c 2.3 2.3 2.1 Trichloromethane 2.2 0.7 5.4 0.2c 0.5 0.1 0.7 1,2,4-Trimethylbenzene 0.8 0.4 1.1 0.1c 0.2 0.1 0.1 Vinyl acetate 0.2 c 0.2 c 0.2 c 0.2c na na na m,p-Xylene 4.1 2.6 5.4 0.1c 0.9 0.7 0.7 o-Xylene 1.0 0.3 1.2 0.1c 0.2 0.1 0.1 

a) Day 1 is Thursday–Friday, Day 2 is Friday–Saturday, Day 3 is Saturday–Sunday b) na: indoor and outdoor concentrations both below the concentration method detection limit thus, no emission rate w

fewer than two emission rates were calculated then no variations were calculated. 

c) The sample was below the mass method detection limit and the concentration was calculated using one-half the md) Emission rates calculated as the difference of the indoor concentration and Day 1 outdoor concentration multiplied 

e) Variation: Absolute variation is the absolute difference between the min and max emission rates; relative variation 

deviation of the emission rates. 

190
Table 48. Multi-day home concentration and emission rates over three 24-hour periods for Home 041. 

Home 041 Multi-Day (Winter-South)

 Concentration 

(ug/m3) 

Emission Rates d 

(ug/m3-h) 

Day 1 Indoor a Day 2 Indoor a Day 3 Indoor a Day 1 Outdoor a Day 1 Day 2 Day 3 

Compound ACH = 0.18 ACH = 0.19 ACH = 0.20 Acetaldehyde 15 19 23 1.7 2.4 3.2 4.2 Benzene 1.2 1.3 1.2 1.0 0.04 0.1 0.04 2-Butoxyethanol 32 4.4 3.2 0.1c 5.8 0.8 0.6 Caprolactam 0.1 c 0.1 c 0.1 c 0.1c na b na na 1,4-Dichlorobenzene 0.1 c 0.1 c 0.1 c 0.1c na na na Ethylene glycol 8.5 12 16 0.6c 1.4 2.2 2.9 Formaldehyde 14 17 23 1.2 2.3 3.0 4.2 Hexanal 7.5 8.7 11 0.3 1.3 1.6 2.0 n-Hexane 0.2 c 1.2 0.9 1.0 na 0.04 -0.03 d-Limonene 7.7 5.8 7.3 0.4 1.3 1.0 1.4 1-Methyl-2-pyrrolidinone 0.2 c 0.2 c 0.2 c 0.2c na na na Naphthalene 0.1 c 0.1 c 0.1 c 0.1c na na na Phenol 2.4 1.7 2.4 1.0 0.3 0.1 0.3 alpha-Pinene 16 18 20 0.1c 3.0 3.5 3.9 Styrene 2.2 1.2 1.2 0.3 0.4 0.2 0.2 Tetrachloroethene 0.2 c 0.2 c 0.2 c 0.2c na na na Toluene 8.5 21 14 2.9 1.0 3.5 2.2 Trichloromethane 0.3 0.17 c 0.2 0.2c 0.02 na 3E-4 1,2,4-Trimethylbenzene 1.0 0.9 1.1 0.4 0.1 0.1 0.1 Vinyl acetate 0.2 c 0.2 c 0.2 c 0.2c na na na m,p-Xylene 3.1 2.9 3.2 1.4 0.3 0.3 0.4 o-Xylene 0.7 0.8 0.7 0.4 0.1 0.1 0.1 

a) Day 1 is Thursday–Friday, Day 2 is Friday–Saturday, Day 3 is Saturday–Sunday 

b) na: indoor and outdoor concentrations both below the concentration method detection limit thus, no emission rate 

fewer than two emission rates were calculated then no variations were calculated. 

c) The sample was below the mass method detection limit and the concentration was calculated using one-half the md) Emission rates calculated as the difference of the indoor concentration and Day 1 outdoor concentration multiplie

e) Variation: Absolute variation is the absolute difference between the min and max emission rates; relative variation 

deviation of the emission rates. 

191
Table 49. Multi-day home concentration and emission rates over three 24-hour periods for Home 059. 

Home 059 Multi-Day (Summer-South)

 Concentration 

 (ug/m3) 

Emission Rates d

(ug/m3-h) 

Day 1 Indoor a Day 2 Indoor a Day 3 Indoor a Day 1 Outdoor a Day 1 Day 2 Day 3 

Compound ACH = 2.25 ACH = 1.79 ACH = 1.25 Acetaldehyde 4.0 5.8 6.7 0.7 7.5 9.2 7.5 Benzene 0.1 c 0.1 c 0.3 0.1c na b na 0.2 2-Butoxyethanol 0.9 1.1 1.4 0.5 0.9 1.0 1.1 Caprolactam 0.1 c 0.1 c 0.1 c 0.1c na na na 1,4-Dichlorobenzene 0.1 c 0.1 c 0.1 c 0.1c na na na Ethylene glycol 0.6 c 0.7 c 1.7 c 0.6c na na na Formaldehyde 11 14 14 3.1 17 20 13 Hexanal 2.3 3.4 1.2 0.2 4.7 5.8 1.2 n-Hexane 0.3 1.0 1.9 0.2c 0.4 1.6 2.1 d-Limonene 0.1 c 0.3 0.2 c 0.2c na 0.2 na 1-Methyl-2-pyrrolidinone 0.2 c 0.2 c 0.3 c 0.2c na na na Naphthalene 0.1 0.3 0.4 0.1 0.1 0.3 0.4 Phenol 0.3 1.1 1.0 0.2 0.3 1.5 1.1 alpha-Pinene 0.3 0.4 0.7 0.1c 0.5 0.5 0.7 Styrene 0.1 0.6 0.7 0.1c 0.1 0.9 0.7 Tetrachloroethene 0.2 c 0.2 c 0.2 c 0.2c na na na Toluene 2.9 7.0 8.9 0.2c 6.1 12 10 Trichloromethane 0.2 c 0.2 c 0.2 c 0.2c na na na 1,2,4-Trimethylbenzene 0.8 2.0 2.2 0.2 1.4 3.1 2.5 Vinyl acetate 0.2 c 0.2 c 0.3 c 0.2c na na na m,p-Xylene 2.3 5.7 6.6 0.2 4.7 10 8.1 o-Xylene 0.7 2.0 2.2 0.1c 1.4 3.4 2.6 

a) Day 1 is Thursday–Friday, Day 2 is Friday–Saturday, Day 3 is Saturday–Sunday b) na: indoor and outdoor concentrations both below the concentration method detection limit thus, no emission rate w

fewer than two emission rates were calculated then no variations were calculated. 

c) The sample was below the mass method detection limit and the concentration was calculated using one-half the md) Emission rates calculated as the difference of the indoor concentration and Day 1 outdoor concentration multiplied 

e) Precision: Absolute variation is the absolute difference between the min and max emission rates; relative variation 

deviation of the emission rates. 

192
Table 50. Multi-day home concentrations and emission rates for three 24-hour periods for Home 099. 

Home 099 Multi-Day (Winter-North)

 Concentration 

 (ug/m3) 

Emission Rates d

(ug/m3-h) 

Day 1 Indoor a Day 2 Indoor a Day 3 Indoor a Day 1 Outdoor a Day 1 Day 2 Day 3 

Compound ACH = na b ACH = 0.17 ACH = 0.16 Acetaldehyde 57 86 57 1.8 na b 14.7 9.0 Benzene 2.4 3.0 2.8 0.8 na 0.4 0.3 2-Butoxyethanol 6.3 4.7 4.8 0.1c na 0.8 0.8 Caprolactam 0.1 c 0.1 c 0.1 c 0.1c na na na 1,4-Dichlorobenzene 0.3 0.1 0.1 0.1c na 0.0 0.0 Ethylene glycol 14 11 13 0.6c na 1.8 2.0 Formaldehyde 86 94 86 3.1 na 15.9 13.6 Hexanal 30 28 29 0.05c na 4.8 4.7 n-Hexane 3.0 4.4 4.5 0.2 na 0.7 0.7 d-Limonene 24 29 29 0.1c na 5.0 4.7 1-Methyl-2-pyrrolidinone 0.2 c 0.2 c 0.2 c 0.2c na na na Naphthalene 0.6 0.6 0.6 0.1c na 0.1 0.1 Phenol 2.2 2.5 2.4 0.4 na 0.4 0.3 alpha-Pinene 15 15 15 0.1c na 2.6 2.4 Styrene 0.8 1.1 1.1 0.1c na 0.2 0.2 Tetrachloroethene 0.2 0.2 0.2 c 0.2c na 0.008 na Toluene 16 21 19 1.1 na 3.4 2.9 Trichloromethane 4.3 4.5 3.6 0.2c na 0.8 0.6 1,2,4-Trimethylbenzene 4.2 4.3 5.6 0.2 na 0.7 0.9 Vinyl acetate 0.2 c 0.2 c 0.2 c 0.2c na na na m,p-Xylene 9.0 10 12 0.7 na 1.7 1.9 o-Xylene 3.5 3.9 5.0 0.2 na 0.7 0.8 

a) Day 1 is Thursday–Friday, Day 2 is Friday–Saturday, Day 3 is Saturday–Sunday b) na: indoor and outdoor concentrations both below the concentration method detection limit thus, no emission rate wa

fewer than two emission rates were calculated then no variations were calculated. 

c) The sample was below the mass method detection limit and the concentration was calculated using one-half the med) Emission rates calculated as the difference of the indoor concentration and Day 1 outdoor concentration multiplied 

e) Precision: Absolute variation is the absolute difference between the min and max emission rates, relative precision i

deviation of the emission rate. 

193
Table 51. Multi-season home concentration and emission rates over 24-hour periods in three seasons for Home 005. 

Home 005 Multi-season

 Concentration 

(ug/m3) 

Emission Rates d

(ug/m3-h) 

Day 1 Indoor a Day 2 Indoor a Day 3 Indoor a Outdoor a Day 1 Day 2 Day 3 

Compound ACH = 0.16 ACH = 0.15 ACH = 0.27 Acetaldehyde 64 49 21 3.3/ 4.5 / 0.2 9.7 6.6 5.6 Benzene 3.1 7.4 4.9 0.1c / 0.1c / 0.6 0.5 1.1 1.2 2-Butoxyethanol 5.7 11 1.5 0.1c / 0.1c / 0.1c 0.9 1.6 0.4 Caprolactam 0.1c 0.1 c 0.1 c 0.1c / 0.1c / 0.1c na b na na 1,4-Dichlorobenzene 451 13 1.8 0.8 / 0.1c / 0.1c 72 1.9 0.5 Ethylene glycol 20 7.2 0.5 c 0.6c / 0.6c / 0.6c 3.2 1.0 na Formaldehyde 111 72 44 6.6 / 3.0 / 2.3 17 10 11 Hexanal 37 27 15 0.0c / 0.0c / 0.7 5.9 4.0 4.0 n-Hexane 4.5 15 11 0.1c / 0.5 / 0.2c 0.7 2.1 2.8 d-Limonene 9.9 12 21 0.1c / 0.1c / 0.9 1.6 1.8 5.3 1-Methyl-2-pyrrolidinone 0.2 c 0.2 c 0.2 c 0.2c / 0.2c / 0.2c na na na Naphthalene 0.5 0.8 0.4 0.1c / 0.2 / 0.1c 0.1 0.1 0.1 Phenol 6.4 4.4 2.9 0.8 / 0.5 / 0.9 0.9 0.6 0.5 alpha-Pinene 43 38 13 0.1c / 0.1c / 0.1c 6.8 5.6 3.6 Styrene 3.7 3.4 1.3 0.1c / 0.5 / 0.3 0.6 0.4 0.3 Tetrachloroethene 0.2 c 0.2 c 0.2 c 0.2c / 0.2c / 0.2c na na na Toluene 31 64 25 1.3 / 3.2 / 1.8 4.7 9.2 6.0 Trichloromethane 0.2 c 0.2 c 0.2 c 0.2c / 0.2c / 0.2c na na na 1,2,4-Trimethylbenzene 5.3 10 3.7 0.1c / 0.8 / 0.4 0.8 1.4 0.9 Vinyl acetate 0.2 c 0.2 c 0.2 c 0.2c / 0.2c / 0.2c na na na m,p-Xylene 17 38 14 0.8 / 2.3 / 1.1 2.6 5.4 3.5 o-Xylene 6.4 12 4.5 0.1c / 0.7 / 0.3 1.0 1.7 1.1 

a) Day 1 is Summer North, Day 2 is Fall North, Day 3 is Winter North field session b) na: indoor and outdoor concentrations both below the concentration method detection limit thus, no emission rat

fewer than two emission rates were calculated then no variations were calculated. 

c) The sample was below the mass method detection limit and the concentration was calculated using one-half the 

limit. 

d) Emission rate is calculated as the difference of the indoor concentration and the outdoor concentration multiplied e) Variation: Absolute variation is the absolute difference between the min and max emission rates, relative variatio

deviation of the emission rates. 

194
Table 52. Multi-season home concentration and emission rates over 24-hour periods in three seasons for Home 006. 

Home 006 Multi-season

 Concentration 

(ug/m3) 

Emission Rates d

(ug/m3-h) 

Day 1 Indoor a Day 2 Indoor a Day 3 Indoor a Outdoor a Day 1 Day 2 Day 3 

Compound ACH = 0.16 ACH = 0.63 ACH = 0.23 Acetaldehyde 43 14 22 3.3 / 4.5 / 0.2 6.4 6.1 5.0 Benzene 1.0 0.3 1.3 0.1c / 0.1c / 0.6 0.1 0.1 0.2 2-Butoxyethanol 3.7 1.2 7.2 0.1c / 0.1c / 0.1c 0.6 0.7 1.6 Caprolactam 0.1c 0.1 c 0.1 c 0.1c / 0.1c / 0.1c na b na na 1,4-Dichlorobenzene 0.1 c 0.1 c 0.1 c 0.8 / 0.1c / 0.1c -0.1 na na Ethylene glycol 7.0 0.5 c 0.6 c 0.6c / 0.6c / 0.6c 1.0 na na Formaldehyde 61 23 33 6.6 / 3.0 / 2.3 8.8 12.5 7.0 Hexanal 28 2.8 15 0.0c / 0.0c / 0.7 4.4 1.7 3.3 n-Hexane 1.8 1.2 1.3 0.1c / 0.5 / 0.2c 0.3 0.5 0.3 d-Limonene 9.9 1.6 19 0.1c / 0.1c / 0.9 1.6 0.9 4.1 1-Methyl-2-pyrrolidinone 0.2 c 0.2 c 0.2 c 0.2c / 0.2c / 0.2c na na na Naphthalene 0.1 0.3 0.1 0.1c / 0.2 / 0.1c 0.01 0.04 0.01 Phenol 3.7 1.5 1.9 0.8 / 0.5 / 0.9 0.5 0.6 0.2 alpha-Pinene 32 10 11 0.1c / 0.1c / 0.1c 5.1 6.4 2.5 Styrene 1.9 1.6 1.1 0.1c / 0.5 / 0.3 0.3 0.7 0.2 Tetrachloroethene 0.2 c 0.2 c 0.2 c 0.2c / 0.2c / 0.2c na na na Toluene 13 11 11 1.3 / 3.2 / 1.8 1.8 4.7 2.1 Trichloromethane 0.2 c 0.2 c 0.2 c 0.2c / 0.2c / 0.2c na na na 1,2,4-Trimethylbenzene 1.1 1.6 1.6 0.1c / 0.8 / 0.4 0.2 0.5 0.3 Vinyl acetate 0.2 c 0.2 c 0.2 c 0.2c / 0.2c / 0.2c na na na m,p-Xylene 5.1 5.2 4.6 0.8 / 2.3 / 1.1 0.7 1.8 0.8 o-Xylene 1.3 1.6 1.1 0.1c / 0.7 / 0.2 0.2 0.6 0.2 

a) Day 1 is Summer North, Day 2 is Fall North, Day 3 is Winter North field session b) na: indoor and outdoor concentrations both below the concentration method detection limit thus, no emission rate w

fewer than two emission rates were calculated then no variations were calculated. 

c) The sample was below the mass method detection limit and the concentration was calculated using one-half the md) Emission rate is calculated as the difference of the indoor concentration and the outdoor concentration multiplied be) Variation: Absolute variation is the absolute difference between the min and max emission rates, relative variation 

deviation of the emission rates. 

195
Table 53. Multi-season home concentration and emission rates over 24-hour periods in three seasons for Home 013. 

Home 013 Multi-season

 Concentration 

(ug/m3) 

Emission Rates d

(ug/m3-h) 

Day 1 Indoor a Day 2 Indoor a Day 1 Outdoor a Day 2 Outdoor a Day 1 Day 2 Ab

Compound ACH = 0.16 ACH = 0.81 0Acetaldehyde 73 15 1.4 3.1 11 9.9 Benzene 2.2 2.1 0.1c 0.2 0.3 1.5 2-Butoxyethanol 5.2 1.5 0.1c 0.1c 0.8 1.2 Caprolactam 0.1c 0.1 c 0.1c 0.1c na b na 1,4-Dichlorobenzene 0.4 0.4 0.1c 0.2 0.04 0.1 Ethylene glycol 30 7.8 0.6c 0.6c 4.7 5.8 Formaldehyde 100 45 0.7 0.2 16 35 Hexanal 22 1.0 0.0c 0.0c 3.5 0.7 n-Hexane 4.3 4.2 0.1c 0.7 0.7 2.8 d-Limonene 19 2.6 0.1c 0.1c 3.1 2.0 1-Methyl-2-pyrrolidinone 0.6 0.2 c 0.2c 0.2c 0.1 na 0Naphthalene 0.4 0.4 0.1c 0.2 0.1 0.1 0Phenol 3.5 1.1 0.7 0.4 0.4 0.6 alpha-Pinene 58 17 0.1c 0.1c 9.3 13 Styrene 2.8 1.0 0.1c 0.1c 0.4 0.7 Tetrachloroethene 0.2 c 0.2 c 0.2c 0.2c na na Toluene 114 66 0.6 5.0 18 50 Trichloromethane 1.3 0.4 0.2c 0.2c 0.2 0.2 01,2,4-Trimethylbenzene 2.5 3.3 0.1c 1.1 0.4 1.7 Vinyl acetate 0.2 c 0.2 c 0.2c 0.2c na na m,p-Xylene 21 16 0.1c 3.2 3.2 11 o-Xylene 5.8 5.1 0.1c 1.0 0.9 3.3 

a) Day 1 is Summer North, Day 2 is Fall North b) na: indoor and outdoor concentrations both below the concentration method detection limit thus, no emission rate w

fewer than two emission rates were calculated then no variations were calculated. 

c) The sample was below the mass method detection limit and the concentration was calculated using one-half the md) Emission rate is calculated as the difference of the indoor concentration and the outdoor concentration multiplied be) Variation: Absolute variation is the absolute difference between the min and max emission rates, relative variation 

deviation of the emission rates. 

196
Table 54. Multi-season home concentration and emission rates over 24-hour periods in three seasons for Home 019. 

Home 019 Multi-season

 Concentration (ug/m3) Emission Rates (ug/m3-h) d 

Day 1 Indoor a Day 2 Indoor a Day 3 Indoor a Outdoor a Day 1 Day 2 Day 3 

Compound ACH = na ACH = 0.29 ACH = 0.11 Acetaldehyde 2.7 15 22 3.1 / 3.1 / 0.7 na b 3.5 2.4 Benzene 0.1c 0.9 1.7 0.1c / 0.2 / 0.7 na 0.2 0.1 2-Butoxyethanol 0.1c 3.6 9.9 0.1c / 0.1c / 0.1c na 1.0 1.1 Caprolactam 0.1c 0.1c 0.1c 0.1c / 0.1c / 0.1c na na na 1,4-Dichlorobenzene 0.1c 0.1c 0.1 0.1c / 0.2 / 0.1c na -0.03 0.005 Ethylene glycol 0.7c 0.5c 0.6c 0.6c / 0.6c / 0.6c na na na Formaldehyde 4.7 24 36 2.2 / 2.0 / 2.9 na 6.4 3.6 Hexanal 0.1c 1.1 14 0.1c / 0.0c / 0.1c na 0.3 1.6 n-Hexane 0.2c 2.0 1.9 0.2c / 0.7 / 0.2c na 0.4 0.2 d-Limonene 0.2c 3.9 12.7 0.2c / 0.1c / 0.2c na 1.1 1.4 1-Methyl-2-pyrrolidinone 0.7 0.2c 0.2c 0.2c / 0.2c / 0.2c na na na Naphthalene 0.1c 0.3 0.2 0.1c / 0.2 / 0.1c na 0.02 0.02 Phenol 0.9 0.9 2.1 0.5 / 0.4 / 0.4 na 0.1 0.2 alpha-Pinene 0.5 8.8 12 0.1c / 0.1c / 0.1c na 2.5 1.3 Styrene 0.1c 0.3 1.4 0.1c / 0.1c / 0.1c na 0.1 0.1 Tetrachloroethene 0.2c 0.2c 0.7 0.2c / 0.2c / 0.2c na na 0.1 Toluene 1.0 13 12 1.1 / 5.0 / 1.0 na 2.3 1.2 Trichloromethane 0.2c 0.2c 0.4 0.2c / 0.2c / 0.2c na na 0.03 1,2,4-Trimethylbenzene 0.1c 1.8 2.1 0.1c / 1.1 / 0.1 na 0.2 0.2 Vinyl acetate 0.2c 0.2c 0.2c 0.2c / 0.2c / 0.2c na na na m,p-Xylene 0.6c 6.0 6.4 1.5 / 3.2 / 0.6 na 0.8 0.7 o-Xylene 0.1c 1.9 2.3 0.1c / 1.0 / 0.1 na 0.2 0.2 

a) Day 1 is Summer North, Day 2 is Fall North, Day 3 is Winter North field session b) na: indoor and outdoor concentrations both below the concentration method detection limit thus, no emission rate wa

no PFT measurement; na: when fewer than two emission rates were calculated then no variations were calculated. 

c) The sample was below the mass method detection limit and the concentration was calculated using one-half the med) Emission rate is calculated as the difference of the indoor concentration and the outdoor concentration multiplied by e) Variation: Absolute is the absolute difference between the min and max emission rates, relative is the relative standa

rates. 

197
198 

Table 55. Normality test results for formaldehyde and acetaldehyde concentration, air exchange 

rate, indoor and outdoor temperature and relative humidity, composite wood loading, home age, 

and window usage. 

Normality Test Results 

Normalized Variable N Kolmogorov-Smirnov 

D 

p 

Log of the formaldehyde concentration 

(μg/m3

) 105 0.062 >0.15 

Log of the acetaldehyde concentration 

(μg/m3

) 105 0.074 >0.15 

Inverse of the air exchange rate 

(hours) 106 0.085 0.06 

Indoor temperature 

(°F) 103 0.080 0.10 

Indoor relative humidity squared 

(%) 103 0.062 >0.15 

Outdoor temperature 

(°F) 39 0.125 0.12 

Outdoor relative humidity 

(%) 39 0.144 0.06 

Log of composite wood loading 

(ft2

/1,000 ft3) a 107 0.082 0.08 

Home age 

(years) 105 0.060 >0.15 

Square root of non-zero window usage 

(ft2

-hrs) 74 0.094 0.10 

a) Log of composite wood loading (i.e., ft2

 of composite wood per 1,000 ft3 of indoor air volume). 
199 

 Table 56. Group comparisons for formaldehyde and acetaldehyde concentrations. 

Formaldehyde and Acetaldehyde Concentrations Group Comparisons a

North vs. South Non-Mechanical Homes 

Formaldehyde N Mean Standard 

Error 

t Degrees of 

Freedom 

Probability of b 

no Difference 

North 25 3.88 0.11 

South 47 3.40 0.08 3.412 50 0.001 

Acetaldehyde 

North 25 3.36 0.16 

South 47 2.78 0.10 0.996 43 0.32 

Summer vs. Winter Seasonal Repeat Homes 

Formaldehyde N Mean Standard 

Error 

t Degrees of 

Freedom 

Probability of no 

Difference 

Summer 19 3.42 0.23 

Winter 19 3.42 0.11 0.001 36 0.50 

Acetaldehyde 

Summer 19 2.68 0.27 

Winter 19 2.98 0.14 0.996 36 0.16 

Mechanical vs. Non-Mechanical 

Formaldehyde N Mean Standard 

Error 

t Degrees of 

Freedom 

Probability of no 

Difference 

DOA 13 4.17 0.11 

NonMechanical 72 3.57 0.07 

4.710 25 0.0001 

HRV 5 3.08 0.37 

NonMechanical 72 3.57 0.07 

1.287 4 0.27 

Acetaldehyde 

DOA 13 3.63 0.18 

NonMechanical 72 2.98 0.09 

3.167 18 0.005 

HRV 5 2.09 0.34 

NonMechanical 72 2.98 0.09 

2.524 4 0.07 

DOA vs. HRV 

Formaldehyde N Mean Standard 

Error 

t Degrees of 

Freedom 

Probability of no 

Difference 

DOA 13 4.17 0.11 

HRV 5 3.08 0.37 2.811 4 0.05 

Acetaldehyde 

DOA 13 3.63 0.18 

HRV 5 2.09 0.34 3.979 4 0.02 

a) The log of formaldehyde and acetaldehyde concentrations (μg/m3

) were used to normalize the data. 

b) Probability that there is a difference between the two population means, p≤ 0.05, are bolded. 
200 

 Table 57. Group comparison for outdoor air exchange rates and window usage. 

Outdoor Exchange Rate and Window Usage Group Comparisons 

North vs. South; Non-Mechanical Homes 

ACH a N Mean Standard Error t Degrees of 

Freedom 

Probability of d

no Difference 

North 25 4.52 0.48 

South 48 4.15 0.31 0.649 44 0.52 

Window Usage b,c 

North 16 12.7 2.50 

South 38 13.7 1.53 0.322 26 0.75 

Summer vs. Winter; Seasonal Repeat Homes 

ACH a N Mean Standard Error t Degrees of 

Freedom 

Probability of 

no Difference 

Summer 19 3.53 0.65 

Winter 19 4.77 0.57 1.433 36 0.08 

Window Usage b,c 

Summer 7 17.2 4.21 

Winter 7 6.1 2.19 2.341 12 0.02 

Mechanical vs. Non-Mechanical 

ACH a N Mean Standard Error t Degrees of 

Freedom 

Probability of 

no Difference 

DOA 13 5.07 0.80 

Non-Mechanical 73 4.28 0.26 0.931 14 0.37 

HRV 5 1.41 0.48 

Non-Mechanical 73 4.28 0.26 5.248 6 0.002 

Window Usage b,c 

DOA 10 14.6 3.40 

Non-Mechanical 54 13.4 1.30 0.340 11 0.74 

HRV 3 24.24 4.81 

Non-Mechanical 54 13.4 1.30 2.181 2 0.16 

DOA vs. HRV 

ACH a N Mean Standard Error t Degrees of 

Freedom 

Probability of 

no Difference 

DOA 13 5.07 0.80 

HRV 5 1.41 0.48 3.906 6 0.008 

Window Usage b,c 

DOA 10 14.6 3.40 

HRV 3 24.2 4.81 1.636 2 0.24 

a) The inverse of air changes per hour (ach), residence time (hrs), was used to normalize the data. 

b) The square root of window usage (ft2

-hrs) was utilized to normalize the data. 

c) Window usage was measured during the 24-hour air sampling period. 

d) Probability that there is a difference between the two population means, p≤ 0.05, are bolded.
201 

Table 58. Correlations of indoor formaldehyde concentrations with home characteristics and with indoor and 

outdoor environmental conditions. 

Indoor Formaldehyde Concentration Correlations 

 

Pearson Correlation a Spearman Correlation 

 

N 

Correlation 

Coefficient 

Probability of d

No Correlation N 

Correlation 

Coefficient 

Probability of d

No Correlation 

Home Characteristics 

Home age 

(years) 102 -0.155 0.121 102 -0.148 0.137 

Composite wood loading c 

(ft2/1,000 ft3) 104 -0.068 0.495 104 -0.052 0.600 

New cabinetry b 

(Y/N within 6 months) 102 -0.105 0.292 102 -0.120 0.230 

New Furniture b 

(Y/N within 6 months) 103 0.132 0.185 103 0.090 0.365 

Air fresheners present b 

(Y/N during Test Day) 88 -0.063 0.559 88 -0.031 0.775 

 

Outdoor air exchange rate c

(Outdoor air residence time - h) 103 0.496 < 0.0001 103 -0.494 < 0.0001 

Environmental Conditions 

Indoor temperature 

(°F) 100 0.236 0.018 100 0.228 0.022 

Indoor relative humidity c 

(%) 100 0.027 0.791 100 0.125 0.215 

Outdoor temperature 

(°F) 92 0.051 0.628 92 0.091 0.386 

Outdoor relative humidity 

(%) 92 0.164 0.119 92 0.163 0.120 

a) Pearson correlations use the normalized log of the indoor formaldehyde concentrations. 

b) Present or absent responses. 

c) Pearson correlations use the normalized variables: log of composite wood loading (i.e., ft2

 of composite 

wood per 1,000 ft3

 of indoor air volume), inverse of the outdoor air exchange rate (i.e., outdoor air 

residence time), and indoor relative humidity squared. 

d) Probability that there is no correlation, p≤ 0.05, are bolded.
202 

 

Table 59. Correlation of indoor acetaldehyde concentrations with home characteristics and with indoor and 

outdoor environmental conditions. 

Indoor Acetaldehyde Concentration Correlations 

 

Pearson Correlation a Spearman Correlation 

 

N 

Correlation 

Coefficient 

Probability of d

No Correlation N 

Correlation 

Coefficient 

Probability of d 

No Correlation

Home Characteristics 

 

Home age 

(years) 102 -0.091 0.363 102 -0.063 0.527 

Composite wood loading c 

(ft2/1,000 ft3) 104 -0.301 0.002 104 -0.289 0.003

New cabinetry b 

(Y/N within 6 months) 102 -0.009 0.925 102 -0.019 0.853

New Furniture b 

(Y/N within 6 months) 103 0.094 0.343 103 0.089 0.374 

Air fresheners present b 

(Y/N during Test Day) 88 -0.089 0.366 88 -0.084 0.394 

 

Outdoor air exchange rate c

(Outdoor air residence time - h) 103 0.651 < 0.0001 103 -0.710 < 0.0001

Environmental Conditions 

 

Indoor temperature 

(°F) 100 -0.093 0.355 100 -0.091 0.367 

Indoor relative humidity c 

(%) 100 -0.109 0.281 100 0.071 0.484 

Outdoor temperature 

(°F) 92 -0.179 0.089 92 -0.139 0.188 

Outdoor relative humidity 

(%) 92 -0.006 0.954 92 0.022 0.832 

a) Pearson correlations use the normalized log of the indoor formaldehyde concentrations. 

b) Present or absent responses. 

c) Pearson correlations use the normalized variables: log of composite wood loading (i.e., ft2

 of composite 

wood per 1,000 ft3

 of indoor air volume), inverse of the outdoor air exchange rate (i.e., outdoor air residence 

time), and indoor relative humidity squared. 

d) Probability that there is no correlation, p< 0.05, are bolded.
203 

Table 60. Homeowner reported mechanical ventilation system operation and choices-1. 

Mechanical Ventilation System Operation and Choices 

Variable N a % 

Was the operation of the system explained to you when you bought or moved 

into the house? – Answered Yes 24 78 

Do you feel you understand how the system works? – Answered Yes 24 63 

Do you feel you understand how to operate it properly? – Answered Yes 24 83 

How is the system typically used in each season? 

 - Summer Continuous 22 32 

 - Summer Frequent 22 45 

 - Summer Infrequent 22 14 

 - Summer Never 22 9.1 

 - Fall Continuous 21 36 

 - Fall Frequent 21 9.1 

 - Fall Infrequent 21 36 

 - Fall Never 21 14 

 - Winter Continuous 22 18 

 - Winter Frequent 22 23 

 - Winter Infrequent 22 32 

 - Winter Never 22 27 

 - Spring Continuous 22 27 

 - Spring Frequent 22 27 

 - Spring Infrequent 22 36 

 - Spring Never 22 14 

Why did you choose the system? 

 - Came with the house 22 91 

 - A household member has health condition 22 0 

 - Wanted filtered fresh outdoor air 22 5 

 - Affordable cost 22 0 

 - Good reliability 22 5 

 - Reduced energy costs 22 5 

 - Other: 22 5 

a) Number of homes with either a DOA or HRV mechanical outdoor air system and with completed responses 

to questions. Does not include nighttime cooling systems (e.g., WHF, RAD), evaporative cooling systems, or 

window fans. Total of 26 homes with mechanical outdoor air systems (i.e., 17 DOA systems and 9 HRV 

systems). 
204 

Table 61. Homeowner reported mechanical ventilation system operation and choices-2. 

Mechanical Ventilation System Operation and Choices 

Variable N a % 

What do you like about the system? 

 - Fresh air 21 52 

 - Quiet 21 48 

 - Reduced odors 21 14 

 - Reduced energy costs 21 19 

 - Reduced allergies 21 10 

 - Reduced concern about indoor air quality 21 24 

 - Other 21 14 

 - None of the above 21 10 

What don’t you like about the system? 

 - Too noisy 19 26 

 - Too drafty 19 26 

 - Increases odors 19 0 

 - Hard to operate 19 0 

 - Hard to maintain 19 11 

 - Too expensive 19 11 

 - Too quiet 19 0 

 - Not Effective 19 32 

 - Other 19 26 

 - None of the above 19 21 

Please list any additional problems or provide any additional comments 

you have 

 - None 14 64 

 - Do have problems or comments 14 36 

a) Number of homes with either a DOA or HRV mechanical outdoor air system and with completed responses 

to questions. Does not include nighttime cooling systems (e.g., WHF, RAD), evaporative cooling systems, 

or window fans. Total of 26 homes with mechanical outdoor air systems (i.e., 17 DOA systems and 9 HRV 

systems). 
205 

 

Table 62. Homeowner reported IAQ related improvement choices. 

Home IAQ Related Improvement Choices 

Variable N a % 

What special measures or choices have you or the builder taken to improve 

the quality of the air in your home? 

None 105 24 

Upgrade my central air filter 105 25 

High efficiency vacuum cleaner with special features such as filters to trap 

more particles 105 27 

Whole house vacuum 105 6.7 

Low-emission carpets, furniture, paint, or cabinets 105 2.9 

Hard flooring instead of carpeting 105 33 

Carbon monoxide alarm 105 28 

Special kitchen range hood 105 7.6 

Extra exhaust fans 105 2.9 

Whole house ventilation system 105 14 

Other (Specify): 105 11 

 a) Number of homes with completed data. 
206 

4.0 Conclusions and Recommendations 

4.1 Summary 

In setting previous building energy design standards, the Energy Commission had

assumed a certain level of outdoor air ventilation from occupant use of windows and

mechanical devices. However, because homes built within the last few years were

designed to be relatively airtight in order to provide comfort and avoid wasting energy,

concerns were raised that the occupant use of windows, doors, and mechanical ventilation

devices may not provide adequate ventilation with outdoor air, and may contribute to

unacceptable indoor air quality. Information on household ventilation practices of

occupants was needed by the Energy Commission. A 2005 mail survey on occupants’ use

of windows and mechanical ventilation equipment in 1,515 new homes in California

indicated that many homeowners never use their windows for ventilation. From this mail

survey, a concern emerged that the current California residential building codes, where

simply providing openable windows is currently a design option, may result in homes that

do not receive adequate ventilation to control indoor air contaminants to acceptable levels.

For this reason a large field study was initiated to measure window and mechanical

ventilation system usage, outdoor air ventilation rates, sources and concentrations of

indoor air contaminants, and occupant perceptions.  

This project had the following six specific study objectives:

1. Determine how residents use windows, doors, and mechanical ventilation devices

such as exhaust fans and central heating and air‐conditioning systems.

2. Measure and characterize indoor air quality (IAQ), ventilation, and the potential

sources of indoor pollutants.

3. Determine occupant perceptions of, and satisfaction with, the IAQ in their homes.

4. Examine the relationships among home ventilation characteristics, measured and

perceived IAQ, and house and household characteristics.

5. Identify the incentives and barriers that influence people’s use of windows, doors,

and mechanical ventilation devices for adequate air exchange.

6. Identify the incentives and barriers related to people’s purchases and practices that

improve IAQ, such as the use of low‐emitting building materials and improved air

filters.
207 

This study provides, for the first time, statewide, accurate and current information on both

ventilation and IAQ in new California homes. Indoor air quality and household ventilation

practices were obtained from multiple seasons and regions of the state, which will help

characterize the full range of indoor air contaminant exposure in such homes. Measured

levels of ventilation and IAQ were compared to current guidelines and standards.

Information on the use of windows, fans, and central systems collected in this field study

will help establish realistic values for developing state standards for building energy

efficiency.  

The Energy Commission may use the study results as a scientific basis to revise the state’s

building energy efficiency standards in order to provide more healthful, energy‐efficient

homes in California. The study results will improve ARB’s ability to identify current

sources of indoor air contaminants, to assess Californians current exposure to measured

toxic air contaminants, and to recommend effective strategies for reducing indoor air

pollution.

4.2 Conclusions 

Objective 1. Determine how residents use windows, doors, and mechanical ventilation

devices, such as exhaust fans and central heating and air‐conditioning systems.

This study’s field measurements consisted of measurements during both the 24‐hour Test

Day and the preceding week. Generally, the results of measurements during the 24‐hour

Test Day reflected the average observed during the preceding week.

Occupant Use of Windows and Doors for Ventilation. According to the UCB mail survey

preceding this field study, many homeowners never open their windows or doors for

ventilation as a result of their concerns for security/safety, noise, dust, and odor concerns.

In this 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.

  

Occupant Use of Mechanical Exhaust Air Systems. A total of 78% of the homes during the

24‐hour Test Day, and 15% during the entire preceding week, never used the kitchen

exhaust fan. A total of 47% never used the bathroom fans during the 24‐hour Test Day and

27% never used the fans during the entire preceding week. Thus, very few homeowners

utilize their kitchen and bathroom exhaust fans.

Occupant Use of Mechanical Outdoor Air Systems. For the two types of mechanical

outdoor air systems encountered in the field study—ducted outdoor air (DOA) systems

and heat recovery ventilator systems (HRV)—the median Test Day usage was 2.5 hours for
208 

the DOA systems (n=14) and 24 hours for HRV systems (n=8). These data indicate that the

DOA systems, which typically are operated intermittently and in conjunction with the

operation of the FAU fan, operate for only a small portion of the day, while the HRV

systems are typically operated continuously. To ensure adequate delivery of outdoor air to

the home, DOA systems should have a fan cycler, so that even if the thermostat fan switch

does not operate the FAU fan, the fan is operated for a minimum percentage of time. Few

of the homes in this study with operational DOA systems had fan cyclers; just 4 of the 14

homes. Three of these four homes met the 2008 Building Energy Efficiency Standards

operational time requirements for intermittently operated residential outdoor air

mechanical ventilation systems. The 10 operational DOA systems, which do not have fan

cyclers and were operated by the thermostat fan switch in the “auto” mode, do not meet

the 2008 Building Energy Efficiency Standards operational time requirements.

It is important to note that while the thermostat fan switch could be set to the “on”

position, and thus overcome the low operational times of some of these DOA systems, this

would not be a very energy‐efficient means of providing outdoor air to the home. The FAU

fan system is a large fan designed to provide the large supply airflow rates required for

heating or cooling the air in the home and operating the FAU fan continuously would be a

large and costly consumption of electricity. The flow rates of outdoor air required for

ventilating homes is just a fraction (e.g., 5%–10%) of the total supply airflow rate delivered

by the FAU fan. Thus, to ensure adequate and energy efficient delivery of outdoor air to

the home, DOA systems should include a fan cycler with fan cycle times and outdoor

airflow rates set to provide sufficient outdoor air ventilation.

Occupant Use of Mechanical Nighttime Cooling Systems. For the two types of nighttime

cooling systems encountered in the field study—whole house fan (WHF) systems and FAU

Return Air Damper (RAD) systems—the median Test Day usage was 0.7 hours for WHF

systems and 5.3 hours for RAD systems. Use of these systems is confined primarily to the

summer months. Thus, the nighttime cooling systems were operated for relatively few

hours each day, with the RAD systems having longer operating times.

Occupant Use of Forced Air Unit (FAU) Systems. The median Test Day usage for FAUs

was 1.1 hours. A total of 32% of the homes had zero usage of the FAU during the 24‐hour

Test Day, and 11% had zero usage during the entire preceding week. Thus, the FAU

systems were operated for relatively few hours each day. As discussed above, this low

operational time of the FAU fan limits the capability of DOA systems, which depend upon

the operation of the FAU fan to deliver the required outdoor air.

Objective 2. Measure and characterize indoor air quality, ventilation, and the potential

sources of indoor pollutants.
209 

Forced Air Heating/Cooling System Duct Leakage. A total of 86% of the homes had duct

leakage exceeding the California Title 24 maximum of 6%. Thus, new homes in California

have relatively leaky ducts.

Home Building Envelope Air Leakage Area. The median ACH50 for the homes in this study

was 4.8 ach, which compares to a median of 5.2 ach for a group of homes built since 1992,

and 8.6 ach for a group of homes built before 1987. Thus, new Californian homes are

generally being built tighter, but not exceptionally tight, as are found in colder climate

regions.  

Home‐to‐Garage Air Leakage. A total of 65% of the homes did not meet the American

Lung Association guideline for a home‐to‐garage negative pressure of at least  ‐49 pascals

(Pa) when the home is depressurized to  ‐50 Pa with respect to the outdoors. In the three‐

home Pilot Study, tracer gas measurements indicated that between 4% and 11% of the

garage sources entered the home. Thus, a substantial amount of air from attached garages,

which often contain air contaminant sources such as vehicle fuel, exhaust fumes, gasoline‐ 

powered lawn equipment, solvents, oils, paints, and pesticides can enter the indoor air of

the home.

Mechanically Supplied Outdoor Airflow Rates. A total of 64% of DOA systems failed to

meet the requirements of the Energy Commission’s new 2008 Building Energy Efficiency

Standards. The very low outdoor air exchange rates for the DOA systems are a result of the

combination of low outdoor airflow rates and short operating times. HRV systems

performed much better. None of the HRV systems failed to meet the new 2008 Building

Energy Efficiency Standards. These results show that, as encountered in this field study,

HRV systems are a more effective outdoor air supply strategy than the DOA systems.

Intermittent mechanical outdoor air systems, such as DOA systems, cannot perform

equivalently to continuous systems such as HRV systems with respect to controlling the

short‐term exposures to indoor air contaminants, especially if the cycle times are long (e.g.,

greater than two hours). The 2008 Building Energy Efficiency Standards, which were

adopted after this study was completed, require a minimum operation time of one hour

every 12 hours. During extended outdoor air ventilation off‐times, intermittent ventilation

systems allow for air contaminants with indoor sources to increase substantially, as

compared to the increases that would occur with a continuous ventilation system. For

some indoor air contaminants, such as those that cause irritation and/or odor, the effects

are initiated by the immediate exposure to the indoor concentration rather than prolonged

exposure to a concentration over a period of time. For such compounds, intermittent

ventilation systems may not be sufficient for reducing indoor concentrations to acceptable

levels.

Provided that DOA systems are equipped with fan cyclers with fan cycle times and

outdoor airflow rates set to provide the required outdoor air ventilation, there is no reason
210 

that these systems cannot perform equivalently to continuous systems, such as HRV

systems, with respect to controlling the long‐term exposures to indoor air contaminants.  

However, as noted above, intermittent mechanical outdoor air systems, such as DOA

systems, cannot perform equivalently to continuous systems such as HRV systems with

respect to controlling the short‐term exposures to indoor air contaminants.

In addition, the increased outdoor air ventilation for intermittent ventilation systems, as

required by the 2008 Building Energy Efficiency Standards and adopted from ASHRAE

62.2‐2007, does not always provide equivalent long‐term average indoor concentrations,

especially for systems with long cycle times (e.g., 12 hours). The long‐term average air

contaminant concentrations can be substantially higher (e.g., 30%), which is important for

health effects such as cancer and cardiovascular disease. The recent ASHRAE 62.2 2008

Addendum b, which has not been adopted by the California Building Energy Efficiency

Standards, further reduces the outdoor air ventilation rates for intermittent residential

mechanical systems, which translates into higher exposures to indoor air contaminants.

Tracer Gas Measurements of Home Outdoor Air Exchange Rates. The median 24‐hour

measurement was 0.26 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 CBC code 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. The median two‐week measurement of outdoor air exchange rates was generally

close to the 24‐hour median value.

Indoor Air Contaminant Concentrations. This study measured the 24‐hour average

concentration of 22 individual volatile organic compounds, including formaldehyde and

acetaldehyde, and the 1‐hour and 8‐hour maximum average carbon monoxide

concentrations. Also measured were the 24‐hour average concentration of PM2.5 particulate

matter and nitrogen dioxide in the 29 homes of the Winter‐North field session. The only

indoor air contaminants that exceeded recommended non‐cancer and non‐reproductive

toxicity guidelines were formaldehyde and PM2.5. For formaldehyde, 98% of the homes

exceeded the Chronic and 8‐hour RELs of 9  μg/m3, 59% exceeded the ARB indoor air

guideline of 33 μg/m3, and 28% exceeded the OEHHA Acute REL of 55 μg/m3. For PM2.5,

only one home, with an indoor concentration of 36 μg/m3, exceeded the EPA PM2.5 24‐hour

ambient air quality standard of 35  μg/m3. Thus, most new homes had indoor

concentrations of formaldehyde that exceeded recommended guidelines

Volatile Organic Compound Proposition 65 Safe Harbor Levels. For each of the seven

volatile organic compounds with NSRLs for cancer, there were some homes that exceeded

the indoor NSRL concentration. For formaldehyde and acetaldehyde, the percentage of

homes exceeding the NSRL concentration were 100% and 92% respectively.
211 

For the five other VOCs, the percentage of homes exceeding the NSRL concentration

ranged from 8% for trichloromethane (chloroform) and tetrachloroethene to 63% for

benzene. For the two volatile organic compounds with MADLs for reproductive toxicity,

only the benzene MADL was exceeded. A total of 20% of the homes had indoor benzene

concentrations that exceeded the calculated indoor MADL concentration. Thus, a

substantial percentage of new homes have indoor concentrations that exceed

recommended guidelines for cancer and/or reproductive toxicity.

Potential Sources of Indoor Air Contaminants. The primary source of the indoor

concentrations of acetaldehyde and formaldehyde, which were the two air contaminants

that most frequently exceed recommended guidelines, is believed to be composite wood

products. While this study was not able to determine the extent to which

formaldehyde‐based resins were used in the composite wood identified in the homes,

formaldehyde‐based resins are the most common resins used in the production of

composite wood products. The composite wood identified in these homes include

particleboard that was used in 99% of the kitchen and bathroom cabinetry, as well as many

pieces of furniture. Other sources of composite wood include plywood and oriented strand

board in walls, subfloors, and attics, and medium density fiberboard in baseboards,

window shades, interior doors, and window and door trims.

While composite wood products are believed to be the major indoor source of both

formaldehyde and acetaldehyde, other indoor sources of both formaldehyde and

acetaldehyde include combustion sources (e.g., tobacco smoking, cooking fireplaces,

woodstoves), cellulose‐based products such as acoustic ceiling tiles, and paints. Additional

sources of formaldehyde include permanent‐pressed fabrics and insulation made with urea

formaldehyde resins.  

In the few measurements that were made in this study of the emission rates of

formaldehyde from FAUs, it does appear that in the summer, when attic temperatures can

become elevated, that the FAU can transport formaldehyde into the home from either

emissions of formaldehyde from fiberglass soundliner directly into the FAU airstream or

from leakage of attic air with elevated formaldehyde concentrations into the return air of

the FAU.  

Potential sources of some VOCs were identified for homes with elevated indoor VOC

concentrations. The following potential sources of indoor air contaminants are suggested

from a comparison of the occupant activity logs and house characteristics with the indoor

contaminant concentrations and emission rates; 1,4‐dichlorobenzene and naphthalene from

mothballs, d‐limonene from furniture polish and cleaning chemicals, 2‐butoxyethanol from

anti‐bacterial wipes, toluene from air fresheners, and tetrachloroethene from dry‐cleaned

clothes or drapes.
212 

Objective 3. Determine occupant perceptions of, and satisfaction with, the IAQ in their

homes.

A total of 28% of the households reported experiencing one or more of nine physical

symptoms during the previous three weeks that they did not experience when they were

away from the home. The three most frequently reported symptoms were nose/sinus

congestion (19%), allergy symptoms (15%), and headache (13%). The three most frequently

reported thermal comfort perceptions were “too cold” (19%), “too hot” (15%), and “too

stagnant (not enough air movement)” (12%).Thus, a substantial percentage of occupants in

new homes report experiencing physical symptoms or thermal discomfort.  

The most frequently reported location where the homeowners reported mold or mildew

was the bathroom, which was reported by 13% of the homeowners. The percentage of

homeowners reporting mold or mildew at other locations ranged from 0.9% and 2.8%.

Objective 4. Examine the relationships among home ventilation characteristics, measured

and perceived IAQ, and house and household characteristics.

Because of the low number of homeowners reporting IAQ related perceptions and

observations, there are insufficient data to prepare statistically meaningful correlations

with home and IAQ characteristics.

Statistical comparisons were conducted for indoor formaldehyde and acetaldehyde

concentrations, outdoor air exchanges rates, and window usage. Formaldehyde and

acetaldehyde were selected for these analyses, as these were the two air contaminants that

most frequently exceeded recommended indoor concentration guidelines. The group

comparisons consisted of homes in the north versus south regions, homes in summer

versus winter seasons, and homes without mechanical outdoor air systems versus homes

with either pure DOA or pure HRV outdoor air ventilation systems. Because of the small

number of homes in the sample groups and the important seasonal and house‐specific

differences, these comparisons should only be considered as suggestive of differences.

Multivariate analyses need to be conducted to further establish any differences between

the groups.

Formaldehyde concentrations were found to be significantly higher in the following group

comparisons:

• Non‐mechanically ventilated North homes  higher than South homes  

• DOA homes higher than homes without mechanical outdoor air ventilation systems

• DOA homes higher than HRV homes  

Acetaldehyde concentrations were found to be significantly higher in the following group

comparisons:
213 

  

• DOA homes higher than homes without mechanical outdoor air ventilation systems

• DOA homes higher than HRV homes  

Window usage was found to be significantly higher in the following group comparisons:

• Summer homes higher than winter homes  

Outdoor air exchange rates were found to be significantly higher in the following group

comparisons:

• HRV homes higher than homes without mechanical outdoor air ventilation systems

• HRV homes higher than DOA homes  

While the DOA homes generally had lower outdoor air exchange rates, and therefore

higher indoor formaldehyde and acetaldehyde concentrations, as noted above, the poor

performance of the DOA systems is a result of a lack of controls (e.g., fan cyclers) to ensure

adequate fractional on‐time of the FAU fan and a lack of proper sizing and balancing of the

outdoor air duct to ensure sufficient outdoor airflow rate into the system when the FAU

fan was operated.  

Correlation analyses were also prepared for indoor formaldehyde and acetaldehyde

concentrations with six home characteristics and four environmental conditions. For both

formaldehyde and acetaldehyde concentrations, the outdoor air exchange rate was

determined to have a significant inverse correlation. For formaldehyde concentrations,

indoor air temperature was determined to have a significant correlation. These results

indicate that as outdoor air exchange rates decrease or the indoor temperate increases, the

indoor concentrations of formaldehyde increase.

An unexpected result was that there was a negative correlation for composite wood

loading and acetaldehyde indoor concentrations and no significant correlation for

composite wood loading and formaldehyde indoor concentrations, despite the knowledge

that composite wood is an indoor emitter of both formaldehyde and acetaldehyde. This

may be the result of incompleteness of the recovery of this variable in the field from the

visible inspection by the field team. Composite wood could not always be accurately

identified because of coverings by laminate or paint. In addition, the inspectors only

estimated the square footage of composite wood from furniture and cabinetry. Other

substantial amounts of composite wood loading that are common in many of these homes,

but are difficult to quantify in the limited time available to the inspectors, include plywood

and oriented strand board in walls, subfloors, and attics, and medium density fiberboard

in baseboards, window shades, interior doors, and window and door trims. Also, the

inspectors estimated the areas of composite wood without separately distinguishing those

areas that were exposed and those areas that were covered with laminate.
214 

The variance introduced by the impact of outdoor air exchange rates upon the indoor

concentrations of formaldehyde and acetaldehyde may also be contributing to the lack of

an observed significant positive correlation between composite wood loading and the

indoor concentrations of formaldehyde and acetaldehyde.

Our multi‐day measurements in four homes indicated a modest variation in the outdoor

air exchange rates (i.e., an average relative standard deviation of 0.19) and indoor air

contaminant concentrations (i.e., an average relative standard deviation of 0.34). Our multi‐

season measurements in four homes indicated a substantially larger variation in the

outdoor air exchange rates (i.e., an average relative standard deviation of 0.67, which is 3.5

times higher than the multi‐day variation) and indoor air contaminant concentrations (i.e.,

an average relative standard deviation of 0.60, which is 1.8 times higher than the multi‐day

variation).

Thus, the larger variations in the indoor air contaminant concentrations in the multi‐season

homes appears to be the combination of larger variations in the outdoor air exchange rates

and the indoor air contaminant emission rates.

Objective 5. Identify the incentives and barriers that influence people’s use of windows,

doors, and mechanical ventilation devices for adequate air exchange.

Of the homeowners with mechanical outdoor air systems (i.e., DOA or HRV systems, not

nighttime cooling systems, evaporative cooling systems, or window fans):

• 78% stated that the operation of the system was explained to them when they

bought or moved into the house

• 63% responded that they understood how the system works

• 83% stated that they felt that they understood how to operate the system properly

A total of 91% stated they chose the system because it came with the house and the things

they liked most about the system were: “Fresh air” (52%), “Quiet” (48%), and “Reduced

concern about indoor air quality” (26%). The things they liked least about the system were:

“Not effective” (32%), ”Too drafty” (26%), and “Too noisy” (26%).

Objective 6. Identify the incentives and barriers related to people’s purchases and practices

that improve IAQ, such as the use of low‐emitting building materials and improved air

filters.

A total of 24% of the 105 respondents stated “none” in response to the question “What

special measures or choices have you or the builder taken to improve the quality of the air
215 

in your home?”. The four most frequent responses to improvements undertaken were:

“Hard flooring instead of carpeting” (33%), “Carbon monoxide alarm” (28%), “High

efficiency vacuum cleaner with special features such as filters to trap more particles” (27%),

and “Upgrade my central air filter” (25%).

The following summarizes the main conclusions from this study of new single family

homes built in California between 2002–2004.

1. Many homeowners never open their windows or doors especially in the winter

months.

2. New homes in California are built relatively tight, such that natural air infiltration

rates through the building envelope can be very low (e.g., 0.1 ach).

3. In new homes with low outdoor air exchange rates, indoor concentrations of air

contaminants with indoor sources, such as formaldehyde and some other volatile

organic compounds, can become substantially elevated and exceed recommended

exposure guidelines.

4. DOA mechanical outdoor air ventilation systems generally did not perform well as

a result of the low outdoor airflow rates and short operating times. A total of 64% of

DOA systems failed to meet the ASHRAE 62.2‐2007 guideline for residential

ventilation, which is referenced in the Energy Commission’s new 2008 Building

Energy Efficiency Standards.

5. HRV mechanical outdoor air ventilation systems performed much better than DOA

systems. All of HRV systems met the Energy Commission’s new 2008 Building

Energy Efficiency Standards

4.3 Recommendations 

The research team recommends the following, based on the study results:

1. Consideration should be given to installing mechanical outdoor air ventilation

systems in new single‐family residences to provide a dependable and continuous

supply of outdoor air to the residence for the purpose of controlling indoor sources

of air contaminants. The reason for this recommendation is that new homes are

built relatively tight, and many people do not use their windows for outdoor

ventilation, which results in homes with low outdoor air exchange rates and

elevated concentrations of contaminants with indoor sources. To this end, the

Energy Commission adopted the 2008 Building Energy Efficiency Standards, which

will require all new low‐rise residential buildings to have a mechanical outdoor air

ventilation system.
216 

2. Consideration should be given to regulating the emissions of air contaminants from

building materials. The Air Resources Board approved a regulation in 2007 to limit

formaldehyde emissions from composite wood products, “Airborne Toxic Control

Measure to Reduce Formaldehyde Emissions from Composite Wood Products,”

which was approved by the Office of Administrative Law on April 18, 2008, with

an implementation date of January 1, 2009.

3. Given the relatively high frequency that indoor formaldehyde concentrations

exceeded recommended exposure guidelines, and the fact that formaldehyde is a

known human carcinogen, consideration should be given to conducting studies

focused on quantifying the emission rates of formaldehyde from all potential

indoor sources (e.g., building materials, furnishings, consumer products) and based

on this research, developing regulations to reduce indoor formaldehyde emissions.  

4. Outreach to public and professional groups should be increased regarding the need

to reduce indoor formaldehyde concentrations in existing homes by sealing

exposed composite wood surfaces, selecting low‐emission furniture, improving

outdoor air ventilation in the home, and controlling indoor humidity.

5. Multivariate analyses of the data collected in this study should be conducted to

further develop the understanding of the relationships between indoor air

contaminant concentrations (e.g., homes with unusually high or low

concentrations), indoor sources, ventilation, season, and other major sources of

variance. The analyses conducted as part of this report were bivariate analyses,

which established statistical associations but not necessarily cause‐and‐effect

relations, as other factors may be found to be equally or more important when

analyzed together in multivariate analyses. Multivariate analyses of indoor

contaminant concentrations are needed in order to adjust the preliminary estimates

from this study by accounting for home volume, outdoor air exchange rate, and

other major sources of variance. Additional sources of indoor formaldehyde

emissions should be considered, such as the presence of new furniture, duct

leakage for potential attic sources, gas stove or fireplace usage, and the presence of

alkenes in the outdoor ozone season.

6. Construction of a statewide population‐weighted exposure assessment from the

data collected in this field study should be performed to better understand the air

contaminant source and ventilation characteristics of new homes. While the UCB

mail survey sample, upon which this study’s sample selection was largely but not

entirely based, was a stratified random sample, the results in this study have not

been weighted to adjust for that stratification or other selection factors.  
217 

7. Additional studies of indoor air quality and ventilation with diurnal wind speed

and temperature swings should be conducted to examine the significance of

nighttime cooling by natural or mechanical means.  

8. Further studies in additional homes with mechanical outdoor air ventilation

systems should be conducted to confirm the findings identified in this study and

with consideration for other building factors. Both installation and field

performance of the mechanical outdoor air ventilation systems should be

evaluated.  

9. Consideration should be given to revising the 2008 Building Energy Efficiency

Standards and the companion Residential Compliance Manual, which refer to

ASHRAE Standard 62.2‐2007, to fix the error in the tabulated ventilation

effectiveness values for mechanical outdoor air ventilation systems with

intermittent fan operation. The ventilation effectiveness values currently do not

provide intermittent ventilation systems enough additional ventilation to provide

long‐term average concentrations of air contaminants with indoor sources that are

equivalent to those for constant ventilation systems. In addition, consider reducing

the maximum cycle time of intermittent ventilation systems from the current

12‐hour maximum to 1–2 hours so that the short‐term exposures to air

contaminants with indoor sources are not substantially higher than those with

constant ventilation systems.

10. Research should be conducted on exhaust‐only ventilation systems, which were not

encountered in this study. These systems are relatively low in cost and likely to be

used in many homes to meet the new 2008 Building Energy Efficiency Standards

requirements in California. However, exhaust‐only systems may not provide good

distribution of the outdoor air and may increase the infiltration of some air

contaminants as a result of depressurization of the air in the home.

11. Home builders should be educated about the importance of conveying to

homeowners the need for outdoor air ventilation in homes and how the ventilation

systems operate, as well as the importance of designing systems that are easy for

homeowners to maintain. In addition, consideration should be given to creating an

easy‐to‐read short fact sheet that can be distributed to the public regarding

residential ventilation systems and the importance of the operation and

maintenance of these systems to indoor air quality.

12. Research should be conducted to investigate residential exposures to ozone‐

initiated reaction products (e.g., formaldehyde and other aldehydes and ultrafine

particles) that are formed when ozone reacts with contaminants, such as

d‐limonene, which is emitted by many air freshener and cleaning products as well

as by some orange oil termite treatments. The database for this project contains
218 

important information for such research, including d‐limonene concentrations,

outdoor air exchange rates, air cleaners that generate ozone, and formaldehyde and

other aldehyde concentrations. 

4.4 Benefits to California 

This was the first large field study of window use, outdoor air ventilation rates, and indoor

air contaminants in new California homes. The data from this study were immediately

useful for the California Energy Commission in guiding the development of building

design standards that protect indoor air quality and comfort in California homes, and for

the California Air Resources Board to improve exposure assessments of indoor and

outdoor air contaminants. In particular, the Energy Commission used the study results as a

scientific basis to revise the state’s building energy efficiency standards in order to provide

more healthful, energy‐efficient homes in California. The study results will also improve

ARB’s ability to identify current sources of indoor air contaminants, to assess Californians

current exposure to measured toxic air contaminants, and to recommend effective

strategies for reducing indoor air pollution.
219 
220 

5.0 References 

American Lung Association. 2006. American Lung Association Health House Builder

Guidelines. St. Paul, Minnesota. Available at: www.healthhouse.org/build/2007‐

2008HHbuilderguidelines.pdf.

ASHRAE. 2004a. ASHRAE Standard 62.2‐2004, Ventilation and Acceptable Indoor Air

Quality in Low‐Rise Residential Buildings. Atlanta, Georgia: American Society of

Heating, Refrigerating and Air‐Conditioning Engineers, Inc.

ASHRAE. 2004b. ASHRAE Standard 62.1‐2004, Ventilation and Acceptable Indoor Air

Quality. Atlanta, Georgia: American Society of Heating, Refrigerating and Air‐

Conditioning Engineers, Inc.

ASHRAE. 2005. 2005 ASHRAE Handbook – Fundamentals, Chapter 27. Atlanta, Georgia:

American Society of Heating, Refrigerating and Air‐Conditioning Engineers, Inc.

ASHRAE. 2007. ASHRAE Standard 62.2‐2007, Ventilation and Acceptable Indoor Air

Quality in Low‐Rise Residential Buildings. Atlanta, Georgia: American Society of

Heating, Refrigerating and Air‐Conditioning Engineers, Inc.

ASHRAE. 2008. ASHRAE Standard 62.2‐2008, Ventilation and Acceptable Indoor Air

Quality in Low‐Rise Residential Buildings  ‐  Addenda a, b, c, and k. Atlanta,

Georgia: American Society of Heating, Refrigerating and Air‐Conditioning

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Ventilation Practices and Household Characteristics in New California Homes. California
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Conference, Research Triangle Park, North Carolina. AWMA. July 21, 2003.
225 
226 

6.0 Glossary of Terms, Abbreviations, and Symbols 

Afloor Floor Area

ACH Air Changes per Hour

ACH50 Air Changes per Hour at 50 pascals

ALA American Lung Association

APT Automated Pressure Testing

ARB California Air Resources Board

ASHRAE American Society of Heating, Refrigeration, and Air Conditioning Engineers

ASTM American Society for Testing and Materials 

ATCM Airborne Toxics Control Measure

Ci Indoor Concentration

Ci-pdch Concentration of PDCH garage tracer in the home Indoor air

Co Outdoor Concentration

Cra Concentration in the FAU Return Air at the return air inlet

Csa Concentration in the FAU Supply Air at the supply air diffuser

CATS Capillary Adsorption Tube Sampler 

CBC California Building Code

CFI Central Fan Integrated mechanical ventilation system (same as DOA)

CO Carbon Monoxide

CO2 Carbon Dioxide

DNPH Dinitrophenylhydrazine

DOA Ducted Outdoor Air mechanical ventilation system (same as CFI)

DOE Department of Energy

E Emission Rate

Efau Emission rate from the FAU

Eg-pdch emission of PDCH garage tracer into garage

Eh/g Percentage of Garage Emissions entering Home

Ehome Emission rate into the home

Ev Emission rate into home-volume specific

EC Evaporative Cooling mechanical ventilation system

EPA Environmental Protection Agency

EqLA Equivalent Leakage Area 

FAU Forced Air Unit

HEPA High Efficiency Particulate Air Filter

HRV Heat Recovery Ventilator mechanical ventilation system 

HVAC Heating, Ventilating, and Air Conditioning

HWPW Hardwood Plywood 

IAQ Indoor Air Quality

IARC International Agency for Research on Cancer
227 

K-S Kolmogorov-Smirnov 

LBNL Lawrence Berkeley National laboratory

MADL Maximum Allowable Dose Levels

MDF Medium Density Fiberboard

MDL Method Detection Limit

MERV Minimum Efficiency Reporting Value

MMDL Method Mass Detection Limit

MADL Maximum Allowable Dose Levels 

MVDL Method Volume Detection Limit

Nbr Number of Bedrooms

NDIR Non-Dispersive Infrared Spectrophotometry

NIOSH National Institute for Occupational Safety and Health

NIST National Institute of Standards and technology

NSRL No Significant Risk Levels 

OEHHA Office of Environmental Health Hazard Assessment

OSB Oriented Strand Board 

Pa Pascals

PB Particleboard

PFT Perfluorocarbon Tracer

PIER Public Interest Energy Research

PM2.5 Particulate Matter Less Than 2.5 μm Aerodynamic Diameter

p-PDCH para-Perfluorodimethylcyclohexane

PMCH Perfluoromethylcyclohexane

PPB Parts per Million by volume

PPM Parts per Billion by volume

Qf Required intermittent mechanical outdoor airflow rate

Qfau Airflow rate of the FAU

Qr Required continuous mechanical outdoor airflow rate

QA/QC Quality Assurance / Quality Control Plan 

RD&D Research, Development, and Demonstration

RAD Return Air Damper nighttime cooling ventilation system 

REL Reference Exposure Level

SIP Structural Insulated Panels

SLA Specific Leakage Area

SOP Standard Operating Procedures

UCB University of California at Berkeley

V Volume of indoor air

VOC Volatile Organic Compound

WDF Window Fan

WHF Whole House Fan nighttime cooling ventilation system 
228 

ε Ventilation effectiveness factor for intermittent ventilation

f Fractional on-time of intermittent ventilation system

λ pft Outdoor air exchange rate determined from PFT measurement
229 
A-i 

APPENDIX A 

Pilot Study Report 
A-ii 
A-iii 

VENTILATION AND INDOOR AIR QUALITY 

IN NEW HOMES 

PILOT STUDY REPORT 

Submitted in Response to 

California Air Resources Board Research Division 

Agreement #04-310 

Submitted by: 

Indoor Environmental Engineering 

1448 Pine Street, Suite 103 

San Francisco, CA 94109 

April 12, 2006 

Principal Investigator 

Francis J. Offermann III PE CIH 

President 

Indoor Environmental Engineering 

San Francisco, CA 

Phone: 415-567-7700 

Fax: 415-567-7763 
A-iv 

Legal Notice 

This report was prepared as a result of work sponsored by the Air Resources Board (ARB) and the 

California Energy Commission (Commission, Energy Commission). It does not necessarily represent the 

views of ARB, the Commission, their employees, or the State of California. The mention of commercial 

products, their source, or their use in connection with reported material herein is not to be construed as 

actual or implied endorsement of such products. The ARB, the Commission, the State of California, its 

employees, contractors, and subcontractors make no warranty, express or implied, and assume no legal 

liability for the information in this report; nor does any party represent that the use of this information 

will not infringe upon the privately owned rights. This report has not been approved or disapproved by 

the ARB or the Commission, nor has the ARB or the Commission passed upon the accuracy or adequacy 

of this information in this report. 
A-v 

Acknowledgements 

We would like to thank the members of the field team subcontractors, Davis Energy Associates and 

Amaro Construction, for their work. We would also like to thank the laboratories: Berkeley Analytical 

Associates for volatile organic compounds, DataChem for nitrogen dioxide, Brookhaven National 

Laboratory for the PFT analyses, and Chester LabNet for PM 2.5. In addition we would like to thank Iain 

Walker of Lawrence Berkeley National Laboratory for assisting with the Delta-Q duct leakage analyses 

and Collin Olson of the Energy Conservatory for assisting with the garage-home zone pressure 

diagnostics. 

This report was submitted in fulfillment of ARB Agreement #04-310 by Indoor Environmental 

Engineering under the sponsorship of the California Air Resources Board and the California Energy 

Commission. 
A-vi 
A-vii 

TABLE OF CONTENTS 

Section Page

INTRODUCTION............................................................................. 1 

HOME SELECTION/RECRUITMENT................................................. 3 

FIELD MEASUREMENTS AND METHODS.......................................... 4

FIELD WORK TEAMS AND WORK ASSIGNMENTS................................ 5 

HOME & SITE CHARACTERISTICS COLLECTION................................. 5 

HOMEOWNER SOURCE ACTIVITY.................................................... 7 

HOMEOWNER IAQ/VENTILATION PERCEPTIONS & DECISION FACTORS 7 

VENTILATION MEASUREMENTS...................................................... 8 

Occupant Use of Windows and Doors for Ventilation........................... 9 

Exhaust Fans........................................................................... 9 

Forced Air Heating/Cooling System................................................ 11 

Mechanically Supplied Outdoor Air Flow Rates.................................. 11 

Forced Air Heating/Cooling System Duct Leakage.............................. 12 

Home Building Envelope Air Leakage Area....................................... 12 

Home to Garage Air Leakage ....................................................... 13 

Tracer Gas Measurements of Home Outdoor Air Exchange Rate............... 13 

Tracer Gas Measurements of Garage Air Contaminants Entering the Home.. 14 

INDOOR AIR QUALITY MEASUREMENTS............................................. 15 

Integrated Time Averaged IAQ Measurements (24 hour)

• Volatile Organic Compounds........................................................ 17 

• Formaldehyde and Acetaldehyde................................................... 17 

• Nitrogen Dioxide..................................................................... 18 

• Particulate Matter (PM2.5)........................................................... 18 

Real-Time IAQ Measurements

• Carbon Monoxide.................................................................... 18 

• Carbon Dioxide...................................................................... 19 

• Temperature and Relative Humidity.............................................. 19 

QUALITY ASSURANCE AND QUALITY CONTROL................................... 20 

DATA MANAGEMENT...................................................................... 20

RESULTS AND DISCUSSION............................................................. 21 
A-viii 

HOME SELECTION/RECRUITMENT..................................................... 21 

HOME & SITE CHARACTERISTICS COLLECTION................................... 22 

HOMEOWNER SOURCE ACTIVITY...................................................... 23 

HOMEOWNER IAQ/VENTILATION PERCEPTIONS & DECISION FACTORS 23 

VENTILATION MEASUREMENTS........................................................ 23 

Occupant Use of Windows and Doors for Ventilation............................ 23 

Exhaust Fans............................................................................ 24 

Forced Air Heating/Cooling System................................................. 25 

Mechanically Supplied Outdoor Air Flow Rates.................................... 25 

Forced Air Heating/Cooling System Duct Leakage................................ 25 

Home Building Envelope Air Leakage Area........................................ 26 

Home to Garage Air Leakage ......................................................... 26 

Tracer Gas Measurements of Home Outdoor Air Exchange Rate................. 27 

Tracer Gas Measurements of Garage Air Contaminants Entering the Home... 27 

Ventilation Calculations................................................................ 27 

INDOOR AIR QUALITY MEASUREMENTS............................................. 28 

Integrated Time Averaged IAQ Measurements (24 hour)

• Volatile Organic Compounds........................................................ 28 

• Formaldehyde and Acetaldehyde................................................... 29 

• Nitrogen Dioxide...................................................................... 30 

• Particulate Matter (PM2.5)............................................................ 30 

Real-Time IAQ Measurements

• Carbon Monoxide..................................................................... 30 

• Carbon Dioxide........................................................................ 30 

• Temperature and Relative Humidity................................................ 31 

QUALITY ASSURANCE AND QUALITY CONTROL....................................31 

DIFFICULTIES ENCOUNTERED IN THE PILOT STUDY............................. 34 

CONCLUSIONS................................................................................. 36 

TABLES.......................................................................................... 37 

FIGURES........................................................................................ 69 

APPENDICES................................................................................ . 82 
A-1

INTRODUCTION 

This report contains a description of the recruiting, field measurement methods, laboratory analyses, and 

data analyses used in a three-home pilot study which was recently conducted as part of the research 

project “Ventilation and Indoor Air Quality in New Homes,” which is sponsored by the California Air 

Resources Board and the California Energy Commission. 

This study’s primary goal is to obtain information on ventilation characteristics and indoor air quality 

(IAQ) in new single-family detached homes in California through a field study. 

Concerns have been raised regarding whether households in new California homes use windows, doors, 

exhaust fans, and other mechanical ventilation devices enough to remove indoor air pollutants and 

excess moisture. Various building materials, heating and cooking appliances, and other products used in 

new homes can emit substantial amounts of formaldehyde, other toxic air contaminants, combustion 

pollutants, and/or water vapor. Building practices and building standards for energy efficiency have led 

to more tightly sealed homes that rely on occupants to open windows for ventilation. However, there is 

very little information on current ventilation practices, IAQ, or indoor pollutant sources in new 

California homes. 

We plan to study 100 new, single-family homes from two climatic regions of the State, including a 

subset of 12 homes with mechanical fresh-air ventilation systems. The field teams will measure and 

record ventilation characteristics, indoor pollutant concentrations, residents’ ventilation practices, 

residents’ IAQ perceptions, and residents’ decision factors for ventilation and IAQ-related actions. 

Measurements of indoor and outdoor air quality and ventilation parameters will be made in the summer 

and winter. Indoor air levels of volatile organic compounds, aldehydes, PM2.5, and nitrogen dioxide will 

be measured over one day. Home ventilation will be determined through tracer gas measurements, 

building leakage measurements, window use measurement, air flow measurements of fan systems, and 

occupant diaries. Some homes will have additional measurements, including spring or fall 

measurements, multiple-day sampling (especially for weekday-weekend differences), and formaldehyde 

sampling in the attic and heating, ventilating, and air-conditioning (HVAC) systems. 
A-2

This project has the following specific objectives: 

1. Determine how residents use windows, doors, and mechanical ventilation devices, such as 

exhaust fans and central heating and air-conditioning systems. 

2. Measure and characterize indoor air quality (IAQ), ventilation, and the potential sources of 

indoor pollutants. 

3. Determine occupant perceptions of, and satisfaction with, the IAQ in their homes. 

4. Examine the relationships among home ventilation characteristics, measured and perceived 

IAQ, and house and household characteristics. 

5. Identify the incentives and barriers that influence people’s use of windows, doors, and 

mechanical ventilation devices for adequate air exchange. 

6. Identify the incentives and barriers related to people’s purchases and practices that improve 

IAQ, such as the use of low-emitting building materials and improved air filters. 

This study will provide, for the first time, representative, accurate and current information on both 

ventilation and IAQ in new California homes. IAQ and household ventilation practices will be obtained 

from multiple seasons and regions of the State, which will help characterize the full range of indoor 

pollutant exposure in such homes. Measured levels of ventilation and IAQ will be compared to current 

guidelines and standards. Information on the use of windows, fans, and central systems will help 

establish realistic values for developing State standards for building energy efficiency. 

The Commission will use the study results as a scientific basis to revise the State’s building energy 

efficiency standards in order to provide more healthful, energy-efficient homes in California. The study 

results will improve ARB’s ability to identify current sources of indoor air pollutants, to assess 

Californians current exposure to measured toxic air contaminants, and to recommend effective strategies 

for reducing indoor air pollution. 
A-3

Indoor Environmental Engineering was awarded this project in June 2005 and has completed the 

preparations of the equipment, protocols, questionnaires, home characteristics checklists, and detailed 

protocols for the field measurements, data management, and quality control. 

This report describes the results of the three-home pilot study that was conducted in 

November/December 2005. The focus of this report is the presentation and evaluation of the 

measurement methods and data analyses. Correlations between house characteristics and ventilation and 

indoor air quality parameters, while not included in this pilot report which contains data from just three 

homes, will be an important discussion contained in the final report of the 100-home study. Based upon 

the results of the pilot study presented in this report, feedback from the field teams, the Science 

Advisory Committee, the ARB, and the Commission will be collected and reviewed to refine the field 

protocols and data analyses for the main field study. 

The main field study is scheduled for the summer of 2006 and the winter of 2007. A final report is 

expected in late 2007. 

HOME SELECTION/RECRUITMENT 

To recruit the three homes for the pilot study we utilized the database from the UC Berkeley Ventilation 

Practices and Indoor Air quality Survey that was administered in 2004–2005. This mail survey to 4,972 

new single family detached homeowners, resulted in 1,448 completed questionnaires (i.e., 31.2% 

response rate) of which 971 respondents (i.e., 67.1 % of the respondents) indicated their willingness to 

participate in the second part of the study involving measurements of ventilation and indoor air quality 

in their homes. In addition to this sample of 971 homeowners we purchased an additional sample of new 

single-family detached homeowners from the neighboring areas. 

From this database we mailed out recruitment letters. This letter asks for the homeowners that are still 

interested in participating in the field study to call the project participant recruiters at their toll-free 

number. This letter also offers a $100 incentive to those homeowners that participate in the field study 

which is in addition to providing the estimated $7,000 of indoor air quality testing free of charge. 
A-4

Upon making contact with the interested homeowners we administered a recruiting script and collected 

information on the home, occupancy, and ventilation systems and described the details of the three field 

visits required by the field teams. In addition, if the homeowners were interested in participating 

following the description of the three field visits and answering any of their questions, this script 

collected information regarding the participants preferences for dates and times of the three field visits. 

In addition, three time periods were offered with the understanding that the same time periods would be 

required for each of the three field visits. These were: 

Time Period 1: 9:00 AM to 12:00 PM 

Time Period 2: 1:00 PM to 4:00 PM 

Time Period 3: 4:00 PM to 7:00 PM 

The homeowners were informed by the recruiters that those that indicated flexibility in the field visit 

dates and times would have a much higher probability of being selected. 

Upon completion of the administration of these recruiting scripts to interested homeowners, we then 

selected the homes for the field study within the constraints of the field study design, which required 

one-half of the homes to be in Northern California climate regions, one-half to be in Southern California 

climate regions, and a minimum of 20 homes to have mechanical outdoor air ventilation. 

Also, to minimize the number of outdoor air contaminant measurement locations, and to provide for 

reasonable logistics, the study design for this research project also required testing clusters of one to 

three homes (e.g., within the same zip code or within one to two miles). 

FIELD MEASUREMENTS AND METHODS 

The following is a description of the field measurements and methods utilized in the three-home pilot 

study. 
A-5

FIELD WORK TEAMS AND WORK ASSIGNMENTS 

The field work is divided amongst three field teams, each consisting of two field technicians. All field 

work will be conducted according to the specific standard operating procedures (SOPs) developed for 

each of the three field teams. These SOPs are detailed in our October 10, 2005, Quality Assurance / 

Quality Control Plan (QA/QC Plan). 

Field Team 1 will install perfluorocarbon tracer (PFT) sources, data loggers on windows and fans, 

administer the occupant fan and window logs and the Indoor Contaminant Source Activity Sheet and 

Occupant Questionnaire one week in advance of the field work performed by Field teams 2 and 3. The 

SOPs for Field Team 1, along with the associated data entry forms and checklists, can be found in 

Appendix A of the QA/QC Plan. 

Field Team 2 will follow Field Team 1, 7–10 days later to allow for the PFT sources to equilibrate, and 

install and start the air contaminant sampling equipment at indoor and outdoor locations, install and start 

the PFT samplers, collect information on home construction characteristics, and inventory indoor air 

contaminant sources. The SOPs for Field Team 2, along with the associated data entry forms and 

checklists, can be found in Appendix B of the QA/QC Plan. 

Field Team 3 will follow Field Team 2 (22–26 hours later). This field team is responsible for the 

removal of the air sampling equipment, the PFT samplers, and window/door and fan logs and loggers, 

and collecting detailed information on building air leakage, duct air leakage, and ventilation system air 

flow rates. The SOPs for Field Team 3, along with the associated data entry forms and checklists, can be 

found in Appendix C of the QA/QC Plan. 

HOME AND SITE CHARACTERISTICS COLLECTION 

Characteristics of each home were collected using forms that were filled out by the field team members 

during the home inspections. The forms utilized to record these data are the Home Characteristics Form 

1, PFT Form, Home Floor Plan Sketch or floor plan provided by the homeowner, Home Characteristics 

Form 2, and Room Tally Form, which are in the Team 1 and Team 2 SOPs. A selection of the home 
A-6

characteristics that were recorded have been included in this report based upon their relevance to indoor 

air quality and ventilation. 

General Characteristics

• number of occupants 

• number of stories 

• foundation type 

• conditioned floor area and volume and envelope area 

• windows and doors 

Mechanical Characteristics

• heating/cooling system - general description, location, filter type, duct locations 

• mechanically supplied outdoor air system 

• exhaust fans - number and controls 

• appliances - fuel type, venting, location 

• other ventilation/conditioning equipment - use and typical usage pattern 

• air cleaning devices - model number and how used 

 

Site Characteristics

• outdoor air contaminant sources (e.g., busy roadways, nearby gasoline stations, etc.) 

• site drainage conditions 

• site shielding 

Home Contaminant Source Characteristics

• vacuum system - type and typical usage frequency 

• number of occupants and pets 

• mechanical system fuels 

• composite pressed wood 

• carpeting 

• moisture staining/damage 
A-7

We calculated the conditioned floor area, envelope area, and air volume from on site dimension 

measurements. We were able to obtain floor plans from the developers homeowner packages for each of 

the three pilot homes. Field Team 1 collected on-site measurements of the home exterior dimensions, 

indoor ceiling heights, and selected indoor wall dimensions. These dimensions were then used to 

calculate a scale factor for the floor plans, and then this scale factor was used to calculate the 

conditioned floor areas, envelope areas and air volumes on a room-by-room basis and for the entire 

home. 

HOMEOWNER SOURCE ACTIVITY 

Homeowner activities potentially related to release of contaminants into the indoor air were recorded by 

the homeowner during the 24-hour IAQ measurement period using a indoor source activity log which 

was administered by Team 1 and collected by Team 3. The form utilized to record these data is the 

Home Owner Questionnaire, which is in the Team 1 SOP. The homeowner was asked to record the 

activity start times, duration, and activity type (e.g., cooking, cleaning, candle burning, dinner parties, 

barbecuing, leaf blowing, grass cutting) starting at 7:00 PM on the day before the 24-hour IAQ 

measurements and ending when Team 3 retrieved the forms. This results in up to a 48-hour time period 

when the homeowner records their source activities, with the first 12–20 hours being practice and the 

last 28–36 hours being the time period during which the 24-hour IAQ measurements will be collected. 

HOMEOWNER IAQ/VENTILATION PERCEPTIONS AND DECISION FACTORS 

Perceptions and decision factors regarding IAQ and ventilation were collected using a questionnaire that 

was administered to the homeowner by Team 1 and collected by Team 3. The form utilized to record 

these data is the Home Owner Questionnaire, which is in the Team 1 SOP. The questionnaire was 

adapted from the one in the UCB mail survey study. This questionnaire collected information regarding 

the homeowners’ perceptions activities that may effect IAQ in the home and key decision factors 

regarding home ventilation and purchasing ventilating equipment, building materials, air cleaners, and 

other products and materials that effect IAQ. The requested recall period was three weeks. 
A-8

VENTILATION MEASUREMENTS 

The approach for measuring ventilation applies a combination of one-time tests and weekly monitoring. 

Collection methods are summarized in this section for the following ventilation parameters: 

• windows and doors 

• mechanical exhaust fans and appliances 

• forced air heating/cooling system 

• mechanically supplied outdoor air system 

• other ventilation fans 

• forced air heating/cooling system duct leakage 

• building leakage area 

• infiltration parameters

The use of select windows and door and operation of mechanical systems were monitored for an 

approximate one-week period by occupant logs and/or HOBO data logging instruments. Below are listed 

the measurement parameter and corresponding type of log device: 

Parameter Device Sampling Frequency 

Window/Door Status HOBO, state logger, two most commonly used. 

Occupant logs, all that are used. 

Event, time recorded 

Bathroom, Laundry Exhaust 

Fan Status 

HOBO, ac-field logger, up to four most 

commonly used. Occupant logs, all others. 

Event, time recorded 

Cloths Drier Status HOBO, vibration or ac-field logger. Event, time recorded 

Range Hood Exhaust Fan 

Status 

Occupant log Event, time recorded 

HVAC System Fan Status HOBO, ac-field logger, each furnace Event, time recorded 

Outdoor Air Ventilation 

System Status 

HOBO, motor loggers, System fan status, 

outdoor air damper status, or ventilation system 

fan status (depending on system type). 

Event, time recorded 

Indoor-Outdoor Temp/RH HOBO, Temp/RH, 1 Indoor Temp/RH at the 

thermostat for every home and one outdoor 

Temp/RH for every ten house regional group. 

Quantity, 15 minute 

intervals 

The following is a description of the methods used to collect data on each of the ventilation parameters. 
A-9

Occupant Use of Windows and Doors for Ventilation. Homeowners were asked to identify the two most 

used windows or doors for natural ventilation. HOBO state loggers were taped to these windows (or 

doors) to capture the time and duration that the window or door was opened. The amount of time that 

windows were open and the opening areas are reported in 24-hour time periods counting back from the 

time that Team 3 entered the home and stopped the IAQ contaminant and PFT measurements. The 

occupants were asked which windows and doors, if any, they use for ventilation. Occupant logs and a 

writing utensil were placed on the glass or panel near where the window or door was opened The 

occupants used these to record the time, duration, and distance of the window or door opening. The 

windows or doors that were verified as never being used were not equipped with window occupant logs. 

The Window/Door Logs and Instructions Sheets are in the Team 1 SOP. 

Measurements of all window and door openings were collected by Team 1. The width and length were 

noted by opening each window or door and using a tape measure. The forms utilized to record these data 

are the Window/Door Log Form, which is in the Team 1 SOP. 

The location, ID and installation/removal times of all loggers were recorded in the Logger Form, which 

is in the Team 1 SOP. 

Exhaust Fans. Data loggers and/or written logs were deployed for all exhaust fans, including bathroom, 

laundry, clothes dryer, and kitchen exhaust fans. 

For bathroom exhaust fans, two HOBO ac-field loggers were placed above the exhaust grille and just 

beneath the motors on the two bathroom fans that the occupants identified as used the most. For these 

bathroom exhaust fans with HOBO loggers, no occupant written logs were installed. The reason for this 

was to minimize the effort required by the homeowners, a concern that was identified during the home 

practice exercise by the beleaguered homeowner. For any additional bathroom exhaust fans beyond the 

two exhaust fans equipped with data loggers, occupant logs and a writing utensil were placed near the 

fan switch for the occupants to log the usage of the fans. 

For clothes dryer exhaust fans, our plan was to position the ac-field or electromagnetic field (EMF) 

HOBO loggers directly on the power cords of the dryer considering electrical dryer fields should be 
A-10

easily captured. Modified extension chords that allowed the HOBO loggers to capture the ac-field by 

isolating one of the live wires and taping the logger directly on the wire to be used. Due to difficulty 

experienced during the home practice exercise with compatibility of the modified extension cords with 

the various outlet/plug configurations for clothes dryers, an alternate method utilizing a vibration HOBO 

logger installed on the back of the control panel was use for Pilot Homes P1 and P2 and an ac-field 

logger applied behind the plate of the appliance outlet, inside the outlet box, was used for Pilot Home 

P3. 

For kitchen exhaust fans, our original plan was to utilize a HOBO ac-field logger placed above the 

exhaust grille and just beneath the motor. However, during the home practice exercise we experienced 

difficulty in receiving an EMF signal from the exhaust fan motor. Apparently, the fan motors for kitchen 

exhaust fans are not close enough to the exhaust grille and are shielded by metal partitions to allow for a 

strong enough EMF signal to be sensed by the loggers. Also, since kitchen exhaust fans typically have 

multiple fan speeds, and since the HOBO ac-field loggers can only sense operation and not fan speed, 

our original plans also included installation of an occupant log sheet to log the time, duration, and fan 

speed associated with the usage of kitchen exhaust fans. Based upon the above experienced difficulties 

with HOBO ac-field loggers for logging kitchen exhaust fan operation, we decided for the pilot study, 

and most likely the main field study, to just utilize occupant logs for kitchen fans. 

All exhaust fan airflow rates were measured in the home (e.g., bathroom, laundry room, and kitchen 

hood fans) using a balometer flow hood. Due to difficulty experienced during the practice home exercise 

accessing an acceptable location to measure the dryer exhaust airflow rate, the flow rate was determined 

by collecting the dryer make and model information onsite and obtaining the information from the 

manufacturer. While onsite the number of bends (e.g., 90°

, 45°) and the length of the ductwork were 

estimated. The manufacturers airflow rate and duct characteristics were then used to calculate the actual 

dryer airflow rate. 

The forms utilized to record these data are the Fan Logs and Instruction Sheets, Exhaust / Outdoor Air 

Fan Log Form, Logger Form, and the Fan Flow Form, which are in the Team 1 and Team 3 SOPs. 
A-11

Forced Air Heating/Cooling System. HOBO ac-field loggers were used to measure forced air 

heating/cooling system operation. They were installed magnetically to the end of the furnace blower 

motor. The access panel to the furnace was removed in all cases to reach the optimum spot on the motor 

for logging. 

Airflow rates were measured at the return grill(s) using a balometer flow hood equipped with a 2 x 4 

foot capture hood. One of the homes (i.e., P3) is a single-fan dual-zoned system with two fan speeds. 

The flow rate for this system was measured with one thermostat in the ”fan-on” position and again with 

both thermostats in the ”fan-on” position. 

The forms utilized to record these data are the Logger Form and the Building Ventilation Form, which 

are in the Team 1 and Team 3 SOPs. 

Mechanically Supplied Outdoor Air Flow Rates. Two types of mechanically supplied outdoor air 

systems were encountered in the pilot study homes. The two types can be classified as a mechanical 

exhaust and supply system with a heat/energy recovery ventilator (HRV) system and a night ventilation 

cooling system. The HRV systems in these homes operate continuously, while the night ventilation 

cooling systems operate intermittently. Pilot Home P1 had both an HRV and night ventilation system, 

Pilot Home P2 only had an HRV system, and Pilot Home P3 had no mechanical outdoor air system. The 

approach used to measure airflow rates for both types of systems was a balometer flow hood. The HRV 

flow rates were measured at the single outdoor air supply air diffuser as well as at the two exhaust air 

grilles (e.g., laundry room and master bathroom). The night ventilation cooling system in Pilot Home P1 

is integrated with the forced air system. A motorized damper switches the air drawn into the forced air 

system between home air (i.e., from the central return air grille) and outdoors air (i.e., from an outdoor 

air intake on the roof). 

The ventilation damper for the night ventilation cooling system was monitored using a relay and HOBO 

state logger combination. We used magnetic tape or a zip-tie to secure the logger with relay to the 

damper and fastened lead wires with alligator clips to the damper 24 VDC motor wiring connections. 

The HRVs operate continuously and were not logged with a HOBO logger of occupant log. 
A-12

The forms utilized to record these data were the Logger Form, Exhaust/Outdoor Air Fan Rate Form, and 

the Building Ventilation Form, which are in the Team 1 and Team 3 SOPs. 

Forced Air Heating/Cooling System Duct Leakage. For the pilot study we used two different methods to 

measure duct leakage of the forced air system. Testing for both methods was conducted in accordance 

with ASTM E1554-03, Standard Test Method for Determining External Air Leakage of Air Distribution 

Systems by Fan Pressurization. 

The first method uses a fan flow meter device (e.g., DuctBlaster) attached to the return air grill to 

pressurize the ducts to 25 pascals (Pa). Figure 4 is a photograph of the DuctBlaster installed at the forced 

air heating/cooling system return air inlet of home P2. In addition, we conducted three different 

variations of this duct pressurization method. The first variation, and standard application of this method 

is to pressurize the ducts to 25 Pa while the supply ducts are sealed. The second variation we employed 

is to pressurize the ducts to 25 Pa while the house is maintained at a positive 25 Pa by a blower door fan 

flow meter and the supply ducts are sealed. The third variation we employed is to pressurize the ducts to 

25 Pa while the house is maintained at a positive 25 Pa by a blower door fan flow meter and the supply 

ducts are not sealed. 

The second method is the Delta-Q method, which uses a combination of four multipoint home blower 

door tests (i.e., a home pressurization and depressurization test with the forced air heating/cooling 

system off and again with the system on). 

The form utilized to record these data is the Building Ventilation Form, which is in the Team 3 SOP. 

Home Building Envelope Air Leakage Area. The building envelope air leakage area was determined at 

each house using both depressurization and pressurization multipoint blower door tests with Automated 

Pressure Testing (APT) instrumentation. Figure 5 is a photograph of the blower door and APT 

instrumentation installed at pilot home P2. For these tests the homes were configured with all windows 

and exterior door closed, all interior doors open (except doors to attached garages), fireplace dampers 

closed, and all exhaust fans off. The continuously operating mechanical outdoor air delivery fans (i.e., 

the HRVs in Pilot Homes P1 and P2) were left operating. Testing was conducted in accordance with 
A-13

ASTM E779-99, Standard Test Method for Determining Air Leakage by Fan Pressurization. The form 

utilized to record these data is the Building Ventilation Form, which is in the Team 3 SOP. 

Home-to-Garage Air Leakage. We used two methods for measuring the potential air leakage between 

the home and the garage. The first method consisted of conducting a zone pressure diagnostic test of the 

garage to home connection. This test consist of conducting two multi-point blower door home 

depressurization tests as described above; one with the home door to the garage closed and one with the 

door open. From these data we calculated the Equivalent Leakage Area (EqLA @ 10 pa) in square 

inches between the garage and the home and between the garage and outdoor. The second test method 

consisted of using a blower door with the Automated Pressure Testing (APT) instrumentation operating 

in “cruise control” to maintain a constant –50 Pa in the home with respect to outdoors. A digital micromanometer was used then used to measure the differential pressure between the home and the garage. 

 

Tracer Gas Measurements of Home Outdoor Air Exchange Rate. The outdoor air exchange rate in the 

homes was measured with a tracer gas technique during the 24-hour air contaminant measurements and 

during a subsequent two-week period. This technique uses a passive constant injection perfluorocarbon 

tracer (PFT). The tracer gas sources were placed by Field Team 1 at locations in each home for 

approximately one week in advance of the tracer gas sampling to allow for the emission rates of the 

sources to equilibrate. The number of sources and placement locations were determined for each home 

based on room volumes and layout to approximate a uniform indoor concentration. Since the emission 

rates from the PFT sources are temperature dependent, we deployed a HOBO air temperature data 

logger, located at the heating/cooling system thermostat, to log the air temperature at 15-minute 

intervals. This temperature data was then input into an equation of the emission rate as a function of 

time that was supplied by Brookhaven National Laboratory, the supplier of the PFT sources, to calculate 

the temperature corrected PFT emission rates. The PFT used for these tests was para-methylcyclohexane 

(p-PMCH). The PFT samplers used for these tests were capillary adsorption tube sampler (CATS). 

These are small passive samplers that were co-located at the indoor air contaminant site (e.g., 

family/living room). A pair of these samplers, along with duplicate samplers, were deployed for the 

24-hour and two-week samplers by Field Team 2. The outdoor air exchange rate was calculated as 

described in ASTM E741. 
A-14

A deviation from the above measurement plan that we needed to make related to the two-week longterm PFT measurements. Since the blower door measurements conducted by Team 3 the day after the 

deployment of the PFT samplers would have a significant and atypical impact on the home ventilation 

rate, we decided to cap the long-term PFT samplers when we shut down the indoor air sampler and 

capped the short-term PFT samplers before the blower door tests. We then asked the homeowners if they 

would uncap the long-term PFT sampler 48 hours later. We called each of the homeowners to confirm 

that the samplers were uncapped and then Field Team three collected the long-term PFT samplers from 

the pilot homes on a second visit to each house approximately two weeks later. 

The form utilized to record these data is the PFT Form, which is in the Team 1 SOP. 

Tracer Gas Measurements of Garage Air Contaminants Entering the Home. The transport of garage air 

contaminants into the indoor air of the home was measured with a tracer gas technique during the 

24-hour air contaminant measurements and during a subsequent two-week period. This technique uses a 

passive constant injection perfluorocarbon tracer (PFT). The tracer gas sources were placed by Field 

Team 1 at a location in the garage, approximately one week in advance of the tracer gas sampling to 

allow for the emission rates of the sources to equilibrate. A total of two sources were placed at a central 

location in the garage. Since the emission rates from the PFT sources are temperature dependent, we 

deployed a HOBO air temperature data logger, co-located with the two PFT sources, to log the air 

temperature at 15-minute intervals. These temperature data were then input into an equation of the 

emission rate as a function of time that was supplied by Brookhaven National Laboratory, the supplier 

of the PFT sources, to calculate the temperature corrected PFT emission rates. The PFT used for these 

tests, para-dimethylcyclohexane (p-PDCH), was a different PFT than was used to measure the outdoor 

air exchange rate of the home. The same PFT samplers that were used to measure the outdoor air 

exchange rate of the home were used to sample the garage-located PFT entering the home. The form 

utilized to record these data is the PFT Form, which is in the Team 1 SOP. 

The percent of the garage air contaminant sources entering the home was determined from the ratio of 

the calculated source of garage PFT entering the home to the calculated source of garage PFT emitted 

into the garage. The emission rate of garage PFT entering the home was calculated from the average 

concentration of the PFT in the home, which was determined from the laboratory analysis of the indoor 
A-15

PFT sampler multiplied by the outdoor air flow rate entering the home, which was determined from the 

tracer gas measurements of the outdoor air exchange rate and the indoor air volume of the home. For the 

emission rate of garage PFT into the garage, we used the temperature corrected calculation of the garage 

PFT emission rates. 

INDOOR AIR QUALITY MEASUREMENTS 

The following is a summary of the indoor air quality parameters that were measured in each home: 

Integrated Time Averaged IAQ Measurements

• Volatile Organic Compounds (VOCs) 

• Formaldehyde and Acetaldehyde 

• Nitrogen Dioxide 

• Particles (PM2.5) 

Real-Time IAQ Measurements

• Carbon Monoxide 

• Carbon Dioxide 

• Temperature and Humidity 

These IAQ parameters were measured for 22- to 26-hour period at one indoor breathing height location 

in the family/living room area of each of the three pilot study homes. In addition, these IAQ parameters 

were also measured over the same time period at an outdoor location. For pilot homes P1 and P2, which 

represented a sampler cluster of two homes located less than 0.1 miles apart in Elk Grove, California, 

IAQ parameters were collected at a single outdoor location in the backyard of P1. For pilot home P3, 

which was located in Sacramento, California, IAQ parameters were collected at a single outdoor 

location in the backyard of P3. Duplicate air samples were collected at the P1 home at the indoor 

location. Integrated sample flow rates were measured at the beginning and end of the sampling period 

using calibrated rotameters. 
A-16

A special air sampler was developed to collect the integrated and real-time air contaminant 

concentrations. Figure 1 is a photograph of the air sampler located at the P3 indoor site and Figure 2 is 

close-up photograph of the air sampler. For the integrated air samples, this air sampler consisted of a 

pair of air sampling pumps contained in an acoustically shielded fiberglass lock box mounted to a tripod. 

The air sampling pumps are SKC AirCheck 2000 air sampling pumps that include an internal flow 

sensor that provides automatic electronic air flow control such that the sample airflow rate is maintained 

to within ± 5%, and 115 VAC battery eliminators to allow operation over the proposed 24-hour 

sampling periods. One of these pumps provides the air sampling flow rate for the PM2.5 measurement. 

The second pump, through the use of a four-port manifold with low flow control valves, provides the air 

sampling flow rate for the volatile organic compounds, nitrogen dioxide, and 

formaldehyde/acetaldehyde measurements. An power on-time meter provides a measurement of the time 

that 110 VAC power is supplied to the air sampler so that if there is a power interruption the duration of 

the interruption is known. The air sampling pumps automatically restart upon restoration of the power 

following a power interruption. In addition, a power cord restraint cover is installed at the connection of 

the power cord to the power receptacle to guard against inadvertent disconnection of the power cord 

plug from the receptacle. For the real-time measurements, a TSI IAQ-Calc is mounted on the tripod next 

to the integrated air sampler manifold. The AC adaptor for the TSI IAQ-Calc is connected to a source of 

AC power inside of the fiberglass lock box. In addition, the TSI IAQ-Calc contains a parallel battery 

pack power supply that allows the instrument to continue operation upon a power interruption. For the 

outdoor air sampler a special rain/radiation shield was fabricated from galvanized sheet metal to enclose 

and protect the air samplers. This rain/radiation shield has screened and louvered vents on two sides to 

allow circulation of outdoor air within the enclosed area. Figure 3 is a photograph of the air sampler 

with the rain/radiation shield installed. 

The following is a detailed description of the air sampling and analytical techniques for each of the IAQ 

parameters. 

Integrated Time Averaged IAQ Measurements (24-hour)

• Volatile Organic Compounds. Volatile organic compounds other than formaldehyde and acetaldehyde 

were measured following U.S. EPA Methods TO-1, TO-15, and TO-17 from the Compendium of 
A-17

Methods for the Determination of Toxic Organic Compounds in Ambient Air (EPA 1999). This method 

involves drawing air at a constant rate with a pump through a multi-sorbent tube (i.e., Berkeley 

Analytical Associates sorbent tubes containing Tenax-TA® backed up with a carbonaceous material to 

prevent breakthrough of the most volatile compounds). Samples were collected at a flow rate of 

approximately 10 cubic centimeters per minute (cc/min), which will provide a detection limit of 

0.4 micrograms per cubic meter (μg/m3

) for most compounds. The samples were split 1:5 to prevent 

overloading of the analytical instrumentation and thermally desorbed and analyzed by gas 

chromatograph/mass spectrometry. For the pilot study, indoor and outdoor samples were be fully 

analyzed to identify all of the compounds detected above 4 μg/m3

 and to quantify abundant air 

contaminant compounds that appear on the Toxic Air Contaminant List (CARB 1999), the California 

Proposition 65 Substance List and the Chronic Reference Exposure List (OEHHA 2003), and any other 

compounds that were detected with concentrations above 3 μg/m3

. Laboratory results for each sampler 

were corrected using a field blank, which was submitted to the lab. 

• Formaldehyde and Acetaldehyde. Formaldehyde and acetaldehyde was measured according to ASTM 

Standard D 5197-03 (ASTM 2003). This method involves drawing air at a constant rate with a pump 

through a solid sorbent cartridge (i.e., Waters Associates Sep-PAK, silica gel impregnated with 

dinitrophenylhydrazine, DNPH). In addition, since ozone is known to interfere with this sample 

analyses, an ozone scrubber was installed directly upstream of the solid sorbent cartridge. This scrubber 

consists of a solid sorbent cartridge filled with granular potassium iodide (i.e., Waters Associates SepPAK Ozone Scrubber). Additionally a scrubber (i.e., Anasorb CSC, coconut charcoal sorbent tube) for 

DNPH was placed downstream of the sampler because this compound would be collected and analyzed 

for in the VOC sampling protocol. The samplers are extracted with acetonitrile and analyzed using 

HPLC. Samples were collected at a flow rate of approximately 70 cc/min, which will provide a detection 

limit of 0.4 μg/m3 for acetaldehyde and 0.3 μg/m3 for formaldehyde. This concentration detection limit is 

well below both the California Environmental Protection Agency/Office of Environmental Health 

Hazard Assessment (Cal/EPA OEHHA) chronic inhalation Reference Exposure Levels (OEHHA 2003) 

of 3 μg/m3 and 9 μg/m3 for formaldehyde and acetaldehyde, respectively, as well as the ARB Indoor Air 

Quality Guidelines (California Air Resources Board 2004) of 33 μg/m3 for formaldehyde for an 8-hour 

exposure. Laboratory results for each sampler were corrected using a field blank which was submitted to 

the lab. 
A-18

• Nitrogen Dioxide. Nitrogen dioxide was measured following NIOSH 6014 (NIOSH 1994a). This 

method involves drawing air at a constant rate with a pump through a two stage solid sorbent tube (i.e., 

SKC 226-40-02 molecular sieve impregnated with triethanolamine). The samplers were extracted with a 

triethanolamine solution and analyzed using spectrophotometry at a wavelength of 540 nanometers 

(nm). Both the front tube section and backup tube section were be separately analyzed to verify that 

there was no significant breakthrough. Samples were collected at a flow rate of approximately 

100 cc/min, which will provide a detection limit of 9 μg/m3

. This concentration detection limit is well 

below both the U.S. Environmental Protection Agency (EPA) National Ambient Air Quality Standard 

(NAAQS) (EPA 1990) standard of 100 μg/m3 for an annual exposure, as well as the ARB Indoor Air 

Quality Guidelines (California Air Resources Board 2004) of 150 μg/m3 for a 24-hour exposure. 

Laboratory results for each sampler were corrected using a field blank, which was submitted to the lab. 

• Particulate Matter (PM2.5). PM2.5 particles were collected following EPA IP-10A, (EPA 1989) with 

gravimetric analyses according to NIOSH 500 (NIOSH 1994b). This method involves drawing air at a 

constant rate with a pump through a PM2.5-size selective inlet (i.e., SKC 761-203 Personal 

Environmental Monitor) containing a 37 millimeter (mm) PVC filter with a 0.8 micron (μm) pore size. 

After sampling, the filters were equilibrated in a climate controlled weighing room and analyzed 

gravimetrically. Samples were collected at a flow rate of 2 liters per minute (L/min) which represents 

the design flow rate of this impactor and which will provide a detection limit of 3.5 μg/m3. This 

concentration detection limit is well below both the EPA NAAQS (EPA 1990) ambient air quality 

standard and the ARB Indoor Air Quality Guidelines (California Air Resources Board 2004) of 

65 μg/m3 for 24-hour exposures. Laboratory results for each sampler were corrected using a field blank, 

which was submitted to the lab. 

Real-Time IAQ Measurements

• Carbon Monoxide. Carbon monoxide was measured with real-time instrumentation following EPA 

method IP-3A (EPA 1989) using an electrochemical sensor. A TSI IAQ-Calc, which incorporates a 

passive diffusive sample element and has built in data-logging capabilities was used. The data logger 

was programmed to record carbon monoxide concentrations at one-minute intervals. The sensor has an 
A-19

accuracy of ± 3% or ± 3 parts per million (ppm), whichever is greater, a precision of ± 2% of reading, a 

resolution of 1 ppm, and a range of 0–500 ppm. This concentration detection limit is well below both the 

EPA NAAQS (EPA 1990) and the ARB Indoor Air Quality Guidelines (California Air Resources Board 

2004) of 9 ppm for 8-hour exposures. The instrument was calibrated immediately prior to the start of 

sampling and checked following the sampling period, using zero and span (35 ppm) calibration gases. 

The sample data logged over the 24-hour period was corrected using a fit to the calibration points that 

was assumed to be linear over time. 

• Carbon Dioxide. Carbon dioxide was measured with real-time instrumentation following EPA method 

IP-3A (EPA 1989) using a sensor that utilizes non-dispersive infrared spectrophotometry (NDIR). A TSI 

Q-Trak, which incorporates a passive diffusive sample element and has built in data-logging capabilities 

was used. The data logger was programmed to record carbon dioxide concentrations at one-minute 

intervals. The sensor has an accuracy of ± 3% or ± 50 ppm, whichever is greater, a resolution of 1 ppm, 

and a range of 0–5000 ppm. This concentration detection limit is well below both the ASHRAE 

(ASHRAE 2004) body odor standard of 700 ppm over the outdoor concentration, which for typical 

outdoor concentrations of 350 to 450 ppm represents an indoor concentration of 1,050 to 1,150 ppm. 

The instrument was calibrated immediately prior to the start of sampling and checked following the 

sampling period, using zero and span (1000 ppm) calibration gases. The sample data logged over the 

24-hour period was corrected using a fit to the calibration points that was assumed to be linear over 

time. 

• Temperature and Relative Humidity. Temperature and relative humidity were measured with real-time 

instrumentation using a thermistor sensor for air temperature and a thin-film capacitive sensor for 

relative humidity. A TSI IAQ-Calc with built-in data logging capabilities was used. The data logger was 

programmed to record temperature and relative humidity at one-minute intervals. The temperature 

sensor has an accuracy of 1°F, a resolution of 0.1°F, and a range of 32°F–122°F. Prior to the field effort, 

the instruments’ temperature sensors were compared to a certified mercury thermometer, and the sample 

data logged over the 24-hour period was corrected using single point correction. The relative humidity 

(RH) sensor has an accuracy of 3 % RH, a resolution of 0.1 %RH, and a range of 5%–95% RH. Prior to 

the field effort, the instruments’ relative humidity sensors were compared with a laboratory probe that 
A-20

was calibrated with salt solutions according to ASTM E104-02 (ASTM 2002). The sample data points 

logged over the 24-hour period were corrected using a single point correction. 

We obtained meteorological data from the Sacramento Mather Airport weather station for the period of 

the pilot study. We obtained hourly wind speed and outdoor air dry bulb temperature. The airport is 

12 miles northeast from the Elk Grove site for P1 and P2 and 15 miles southeast from the Sacramento 

site for P3. 

QUALITY ASSURANCE AND QUALITY CONTROL

For this pilot study of three homes we followed our October 10, 2005, Quality Assurance / Quality 

Control Plan (QA/QC Plan). For each of the integrated air contaminant measurements, VOCs, NO2, 

formaldehyde/acetaldehyde, and PM2.5, we collected and analyzed a single field blank and a single 

duplicate, with the exception for PM2.5, for which we collected four field blanks. For the PFT 

measurements we collected and analyzed a single field blank and two 24-hour duplicate samples and 

one two-week duplicate sample. As per our QA/QC plan, the PFT sources and PFT samplers were stored 

and shipped separately. 

We also evaluated the air sampling flow rate stabilities by comparing the rotameter measurements of the 

air sampling flow rates at the beginning and end of the 24-hour air sampling period for each of the 

integrated air samples. We calculated the relative standard deviation for each of the beginning and end 

pairs of flow rate measurements. 

 

DATA MANAGEMENT

For this pilot study we created in Excel all of the field data sheets contained in the SOPs that are detailed 

in our October 10, 2005, Quality Assurance / Quality Control Plan (QA/QC Plan). Hard copies of these 

field data sheets were taken into the field and used to record the data. The data on these hard copy field 

data sheets were then entered into identical electronic copy field data sheets. These Excel sheets contain 

all of the calibrations and calculations for converting the collected field data into the various ventilation 

and indoor air quality parameters. 
A-21

RESULTS AND DISCUSSION 

HOME SELECTION/RECRUITMENT 

We mailed a total 64 recruitment letters to new single-family homes to each of the addresses in the 

Sacramento and Elk Grove communities that were in the University of California (UC) Berkeley 

database. A total of two letters were returned with notes of “no such name” suggesting the original 

homeowner had moved. During the next two weeks we received a total of seven responses for an 11% 

response rate from the mailing. The following are the results of the follow-up call to these seven 

respondents: 

• 2 were interested, but not qualified because they were moving soon. 

• 5 were interested in participating in the pilot study. 

As indicated in the Methods section there were no phone numbers contained in the UC Berkeley 

database. We went to the library and looked up phone numbers for the 57 homes that did not respond, 

and we were able to find 25 phone numbers with a name or address match (a 44% find rate). We 

attempted a minimum of three calls to each number. The following are the results of the follow-up call 

to these 25 phone calls: 

• 12 were left messages that newer returned the call 

• 4 were bad phone numbers 

• 4 were interested in participating in the pilot study 

• 3 were not interested (one with an infant) 

• 1 was interested, but not qualified because they were moving soon 

• 1 was interested but at a later date 

Thus the mailing to 64 homes netted 5 interested pilot study participants, and the 25 phone calls netted 

an additional 4, for a total of 9 homes. 
A-22

We then established clusters for those homes based on their relative clusters and based upon which of 

the two sets of measurement dates and three inspection times each of the homes noted as being required 

or preferred. From these potential clusters we then looked for two clusters that satisfied the requirements 

of having one home with mechanical outdoor air ventilation and having homes from two different 

developments. 

For this pilot study of three homes we selected a two-home cluster in Elk Grove and a one-home cluster 

in Sacramento. The two homes we selected from Elk Grove are in the same development and are 

approximately 0.1 miles apart. They are both single-story wood frame structures with a slab-on-grade 

foundation and attached garages. The both have forced air ventilation systems installed in the attic, and 

they both have a separate dedicated outdoor air heat recovery ventilator systems (HRV), also installed in 

the attic. We selected a single home from Sacramento. This home is a two-story wood frame structure 

with a slab-on-grade foundation and an attached garage, and it has a forced air ventilation system 

installed in the attic and no mechanical outdoor air system. 

Figures 6–8 are photographs of the three pilot homes, and Figures 9–12 are floor plans. 

HOME AND SITE CHARACTERISTICS COLLECTION 

Table 1 summarizes the characteristics of each of the three pilot homes, including general 

characteristics, contaminant source characteristics, and ventilation and air cleaning characteristics. These 

are average-sized homes with low occupancies. During the field study the occupancy of pilot home P3 

increased from two to three with birth of a daughter. Table 2 is a summary of the homeowner reported 

home renovations, maintenance, and other IAQ related activities. Table 3 is a summary of the 

homeowner-reported building system failures and home IAQ improvements. Home P2 had a reported 

plumbing leak, and homes P1 and P2 noted the installation of upgraded filters (these filters turned out to 

have a lower efficiency than typical residential furnace filters). 
A-23

HOMEOWNER SOURCE ACTIVITY LOG 

Table 4 summarizes the indoor source activities reported by the homeowners for the 24-hour period 

during which the indoor air contaminant measurements occurred. As can be seen, there was little source 

activity occurring in these three homes. Homes P1 and P2 have retired occupants who apparently eat out 

a lot. Home P3, had some cooking activity, but this was also not much, perhaps because the mother was 

about to give birth. 

HOMEOWNER IAQ/VENTILATION PERCEPTIONS AND DECISION FACTORS 

Table 5 summarizes the homeowner reported perceptions and physical symptoms over a three-week 

recall period. P2 reported environmental conditions “too drafty” and “too dusty,” and P3 reported “too 

cold.” P1 reported odors from cabinetry. P1, whose occupants have diagnosed allergies and asthma, 

reported the following physical symptoms: nose/sinus congestion, allergy symptoms, and headache. P2, 

whose occupants have no diagnosed allergy or asthma conditions, reported allergy symptoms. 

VENTILATION MEASUREMENTS 

The following is a description of the results of our ventilation measurements in the three pilot homes. 

Occupant Use of Windows and Doors for Ventilation. Table 6 summarizes for each of the three pilot 

study homes, one week of daily openings and closings of doors expressed as square foot-hours (ft2

-hrs). 

As can be seen from these data, P1 and P2 hardly used their windows or doors at all—they were all 0 

except 0.1 ft2

-hr for P2 on Day 7 ( i.e., the air sampling day). P3 had window usage ranging from 0 to 

163 ft2-hr with 51 ft2-hr on Day 7 ( i.e., the air sampling day). For the two windows in each home with 

dataloggers monitoring the openings and closings, we compared the data logger records of window 

openings and the occupant written logs. In P1 the occupants logged 0 of 1 opening events. In P2 the 

occupants logged 0 of 3 opening events. In P3 the occupants logged 1 of 3 opening events. Thus the 

accuracy of the occupant logs does not appear to be very good. 
A-24

Exhaust Fans and Appliances. The exhaust air flow rates and associated building guidelines and codes 

are summarized in Table 7. P1 and P2 have continuous exhaust air from the master bathroom and 

laundry room that is associated with the HRV systems in these two homes. All other bathroom and 

laundry room exhaust fans operate intermittently with a user-controlled wall switch. 

For the 4 bathrooms with continuous exhaust ventilation from the HRVs, all 4 exceeded the minimum 

ASHRAE 62.2-2003 guideline of 20 cubic feet per minute (cfm). 

For the 9 bathrooms with intermittent exhaust ventilation, 7 of the 9 failed the minimum ASHRAE 62.2-

2003 guideline of 50 cfm. 

For the 13 bathrooms with continuous or intermittent exhaust ventilation, 6 of the 13 failed the 

minimum California Building Code 2001 requirement of 5 air changes per hour (ach). 

For the 6 bathrooms with openable windows, 1of 6 failed the minimum California Building Code 2001 

requirement of an openable area equal to 5% of the floor area for bathrooms and 4% of the floor area for 

toilet rooms. The one bathroom with window openings less than the guideline also had mechanical 

exhaust systems, which were also under one or more of the recommended guidelines. 

For the 6 bathrooms with openable windows, all 6 met the minimum California Building Code 2001 

requirement of an openable area equal to 1.5 ft2

. 

Overall, 7 of the 13 bathrooms either met the openable window or mechanical exhaust requirements; 

3 of 4 in P1 and P2, and 1 of 5 in P3. 

Table 8 summarizes the kitchen exhaust air flow rate measurements. All three pilot homes had 

intermittent kitchen exhaust fan systems that were ducted to outdoor and met the ASHRAE 62.2. 

guideline of 100 cfm. 

Table 9 summarizes all of the exhaust fan operation in each home for a seven-day period. Day seven is 

the 24-hour test period during which the outdoor air exchange rate and indoor air quality parameters 
A-25

were measured. The daily operation time for each of the fans as determined from the HOBO data 

loggers and/or written occupant logs was multiplied by the measured air flow rates to produce the cfmhours of operation for each fan systems. Pilot homes P1 and P2 have exhaust air operations dominated 

by the continuously operating HRVs. 

For the other intermittent exhaust fans, averaged over the one-week monitoring period, the exhaust 

ventilation was dominated by the clothes drier exhaust ( 88%–221% of 252 cfm) in P1, by the clothes 

drier in P2 ( 75%–80% of 107 cfm), and by the kitchen (50%–48% of 97 cfm) and the master bathroom 

toilet exhaust (40%–40% of 97 cfm) in P3. 

Forced Air Heating/Cooling System. The return air flow rates and percent on-times for the forced air 

heating/cooling systems are summarized in Table 10. The percent on-times for the forced air 

heating/cooling systems during the one-week period of monitoring ranged from 7%–20% in P1, and 0% 

in P2, and 2%–23% in P3. We examined the indoor air temperature data for P1 and while the data logger 

indicated no operation during the week, the air temperatures suggested that there was some heating. In 

addition, the data logger appeared to be working, as it registered the operation of the forced air 

heating/cooling systems during the time that Field Team 3 operated the system to measure the system air 

flow rate. 

 

Mechanically Supplied Outdoor Air Flow Rates. Table 11 contains the measurements of the mechanical 

outdoor air ventilation rates in pilot homes P1 and P2, which both had continuously operating HRVs. In 

P2, the measured flowrates of outdoor air exceeded the recommendations of both ASHRAE 62.2. and 

the Energy Commission in P2, but in P1 the measured flow rates, while exceeding the ASHRAE 62.2. 

guideline, were below the Energy Commission guideline. 

Forced Air Heating/Cooling System Duct Leakage. We note that we were not able to measure the duct 

leakage in P3 as a result of the homeowners request to end the testing because of noise/disruption to a 

new baby. Table 12 contains the duct pressurization measurements of air leakage for homes P1 and P2. 

These tests were conducted with three different configurations, as discussed in the methods section. The 

standard duct leakage method of pressurizing the ducts to 25 Pa while the supply ducts are sealed 

resulted in 4.9% air leakage for both homes P1 and P2. This air leakage was reduced to 4.6% in P1 and 
A-26

3.0% in P2, when the house was pressurized to 25 Pa with the supply air registers still sealed. This air 

leakage was further reduced to 2.5% in P1 and 0.2% in P2 when the house was pressurized to 25 Pa with 

the supply air registers unsealed. 

The results of the Delta-Q test method are summarized in Table 13. The supply air leakage and return air 

leakage were 61 cfm and 42 cfm, respectively, for P1, and they were 20 cfm and 43 cfm, respectively, 

for P2. We note that the estimated measurement uncertainty is ± 20 cfm for this measurement method. 

Table 14 summarizes the of the home indoor differential pressure with respect to outdoors with the 

forced air heating/cooling system fan on and off. In the California Energy Commission, Title 24, 2001 

Residential ACM approval Manual, if the Standard Leakage Area is less than 1.5 mechanically supplied 

outdoor air is required and the home differential air pressure with respect to outdoors must be 

maintained greater than -5 Pa with all continuous ventilation fans operating. Both P1 and P2 had 

differential pressures greater than –5 Pa. In addition there was no significant difference between 

differential pressures with the furnace fan on or off. 

Home Building Envelope Air Leakage Area. The building envelope leakage area measurements of the 

three homes are summarized in Table 15. We note that we were only able to measure the building air 

leakage area with depressurization in P3 as a result of the homeowners request to end the testing because 

of noise/disruption to a new baby. The ACH50 from the depressurization measurements were 4.31 ach 

in P1, 6.26 ach in P2, and 3.97 ach in P3. The specific leakage area (SLA), as defined by the California 

Energy Commission, Title 24, 2001 Residential ACM Approval Manual, with depressurization ranged 

from 2.74 in P1, 3.97 in P2, and 2.05 in P3. Thus, both P1 and P3 have SLAs less than 3.0 and greater 

than 1.5, and thus are required to have a mechanical supply of outdoor air of no less than 0.047 cfm/ft2

. 

In Table 11, our calculations indicate that in P1 the measured outdoor air flow rates, while exceeding the 

ASHRAE 62.2 guideline, were below the Energy Commission guideline. There was no mechanical 

outdoor air delivery system in P3. 

House-to-Garage Air Leakage. The results of the zone pressure diagnostics of the garage to home 

connection are summarized in Table 16. We note that all three homes had self-closing and weatherstripped doors to the garages. The house-to-garage leakage areas (EqLA – 10 Pa, inches2

) ranged from 
A-27

4 square inches (in2 ) in P3 to 8.5 in2 in P2 to 20 in2 in P3. There are no guidelines for garage-to-house air 

leakage areas; however, as a perhaps more meaningful metric with respect to potential contamination of 

the house air with garage air, we have calculated the percentage of the house-to-garage leakage to the 

total leakage area of the house-to-outdoor and the garage-to-outdoor. This percentage ranged from 1% in 

P1 to 2% in P2 to 3% in P3. We also measured the house-to-garage pressure with the house-to-outdoor 

air pressure held at 50 Pa. The garage pressures ranged from –049.8 Pa for P3 to –49.4 Pa for P1 to 

–49.4 Pa for P3. These house-to-garage pressures are all meet the American Lung Association (ALA) 

guideline of a minimum of –49 Pa. 

Tracer Gas Measurements of Home Outdoor Air Exchange Rate. The results of the tracer gas 

measurements of outdoor air exchange rates are summarized in Table 17. The locations of the PFT 

sources and samplers are depicted in Figures 9–12. The 24-hour measurements ranged from 0.26 ach in 

P3 to 0.37 (0.37 ach duplicate) ach in P1 to 0.73 ach (0.71 ach duplicate) in P2. The long-term two week 

samples resulted in 0.29 ach in P1, 0.57 ach in P2, and 0.30 (0.34 ach duplicate) in P3. 

These air exchange rates may be compared to the ASHRAE 62-1989 and the Energy Commission ACM 

recommendations of 0.35 air changes per hour. 

 

Tracer Gas Measurements of Garage Air Contaminants Entering the Home. The results of the 

measurement of garage source emissions entering the house are summarized in Table 18. The locations 

of the PFT sources and samplers are depicted in Figures 9–12. For the 24-hour measurement period the 

percentage of the garage sources entering the home ranged from 2.6% (1.9% duplicate) for P1 to 9.8% 

for P3 to 10.1% (11.9% duplicate) for P2. For the two-week measurement period, the percentage of the 

garage sources entering the home ranged from 4.0% for P1 to 7.2% for P2 to 11.3% (11.4% duplicate) 

for P3. 

Ventilation Calculations. In Table 19 we calculate the combined outdoor air exchange rate resulting 

from the natural infiltration rate and the mechanical ventilation rates and compare this calculated total 

rate to the PFT measurements of the outdoor air exchange rate. We have used to models to calculate the 

combination of the natural and mechanical outdoor air ventilation rates. The first calculation is 

according to ASHRAE 136, which calculates the total outdoor airflow rate as the square root of the sum 
A-28

of the squares of the natural and mechanical airflow rates. The second calculation is according to the 

Palmiter/Bond 0.5 Rule, which calculates the total outdoor air flow rate as either (1) the sum of the 

balanced mechanical flowrates, the natural infiltration rate, and one-half the unbalanced mechanical 

flow rates if the unbalanced mechanical air flow rates are less than twice the natural infiltration air flow 

rates, or (2) if the unbalanced mechanical air flow rates are greater than twice the natural infiltration air 

flow rates, as the maximum of the total mechanical exhaust or total mechanical outdoor air flowrates. 

We note that neither of these models nor any other simple models can incorporate the outdoor air 

exchange rate resulting from openable windows and doors. In addition, we note that these calculations 

were performed using 24-hour averages for the exhaust and outdoor air mechanical flow rates and 

because of the non-linearities in combining mechanical air flow rates and air flow rates through the 

building envelope, a more accurate calculation is to perform the calculations using hourly averaged data. 

We note that an hourly calculation, while beyond the scope and resources of this study, could be done as 

there is hourly data available for all of the parameters. 

The calculated outdoor air exchange rates from the ASHRAE 136 and Palmiter/Bond, respectively, 

ranged from 0.35 ach / 0.36 ach for P1 to 0.66 ach / 0.66 ach for P2 to 0.12 ach / 0.12 ach in P3 using 

the P2 Delta-Q duct leakage data and to 0.10 ach / 0.11 ach in P3 assuming no duct leakage. 

These calculations of total outdoor air exchange rates for the 24-hour measurement period agree 

reasonable well with the PFT measurements for P1 and P2, which both had continuous mechanical 

outdoor air ventilation and none to little reported use of openable windows and doors. The calculated 

outdoor air exchange rate for P3, 0.10–0.12 ach, was less than half of the measured value of 0.26 ach. 

Part of this discrepancy may be the result of the use of openable windows and doors to ventilate this 

residence, as there were a total of 50.8 ft2

-hrs of openings in P3. 

INDOOR AIR QUALITY MEASUREMENTS 

The locations of the indoor and outdoor air samplers are depicted in Figures 9–12. 
A-29

Integrated Time-Averaged IAQ Measurements (24-hour)

• Volatile Organic Compounds. The indoor and outdoor concentrations of volatile organic compounds 

are summarized along with recommended indoor guidelines in Tables 20–23. The first basis for our 

selection of non-industrial irritant guidelines is the California Air Resources Board, Indoor Air Pollution 

in California, Table 4.1 ARB Indoor Air Quality Guidelines, July 2005 (CARB 2005). Our second basis 

for selection, for those compounds without ARB indoor air guidelines is the California Office of 

Environmental Health Hazard Assessment Chronic Reference Exposure Guidelines (OEHHA CRELs). 

Our final basis of selection, for those compounds, with neither ARB indoor guidelines or OEHHA 

CRELs, is 2.5% of the occupational standard. This recommendation is based upon the different exposure 

periods (40-hour per week for an industrial worker versus a 168-hour per week for a full-time occupant) 

and to provide a safety factor of ten for more sensitive populations (Nielsen et al. 1997). 

The percent of the indoor guideline for the maximum indoor concentrations observed in the three pilot 

homes ranged from 9.3% for toluene in P1 and P2 to 6.3% for benzene in P1 to 3.5% for ethylene glycol 

in P1 to 2.5% for ethanol in P1 to 2.1% for propanol in P1. All other compounds were less than 2% of 

the indoor guidelines. 

• Formaldehyde and Acetaldehyde. The indoor and outdoor concentrations of formaldehyde and 

acetaldehyde are summarized along with recommended indoor guidelines in Table 24. For formaldehyde 

we utilized the 33 μg/m3

 guideline recommended by the ARB (CARB 2005). For acetaldehyde we 

utilized the Chronic Reference Exposure Guidelines of 9 μg/m3

 recommended by OEHHA (OEHHA 

2003). 

For formaldehyde, homes P1 and P2 were below the recommended guideline of 33 μg/m3

, however P3, 

with a concentration of 45 μg/m3

 was above this guideline. 

For acetaldehyde, home P2 was below the recommended guideline of 9 μg/m3

, however homes P1 and 

P3, with indoor concentrations of 10 μg/m3 (11 μg/m3 duplicate) an 17 μg/m3, respectively, were above 

this guideline. 
A-30

• Nitrogen Dioxide. The indoor and outdoor concentrations of nitrogen dioxide are summarized along 

with recommended indoor guidelines in Table 25. The basis for our selection of non-industrial irritant 

guidelines for nitrogen dioxide is the CARB 2001 (Table 4.1) recommendation of 150 μg/m3

 for a 24-

hour exposure. The indoor concentrations, which ranged from < 9 μg/m3

 in P1 and P3 to 10 μg/m3 in P2, 

were all well below this guideline. 

• Particulate Matter (PM2.5). The indoor and outdoor concentrations of PM2.5 are summarized along with 

recommended indoor guidelines in Table 25. The basis for our selection of non-industrial irritant 

guidelines for nitrogen dioxide is the CARB 2001 (Table 4.1) recommendation of 65 μg/m3 for a 

24-hour exposure. The indoor concentrations which ranged from 11 μg/m3 in P2 and P3 to 12 μg/m3

(17 μg/m3

 duplicate) in P1, were all well below this guideline. 

Real-Time IAQ Measurements

• Carbon Monoxide (CO). The indoor and outdoor concentrations of CO are summarized along with 

recommended indoor guidelines in Table 25. The basis for our selection of non-industrial irritant 

guidelines for CO is the CARB 2001 (Table 4.1) recommendation of 9 ppm for an 8-hour exposure and 

20 ppm for a 1-hour exposure. For the 8-hour maximum exposures the indoor concentrations, which 

ranged from less than 0.5 ppm in P2 to 1.0 ppm (<0.5 ppm duplicate) in P1 to 1.4 ppm in P3, were all 

well below the 8-hour guideline of 9 ppm. For the 1-hour maximum exposures the indoor 

concentrations, which ranged from less than 0.5 ppm in P2 to 1.6 ppm (<0.5 ppm duplicate) in P1 to 

1.8 ppm in P3, were all well below the 1-hour guideline of 20 ppm. 

• Carbon Dioxide (CO2). The indoor and outdoor concentrations of CO2 are summarized along with 

recommended indoor guidelines in Table 26. The basis for our selection of non-industrial irritant 

guidelines for CO2 is the ASHRAE 62.1-2004 guideline of a maximum indoor concentration of less than 

700 ppm above the outdoor concentration. We note that this guideline is established for body odor and 

not health concerns. 

The maximum CO2 concentration ranged from 2,251 ppm (2,236 ppm duplicate) in P1 to 1,228 ppm in 

P2 to 1,343 ppm in P3. Thus the maximum concentration of CO2 exceeded the ASHRAE recommended 
A-31

maximum of 700 ppm over outdoors in P1 and P3. We also note that the maximum indoor CO2 

concentrations in all three homes occurred during the time that the field teams were either deploying or 

retrieving the air sampling equipment. Figure 13 is a plot of the CO2 indoor concentration as a function 

of time for the 24-hour sampling period. In this home, there were a large number of observers and field 

technicians present (e.g., 6–8) at the start of the air sampling contributing to the indoor CO2 air 

concentrations. In the main field study, there will be only two field technicians present at any one time. 

• Temperature and Relative Humidity. The indoor and outdoor temperature and relative humidity 

measurements are summarized in Table 26. The 24-hour average indoor air temperatures ranged from 

67°

F (67°F duplicate) at P1 to 68°F at P2 to 64°F at P3. The average outdoor temperature averaged 45°F at 

the P1/P2 outdoor site and 49°

F at the P3 outdoor site. The 24-hour average indoor relative humidity 

ranged from 42% (41% duplicate) at P1 to 35% at P2 to 52% at P3. The average outdoor relative 

humidity averaged 70% at the P1/P2 outdoor site and 90% at the P3 outdoor site. 

QUALITY ASSURANCE AND QUALITY CONTROL

The results of the air sampling flow rate stability analyses are summarized in Table 27. This table 

summarizes the minimum, maximum, and average of the standard deviations in the recorded start and 

stop sample flow rates. 

For the VOC measurements, a total of two samplers were deployed at each sampling site. The second 

sample was collected as a back-up sample to the first, should the sample be overloaded. Of the 12 VOC 

air samples (i.e., 6 pairs of 2 samples) the average relative standard deviation was 0.08 with a minimum 

of 0.0 and a maximum of 0.23. From each pair of VOC samplers at each site the sampler with the more 

stable flow rate was submitted for analyses. For the 6 VOC air samples submitted, the average relative 

standard deviation was 0.03, with a minimum of 0.0 and a maximum of 0.07. 

For the NO2 measurements, the average relative standard deviation was 0.03, with a minimum of 0.01 

and a maximum of 0.05. 
A-32

For the formaldehyde/acetaldehyde measurements, the average relative standard deviation was 0.11 with 

a minimum of 0.02 and a maximum of 0.54. We note that the outdoor sample for P3 had an atypically 

high relative standard deviation associated with the start and stop flow rates. The sample start flow rate 

was 101 cc/min, and the sample stop flow rate was 45 cc/min. If we eliminate this one sample, then the 

average relative standard deviation was 0.03 with a minimum of 0.02 and a maximum of 0.05. We note 

that there was very heavy rain during the start of this air sampling, and we suspect that the DNPH 

sampler swallowed a drop of rain water during the startup of the sampler. The field technician reports 

that he did not have an umbrella to protect the air samplers during the time that the radiation/rain shield 

was off and the sample start flow rates were being measured. For the main field study the field teams 

will make sure to pack umbrellas. 

For the PM2.5 measurements, the average relative standard deviation was 0.03 with a minimum of 0.01 

and a maximum of 0.04. 

The results of the carbon monoxide and carbon dioxide calibration stability analyses are summarized in 

Table 28. This table summarizes the minimum, maximum, and average difference between the 

post-calibration check reported by the instrument and the actual calibration concentration. 

For carbon monoxide the six zero calibration checks averaged a 0 ppm difference with a minimum 

difference of 0 ppm and a maximum difference of 0 ppm. For carbon monoxide the six span calibration 

checks averaged a 1 ppm difference with a minimum difference of -3 ppm and a maximum difference of 

1 ppm. 

For carbon dioxide the six zero-calibration checks averaged a 21 ppm difference with a minimum 

difference of 0 ppm and a maximum difference of 63 ppm. For carbon dioxide the six span calibration 

checks averaged a 39 ppm difference with a minimum difference of -16 ppm and a maximum difference 

of 120 ppm. We note that the outdoor sample for P3 had an atypically large difference associated with 

the stop calibration. If we eliminate this one sample, then the calibrations averaged a 22 ppm difference 

with a minimum difference of -16 ppm and a maximum difference of 60 ppm. 
A-33

The results of the VOC sample duplicate analyses are summarized in Tables 29 and 30. This table 

summarizes for each VOC the relative standard deviation between the pair of duplicate samples 

collected in P1 where both samples were above the quantification limit. The relative standard deviation 

ranged from 0.00 to 0.19. Only two compounds had relative standard deviations greater than 0.09: 0.15 

for 2,2,4-Trimethyl-1,3-pentanediol momoisobutyl ether, isomer 3, and 0.19 for d-limonene. 

The results of the sample duplicate analyses for acetaldehyde, formaldehyde, carbon dioxide, carbon 

monoxide, nitrogen dioxide, and PM2.5 are summarized in Table 31. This table summarizes, for each 

compound, the relative standard deviation between the pair of duplicate samples collected where both 

samples were above the quantification limit. 

The results of the sample duplicate analyses for the PFT measurements are summarized in Tables 32. 

This table summarizes the relative standard deviation between the pair of duplicate samples. For the 

24-hour short-term PFT measurements of outdoor air exchange rate the relative standard deviation 

ranged from 0.00 for the P1 pair of samples to 0.03 for the P2 pair of samples. For the two-week longterm PFT measurements of outdoor air exchange rate the relative standard deviation was 0.09 for the P3 

pair of samples. For the 24-hour short-term PFT measurements of garage source entry into the home the 

relative standard deviation ranged from 0.20 for the P1 pair of samples to 0.11 for the P2 pair of 

samples. For the two-week long-term PFT measurements of garage source entry into the home the 

relative standard deviation was 0.01 the P3 pair of samples. 

The single VOC field blank sample analyzed contained only one compound above the minimum mass 

quantification limit, ethanol with a field blank mass of 129 ng and a minimum quantification limit of 

75 ng. A total of seven additional compounds had detectable concentrations in the field blank but with 

masses all below the quantification limit. These compounds were: 

Acetephenone: 1 ng blank – 5 ng minimum quantification limit 

Benzaldehyde: 4.4 ng blank – 5 ng minimum quantification limit 

Butanol: 16.8 ng blank – 25 ng minimum quantification limit 

Decanal: 10 ng blank – 5 ng minimum quantification limit 

Limonene: 3.2 ng blank – 5 ng minimum quantification limit 
A-34

Nonanal: 6.8 ng blank – 50 ng minimum quantification limit 

Octanal: 1.3 ng blank – 25 ng minimum quantification limit 

For acetaldehyde, the single field blank sample analyzed contained a detectable mass of 34 ng, which is 

below the minimum mass quantification limit of 40 ng. 

For formaldehyde, the single field blank sample analyzed contained no detectable mass. 

For nitrogen dioxide the single field blank sample analyzed contained no detectable mass. 

For PM2.5. the four field blank samples analyzed contained detectable masses averaging -3.25 μg, and 

ranging from -1 μg to -6 μg. These sample blank masses are below the minimum mass quantification 

limit of 10 μg. 

DIFFICULTIES ENCOUNTERED IN THE PILOT STUDY 

The following are difficulties that we encountered during the pilot study, followed by the corrective 

action that that will be incorporated onto the main study. 

1.) During inspection of the pilot homes we had problems with dust and debris from the attic falling out 

of the access onto surfaces in the occupied space of the home. 

Future action: Field teams that access the attic will be equipped with portable HEPA vacuums to 

clean up the dust and debris at the end of their inspection. 

2.) Following installation of loggers on the surfaces of windows or doors that are most commonly used, 

we experienced difficulty with the logger tape losing its adhesion properties over time, resulting in 

loggers falling to the floor. Homeowners were quick to report that the loggers had fallen off resulting 

in minimal data loss. 

Future action: The field team has selected and utilized with success a tape adhesive that keeps the 

loggers attached to these surfaces for the required duration of time. 
A-35

3.) Following collection of HOBO loggers by Team 3 and during shipping of the loggers back to Team 

1, one of the loggers was broken. 

Future action: Special shipping boxes will be employed to ensure that loggers are protected during 

shipping to prevent damage to the instrument and loss of the contained data. 

4.) The comparison of the data logger records of window openings and the occupant written logs 

indicate that the occupants logged only one of the data logger recorded openings. 

Future action: Consider improving the communication and occupant written logging methods to 

increase the accuracy with which the occupants log their window openings. 

5.) During setup and launching of loggers the logging interval on a single logger was incorrectly set so 

that the logger became full before the end of the required sampling duration. 

Future action: The protocol for setup and launching of loggers will be evaluated to see if the 

standard operating procedures can be modified to prevent this from happening. 

6.) Following installation of a the logger on the heating/cooling mechanical system of one pilot home, 

the homeowner called to report that their heating/cooling mechanical system no longer worked. It 

was discovered by field staff that heating/cooling mechanical system door had not been replaced 

correctly. 

Future action: The protocol for instillation of the heating/cooling mechanical system logger will be 

evaluated to see if the standard operating procedures can be modified to prevent this from 

happening. 

7.) The fifth and final blower door test failed three times in the field due to pressure fluctuations 

experienced during the collection of the last and lowest pressure data point. Since the blower door 

software we were using (Tectite 1.0) does not save any of the data from failed tests, we lost all of the 

data from this test. 

Future action: We have since upgraded to Tectite 3.1, which allows the user to save the data from 

interrupted failed tests. 
A-36

8.) The large change in the air sampling rate for the outdoor formaldehyde sample at P3 has been 

attributed to entrainment of rain drops into the DNPH sampler during the time that the field 

technician had the radiation/rain shield off and was calibrating the starting sample flow rates. 

Future action: We will include umbrellas with each of the field teams to protect the outdoor air 

samples during the start and stop calibrations. 

9.) Not enough time to complete all of the pilot field measurements with two-man field crews in the 

three-hour allotted time periods. This is especially true for Field Team 3, which conducted five 

blower door tests, and three pressurization duct leakage tests in addition to the shutting down the air 

samplers and PFTs and measuring all of the mechanical ventilation system flow rates. 

Future action: We will work with the ARB, the Energy Commission, and the Science Advisory 

Board to streamline the field protocols for each of the three field times so that quality work can be 

performed within the three hours of field time allocated to each of the three field teams. 

CONCLUSIONS 

The field SOPs and laboratory analyses developed for the pilot study appear to be acceptable for 

deployment in the main field study, which begins this summer in July and August 2006. Based upon the 

results from the three-home pilot study, we look forward to working with the ARB, the Energy 

Commission, and the Science Advisory Board to make refinements and improvements in the field SOPs 

and laboratory analyses that can improve the quality of the collected data. 
A-37

Table 1. Home characteristics collected in P1, P2, and P3 pilot test homes. 

House Characteristics 

House ID P1 P2 P3 

General 

Age of house 2.5 yrs. 2.75 yrs. 2.5 yrs. 

Number of stories 1 1 2 

Foundation type (slab, basement, crawl-space) Slab Slab Slab 

Conditioned floor area (ft2) 2,500 1,670 2,580 

Conditioned envelope area (ft2) 5,450 3,834 5,200 

Conditioned air volume (ft3) 24,990 16,670 21,700 

Sources 

Number of occupants (Adults/Children) 2/0 2/0 2/0 

Attached garage – Self closing / gasketed door Yes / Yes Yes / Yes Yes / Yes 

Cooking Fuel G/E G G 

Hot Water Fuel G G G 

Heating Fuel G G G 

Clothes Drying Fuel E E E 

Unvented Combustion Heaters 0 0 0 

Carpeting (ft2) 1,512 923 1,862 

Composite Pressed Wood (ft2) 421 555 598 

Moisture Staining/Damage (ft2) 0 0 0 

Visible Potential Fungal Growth (ft2) 0 0 0 

Outdoor Sources (within 500 feet) None None Yes a

Ventilation and Air Cleaning 

Exterior Window/Door Openings (% of floor area) 5.6 5.7 5.5 

Forced Air System (Heating, Cooling) Attic / H/C Attic / H/C Attic / H/C 

Forced Air Filter Efficiency (MERV) ~ 6 b ~ 6 b 8 

Forced Air Fan Control Auto Auto Auto 

Mechanical Outdoor Air Delivery System Attic / Yes Attic / Yes No 

Mechanical Outdoor Air Delivery System Control Continuous Continuous NA

Mechanical OA System Filter Efficiency (MERV) ~ 6 b ~ 6 b NA

Night Cooling System Yes No No 

Night Cooling System Controls Auto NA NA

a.) Construction road work and open fields. 

b.) No ASHRAE 52.2 MERV rating. ASHRAE 52.1 average atmospheric dust spot 

efficiency is 3%. 
A-38

Table 2. Homeowner reported home renovations, maintenance, and other IAQ-related 

activities collected in P1, P2, and P3 pilot test homes. 

Renovations, Maintenance, and Other IAQ-Related Activities 

House ID P1 P2 P3 

Construction Completion Date 05/2003 03/31/03 08/2003 

Move-in Date 05/2003 04/01/03 08/2003 

Are You the First Owner Yes Yes Yes 

Number of Occupants 2 2 2 

Number of Cigarette/Cigar 

Smokers 0 0 0 

Number of Pets 0 0 0 

Are Shoes Worn in Home Yes No No 

Renovations No No Yes a 

Duct Cleaning No No No 

Pesticide Applications Yes b No Yes b 

Construction, 

Occupancy, 

Renovations, and 

Other IAQ-Related 

Activities 

Fire/Smoke Damage No No No 

Twice per Week, or More 

Once per Week X X 

Once per Fortnight 

Once Every Three to Four 

Weeks 

Less that Once per Month X 

Last Vacuuming Date 12/04/05 11/26/05 09/01/05 

Carpet 

Cleaning 

Last Spot Cleaning Date 11/20/05 11/26/05 12/03/05 

Portable Air Cleaners No No No 

Vacuum Cleaners Yes c Yes c Yes c 

Window Fans No No No

Air Cleaners and 

Ventilation Fans 

Window Air Conditioners No No No 

Air Fresheners (manual, 

continuous) 1-manual No No 

Candles Yes d Yes d Yes d 

Incense No No No 

Mothballs No No No 

Air Fresheners and 

Other Sources 

Hobbies/Crafts No No No 

Paints, Thinners, Varnishes Yes e Yes e Yes f

Gasoline, Fertilizers, etc. Yes g No Yes e

Detergents, Bleach, Chlorine, 

etc. Yes f Yes f Yes g

Chemical Storage 

Items 

Pesticides, Insecticides, etc. Yes g No Yes e 

a.) Garage Painting 11/23/05. 

b.) P1 exterior application on 11/1/05; P3 exterior application – no date 

c.) P1 – B & D Dirt Buster/Orek XL 2Ceo-Hypo Allergenic Plus; P2 – Dirt 

Devil/Kenmore Whisper; P3 – Dirt Devil. 

d.) P1 – 4; P2 – 7; P3 – 5. 

e.) Garage 

f.) Kitchen 

g.) Shed/Storage Room 
A-39

Table 3. Homeowner reported building system failures and home IAQ improvements 

collected in P1, P2, and P3 pilot test homes. 

Building System Failures and Home IAQ Improvements 

House ID P1 P2 P3 

Building System Failures 

Condensation (includes windows/interior walls) No No No 

Roof Leaks No No No 

Plumbing Leaks No Yes No 

Window or Wall Leaks No No No 

Flooding No No No 

Poor Site Drainage No No No 

Bothersome Carpet Odors No No No 

Bothersome Cabinetry Odors No No No 

Other Moisture Problems No No No 

Home IAQ Improvements 

None (As Built Equipment/Configuration) No No Yes 

Upgrade Central Air Filter Yes Yes No 

High Efficiency Vacuum Cleaner (includes HEPA) No No No 

Entire House Vacuum System No No No 

Low-Emission Carpets, Cabinets, Furniture, etc. No Yes a No 

Carbon Monoxide Alarm No No No 

Special Range Hood No No No 

Extra Exhaust Fans No No No 

Entire House Ventilation System Yes No No 

Other Yes b No No 

a.) Furniture 

b.) Heat Recovery Ventilator (HRV) 
A-40

Table 4. Homeowner reported source activities during the 24-hour ventilation and IAQ 

contaminant measurement period collected in P1, P2, and P3 pilot test homes. 

IAQ Source Activities 

House ID P1 P2 P3 

Activities Duration in Minutes

Toasting 

Frying 

Sautéing 

Baking 

Broiling 

Warming/Boiling Water, Soups, 

etc. 7 10 

Microwave 1 14 

Cooking 

Activities 

Other 

Total Minutes 7 1 24 

Vacuuming 

Sweeping 

Dusting 

Floor Stripping 

Floor Waxing 

Cleaning 

Activities 

Use of Cleaners or Furniture 

Polish 

Total Minutes 0 0 0 

Smoking 

Wood Burning 

Candle Burning 

Incense Burning 

Painting 

Nail Polish Application/Removal 

Spray Air Fresheners 

Occupant 

Special 

Activities 

Large Party/Dinner Gatherings 

Total Minutes 0 0 0 

Grass Cutting 

Leaf Blowing/Sweeping 

Painting 

Barbecuing 

Outdoor 

Activities 

Pesticide Application 

Total Minutes 0 0 0 

a.) If no entry, then no minutes of activity. 
A-41

Table 5. Homeowner-reported occupant perceptions and physical symptoms collected in 

P1, P2, and P3 pilot test homes. 

Occupant Perceptions and Physical Symptoms 

House ID P1 P2 P3 

Environmental Conditions 

Too Hot No No No 

Too Cold No No Yes 

Too Dry No No No 

Too Humid No No No 

Too Drafty No Yes No 

Too Stagnant No No No 

Too Dusty No Yes No 

Mold, Mildew, or Other Odors

Bathroom No No No 

Basement/Crawlspace NA NA NA

Walls or Ceilings No No No 

Carpets No No No 

Cabinetry No No No 

Other Yes a No No 

Physical Symptoms

Eye Irritation No No No 

Nose/Sinus Congestion Yes No No 

Nose Irritation No No No 

Allergy Symptoms Yes Yes No 

Headache Yes No No 

Skin Irritation No No No 

Difficulty Concentrating No No No 

Asthma Symptoms No No No 

Other No No No 

Diagnosed Conditions

Allergies Yes No No 

Asthma Yes No No 

Chemical Sensitivity No No No 

 

a.) Tap Water 
A-42

Table 6. Occupant use of windows and doors collected by occupant logs in P1, P2, and P3 pilot test homes. 

Location Day 1 

(ft2 *hr) Day 2 (ft2 *hr) Day 3 (ft2 *hr) Day 4 (ft2 *hr) Day 5 (ft2 *hr) Day 6 (ft2 *hr) Day 7a (ft2 *hr) 

Pilot Home 1 

Window & Door Opening Area*Hours Open 

0.0 0.0 0.0 0.0 0.0 0.0 0.0 

Pilot Home 2 

Window & Door Opening Area*Hours Open 

0.0 0.0 0.0 0.0 0.0 0.0 0.1 

Pilot Home 3 

Window & Door Opening Area*Hours Open 

0.0 37.7 0.0 0.0 0.6 163.1 50.8 

a.) Day 7 is the 24-hour test period during which indoor air quality contaminant parameters were 

measured. 
A-43

Table 7. Bathroom and laundry exhaust flow rate measurements in P1, P2, and P3 pilot test homes. 

Location Exhaust 

(CFM) 

Exhaust 

(ACH) 

Ventilation by Exterior 

Openings 

(% floor area) 

Are

O

Pilot Home 1 – 2,499 sq ft Continuous a Intermittent a Master Bathroom Master Bathroom Toilet Room Bathroom #2 Laundry 

46 

na

na

41 

na

41 19 

na

2.2 

16 

2.1 4.7 

24 

4.0 5.5 

0 

Pilot Home 2 – 1,667 sq ft Master Bathroom Master Bathroom Toilet Room Bathroom #2 Laundry 

68 

na

na

62

na

49 37 

na

6.7 

19 

4.2 8.1 

5.7 

0 

7.4 

0 

Pilot Home 3 – 2,583 sq ft Master Bathroom Master Bathroom Toilet Room Bathroom #2 Bathroom #3 Laundry 

na

nananana

86 51 39 42 38 

3.7 7.1 6.0 4.6 8.3 

3.7 

0 0 0 0 

ASHRAE 62.2-2003 Guidelines b 20 50 na 4c California Building Code 2001b na na 5 5 (4 for toilet rooms) 1.5 – 

lau

a.) na indicates that the value was not reported because the mechanical fan was not operated in this mode. 

b.) na indicates no applicable guidelines reported. 

c.) ASHRAE 63.2-2004 guideline of ventilation openings not less than 4% of the floor area with a minimum of 1.5 

Utility rooms with dryer exhaust duct and toilet rooms within bathrooms. 
A-44

Table 8. Kitchen exhaust flow rate measurements in P1, P2, and P3 pilot test homes. 

Location Intermittent Exhaust 

Minimum / Maximum CFM 

Continuous Exhaust 

Minimum / Maximum ACH 

Pilot Home 1 

Kitchen 213 / 249 na

Pilot Home 2 

Kitchen 298 / 392 na

Pilot Home 3 

Kitchen 175 / 305 na

ASHRAE 62.2 Recommended Guidelines 

100 5 

a.) na indicates that the value was not reported because the mechanical fan was intermittently 

operated. 
A-45

Table 9. Exhaust fan flow rate operation measurements in P1, P2, and P3 pilot test homes. 

Location Flow rate 

(cfm) 

Day 1 

(cfm*hr) 

Day 2 

(cfm*hr) 

Day 3 

(cfm*hr) 

Day 4 

(cfm*hr) 

Day 5 

(cfm*hr) 

Day 6 

(cfm*h

Pilot Home 1 

Kitchen 213/249 0 0 0 0 0 0 Master Bath Room a 46 1,104 1,104 1,104 1,104 1,104 1,104 Master Bath Room Toilet 41 0 0 0 1 8 46 Bath Room #2 19 12 10 36 44 26 6 Laundry a 41 984 984 984 984 984 984 Cloths Dryer 136 374 580 256 0 165 117 Totals 2473 2678 2380 2133 2286 2257 Pilot Home 2 Kitchen 298/392 0 0 0 0 0 0 Master Bath Room a 68 1,632 1,632 1,632 1,632 1,632 1,632 Master Bath Room Toilet 49 2 55 16 25 0 22 Bath Room #2 37 9 12 13 12 0 0 Laundry a 62 1,488 1,488 1,488 1,488 1,488 1,488 Cloths Dryer 118 0 197 <1 303 <1 56 Totals 3,131 3,384 3,149 3,461 3,120 3,198 Pilot Home 3 Kitchen 175/305 0 0 66 0 178 92 Master Bath Room 86 26 0 31 0 0 0 Master Bath Toilet Room 51 69 77 11 32 11 2 Bath Room #2 39 0 0 0 0 0 0 Bath Room #3 42 0 0 0 0 0 0 Laundry Room 38 0 0 0 0 0 0 Cloths Dryer 99 0 0 0 0 0 0 Totals 96 77 107 32 189 94 

a.) Mechanical heat recovery ventilation (HRV) system exhaust air flowrates – continuous. 

b.) Day 7 is the 24-hour test period during which the tracer gas air exchange rate and indoor air quality co

parameters were measured. 
A-46

Table 10. Return air flow rates and forced air heating/cooling system percent on-time in P1, P2, and P3 pil

Location Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Pilot Home 1 

Forced air heating/cooling system on-time (%) Return air flow rate – 1,180 cfm 

13 8 7 20 14 19 

Pilot Home 2 

Forced air heating/cooling system on-time (%)b Return air flow rate – 928 cfm 

0 0 0 0 0 0 

Pilot Home 3 

Forced air heating/cooling system on-time (%) Return air flow rate–1,010/1,160 cfm b 

2 6 15 23 13 18 

a.) Day 7 is the 24-hour test period during which indoor air quality contaminant parameters were measured. 

b.) Dual zone system: cfm on low speed – one zone / cfm on high speed – two zones. 
A-47

Table 11. Mechanical outdoor air ventilation measurements in P1, P2, and P3 pilot test homes. 

Location Floor Area 

(ft2) 

# Bedrooms Percent 

On-time 

(%) 

Outdoor Air 

Flow Rate 

(cfm) 

Air Changes 

per Hour 

ASHRA

Guidelin

(cfm / a

100d Pilot Home 1 2,500 3 88 0.21 

0e 1,180 0 

55 / 0.

Pilot Home 2 1,670 2 100d 132 0.48 39 / 0.Pilot Home 3c 2,580 3 na na na 56 / 0.

a.) ASHRAE 62.2 Recommended Guidelines for ventilation requirements on a cubic feet per minute (cfm) / 

(ach) basis. 

b.) California Energy Commission, Title 24, 2001 Residential ACM Approval Manual. If Standard Leakage A

> 3.0 - no mechanically supplied outdoor air (OA) required. 1.5 < 3.0 - mechanically supplied OA required, minimum of 0.047 cfm/ft2 conditioned floor area. 

< 1.5 - mechanically supplied OA required, house maintained greater than -5 Pa with all continuous ven

c.) na indicates no mechanical whole building ventilation provided. 

d.) Operation of heat recovery ventilation system (HRV). 

e.) Operation of night time cooling ventilation system. 
A-48

Table 12. Forced air heating/cooling system fan pressurization duct leakage areas measurements in P1and P3 pilot test homes. 

Location Pilot Home 1 Pilot Home 2 Pilot Home 3c GuForced air heating/cooling system return air flow rate (cfm)b

1,180 928 1,010/1,160 

Forced Air System at 25 pascals, registers sealed with tape  Percent leakage of total system flow rate (%) 4.9 4.9 na Forced Air System at 25 pascals, registers sealed, home at 25 pascals  Percent leakage of total system flow rate (%) 4.6 3.0 na Forced Air System at 25 pascals, registers unsealed, home at 25 pascals  Percent leakage of total system flow rate (%) 2.5 0.2 na 

a.) California Energy Commission, Title 24, 2001 Energy Efficiency Standards for Residential and Nonres

Buildings. 

b.) dual zone system: cfm on low speed – one zone / cfm on high speed – two zones. 

c.) na indicates data was not collected due to occupant request to end testing because of noise/disruption 

baby. 
A-49

Table 13. Forced air heating/cooling system Delta-Q duct leakage areas measurements in P1, P2, and P3 pilot test homes. 

Location Pilot Home 1 Pilot Home 2 Pilot Home 3a Delta-Q  Supply leakage (cfm)b 61 20  Return leakage (cfm)b 42 43  Total (cfm) 103 63 

a.) na indicates data was not collected due to occupant request to end testing because of noise/disruptio

to a new baby. 

b.) Uncertainty of the measurement is +/- 20 cfm. 

Table 14. Home differential pressure measurements with the forced air system on and off in P1, P2, apilot test homes. 

Location Pilot Home 1 Pilot Home 2 Pilot Home 3 Home Air Pressure with Respect to Outdoors  Forced air heating/cooling system off (Pa) -1.2 -1.0 -1.1  Forced air heating/cooling system on (Pa) -1.0 -0.8 -1.5 

a.) California Energy Commission, Title 24, 2001 Residential ACM Approval Manual. If the Standard Lea

less than 1.5, then mechanically supplied OA is required, and the house air pressure with respect to obe greater than -5 Pa with all continuous ventilation fans operating. 
A-50

Table 15. Building air leakage area measurements in P1, P2, and P3 pilot test homes. 

Location Pilot Home 1 Pilot Home 2 Pilot Home 3a Indoor Temperature (

°

F) - HOBO/Q-Trak 

Outdoor Temp. (

°

F) - HOBO/weather data

68 / 67 47 / 44 

68 / 68 

44 

68 / 64 

51 

Wind Speed (mph) 0.5 1.4 5.8 Effective Leakage Area@4 Pa (in2) Depressurization 98.8 95.3 76.3 Pressurization 95.4 91.0 na Average 97.1 93.2 na Air Changes Per Hour at 50 Pa Depressurization 4.31 6.26 3.97 Pressurization 3.80 5.85 na Average 4.06 6.06 na Standard Leakage Area Depressurization 2.74 3.97 2.05 Pressurization 2.65 3.79 naAverage 2.70 3.88 na

a.) na indicates measurements not available due to unstable pressure measurement. 

b.) California Energy Commission, Title 24, 2001 Residential ACM approval Manual. 

> 3.0 - no mechanically supplied outdoor air (OA) required. 1.5 < 3.0 - mechanically supplied OA required, minimum of 0.047 cfm/ft2 conditioned floor area. 

< 1.5 - mechanically supplied OA required, house maintained greater than -5 Pa with all continuous venoperating. 

c.) na indicates no applicable guidelines reported. 
A-51

Table 16. House to garage air leakage measurements in P1, P2, and P3 pilot test homes. 

Location Pilot Home 1 Pilot Home 2 Pilot Home 3 GuidelHouse to garage pressure with house at -50 Pa to outdoor air (pascals) 

-49.5 -49.4 -49.8 >-

House to garage leakage area, EqLA at 10 Pa 

(inches2) 20 (+/- 15) 8.5 (+/- 8.5) 4 (+/- 4) 

Garage to outdoors leakage area, EqLA at 10 Pa 

(inches2) 433 (+/- 14) 193 (+/- 19) 141 (+/- 8) 

House to garage leakage area / (house to outdoors leakage area + garage to outdoors leakage area) * 100 (%) 

3 2 1 

a.) American Lung Association. Healthy House Builder Guidelines 2004. 

b.) na indicates that no applicable guidelines were reported. 
A-52

Table 17. PFT tracer measurements of the outdoor air exchange rate in P1, P2, and P3 pilot test home

Location Pilot Home 1 Pilot Home 2 Pilot Short Term  Duration (Days) 0.93 0.99  Sample 1 (Outdoor air changes per hour) 0.37 0.73  Sample 1 Duplicate (Outdoor air changes per hour) 0.37 0.71 Long Term  Duration (Days) 13.97 13.98 2 Sample 1 (Outdoor air changes per hour) 0.29 0.57  Sample 1 Duplicate (Outdoor air changes per hour) na na 

a.) na indicates that there was no sample collected. 
A-53

Table 18. Short- and long-term measurements of home to garage zone air leakage using PFT tracer and P3 pilot test homes. 

Location Pilot Home 1 Pilot Home 2 PilShort Term  Duration (Days) 0.93 0.99  Sample 1 (% garage source into home) 2.6 10.1  Sample 1 Duplicate (% garage source into home) 1.9 11.9 Long Term  Duration (Days) 13.97 13.98  Sample 1 (% garage source into home) 4.0 7.2  Sample 1 Duplicate (% garage source into home) na na 

a.) na indicates that there was no sample collected. 
A-54

Table 19. Outdoor air ventilation rates calculations for P1, P2, and P3 Pilot test homes. 

Location Pilot Home 1 Pilot Home 2 Natural outdoor air exchange rate a 0.12 0.18 Balanced mechanical outdoor air exchange rate b 0.23 0.48 Unbalanced mechanical outdoor air exchange rate c 0.01 0.02 Natural + mechanical outdoor air exchange rate (ASHRAE 136) d 0.35 0.66 Natural + mechanical outdoor air exchange rate (Palmiter/Bond 0.5 Rule) e 0.36 0.66 PFT Measurement 0.37 0.72 Window / Door Opening (ft2-hr) 0.0 0.1 Energy Commission Guideline g 0.35 0.35 

a.) Calculated using the “Enhanced Method” in ASHRAE Fundamentals, Chapter 27. b.) Smaller of the total 24-hour average exhaust air or outdoor airflow rate. 

c.) Larger – smaller of the total 24-hour average exhaust air or outdoor airflow rate. 

d.) Calculated according to ASHRAE 136-1993 (RA2001). The total outdoor air ventilation rate equals the s

total supply and total exhaust airflow + the square root of (the absolute value of the difference between and total exhaust airflow) squared + the infiltration airflow squared). 

e.) Palmiter/Bond 0.5 Rule. If the unbalanced mechanical ventilation flow rate < 2 * the natural infiltration ra

total outdoor air ventilation rate is calculated by the balance portion of the mechanical ventilation flow rainfiltration rate + 1/2 the unbalanced portion of the mechanical ventilation flow rate. If the unbalanced mventilation flow rate > 2 * the natural infiltration rate, then the total outdoor air ventilation rate is calculategreater of the exhaust or outdoor air flow rate. 

f.) Calculated using P2 supply air and return air forced air heating/cooling system duct air leakage / Calcul

any supply air and return air forced air heating/cooling system duct air leakage. 

g.) California Energy Commission, Title 24, 2001 Residential ACM Approval Manual guideline for natural + 

outdoor air exchange rate. 
A-55

Table 20. Concentrations of individual volatile organic compounds measured indoors and outdoor

pilot test homes. 

Concentrations of Volatile Organic Compounds (μg/m3) 

Compound Detection 

Limit 

P1 

Indoors 

P1 

Indoor 

Duplicate 

P2 

Indoors 

P1 (P2)a

Outdoors 

P3 

Indoors 

Acetic acid est. 0. 4 Acetonitrile est. 0.4 Acetophenone 0.4 0.7 0.6 0.5 0.5 1.5 Benzaldehyde 0.4 3.2 3.6 2.6 0.3 4.4 Benzene 0.4 3.7 3.8 3.1 2.8 3.1 1-Butanol 2 3.4 3.6 4.6 5.3 2-Butanone 0.8 2-Butoxyethanol 0.4 4.0 4.1 1.3 36 tert-Butyl methyl ether 0.4 4.4 4.5 Caprolactam 0.8 Carbon tetrachloride 0.4 Chloroform 0.4 Cresol mix 0.4 Cyclohexane est. 2 7.0 7.3 Decanal 4 n-Decane 0.4 

a.) Outdoor air sampled at one location, P1, for the two-home cluster of P1 and P2. 

b.) OEHHA Chronic Reference Exposure Levels, 2003. na = no available guideline. 

c.) 1/40th the 8-hour occupational health guideline (e.g., the California Division of Occupation

(Cal/OSHA) Permissible Exposure Limits (PELs), American Conference of Governmental Indust

Threshold Limit Values (TLVs), Deutsche Forschungsgemeinschaft (DFG) Maximum Allowable Cna = no available guideline. 

 Note: Samples with no values reported are below the detection limit. 
A-56

Table 21. Concentrations of individual volatile organic compounds measured indoors and outdoors 

pilot test homes. 

Concentrations of Volatile Organic Compounds (μg/m3)

Compound Detection 

Limit 

P1 

Indoors 

P1 

Indoor 

Duplicate 

P2 

Indoors 

P1 (P2)a

Outdoors 

P3 

Indoors 

Di(ethylene glycol)butyl ether est. 2 3.7 1,4-Dichlorobenzene 0.4 1,1-Dichloroethene 2 n-Dodecane 0.4 Ethanol 6 1,173 1,181 221 162 Ethoxyethanol 0.4 2-Ethoxyethyl acetate 0.4 Ethyl acetate est. 0.4 2.2 2.1 2.8 5.2 2-Ethyl-1-hexanol 0.8 0.9 1.2 Ethylbenzene 0.4 2.1 1.9 1.2 1.2 4.3 Ethylene glycol est. 2 14 14 8.0 2-Furancarboxaldehyde 0.4 1.4 1.4 1.1 4.4 Heptanal 0.4 0.6 0.6 1.9 n-Heptane 0.4 Hexanal 2 10 9.8 2.9 33 

a.) Outdoor air sampled at one location, P1, for the two-home cluster of P1 and P2. 

b.) OEHHA Chronic Reference Exposure Levels, 2003. na = no available guideline. 

c.) 1/40th the 8-hour occupational health guideline (e.g., Cal/OSHA PELs, ACGIH TLVs, DFG MA

guideline. 

 Note: Samples with no values reported are below the detection limit. 
A-57

Table 22. Concentrations of individual volatile organic compounds measured indoors and outdoor

pilot test homes. 

Concentrations of Volatile Organic Compounds (μg/m3)

Compound Detection 

Limit 

P1 

Indoors 

P1 

Indoor 

Duplicate 

P2 

Indoors 

P1 (P2)a

Outdoors 

P3 

Indoors 

n-Hexane 0.4 3.8 3.9 3.0 2.5 3.3 d-Limonene 0.4 24 19 3.1 0.5 22 1-Methoxy-2-propanol 0.4 2-Methoxyethanol est. 2 2-Methoxyethyl acetate 0.4 4-Methyl-2-pentanone (MIBK) 0.4 0.5 0.5 0.6 1-Methyl-2-pyrrolidinone 0.4 0.9 Naphthalene 0.4 Nonanal 4 4.7 3.6 9.6 Octanal 2 2.5 Pentanal 2 8.2 7.9 3.7 21.3 Phenol 4 alpha-Pinene 0.4 13 14 10 0.9 29 beta-Pinene 0.4 3.0 3.1 1.1 4.2 2-Propanol 0.8 146 149 18 6.5 

a.) Outdoor air sampled at one location, P1, for the two-home cluster of P1 and P2. 

b.) OEHHA Chronic Reference Exposure Levels, 2003. na = no available guideline. 

c.) 1/40th the 8-hour occupational health guideline (e.g., Cal/OSHA PELs, ACGIH TLVs, DFG MA

guideline. 

Note: Samples with no values reported are below the detection limit. 
A-58

Table 23. Concentrations of individual volatile organic compounds measured indoors and outdoor

pilot test homes. 

Concentrations of Volatile Organic Compounds (μg/m3)

Compound Detection 

Limit 

P1 

Indoors 

P1 

Indoor 

Duplicat

e 

P2 

Indoors 

P1 (P2)a

Outdoors 

P3 

Indoors 

2-Propanone 4 72 74 36 65 2-Propoxyethanol est. 2 Styrene 0.4 1.0 0.9 0.6 4.4 Tetrachloroethene 0.4 0.5 Toluene 0.4 27 28 28 6.4 13 1,1,1-Trichloroethane 0.4 Trichloroethene 0.4 2,2,4-Trimethyl-1,3-pentanediol diisobutyl ether 2 2,2,4-Trimethyl-1,3-pentanediol monoisobutyl ether, isomer 1 0.4 1.3 1.6 2.1 9.7 2,2,4-Trimethyl-1,3-pentanediol monoisobutyl ether, isomer 3 0.4 1.5 1.4 1.7 7.3 1,2,4-Trimethylbenzene 0.4 2.5 2.4 1.1 1.3 16.6 n-Undecane 0.4 Vinyl acetate 0.4 m-,p-xylene 0.4 4.7 4.5 3.1 3.1 10.1 o-xylene 0.4 2.2 2.0 1.5 1.5 8.2 

a.) Outdoor air sampled at one location, P1, for the two-home cluster of P1 and P2. 

b.) OEHHA Chronic Reference Exposure Levels, 2003. na = no available guideline. 

c.) 1/40th the 8-hour occupational health guideline (e.g., Cal/OSHA PELs, ACGIH TLVs, DFG MA

guideline. 

 Note: Samples with no values reported are below the detection limit. 
A-59

Table 24. Concentrations of formaldehyde and acetaldehyde measured indoors and outdoors at P1homes. 

Concentrations of Formaldehyde and Acetaldehyde Compounds (μg/m3)

Compound Detection 

Limit 

P1 

Indoors 

P1 

Indoor 

Duplicate 

P2 

Indoors 

P1 (P2)a

Outdoors 

P3 

Indoors 

Acetaldehyde 0.4 10 11 6.8 3.3 17 Formaldehyde 0.3 26 27 28 1.9 45 

a.) Outdoor air sampled at one location, P1, for the two-home cluster of P1 and P2. 

b.) Acetaldehyde - OEHHA Chronic Reference Exposure Level, 2003. Formaldehyde – Californ

Indoor Air Quality Guideline, 2005. na = no available guideline. 
A-60

Table 25. Concentrations of carbon monoxide, nitrogen dioxide, and PM2.5 particulate matter meaoutdoors at P1, P2, and P3 pilot test homes. 

Concentrations of Carbon Monoxide, Nitrogen Dioxide, and PM2.5 Particulate Ma

Compound Detection 

Limit 

P1 

Indoors 

P1 

Indoor 

Duplicate 

P2 

Indoors 

P1 (P2)a

Outdoors 

P3 

Indoors 

Carbon Monoxide (ppm) - 24-hour average 0.5 0.8 2.0 1.3 - maximum eight-hour average 0.5 1.0 2.9 1.4 - maximum one-hour average 0.5 1.6 3.3 1.8 Nitrogen Dioxide (μg/m3) – 24-hour 

average 9 10 12 

PM2.5 Particulate Matter (μg/m3) – 

24-hour average 3.5 12 17 11 24 11 

a.) Outdoor air sampled at one location, P1, for the two-home cluster of P1 and P2. 

b.) California Air Resources Board Indoor Air Quality Guideline, 2005. na = no available guideline. 

Note: Samples with no values reported are below the detection limit. 
A-61

Table 26. Temperature, relative humidity, and carbon dioxide concentrations measured indoors anand P3 pilot test homes over a 24-hour period. 

Temperature, Relative Humidity and Carbon Dioxide Concentrations

Compound P1 

Indoors 

P1 

Indoor 

Duplicate 

P2 

Indoors 

P1 (P2)a

Outdoors 

P3 

Indoors 

Ou

Carbon Dioxide (ppm) - 24-hour average 656 678 532 407 620 - maximum 2,251 2,236 1,228 495 1354 - minimum 491 516 421 352 465 Temperature (°F) - 24-hour average 67 67 68 45 64 - maximum 70 70 73 67 71 - minimum 62 62 67 36 60 Relative Humidity (%) - 24-hour average 42 41 35 70 52 - maximum 48 44 40 28 55 - minimum 40 39 34 93 45 

a.) Outdoor air sampled at one location, P1, for the two-home cluster of P1 and P2. 

b.) Carbon dioxide; ASHRAE 62.1-2004, na = no available guideline. 
A-62 

Table 27. Pilot study air sampling flow rate stability for P1, P2, and P3 pilot test homes. 

Air Sampling Flowrate Stability – Relative Standard Deviations a

Minimum Maximum Average 

VOCs 

(all 12 samples) 0.00 0.23 0.08 

VOCs 

(6 analyzed samples- with most stable flow rates) 0.00 0.07 0.03 

Nitrogen Dioxide 

(all 6 samples) 0.01 0.05 0.03 

Formaldehyde/Acetaldehyde 

(all 6 samples) 0.02 0.54 0.11 

Formaldehyde/Acetaldehyde 

(5 samples w/o sample P3-F2) 0.02 0.05 0.03 

Particulate Matter – PM2.5 

(all 6 samples) 0.01 0.04 0.03 

a.) Relative standard deviations, calculated as the standard deviation divided by the 

average of each pair of air sampling flow rate measurements (i.e., start and stop flow 

rate measurements). 
A-63 

Table 28. Pilot study carbon dioxide and carbon monoxide calibration stability for P1, P2, 

and P3 pilot test homes. 

Carbon Monoxide and Carbon Dioxide Calibration Stability (ppm) a

Minimum Maximum Average 

Carbon Monoxide Zero - 0 ppm 

 (all 6 samples – 24-hour collection periods) 0 0 0 

Carbon Monoxide Span - 35 ppm 

 (six 24-hour collection periods) -3 1 -1 

Carbon Dioxide Zero - 0 ppm 

 (six 24-hour collection periods) 0 63 21 

Carbon Dioxide Span - 1000 ppm 

 (six 24-hour collection periods) -16 120 39 

Carbon Dioxide Span - 1000 ppm 

 (5 samples w/o sample P3-C2) -16 60 22 

a.) Calibration stability calculated as the difference between the post-calibration 

concentration check and the calibration gas concentration. 
A-64 

Table 29. Pilot study air contaminant measurement precision for volatile organic 

compounds at P1, P2, and P3 pilot test homes. 

Air Contaminant Measurement Precision 

Sample 1 

(μg/m3

) 

Sample 2 

Duplicate 

Sample 

(μg/m3

) 

Relative a

Standard 

Deviation 

Acetic acid 0.8 0.7 0.09 

Acetonitrile 3.6 4.0 0.07 

Acetophenone 3.7 3.8 0.02 

Benzaldehyde 4.6 4.9 0.04 

Benzene bql bql na

1-Butanol 4.0 4.1 0.02 

2-Butanone 4.4 4.5 0.02 

2-Butoxyethanol bql bql na

tert-Butyl methyl ether bql bql na

Caprolactam bql bql na

Carbon tetrachloride bql bql na

Chloroform 7.0 7.3 0.03 

Cresol mix bql bql na

Cyclohexane bql bql na

Decanal bql bql na

n-Decane bql bql na

Di(ethylene glycol)butyl ether bql bql na

1,4-Dichlorobenzene bql bql na

1,1-Dichloroethene 1,173 1,181 0.00 

n-Dodecane bql bql na

Ethanol bql bql na

Ethoxyethanol 2.2 2.1 0.03 

2-Ethoxyethyl acetate bql 0.9 na

Ethyl acetate 2.1 1.9 0.07 

2-Ethyl-1-hexanol 14 14 0.00 

Ethylbenzene 1.4 1.4 0.00 

Ethylene glycol 0.6 0.6 0.00 

2-Furancarboxaldehyde bql bql na

Heptanal 10 9.8 0.01 

n-Heptane 0.8 0.7 0.09 

Hexanal 3.6 4.0 0.07 

a.) Relative standard deviation calculated as the standard deviation divided by the 

average for each pair of duplicate 24-hour samples. na = not applicable for sample 

pairs with one of samples below quantification limit (bql). 
A-65 

Table 30. Pilot study air contaminant measurement precision for volatile organic 

compounds at P1, P2, and P3 pilot test homes. 

Air Contaminant Measurement Precision 

Sample 1 

(μg/m3

) 

Sample 2 

Duplicate 

Sample 

(μg/m3

) 

Relative a

Standard 

Deviation 

n-Hexane 3.8 3.9 0.02 

d-Limonene 25 19 0.19 

1-Methoxy-2-propanol bql bql na

2-Methoxyethanol bql bql na

2-Methoxyethyl acetate bql bql na

4-Methyl-2-pentanone (MIBK) 0.5 0.5 0.00 

1-Methyl-2-pyrrolidinone bql bql na

Naphthalene bql bql na

Nonanal bql 5.2 na

Octanal bql bql na

Pentanal 8.2 7.9 0.03 

Phenol bql bql na

alpha-Pinene 13 14 0.05 

beta-Pinene 3.0 3.1 0.02 

2-Propanol 146 149 0.01 

2-Propanone 72 74 0.02 

2-Propoxyethanol bql bql na

Styrene 1.0 0.9 0.07 

Tetrachloroethene bql bql na

Toluene 27 28 0.03 

1,1,1-Trichloroethane bql bql na

Trichloroethene bql bql na

2,2,4-Trimethyl-1,3-pentanediol diisobutyl ether bql bql na

2,2,4-Trimethyl-1,3-pentanediol monoisobutyl 

ether, isomer 1 1.3 1.6 0.15 

2,2,4-Trimethyl-1,3-pentanediol monoisobutyl 

ether, isomer 3 1.5 1.4 0.05 

1,2,4-Trimethylbenzene 2.5 2.4 0.03 

n-Undecane bql bql na

Vinyl acetate bql bql na

m-,p-xylene 4.7 4.5 0.03 

o-xylene 2.2 2.0 0.07 

a.) Relative standard deviation calculated as the standard deviation divided by the 

average for each pair of duplicate 24-hour samples. na = not applicable for sample 

pairs with one of samples below quantification limit (bql). 
A-66 

Table 31. Pilot study air contaminant measurement precision for acetaldehyde, carbon 

dioxide, carbon monoxide, formaldehyde, nitrogen dioxide, and particulate matter PM2.5 

at P1, P2, and P3 pilot test homes. 

Air Contaminant Measurement Precision 

Sample 1 Sample 1 

Duplicate 

Relative a

Standard 

Deviation 

Acetaldehyde (μg/m3) 10 11 0.07 

Formaldehyde (μg/m3) 26 27 0.03 

Carbon Dioxide (ppm) 626 678 0.06 

Carbon Monoxide (ppm) 0.8 bql na

Nitrogen Dioxide (μg/m3) bql bql na

Particulate Matter – PM2.5 (μg/m3) 12 17 0.24 

a.) Relative standard deviation calculated as the standard deviation divided by the average 

for each pair of duplicate 24-hour samples. na = not applicable for sample pairs with 

one of samples below quantification limit (bql). 
A-67 

Table 32. PFT measurement precision for P1, P2, and P3 Pilot test homes. 

PFT Measurement Precision 

Sample 1 Sample 1 

Duplicate 

Sample 

Relative a

Standard 

Deviation 

Pilot Home 1 

 Indoor Tracer short term, PMCH (ach) 0.37 0.37 0.00 

 Garage Tracer, short term, p-PDCH (%) 2.6 1.9 0.20 

Pilot Home 2 

 Indoor Tracer short term, PMCH (ach) 0.73 0.71 0.03 

 Garage Tracer, short term, p-PDCH (%) 10.1 11.9 0.11 

Pilot Home 3 

 Indoor Tracer long term, PMCH (ach) 0.30 0.34 0.09 

 Garage Tracer, long term, p-PDCH (%) 11.3 11.4 0.01 

a.) Relative standard deviation calculated as the standard deviation divided by the 

average for each pair of duplicate 24-hour samples. 
A-68 

Figure 1. Pilot Home P3, photograph of air sampling rig in the family room. 
A-69 

Figure 2. Close-up of air sampling rig. 
A-70 

Figure 3. Close-up of air sampling rig with outdoor radiation/rain shield. 
A-71 

Figure 4. Pilot Home P2, Duct Blaster installed at return air inlet of forced air 

heating/cooling system. 
A-72 

Figure 5. Pilot Home P2, Blower Door and APT installed. 
A-73 

Figure 6. Pilot Home P1, photograph of front elevation. 
A-74 

Figure 7. Pilot Home P2, photograph of front elevation. 
A-75 

Figure 8. Pilot Home P3, photograph of front elevation. 
A-76 

Figure 9. Floor plan of Home P1 depicting the locations of the air samplers and the PFT 

sources. 
A-77 

Figure 10. Floor plan of P2 depicting the locations of the air samplers and the PFT sources. 
A-78 

Figure 11. Floor plan of P3 first floor, depicting the locations of the air samplers and the 

PFT sources. 
A-79 

Figure 12. Floor plan of P3 second floor, depicting the locations of the PFT sources. 
A-80 

Carbon Dioxide

P1-C1-051206

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

10:3111:1111:5112:3113:1113:5114:3115:1215:5216:3217:1217:5218:3219:1219:5320:3321:1321:5322:3323:1323:53

0:341:141:542:343:143:544:345:145:556:357:157:558:35

Time

Carbon Dioxide (ppm)

Carbon Dioxide

Figure 13. Concentration of carbon dioxide measured indoors at one-minute intervals in 

pilot home P1 between 10:19 on December 6, 2005, and 9:22 on December 7, 2005. 
A-81 

REFERENCES 

ASHRAE. 2004. ASHRAE Standard 62.1‐2004, Ventilation and Acceptable Indoor Air

Quality. Atlanta, Georgia: American Society of Heating, Refrigerating and Air‐

Conditioning Engineers, Inc.

ASTM. 2002. ASTM Standard E 104, Standard Practice for Maintaining Constant Relative

Humidity by Means of Aqueous Solutions. West Conshohocken: American Society

for Testing and Materials Standards.

California Air Resources Board. 1999. Final Staff Report – Update to the Toxic Air

Contaminant (TAC) List. California Environmental Protection Agency, Sacramento,

California. Available at http://www.arb.ca.gov/toxics/id/finalstaffreport.htm.

California Air Resources Board. 2005. Report to the California Legislature: Indoor Air Pollution

in California. California Environmental Protection Agency, Sacramento, California.

Available at www.arb.ca.gov/research/indoor/ab1173/ab1173.htm.

EPA (Environmental Protection Agency). 1989. Compendium of Methods for the

Determination of Air Pollutants in Indoor Air. Washington, D.C.  

EPA (Environmental Protection Agency). 1990. National Air Quality Standards (NAAQS).

Washington, D.C. Available at: www.epa.gov/air/criteria.html.

EPA (Environmental Protection Agency). 1999. Compendium Method TO‐15. Washington,

D.C. www.epa.gov/ttnamti1/files/ambient/airtox/to‐15r.pdf.

Nielson, G. D., L. F. Hansen, and P. Wolkoff. 1997. “Chemical and Biological Evaluation of

Building Material Emissions. II. Approaches for Setting Indoor Air Standards or

Guidelines for Chemicals.” Indoor Air 7:17–32.

NIOSH (National Institute for Occupational Safety and Health). 1994a. Method 6014‐Nitric

Oxide and Nitrogen Dioxide. NIOSH Manual of Analytical Methods (NMAM), 4th

Edition, Cincinnati, Ohio.

NIOSH (National Institute for Occupational Safety and Health). 1994b. Method 0500‐

Particulates Not Otherwise Regulated, Total. NIOSH Manual of Analytical

Methods (NMAM), 4th Edition. Cincinnati, Ohio.

OEHHA (Office of Environmental Health Hazard Assessment). 2003. All Chronic

Reference Exposure Levels Adopted by OEHHA as of August 2003.
A-82 
A-83 

Appendix A 

Pilot Study 

Recruitment Letter
A-84 

<<Customer Name>> 

<<Address>> 

<<City>>, <<CA>>, <<Zip code>> 

November 8, 2005 

Dear <<Customer Name>>, 

SUBJECT: Energy, Ventilation, and Indoor Air Quality Study 

Thank you again for completing the UC Berkeley Ventilation Practices and Indoor Air Quality 

Survey sent to you in 2004–2005. As you may recall, this important research is sponsored by the 

California Energy Commission and the California Air Resources Board (ARB) to help improve 

the energy efficiency and indoor air quality of newer homes in California. In the Survey, you 

expressed interest in participating in the second part of the study, which involves measuring 

ventilation and indoor air quality in new homes. 

We are contacting you to request your participation in the second part of the study, entitled 

“Ventilation and Indoor Air Quality in New Homes.” Your home was randomly selected for this 

study, and receipt of this letter does not mean there is a problem with ventilation or indoor air 

quality in your home. Because your home was randomly selected to obtain a representative 

group of homes, your participation is critical to the success of this study. In addition, your 

participation is very important to the State of California as it prepares to update building energy 

design standards and strives to assure healthful indoor air quality in our new homes. 

What Do I Receive for My Participation?

The ARB is offering to thoroughly measure the ventilation and indoor air quality of your home at 

no cost to you. This type of air quality testing would typically cost as much as $7,000 per home. 

We recognize that your participation in this study may present an inconvenience to you, so we 

are pleased to offer you $100 to thank you for your participation in this research. 

All test results and personal information about your home will be kept strictly confidential. You 

will receive a summary of the final report for the study and be notified when the final report is 

available on the internet. The final report will include a description of the measurements and the 

collective results of the 100 homes tested. For your home, test results will be available upon your 

request. This information can be used to improve the energy efficiency and air quality of your 

home. 

What Does the Study Involve?

9 We ask that you conduct your normal household activities during the testing period. 

9 Field teams will visit your home on 3 days within an 8–10 day period. 

State of California 

 

Governor Arnold Schwarzenegger 

California Energy Commission
A-85 

o Each visit will last approximately 2–3 hours. Each visit will be scheduled with 

you and will occur between 9 a.m. and 7 p.m. The teams may also need to inspect 

your home’s attic or crawlspace. 

o Team members will be fully bonded and will wear identification badges. 

o If you would like to participate but believe you won’t be able to accommodate 

each visit, a key lockbox can be provided. 

9 A field team will place small data loggers (matchbox sized) in a few windows and ventilation 

fans to collect usage information (Days 1–8). These data loggers will not interfere with 

opening, closing, or locking your windows. 

9 You will be provided with forms to track your: 

o Household window and fan usage for 1 week (Days 1–8). 

o Household activities such as cooking, painting, candle burning, smoking, and 

vacuuming for a 2-day period (Days 7–8). 

9 You will be asked to complete a brief ventilation and indoor air quality questionnaire. 

9 A field team will install air quality testing equipment in your home’s main living area on 

Day 7. The equipment will operate for a 22–26 hour period (see the photo below); it is 

very quiet and safe. 

9 A field team will remove the data loggers and testing equipment on Day 8. 

A more detailed description of the in-home visits will be provided when you schedule an 

appointment. 

How Do I Enroll in the Study?

We hope that you will agree to participate in this study. To enroll or obtain additional 

information, please call Bud Offermann at this toll-free number, 1-888-567-7700, by 

November 15, 2005. 

Thank you for your consideration. 

Sincerely,

 

Francis “Bud” Offermann 

Under ARB Contract No. 04-310 

Administrator of Research Recruitment 

Indoor Environmental Engineering 

1448 Pine St., Suite103 

San Francisco, CA 94109 

www.IEE-SF.com 

1-888-567-7700 

Thomas J. Phillips, Contract Manager 

Indoor Exposure Assessment Section 

Research Division 

California Air Resources Board 

1001 - I St., POB 2815 

Sacramento, CA 95812 

www.arb.ca.gov/research/indoor/indoor.htm 

916-322-7145

Quiet indoor air sampler, 

typically installed in the living 

room for a 22 - 26 hour period. 
A-86 
A-87 

Appendix B 

Pilot Study 

Recruitment Script 
A-88 

Air Resource Board Ventilation & Indoor Air Quality Study 

Recruiting Instrument 

Recruiting ID:________ Initial Mailing: Pilot Mailing, November 9, 2005 

Initial Contact Information (collect at start of call) 

Participant Name (if different than database):________________________________________ 

Home Address (if different than database):___________________________________________ 

Phone-Home: __________________________ 

Additional Contact Information (collect at end of call) 

Name and e-mail:_______________________ Name and e-mail:_______________________ 

 _______________________ _______________________ 

Name and Phone-Work: _________________ Name and Phone-Work: _________________ 

 _________________ _________________ 

 

Name and Phone-Cell: __________________ Name and Phone-Cell: __________________ 

 __________________ __________________ 

Circle best number and time to call: ____________________________________ 

Call Log

Codes: 

1=Completed and agrees to participate 2=Callback 3=Left Message 

4=Busy 5=No Answer 6=Refusal 

7=Termination 8=Wrong Number 9=Disconnected Number 

 

10=Language Barrier 

 

 Date: Time: Outcome Notes 

Call 1 / : 

AM 

PM 

 

Call 2 / : 

AM 

PM 

 

Call 3 / : 

AM 

PM 

 

Call 4 / : 

AM 

PM 

 

Call 5 / : 

AM 

PM 

 

Call 6 / : 

AM 

PM 

 

Call 7 / : 

AM 

PM 

 
A-89 

Concerned Customers: Customers may call the California Air Resources Board to 

confirm the validity of our study. Contact Thomas J. Phillips, Contract Manager at 

916.322.7145. 

Additional information on indoor air quality is available on the web at 

http://www.arb.ca.gov/research/indoor/indoor.htm and 

http://www.arb.ca.gov/research/research.htm. 

INTRODUCTION: 

Hello this is Bud Offermann. I am the Principle Investigator for the California Air 

Resources Board Research Project “Ventilation and Indoor Air Quality in New Homes”. 

Are you interested in finding more about this research project and perhaps 

participating ??

Yes. Great ! First let me confirm your name, address, and phone number. Enter 

information on page 1, Initial Contact Information. 

No. Well then how can I help you ? 

Notes from homeowner: 

Or (if Bud is not in) 

Hello, Mr. Offermann is not available at this time. My name is Jonathan Robertson and I 

am the field team manager for the California Air Resources Board Research Project 

“Ventilation and Indoor Air Quality in New Homes”. Are you interested in finding 

more about this research project and perhaps participating ?

Yes. Great ! First let me confirm your name, address, and phone number. Enter 

information on page 1, Initial Contact Information. 

No. Well then how can I help you ? 

Notes from homeowner: 

LOG in call start time:___________ LOG in call stop time:_____________ 

I first need to ask you a few questions to confirm that your home qualifies for the 

study. 
A-90 

QUALIFIER QUESTIONS 

1. Are you the original owner? 

1. Yes 

2. No I am the 2nd, 3rd, 4th owner. (Circle, which one applies) 

3. No, I am a renter. Thank and terminate call (explain that this study is only open 

to owner occupied homes) 

2. How long have you lived at this house ?

Months______ / Years_______ 

If less than one year by the time that the field study is to be scheduled then 

terminate call (this study is only open to owners who have lived in there house for 

more than one year). 

3. Is this your primary residence? 

1. Yes 

2 No. Thank and terminate call (this study is only open to the primary residences 

of owner occupied homes) 

4. Can you tell me if your home was constructed before or after 2002? 

1. Yes, built before 2002. (Thank and terminate call, this study is only open to the 

new homes built after 2002) 

2. No, built after 2002. (Proceed) 

98. Don’t Know. Ask who might know; _____________________________ 

5. Do you recall the month and year your home was completed? 

Month/Year: ____________________ 

Not sure, estimate: _______________ 

6. Has your home had any major fire, smoke, or water damage? 

1. Describe what and when:____________________________________ 

____________________________________________________________ 

____________________________________________________________ 

2. No. 

7. I need to find out if your home has a fresh air ventilation system. Typically these 

system have an air duct connected to your forced air heating and cooling system 

to bring in outdoor air. Or some fresh air systems have a separate fan and 

ductwork that distributes air continuously throughout the house. A whole house 

exhaust fan that is used to cool the house at night does not qualify. Does your 

home have a fresh air ventilation system ? 
A-91 

1. Yes 

2. Not sure 

3. No 

98. Don’t Know 

8. If yes, is the system operational ? 

1. Yes 

2. Not sure 

3. No 

98. Don’t Know 

9. If yes, do you run the fan for this system continuously or most of the time 

when the house is occupied? 

1. Yes 

2. Not sure 

3. No 

98. Don’t Know 

Great! It appears that your home will qualify for the study. 

I’d like to go over the details of our visits, and make sure you understand what 

participants must do. 

10. We are requesting permission to conduct ventilation and indoor air quality tests 

in your home. There would be three home visits over an 8-day period (e.g., one 

visit each on days 1, 7 and 8. Each visit would require approximately 2–3 hours 

and will be scheduled with you to occur between 9 a.m. and 7 p.m. (e.g., 9–12, or 

1–4, or 4–7). Would you be willing to accommodate us with this request? 

1. Yes, (skip Q11) 

2. Not sure, depends on the hours go to Q11. 

3. Not sure, Have other concerns or questions. Go to Participant FAQ.

4. No, ask why and go to Q11 unless homeowner terminates call. 

Notes from homeowner Comments or concerns: 

11. To facilitate the scheduling of these three home tests, we can offer you the option 

of a lock box. By utilizing the lockbox, you don’t have to be home for the entire 

visit or for all of the visits. Would you be interested in getting a lockbox? 

1. Yes, (provide more information ask about getting a lock box) 

2. Not sure, (provide more information on how it works) 

3. No, thank and terminate call if also no to Q.10 
A-92 

FIRST HOME VISIT 

12. Each visit to your home has a unique purpose. During the first visit we would 

like to view a copy of the floor plan. Do you have a copy of the floor plan and 

the homeowner’s package? It may have been included in the homeowner’s 

package. 

1. Yes, I have both a floorplan and a homeowner’s package. (Ask for them to pull 

it out for first visit and we’ll be borrowing it to be returned the following visit). 

2. Yes, I have homeowners package but don’t know if there is a floor plan, but I 

will check and call you back. (Inform them if we don’t get your floor plan, then 

we will need to make a sketch of the location and size of each room.) 

3. No, I don’t have the homeowner’s package but I have a floor plan. 

4. No, I don’t have either. (Inform them we will need to make a sketch of the 

location and size of each room.) 

13. The primary purpose of the first home visit is to install the small data loggers that 

collect information on window and fan usage. The small matchbox sized 

dataloggers are placed on selected windows and will not interfere with your 

opening, closing or locking your windows. A few dataloggers will also be placed 

on ventilation system fan motors. Would you agree these data loggers to be 

installed in your home? 

1. Yes 

2. Not Sure, (Describe in greater detail nature and location of loggers). 

3. No, terminate and inquire as to why. 

Notes from homeowner Comments or concerns: 

14. During this visit our technicians will also provide with a short questionnaire and 

log sheets to log your window and fan usage and indoor activities such as 

cooking. We ask you to complete these befor5e the last visit on day 8. Will you 

have time to complete the questionnaire and log sheets? 

1. Yes 

2. Not Sure, (Explain what to expect.) 

3. No, terminate and inquire as to why. 

Notes from homeowner Comments or concerns: 

SECOND HOME VISIT 

A week later, we would make our second visit. During this visit our technicians will 

be installing an air sampler which quietly measures the air quality in your home. The air 
A-93 

sampler is quiet, childproof, and pet-proof. You may recall having seen a photo of the air 

sampler in the letter. Would you agree to allow the air sampler(s) in your home for 24 

hours? 

1. Yes 

2. Not Sure (Explain what to expect.) 

3. No, terminate and inquire as to why. 

Notes from homeowner Comments or concerns:

15. During the second home visit, we will also need to access the ventilation system 

and collect data on the house characteristics. This work requires inspecting the 

attic spaces and or crawlspaces. Would you agree to allow us to inspect the 

ventilation system, and attic and crawlspaces? 

1. Yes 

2. Not Sure (Explain what to expect.) 

3. No, terminate and inquire as to why. 

Notes from homeowner Comments or concerns: 

16. Is your ventilation equipment in the attic or the crawlspace? 

1. Attic 

2. Crawlspace 

3. Garage 

4. Indoor closet space 

5. Not Sure 

17. On a typical weekday, how many adults and children can be expected to be 

in the home at sometime during daytime hours (9 a.m. - 5 p.m.)? 

Number of adults: ______

Number of children: ______ 

THIRD HOME VISIT 

18. The third and last visit will need to occur approximately 24 hours after the 

previous appointment. The purpose of this visit is to shut down and retrieve the 

air sampler, and to collect the data loggers. Again, we can provide you with a 

lock box to facilitate this scheduling if you wish. Will you be able to 

accommodate our request to return approximately 24 hours later? 

1. Yes 

2. Not Sure (Explain what to expect.) 

3. No, terminate and inquire as to why. 

Notes from homeowner Comments or concerns: 
A-94 

19. During the third visit, we need to determine how airtight your home is by 

conducting a building envelope leakage test. All doors and windows will be 

closed and a special fan will be temporarily installed on one door that will remain 

open. The fan runs for approximately 10–15 minutes and is used to measure 

airflow. Would you agree to allow the leakage testing of your building?

1. Yes 

2. Not Sure (Explain what to expect.) 

3. No, terminate and inquire as to why. 

Notes from homeowner Comments or concerns: 

20. A similar test will be run on the home’s ventilation system to see how airtight the 

ducts are. This test runs for about five to ten minutes. Would you agree to allow 

the duct leakage testing?

1. Yes 

2. Not sure (Explain what to expect). 

3. No, terminate and inquire as to why. 

Notes from homeowner Comments or concerns: 

Lastly, our technicians will collect the questionnaires and log sheets and provide you with 

a $100 money order to thank you for participating. 

21. Do you have any additional questions or concerns that we have not 

addressed already? 

1. Yes 

2. No 

Notes from homeowner Comments or concerns: 

22. Would you like to participate? 

1. Yes 

2. No. Ask why not and terminate. 

Notes from homeowner : 

23. If yes on Q22 then “GREAT”. Can we take a minute to discuss the scheduling 

of the three home inspections?

1. Yes 

2. No. If no, then when, with whom, and at what number can we discuss the 

scheduling. 

Notes from homeowner 
A-95 

SCHEDULING QUESTIONS 

24. We currently are looking to schedule three homes for inspections to be conducted 

between November 29 through December 8. Do either of the following sets of 

three dates work for you, with or without a lock box ?

 

Set 1. Home Visit 1: Tuesday, November 29 

 Home Visit 2: Tuesday, December 6 

 Home Visit 3: Wednesday, December 7 

Set 2. Home Visit 1: Wednesday, November 30, 

 Home Visit 2: Wednesday, December 7 

 Home Visit 3: Thursday, December 8 

1. Either Set ______ 

2. Set 1 Only______ 

3. Set 2 Only______ 

25. If yes to Q24 skip to Q26. 

If no to Q24. Would you be interested in possibly participating in any of the 

future study periods ? Circle periods of interest. 

• Spring, April, 2006 

• Summer, July/August, 2006 

• Winter, January/February, 2007 

3. Is there a preference ? ________________________________________ 

26. If yes to Q24. Do any of the following 2–3 hour time periods for the three 

home visits work for you, with or without a lock box ? 

 

1. 9AM to 12PM 

2. 1PM to 4PM 

3. 4PM to 7PM 

4. Is there a preference, 1st or 2nd? ___________________________ 

 
A-96 

Notes from homeowner 

Excellent. We will be calling you back very shortly to confirm the exact dates and 

times of the inspections. Do you have any further questions at this time ? 

Notes from homeowner : 

Finally, since the ventilation and indoor air quality factors can vary from season to season 

we will be asking a few residences to participate in a second set of inspections in a 

different season than the first set. These homeowners will receive an additional $100 for 

participating in a second set of inspections. Provided the first set of inspections went 

smoothly for you, would you consider participating in a second set ?

1. Yes 

2. No. If no ask why not. 

Notes from homeowner 

Can you please provide us with some additional contact information to 

facilitate future communications ? Get additional contact information and 

log in on page 1. 

Thank you for taking this time to discuss your participation in the 

important research project. 

!!!!! Log in on page 2 the time of the end of the call. !!!!! 
B-1 

Appendix B 

Volatile Organic Compound Analytical Method 
B-2 

Analytical Methods 

VOC Sorbent Tubes 

The multi-sorbent samplers used in this study contained Tenax®-TA 60/80 mesh 

backed up by a section of a carbonaceous sorbent, CarbosieveTM S-III 60/80 

mesh (Part No. 10184, Supelco, Inc.). These sorbents were packed in series 

within a 10-centimeter (cm) long by 0.64-cm OD stainless steel tube passivated 

with a Silcosteel® coating (Custom order, Supelco, Inc.). The sorbent samplers 

were conditioned in the laboratory prior to shipment. For conditioning, batches of 

20 samplers were heated at 300o

C for 30 or more minutes with helium purge 

flow. One sampler out of every batch was analyzed. This analysis demonstrated 

that the background levels of target VOCs in conditioned samplers were below 

2 ng/sampler and the levels of summed VOCs were below 10 ng/sampler. 

GC/MS Analysis of VOCs 

The thermal desorption – gas chromatography/mass spectrometry (GC/MS) 

method used for the analysis of VOCs is based on U.S. EPA Method TO-17, 

"Determination of Volatile Organic Compounds in Ambient Air Using Active 

Sampling onto Sorbent Tubes" (U.S. EPA 1999). 

Prior to analysis, the sorbent samplers were purged at room temperature for 30 

minutes with helium flowing at 100 cubic centimeters per minute (cm3

/min). 

Then, a gaseous internal standard (ISTD) was added to each sampler using a 

loading rig fitted with a calibrated sampling loop and additional helium flow was 

passed through the tube for three minutes. The ISTD was 191 nanograms (ng) of 

1-bromo-4-fluorobenzene (BFB) supplied as a certified gas mixture (14.9 ppm 

±2%, balance nitrogen; Scott Specialty Gases). The ISTD was used to check on 

the operation of the system, to provide a retention-time marker, and to enable 

quantitative analysis. 

The sorbent samplers were thermally desorbed (UltrA TD-UNITY, Markes 

International, Ltd.) and introduced into a GC/MS system (Models 6890 GC/5973 

MSD, Agilent). The GC was fitted with a 30-m, 0.25- millimeter (mm) ID, 1-micron 

(μm) film moderately polar column (Model DB-1701, Part No. 122-0733; Agilent). 

The MS detector was operated in the SCAN mode over a mass range of m/z 30–

450 amu. The samples were split during the injection phase of the analysis. For 

this study, the split ratio was 5:1. The thermal desorption, GC, and MS conditions 

for the analyses are summarized in Tables 1–3, respectively. 

Low-Molecular Weight Carbonyl Sampling and Analysis 

The methods used for the sampling and analysis of formaldehyde and 

acetaldehyde are based on ASTM D 5197-03, “Standard Test Method for 

Determination of Formaldehyde and Other Carbonyl Compounds in Air (Active 

Sampler Methodology” (ASTM 2003). 
B-3 

Sep-Pak XPoSure Aldehyde Samplers (Part number WAT047205, Waters, 

Corp.) were used to collect air samples for formaldehyde and acetaldehyde. 

When air is pulled through a sampler, the acidified 2,4-dinitrophenylhydrazine 

(DNPH) reagent in the sampler reacts with carbonyl compounds to form the 

stable hydrazone derivatives that are retained by the sampler. In the laboratory, 

the hydrazone derivatives were eluted from each sampler with 2 milliliter (mL) 

acetonitrile. An aliquot of a sample was analyzed for the hydrazone derivatives of 

formaldehyde and acetaldehyde using reverse-phase high-performance liquid 

chromatography (HPLC) with ultraviolet (UV) detection (Model 1050, HewlettPackard). The absorbance of the derivatives was measured at 360 nm. The 

HPLC conditions for the analyses are summarized in Table 4. 

Sampler Storage 

Upon arrival at the laboratory, all samplers were logged, checked for integrity, 

and transferred to a freezer dedicated to sample storage. VOC samples were 

analyzed within one week of receipt. Aldehyde samples were analyzed within 

approximately four weeks of receipt. 

Calibrations 

VOCs 

Two custom calibration mixtures for the analysis of VOCs were prepared by 

Absolute Standards, Inc. These mixtures were accompanied by certified weight 

reports containing all of the necessary data for ISO-17025 compliance. One 

calibration mixture contained 20 target VOCs. It was prepared in methanol. The 

other mixture contained vinyl acetate only and was prepared in water. The 

compounds and their assigned concentrations in the mixtures based on the 

weight measurements are listed in Table 5. The uncertainty for each compound 

was less than 0.5%. 

Calibration standards for VOCs were prepared in the laboratory by diluting the 

vinyl acetate mixture and the 20-component mixture as described below. 

Problems encountered with the analysis of vinyl acetate, n-hexane, and ethylene 

glycol in the first VOC external proficiency test (see below) led us to prepare 

additional standards. Subsequently, the standard for the 

20-component mixture was prepared without the addition of vinyl acetate. A 

standard for ethylene glycol was prepared individually in methanol, and a gas 

standard containing vinyl acetate and n-hexane also was prepared. 

Two working standards of the 20-component mixture with and without vinyl 

acetate were prepared by dilution of the stock solution(s) in methanol. The high 

standard was a 1:20 dilution of the 20-component mixture (1:200 of the vinyl 

acetate mixture) resulting in VOC concentrations of 100 μg/mL (100 ng/μL). The 

low standard was a 1:100 dilution of the 20-component mixture (1:1000 of the 

vinyl acetate mixture) resulting in concentrations of 20 μg/mL (20 ng/μL). A single 
B-4 

working standard of ethylene glycol in methanol was prepared in the laboratory 

from the pure compound (Part. No. 32,455–8, 99+%; Aldrich Chemical Co.). The 

concentration was 111 μg/mL (111 ng/μL). 

Aliquots of the working standards of the 20-component mixture with and without 

vinyl acetate were spiked onto multi-sorbent tubes using an Adsorbent Tube 

Injector System (ATIS, Supelco, Inc.). The aliquots were transferred to the ATIS 

with modified microliter syringes (7000 Series, Hamilton Co.). The ATIS flash 

vaporized the compounds into a continuous flow of helium gas that swept the 

compounds onto the tube. The ATIS parameters were 100oC with 50 cm3/min 

flow rate. Multi-sorbent tubes spiked with the different levels of VOCs were 

analyzed by the same method used for the analysis of the field samples. 

The ATIS spiking method did not work adequately for ethylene glycol. Instead, 

microliter aliquots of the ethylene glycol working solution were spiked directly into 

the inlet of sorbent tubes containing Tenax TA only. 

A gas standard was prepared for n-hexane and vinyl acetate in a static dilution 

bulb (SDB) following the method described in TO-1 (U.S. EPA 1984) using pure 

compounds (Part No. 13,938–6, 99+% and Part No. V150-3, 99+%, respectively; 

Aldrich Chemical Co.). Five microliters of each chemical were added to a SDB, 

producing gas concentrations of 1.66 and 2.35 ng/μL for n-hexane and vinyl 

acetate, respectively. Known volumes of gas (25 to 200 μL) were withdrawn from 

the SDB using a gas-tight syringe with locking mechanism and injected onto 

sorbent tubes to create the calibration levels. 

Three full calibrations were produced for the multi-component mixture. Each of 

these consisted of six or more concentration levels. The masses of the individual 

VOCs ranged from 20 to 500 ng. Two calibrations were generated during the 

analysis of field samples collected from August to October 2006, and one 

calibration was generated during the analysis of samples collected from January 

to March 2007. The variation in the linear term over this period was 9% relative 

standard deviation (RSD), or better, with the exception of caprolactam, which had 

a RSD of 15%. 

Two calibrations were produced for ethylene glycol, one for the analysis of 

samples from each of the two field collection periods. These contained three 

concentration levels over a range of 78 to 222 ng. The linear terms were nearly 

identical; however, the second calibration had a large negative intercept 

equivalent to 57 ng of ethylene glycol. A single calibration, consisting of five 

concentration levels, was generated for n-hexane and vinyl acetate. 

All calibrations were produced using the internal standard method. For each 

compound, one extracted ion served as the quantitative ion and one to two other 

extracted ions were used as qualifiers. The quantitative ion for the internal 

standard (ISTD), 1-bromo-4-fluorobenzene, was m/z 95. The ISTD also served 

as a time reference for each calibration. All retention times of the individual VOCs 

relative to the retention time of the ISTD were stable throughout the study. Two 
B-5 

xylene isomers, m-xylene and p-xylene, co-elute and were treated as a single 

compound (termed m/p-xylene). The calibration data for each VOC were fit to a 

linear function. The coefficients of determination for the fit of the data points were 

0.98, or better. The calibration data are summarized in Table 6. 

Aldehydes 

A custom calibration mixture prepared by Absolute Standards, Inc. was used to 

calibrate the HPLC for the analysis of formaldehyde and acetaldehyde. The 

mixture contained the 2,4-dinitrophenylhydrazine (DNPH) derivatives of 

formaldehyde, acetaldehyde, and glutaraldehyde (not used for this study) with 

acetonitrile as the solvent. The concentration of each target compounds as the 

aldehyde was 100 μg/mL with an uncertainty of less than 0.5%. The aldehyde 

mixture was diluted in acetonitrile to produce seven or eight calibration levels 

ranging from 0.025 to 4.0 ng/μL. The calibration data were fit to a linear function 

with calculated intercept. The coefficients of determination for the fit of the data 

points were >0.999. 

For the August to October 2006 sampling period, a prior external standard 

calibration created in March 2006 was verified by the analysis of freshly prepared 

check standards. The March 2006 calibration prepared using calibration mixture 

Part No. 93594, Lot No. 21004. The formaldehyde linear term was 721 with an 

intercept of 3.8; the acetaldehyde linear term was 565 with an intercept of 5.5. A 

new calibration was created for the January to March 2007 sampling period using 

calibration mixture Part No. 93594, Lot No. 20107. The formaldehyde linear term 

was 747 with an intercept of 11.4; the acetaldehyde linear term was 569 with an 

intercept of 1.9. 

Method Detection Limits 

Method detection limits (MDLs) for the target VOCs were determined in 

conjunction with the analysis of the samples collected from August to October 

2006. This was accomplished by making three replicate injections of a low mass 

VOC calibration standard that approximately was within a factor of five to ten of 

the anticipated detection limits. Ethylene glycol was analyzed separately using a 

higher mass standard due to its higher MDL. For each VOC, the MDL was 

defined as the product of the standard deviation of the measurements and the 

student’s t-value for a 95% confidence level (t = 2.92, p = 0.05, df = 2). The 

results are shown in Table 7. Typically, the calculated MDLs were 5 ng or less. 

Compounds with higher MDLs were ethylene glycol, 1-methyl-2-pyrrolidinone, 

and vinyl acetate. The MDL for ethylene glycol in the second calibration is equal 

to the intercept of 57 ng plus the calculated value of 16 ng, or 71 ng. 

MDLs for formaldehyde and acetaldehyde were determined in May 2006. Seven 

replicate cartridges were prepared by injecting one microliter of the standard 

(100 ng of each compound) onto the inlet of each cartridge and purging with 

helium. The cartridges were extracted and analyzed in the same manner as the 
B-6 

field samples. The MDLs defined as the product of the standard deviation of the 

measurements and the student’s t-value for a 95% confidence level (t = 1.94, 

p = 0.05, df = 6) were about 9 ng for each compound. Using the t-value for a 99% 

confidence level (t = 3.14, p = 0.01, df =6), the MDLs were 13 to 15 ng. 

External Proficiency Tests 

External proficiency tests were conducted in October 2006 and March 2007 in 

conjunction with the analyses of samples for the two collection periods (August to 

October 2006 and January to March 2007). The proficiency test (PT) standards 

were prepared by Absolute Standards, Inc. under their AbsoluteGrade PT 

Program. There were three separate standards: one for formaldehyde and 

acetaldehyde; one for vinyl acetate; and one for the 20-component VOC mixture 

(19 components with m/p-xylene treated as a single component). 

For the VOCs, the vinyl acetate PT mixture and the multi-component VOC PT 

mixture were diluted 1:100 in methanol. The combined diluted mixture was mixed 

by sonication. One microliter (1 μL) of the mixture was injected onto each of three 

multi-sorbent tubes. The ISTD was added and the tubes were purged with 

helium. The tubes were analyzed as described for samples and other standards. 

The results for the three tubes were averaged and reported to Absolute 

Standards, Inc. as concentrations in μg/mL. 

For the aldehydes, the PT mixture was diluted 1:100 in acetonitrile and 

sonicated. Aliquots of the diluted mixture were analyzed in triplicate. The average 

values in μg/mL were reported to Absolute Standards, Inc. 

The results for the first PT conducted in October 2006 are presented in Table 8. 

For formaldehyde and acetaldehyde, the reported results were “Acceptable,” i.e., 

they were within less than ±20% of the assigned value. For VOCs, the reported 

results for vinyl acetate and ethylene glycol were outside of the warning limits 

(±20%), and the reported results for n-hexane and m/p-xylene were outside of 

the acceptance limits (±40%). A check of the reported data revealed that the “Not 

Acceptable” result for m/p-xylene was due to a factor of two error in setting up 

the calibration for this compound. Correction of the error resulted in an 

Acceptable result. All of the Acceptable results were within ±10% of the assigned 

values, except alpha-pinene which was 11.7% high. 

As described above, separate calibrations were prepared for ethylene glycol 

using a one-component mixture and for vinyl acetate plus n-hexane using 

different calibration technique. Recalculation of the PT sample results using 

these new calibrations produced Acceptable results for all three compounds as 

shown in Table 8. 

The results for the second PT conducted in March 2007 are presented in Table 

9. The results for all aldehyde and VOC target compounds were Acceptable. 

With the exceptions of vinyl acetate, ethylene glycol, and phenol, the results were 
B-7 

within ±12% of the assigned values. Vinyl acetate was 14.4% low; ethylene 

glycol was 15.5% high; and phenol was 13.5% high. 

Analysis of Field Samples 

Problems Encountered 

A problem was encountered with the analysis of aldehyde samples collected in 

the Winter-South sampling campaign. This problem was not discovered until after 

all of the samples for this sampling campaign had been processed. A review of 

all of the data showed that the chromatographic peak representing the unreacted 

DNPH was substantially lower in two samples, 084-f2-020107 and 086-f1d020507. The cartridges contain approximately sufficient DNPH to collect 70 μg of 

formaldehyde or 2.3 μmol of total carbonyl, which is well in excess of the amount 

required for most environmental samples. The DNPH peak areas in these two 

samples were apparent low outliers. These areas fell below the lower 95% 

confidence interval for the area responses of the DNPH peak in all of the other 

samples. In addition, the summed areas of the carbonyl hydrazone derivatives in 

these samples were low relative to the other similar samples suggesting that 

there was a problem either with the automated injection of the samples into the 

HPLC instrument or that the extracts of these samples had not been properly 

mixed during preparation. Results for these two samples were not reported due 

to an assumed laboratory error. 

References 

ASTM. 2003. Standard Test Method for Determination of Formaldehyde and 

Other Carbonyl Compounds in Air (Active Sampler Methodology). ASTM 

International, West Conshohocken, Pennsylvania. 

U.S. EPA. 1984. Method TO-1, Revision 1.0: Method for the Determination of 

Volatile Organic Compounds in Ambient Air Using Tenax Adsorption and 

Gas Chromatography/Mass Spectrometry (GC/MS). Center for 

Environmental Research Information, Office of Research and Development, 

U.S. Environmental Protection Agency, Cincinnati, Ohio. 

U.S. EPA. 1999. Compendium Method TO-17; Determination of Volatile Organic 

Compounds in Ambient Air Using Active Sampling Onto Sorbent Tubes. 

Center for Environmental Research Information, Office of Research and 

Development, U.S. Environmental Protection Agency, Cincinnati, Ohio. 
B-8 

Table 1. Thermal desorption conditions. 

Parameter Value 

Instrument Markes Intn. Unity / Ultra TD 

Purge time 1 min 

Tube desorb time 10 min 

Tube desorb temperature 285oC 

Trap temperature -6oC 

Trap hold time 3 min 

Trap desorb temperature 300oC 

Trap heating rate Maximum 

Trap desorb split ratio 5:1 

Flow path temperature 175oC 
B-9 

Table 2. GC conditions. 

Parameter Value 

Instrument Agilent 6890N GC 

Column type Agilent DB-1701 

Column dimensions 1 μm, 0.25 mm, 30 m 

Initial pressure 13.5 psi 

Initial pressure time 10 min 

Pressure ramp rate 0.4 psi/min 

Final pressure 18 psi 

Initial temperature 1oC 

Initial temperature time 6.5 min 

Temperature ramp rate 1 5oC/min 

Final temperature 1 100oC 

Temperature ramp rate 2 12 oC/min 

Final temperature 2 225oC 

Final temperature 2 time 2 min 

Post run temperature 250oC 

Post run temperature time 2 min 
B-10 

Table 3. MS conditions. 

Parameter Value 

Instrument Agilent 5973N MSD 

Solvent delay 2.25 min 

Low scan mass, m/z 30 amu 

High scan mass, m/z 450 amu 

Threshold 500 

Scan rate 0.5 Hz 

Table 4. HPLC conditions. 

Parameter Value 

Instrument Hewlett-Packard 1050 

Solvent A Acetonitrile (ACN) 

Solvent B 65% H20 / 35% ACN 

Flow rate 0.3 mL/min 

Initial solvent time 2 min 

Initial solvent 100% B 

Solvent ramp 2–9 min 

Final solvent 45% B 

Solvent hold 9–6 min 

Post run time 5 min 

Injection volume 6 μL 

Detector wavelength 360 nm 
B-11 

Table 5. VOC calibration mixtures prepared by Absolute Standards, Inc. Vinyl 

acetate mixture Part No. 82477, Lot No. 070506 was prepared in water. Multicomponent VOC mixture Part No. 94336, Lot No. 080206 was prepared in 

methanol. Both mixtures were prepared using pure (98% purity or higher) 

compounds. Compound amounts were determined by weighing. Uncertainty was 

±0.2% (except caprolactam ±0.5%). 

Compound CAS No. Conc 

(μg/mL) 

Vinyl acetate 108-05-4 20,010 

Benzene 71-43-2 2,003 

2-Butoxyethanol 111-76-2 2,001 

Caprolactam 105-60-2 2,003 

Chloroform 67-66-3 2,003 

1,4-Dichlorobenzene 106-46-7 2,001 

Ethylene glycol 107-21-1 2,003 

Hexanal 66-25-1 2,001 

n-Hexane 110-54-3 2,002 

R-(+)-Limonene 5989-27-5 2,001 

1-Methyl-2-pyrrolidinone 872-50-4 2,003 

Naphthalene 91-20-3 2,002 

Phenol 108-95-2 2,002 

(1R)-(+)-alpha-Pinene 7785-70-8 2,001 

Styrene 100-42-5 2,004 

Tetrachloroethene 127-18-4 2,002 

Toluene 108-88-3 2,003 

1,2,4-Trimethylbenzene 95-63-6 2,003 

o-Xylene 95-47-6 2,002 

m-Xylene 108-38-3 1,001 

p-Xylene 106-42-3 1,002 
B-12 

Table 6. Summary of calibration data showing for each individual VOC the 

quantitative ion, the number of full multi-point calibrations performed, the 

compound retention times relative to the retention time of the internal standard 

(ISTD), and the average linear term (±1 standard deviation) for the calibration. 

Compound Quant Ion

(m/z) 

No. 

Calib

Relative RT 

Avg ± 1 Stdev 

Linear Term 

Avg ± 1 Stdev 

1-Bromo-4-fluorobenzene 95 -- ISTD -- 

n-Hexane 57 1 0.311 ± 0.002 1.01 

Vinyl acetate 43 1 0.424 ± 0.001 1.71 

Ethylene glycol 31 2 0.867 ± 0.002 0.853 ± 0.006 

Benzene 78 3 0.542 ± 0.002 2.62 ± 0.14 

2-Butoxyethanol 57 3 1.007 ± 0.002 1.70 ± 0.12 

Caprolactam 113 3 1.359 ± 0.021 0.716 ± 0.110 

Chloroform 83 3 0.528 ± 0.002 1.13 ± 0.08 

1,4-Dichlorobenzene 146 3 1.094 ± 0.001 2.24 ± 0.20 

Hexanal 44 3 0.835 ± 0.001 0.571 ± 0.015 

R-(+)-Limonene 68 3 1.062 ± 0.001 1.32 ± 0.03 

1-Methyl-2-pyrrolidinone 99 3 1.199 ± 0.003 1.26 ± 0.07 

Naphthalene 128 3 1.242 ± 0.003 6.63 ± 0.25 

Phenol 94 3 1.184 ± 0.002 2.43 ± 0.03 

(1R)-(+)-alpha-Pinene 93 3 0.926 ± 0.001 1.91 ± 0.05 

Styrene 104 3 0.942 ± 0.001 2.52 ± 0.09 

Tetrachloroethene 166 3 0.754 ± 0.001 1.01 ± 0.03 

Toluene 91 3 0.729 ± 0.001 3.03 ± 0.03 

1,2,4-Trimethylbenzene 105 3 1.056 ± 0.001 3.54 ± 0.12 

o-Xylene 91 3 0.928 ± 0.001 3.03 ± 0.14 
B-13 

Table 7. Determination of VOC method detection limits (MDLs), Aug.–Oct. 2006 

analysis period. Calculated as 95% confidence interval for three replicate 

analyses of a low mass calibration standard. 

 

Compound Avg ± 1 Sdev

(ng) 

RSD 

(%) 

MDL 

(ng) 

Benzene 20.7 ± 1.2 5.8 3.5 

2-Butoxyethanol 11.7 ± 0.6 5.5 1.9 

Caprolactam 41.0 ± 1.2 2.8 3.4 

Chloroform 18.3 ± 1.7 9.1 4.9 

1,4-Dichlorobenzene 21.9 ± 1.0 4.6 2.9 

Ethylene glycol 69.0 ± 5.6 8.1 16.4 

Hexanal 26.8 ± 0.5 1.8 1.4 

n-Hexane 3.6 ± 1.5 40 4.2 

R-(+)-Limonene 21.7 ± 1.5 6.7 4.2 

1-Methyl-2-pyrrolidinone 28.0 ± 2.1 7.4 6.0 

Naphthalene 24.5 ± 0.7 2.8 2.0 

Phenol 24.5 ± 0.9 3.8 2.8 

(1R)-(+)-alpha-Pinene 21.0 ± 1.0 4.9 3.0 

Styrene 22.5 ± 1.1 4.8 3.1 

Tetrachloroethene 20.3 ± 1.6 7.9 4.6 

Toluene 21.5 ± 1.7 7.9 4.9 

1,2,4-Trimethylbenzene 19.9 ± 1.1 5.7 3.3 

Vinyl acetate 19.1 ± 1.9 10.0 5.6 

o-Xylene 21.1 ± 1.1 5.2 3.2 

m/p-Xylene 21.9 ± 1.3 6.0 3.8 
B-14 

Table 8. External PT sample results for October 2006, Absolute Standards, Inc. 

Formaldehyde-DNPH and Acetaldehyde-DNPH Part No. 38178, Lot No. 092106. 

Vinyl Acetate Part No. 38198, Lot No. 092106. VOCs Part No. 38197, Lot No. 

092106. 

 

Compound Reported

(μg/mL) 

Assigned

(μg/mL) 

Deviation 

(%) 

Performance

Evaluation 

Formaldehyde 1.23 1.34 -8.2 Accept 

Acetaldehyde 1.71 1.77 -3.4 Accept 

Vinyl acetate 350 251 +39.4 Not Accept 

Vinyl acetate – new calib (264)* 251 (+5.2) (Accept) 

Benzene 343 314 +9.2 Accept 

2-Butoxyethanol 349 335 +4.2 Accept 

Caprolactam 332 307 +8.1 Accept 

Chloroform 82.4 76.7 +7.4 Accept 

1,4-Dichlorobenzene 312 295 +5.8 Accept 

Ethylene glycol 617 482 +28.0 Not Accept 

Ethylene glycol – new calib (393) 482 (-18.5) (Accept) 

Hexanal 60.5 63.2 -3.6 Accept 

n-Hexane 290 194 +49.5 Not Accept 

n-Hexane – new calib (221) 194 (+13.9) Accept 

R-(+)-Limonene 150 152 -1.3 Accept 

1-Methyl-2-pyrrolidinone 416 395 +5.3 Accept 

Naphthalene 105 111 -5.4 Accept 

Phenol 126 133 -5.3 Accept 

(1R)-(+)-alpha-Pinene 297 266 +11.7 Accept 

Styrene 113 111 +1.8 Accept 

Tetrachloroethene 138 136 +1.5 Accept 

Toluene 154 150 +2.7 Accept 

1,2,4-Trimethylbenzene 455 452 +0.7 Accept 

o-Xylene 186 182 +2.2 Accept 

m/p-Xylene 634** 596 +6.4 Accept 

*Values in parentheses were calculated using new calibrations for these target 

compounds 

**Originally reported as 1238 μg/mL 
B-15 

Table 9. External PT sample results for March 2007 analysis period, Absolute 

Standards Inc. Formaldehyde-DNPH and Acetaldehyde-DNPH Part No. 38178, 

Lot No. 020507. Vinyl Acetate Part No. 38198, Lot No. 020507. VOCs Part No. 

38197, Lot No. 020507. 

Compound Reported

(μg/mL) 

Assigned 

(μg/mL) 

Deviation 

(%) 

Performance

Evaluation 

Formaldehyde 1.55 1.69 -8.3 Accept 

Acetaldehyde 1.33 1.45 -8.3 Accept 

Vinyl acetate 95.9 112 -14.4 Accept 

Benzene 155 156 -.06 Accept 

2-Butoxyethanol 77.2 69.4 +11.2 Accept 

Caprolactam 88.2 87.8 +0.5 Accept 

Chloroform 160 152 +5.3 Accept 

1,4-Dichlorobenzene 210 189 +11.1 Accept 

Ethylene glycol 216 187 +15.5 Accept 

Hexanal 55.1 55.0 +0.2 Accept 

n-Hexane 60.1 63.6 -5.5 Accept 

R-(+)-Limonene 232 219 +5.9 Accept 

1-Methyl-2-pyrrolidinone 382 367 +4.1 Accept 

Naphthalene 113 103 +9.7 Accept 

Phenol 89.1 78.5 +13.5 Accept 

(1R)-(+)-alpha-Pinene 253 241 +5.0 Accept 

Styrene 476 459 +3.7 Accept 

Tetrachloroethene 281 263 +6.8 Accept 

Toluene 61.1 57.2 +6.8 Accept 

1,2,4-Trimethylbenzene 453 457 -0.9 Accept 

o-Xylene 54.5 53.2 +2.4 Accept 

m/p-Xylene 312 297 +5.1 Accept 
B-16 
C-1

APPENDIX C 

“All Homes” Sample Frame List 

Appendix Key 

Label Description 

DOA Ducted Outdoor Air Mechanical Outdoor Air Ventilation System WHF Whole House Fan Nighttime Cooling System HRV Heat Recovery Ventilator Mechanical Outdoor Air Ventilation System RAD Forced Air Unit Return Air Damper Nighttime Cooling System WDF Window Fan EC Evaporative Cooler 
C-2

Home 

ID 

UCB 

ID Season Region City 

Zip 

Code 

UCB 

Statewide 

UCB 

Builder Supplemen

001 210052 Summer North Brentwood 94513 X 002 Winter North Brentwood 94513 X 003 310030 Summer North Brentwood 94513 X 004 Summer North Brentwood 94513 X 005 110033 Winter North Discovery Bay 94514 X 006 Winter North Discovery Bay 94514 X 008 610013 Summer North Brentwood 94513 X 009 Summer North Brentwood 94513 X 010 Summer North Brentwood 94513 X 011 Winter North Brentwood 94513 X 012 Summer North Brentwood 94513 X 013 Summer North Elk Grove 95624 X 014 Summer North Elk Grove 95624 X 015 210456 Summer North Elk Grove 95624 X 016 210518 Summer North Elk Grove 95758 X 017 110261 Winter North Elk Grove 95758 X 018 210512 Summer North Elk Grove 95758 X 019 110228 Summer North Elk Grove 95624 X 020 110225 Summer North Elk Grove 95624 X 021 210482 Summer North Elk Grove 95624 X 022 Summer North Sacramento 95835 X 023 110313 Summer North Sacramento 95835 X 024 Summer North Sacramento 95835 X 025 210516 Summer North Elk Grove 95758 X 026 Summer North Elk Grove 95758 X 027 Summer North Elk Grove 95758 X 029 Summer North Manteca 95337 X 
C-3

Home 

ID 

UCB 

ID Season Region City 

Zip 

Code 

UCB 

Statewide 

UCB 

Builder Supplemen

030 Summer North Manteca 95337 X 031 231940 Summer North Manteca 95337 X 032 130965 Summer North Manteca 95337 X 033 330997 Summer North Rancho Murrieta 95683 X 034 231990 Summer North Rancho Murrieta 95683 X 037 631001 Summer South Valencia 91381 X 038 Winter South Valencia 91381 X 039 631002 Winter South Valencia 91381 X 040 Summer South Castaic 91384 X 041 330036 Winter South Castaic 91384 X 042 330048 Summer South Castaic 91384 X 043 Summer South Santa Clarita 91390 X 044 220248 Summer South Santa Clarita 91390 X 045 Summer South Santa Clarita 91390 X 046 Summer South Canyon Country 91387 X 047 620046 Summer South Canyon Country 91387 X 048 620037 Summer South Canyon Country 91387 X 049 130106 Winter South Chula Vista 91914 X 050 230210 Summer South Chula Vista 91914 X 053 220452 Summer South San Diego 92129 X 054 220454 Summer South San Diego 92129 X 055 220507 Summer South San Diego 92129 X 056 220499 Summer South San Diego 92129 X 058 230500 Winter South San Marcos 92078 X 059 130200 Summer South San Marcos 92078 X 061 Summer South Castaic 91384 X 062 230104 Summer South Castaic 91384 X 064 Summer South Santa Clarita 91390 X 065 Summer South Santa Clarita 91390 X 066 Summer South Santa Clarita 91390 X 
C-4

Home 

ID 

UCB 

ID Season Region City 

Zip 

Code 

UCB 

Statewide 

UCB 

Builder Supplemen

067 Summer South Palmdale 93551 X 068 Summer South Palmdale 93551 X 069 Summer South Palmdale 93551 X 070 330737 Summer South Palmdale 93551 X 071 Summer South Palmdale 93551 X 072 Summer South Palmdale 93551 X 073 Winter South Santa Clarita 91390 X 074 120138 Winter South Santa Clarita 91390 X 075 Winter South Valencia 91381 X 076 130051 Winter South Castaic 91384 X 077 Winter South Santa Clarita 91390 X 078 Winter South San Marcos 92069 X 079 Winter South San Marcos 92069 X 080 230214 Winter South Chula Vista 91914 X 081 Winter South San Marcos 92078 X 083 220423 Winter South San Diego 92129 X 084 Winter South San Diego 92129 X 085 Winter South San Diego 92129 X 086 Winter South Fontana 92336 X 087 Winter South Fontana 92336 X 088 Winter South Fontana 92336 X 089 Winter South Fontana 92336 X 090 Winter South Fontana 92336 X 091 Winter South Fontana 92336 X 092 Winter South Fontana 92336 X 093 Winter South Fontana 92336 X 094 Winter South Riverside 92508 X 095 Winter South Riverside 92508 X 096 Winter South Riverside 92508 X 097 Winter North Elk Grove 95624 X 098 Winter North Elk Grove 95624 X 099 Winter North Sacramento 95835 X 
C-5

Home 

ID 

UCB 

ID Season Region City 

Zip 

Code 

UCB 

Statewide 

UCB 

Builder Supplemen

101 Winter North Sacramento 95835 X 102 Winter North Sacramento 95835 X 104 Winter North Sacramento 95835 X 105 210066 Winter North Discovery Bay 94514 X 106 Winter North Stockton 95219 X 107 Winter North Stockton 95219 X 108 Winter North Stockton 95219 X 109 510018 Winter North Brentwood 94513 X 110 510034 Winter North Brentwood 94513 X 112 Winter North El Dorado Hills 95762 X 113 Winter North El Dorado Hills 95762 X 114 Winter North El Dorado Hills 95762 X 115 Winter North El Dorado Hills 95762 X 116 Winter North El Dorado Hills 95762 X 117 Winter North Lincoln 95648 X 118 Winter North Lincoln 95648 X 119 530015 Winter North Lincoln Hills 95648 X 120 Winter North Folsom 95630 X 121 Winter North Folsom 95630 X 
C-6
D-1 

APPENDIX D 

Home-Season Test List 

Appendix Key 

Label Description 

DOA Ducted Outdoor Air Mechanical Outdoor Air Ventilation 

System 

WHF Whole House Fan Nighttime Cooling System 

HRV Heat Recovery Ventilator Mechanical Outdoor Air 

Ventilation System 

RAD Forced Air Unit Return Air Damper Nighttime Cooling 

System 

WDF Window Fan 

EC Evaporative Cooler 
D-2 

Home ID Season Region City Mechanical 

001 Summer North Brentwood DOA 

002 Summer North Brentwood 

002 Winter North Brentwood 

003 Summer North Brentwood 

004 Summer North Brentwood DOA 

004 Winter North Brentwood DOA 

005 Summer North Discovery Bay 

005 Winter North Discovery Bay 

005 Fall North Discovery Bay 

006 Summer North Discovery Bay 

006 Winter North Discovery Bay 

006 Fall North Discovery Bay 

008 Summer North Brentwood DOA 

008 Winter North Brentwood DOA 

009 Summer North Brentwood DOA 

010 Summer North Brentwood DOA 

011 Summer North Brentwood DOA 

011 Winter North Brentwood DOA 

012 Summer North Brentwood DOA 

013 Summer North Elk Grove 

013 Fall North Elk Grove 

014 Summer North Elk Grove 

015 Summer North Elk Grove WHF 

016 Summer North Elk Grove HRV 

017 Summer North Elk Grove HRV 

017 Winter North Elk Grove HRV 

018 Summer North Elk Grove HRV, RAD 

018 Winter North Elk Grove HRV, RAD 

019 Summer North Elk Grove RAD 

019 Winter North Elk Grove RAD 

019 Fall North Elk Grove RAD 

020 Summer North Elk Grove 

021 Summer North Elk Grove DOA 

022 Summer North Sacramento HRV 

023 Summer North Sacramento 

024 Summer North Sacramento WHF, HRV 

025 Summer North Elk Grove HRV, RAD 

025 Winter North Elk Grove HRV, RAD 

026 Summer North Elk Grove HRV 

027 Summer North Elk Grove 

029 Summer North Manteca 

030 Summer North Manteca 

031 Summer North Manteca 

032 Summer North Manteca 

033 Summer North Rancho Murrieta 

034 Summer North Rancho Murrieta WHF 

037 Summer South Valencia 
D-3 

Home ID Season Region City Mechanical 

038 Summer South Valencia 

038 Winter South Valencia 

039 Summer South Valencia 

039 Winter South Valencia 

040 Summer South Castaic 

041 Summer South Castaic 

041 Winter South Castaic 

042 Summer South Castaic 

043 Summer South Santa Clarita 2 x DOA 

044 Summer South Santa Clarita WD, WHF 

044 Winter South Santa Clarita WD, WHF 

045 Summer South Santa Clarita 

045 Winter South Santa Clarita 

046 Summer South Canyon Country 

047 Summer South Canyon Country 

048 Summer South Canyon Country 

049 Summer South Chula Vista 

049 Winter South Chula Vista 

050 Summer South Chula Vista 

050 Winter South Chula Vista 

053 Summer South San Diego 

054 Summer South San Diego 

055 Summer South San Diego 

056 Summer South San Diego 

058 Summer South San Marcos DOA, EC 

058 Winter South San Marcos DOA, EC 

059 Summer South San Marcos 

059 Winter South San Marcos 

061 Summer South Castaic 

062 Summer South Castaic 

062 Winter South Castaic 

064 Summer South Santa Clarita 

065 Summer South Santa Clarita 

066 Summer South Santa Clarita 

067 Summer South Palmdale 

068 Summer South Palmdale 

069 Summer South Palmdale 

070 Summer South Palmdale 

071 Summer South Palmdale 

072 Summer South Palmdale 

073 Winter South Santa Clarita 

074 Winter South Santa Clarita 

075 Winter South Valencia 

076 Winter South Castaic 

077 Winter South Santa Clarita 

078 Winter South San Marcos 

079 Winter South San Marcos 

080 Winter South Chula Vista 

081 Winter South San Marcos 

083 Winter South San Diego DOA 
D-4 

Home ID Season Region City Mechanical 

084 Winter South San Diego 

085 Winter South San Diego 

086 Winter South Fontana 

087 Winter South Fontana 

088 Winter South Fontana WHF 

089 Winter South Fontana 

090 Winter South Fontana 

091 Winter South Fontana 

092 Winter South Fontana 

093 Winter South Fontana 

094 Winter South Riverside 

095 Winter South Riverside 

096 Winter South Riverside 

097 Winter North Elk Grove HRV 

098 Winter North Elk Grove 

099 Winter North Sacramento DOA 

101 Winter North Sacramento 

102 Winter North Sacramento DOA 

104 Winter North Sacramento HRV 

105 Winter North Discovery Bay 

106 Winter North Stockton 

107 Winter North Stockton 

108 Winter North Stockton 

109 Winter North Brentwood DOA 

110 Winter North Brentwood DOA 

112 Winter North El Dorado Hills RAD 

113 Winter North El Dorado Hills 

114 Winter North El Dorado Hills 

115 Winter North El Dorado Hills 

116 Winter North El Dorado Hills RAD 

117 Winter North Lincoln RAD 

118 Winter North Lincoln DOA 

119 Winter North Lincoln Hills DOA 

120 Winter North Folsom 

121 Winter North Folsom 
E-1 

APPENDIX E 

Air Contaminant and Outdoor Air Exchange Rate PFT Measurements 
E-2

Appendix Key 

Compound Abbreviation Sample ID 

Acetaldehyde Acet hhh-sample type-location-date Benzene Benz hhh = 2-Butoxethanol 2Bto Sample type Caprolactam Capr V = Volatile 1,4-Dichlorobenzene Dchl F = FormaldEthylene glycol Ethy N = NFormaldehyde Form P = ParticHexanal Hxan B = n-Hexane NHex C/CC = Cd-Limonene dLim T= 1-Methyl-2-pyrrolidinone MePy Sample Location Naphthalene Naph 1 = Phenol Phen 2 = OAlpha-Pinene AlP 1D = InStyrene Styr 2D = OTetrachloroethene Tchlr FAA/AA = Toluene Tolu FSA/SA/SA1/SA2 = Trichloroethene (chloroform) Clr FRA/RA = 1,2,4- Trimethylbenzene 124T Date Vinyl acetate Viny BOLD concentration or mass Concentrm,p-Xylene mpXy o-Xylene oXyl ND 
E-3

Volatile organic compound, sample IDs and concentrations. 

Home 

ID Sample ID 

Benz 

(μg/m3) 

2Bto 

(μg/m3) 

Capr 

(μg/m3) 

Dchl 

(μg/m3) 

Ethy 

(μg/m3) 

Hxan 

(μg/m3) 

nHex 

(μg/m3) 

d

(μg

001 001-v1a-080706 0.23 15.91 0.21 0.48 41.77 5.74 0.27 7002 002-v1a-080706 0.25 0.13 0.24 0.21 4.10 0.74 0.30 0002 002-v2a-080706 0.24 0.13 0.23 0.20 1.12 0.10 0.29 0002 002-v1a-030107 0.72 1.16 0.26 0.23 1.27 6.84 0.92 30003 003-v1b-080706 0.18 4.44 0.17 0.15 24.80 6.56 0.22 1004 004-v1b-080806 0.25 11.28 0.24 0.21 12.82 4.76 0.30 6004 004-v1a-030107 3.51 6.02 0.25 0.22 1.21 20.27 2.00 12005 005-v1b-080806 3.13 5.67 0.23 451.05 20.26 36.96 4.48 9005 005-v2a-080806 0.24 0.13 0.23 0.77 1.11 0.10 0.29 0005 005-v1b-102306 7.44 10.87 0.24 12.76 7.16 26.75 14.56 1005 005-v1a-022707 4.90 1.54 0.22 1.78 1.09 15.37 10.66 20006 006-v1b-080806 1.02 3.67 0.22 0.20 6.95 27.56 1.75 9006 006-v1a-102306 0.30 1.22 0.22 0.20 1.09 2.76 1.24 1006 006-v2b-102306 0.24 0.13 0.23 0.20 1.10 0.09 0.52 0006 006-v2bd-102306 0.24 0.13 0.23 0.20 1.12 0.10 0.53 0006 006-v1a-022707 1.28 7.23 0.25 0.22 1.21 14.89 1.26 18006 006-v2a-022707 0.61 0.13 0.24 0.21 1.17 0.68 0.30 0008 008-v1a-080906 1.06 5.58 0.24 35.63 46.63 12.81 0.60 8008 008-v2b-080906 0.25 0.13 0.24 0.21 1.16 0.10 0.30 0008 008-v1b-030107 1.67 1.29 0.26 36.86 1.25 68.09 0.56 9008 008-v2a-030107 0.66 0.14 0.24 0.21 1.19 0.10 0.31 0009 009-v1b-080906 0.24 0.13 0.23 0.20 51.67 17.38 0.29 3009 009-v1db-080906 0.23 0.12 0.22 0.19 47.09 16.23 0.38 29010 010-v1a-081006 1.27 34.31 0.24 0.21 119.48 35.05 1.45 4011 011-v1a-081006 0.27 183.73 0.25 0.22 101.89 38.59 1.02 17011 011-v2b-081006 0.25 0.13 0.23 0.20 1.14 0.23 0.29 0011 011-v1a-030207 0.71 34.17 0.23 0.20 16.80 18.24 0.67 8012 012-v1a-081006 0.15 3.22 0.23 0.20 15.72 3.53 0.28 0013 013-v1a-081406 2.16 5.16 0.22 0.35 29.71 21.85 4.31 1013 013-v1a-102406 2.11 1.55 0.22 0.36 7.79 0.95 4.17 2013 013-v2b-102406 0.22 0.13 0.23 0.18 1.14 0.10 0.71 0
E-4

Volatile organic compound, sample IDs and concentrations. 

Home 

ID 

Sample ID Naph 

(μg/m3) 

Phen 

(μg/m3) 

alP 

(μg/m3) 

Styr 

(μg/m3) 

TChlr 

(μg/m3) 

Tolu 

(μg/m3) 

Clr 

(μg/m3) 

124T 

(μg/m3) 

Viny 

(μg/m3) 

m

(μg

001 001.v1a.080706 0.13 2.38 11.19 0.49 0.29 3.01 0.31 0.21 0.35 2002 002.v1a.080706 0.14 0.42 0.21 0.22 0.33 0.78 0.34 0.23 0.39 0002 002.v2a.080706 0.14 0.57 0.21 0.21 0.32 0.19 0.33 0.22 0.38 0002 002.v1a.030107 0.08 0.75 5.05 1.08 0.36 19.46 0.42 0.83 0.43 1003 003.v1b.080706 0.06 4.12 5.47 0.16 0.24 3.86 0.25 0.17 0.28 0004 004.v1b.080806 0.54 2.55 15.29 0.22 0.33 4.43 0.34 0.33 0.39 1004 004.v1a.030107 2.48 3.04 39.09 2.82 0.34 27.20 0.34 2.96 0.41 7005 005.v1b.080806 0.53 6.40 42.53 3.69 0.32 30.84 0.34 5.26 0.39 1005 005.v2a.080806 0.14 0.80 0.20 0.21 0.31 1.34 0.33 0.22 0.38 0005 005.v1b.102306 0.77 4.43 37.56 3.39 0.34 64.44 0.35 10.00 0.40 3005 005.v1a.022707 0.42 2.85 13.49 1.27 0.31 24.16 0.32 3.65 0.37 1006 006.v1b.080806 0.13 3.73 32.21 1.88 0.31 12.67 0.32 1.15 0.37 5006 006.v1a.102306 0.27 1.49 10.26 1.58 0.31 10.66 0.32 1.60 0.37 5006 006.v2a.102306 0.20 0.46 0.20 0.47 0.31 3.18 0.33 0.84 0.37 2006 006.v2bd.102306 0.21 0.50 0.21 0.41 0.32 3.07 0.33 0.79 0.38 2006 006.v1a.022707 0.13 1.91 11.14 1.08 0.34 10.79 0.36 1.57 0.41 4006 006.v2a.022707 0.14 0.87 0.22 0.28 0.33 1.82 0.35 0.41 0.40 1008 008.v1a.080907 0.11 2.68 30.00 1.42 0.33 13.69 1.66 0.92 0.39 4008 008.v2b.080907 0.14 0.68 0.21 0.22 0.33 1.36 0.34 0.23 0.39 0008 008.v1b.030107 0.08 1.65 14.76 2.39 0.59 20.24 0.58 0.78 0.42 3008 008.v2a.030107 0.14 0.56 0.22 0.23 0.34 0.60 0.35 0.14 0.40 0009 009.v1b.080906 0.18 3.16 30.87 0.77 0.32 3.97 0.33 0.35 0.38 1009 009.v1bd.080906 0.17 2.92 28.49 0.75 0.31 3.77 0.32 0.32 0.37 1010 010.v1a.081006 0.49 4.50 65.10 4.65 0.34 24.03 0.35 2.06 0.40 4011 011.v1a.081006 0.74 9.62 100.59 4.97 0.35 15.02 0.36 2.06 0.42 3011 011.v2b.081006 0.14 0.91 0.13 0.22 0.32 1.53 0.34 0.23 0.39 0011 011.v1a.030207 0.24 3.86 27.90 1.60 0.31 47.53 0.33 1.22 0.29 14012 012.v1a.081006 0.13 3.56 9.20 0.36 0.31 4.93 0.33 0.22 0.37 1013 013.v1a.081406 0.40 3.48 58.34 2.81 0.31 114.40 1.31 2.50 0.37 2013 013.v1a.102406 0.37 1.09 16.63 1.00 0.30 66.11 0.40 3.29 0.36 1013 013.v2b.102406 0.21 0.39 0.21 0.22 0.32 5.03 0.34 1.14 0.39 3
E-5

 Volatile organic compound, sample IDs and concentrations. 

Home 

ID 

Sample ID Benz 

(μg/m3) 

2Bto 

(μg/m3) 

Capr 

(μg/m3) 

Dchl 

(μg/m3) 

Ethy 

(μg/m3) 

Hxan 

(μg/m3) 

nHex 

(μg/m3) 

d

(μg

014 014-v1b-081406 0.25 0.13 0.23 0.20 1.14 1.16 0.29 0014 014-v2b-081406 0.25 0.13 0.24 0.21 1.15 0.10 0.30 0015 015-v1a-081406 0.25 0.13 0.23 0.86 3.31 0.93 0.29 0016 016-v1b-081506 0.23 0.12 0.22 0.68 0.85 0.64 0.28 0017 017-v1a-081506 0.26 1.00 0.24 0.21 1.19 0.45 0.31 1017 017-v2b-081506 0.25 0.13 0.23 0.20 1.14 0.05 0.29 3017 017-v1a-022107 0.44 2.63 0.27 0.23 5.17 3.91 0.34 7017 017-v2a-022107 0.32 0.14 0.26 0.23 1.26 0.50 0.33 0018 018-v1a-081506 0.22 2.20 0.21 0.19 3.04 1.31 0.27 0018 018-v1bd-081506 0.23 1.84 0.22 0.19 3.43 1.66 0.28 0018 018-v1b-022107 0.42 4.88 0.25 0.22 8.69 3.04 0.32 1019 019-v1a-081606 0.28 0.15 0.27 0.24 1.31 0.11 0.34 0019 019-v1b-102406 0.94 3.64 0.22 0.19 1.07 1.15 1.97 3019 019-v1b-022007 1.74 9.89 0.24 0.15 1.15 14.32 1.86 12019 019-v1bd-022007 1.85 1.55 0.25 0.15 1.22 17.21 1.88 12020 020-v1b-081606 5.45 1.21 0.22 0.19 35.69 15.38 12.67 7020 020-v2b-081606 0.26 0.14 0.25 0.22 1.21 0.10 0.31 0021 021-v1a-081606 0.82 6.03 0.24 3.08 0.89 24.09 1.08 1022 022-v1b-081706 0.28 0.90 0.27 161.32 11.36 7.93 0.45 2023 023-v1b-081706 0.27 0.14 0.26 0.23 69.42 17.78 0.47 2023 023-v2a-081706 0.26 0.14 0.24 0.21 1.19 0.10 0.31 0024 024-v1b-081706 0.27 0.14 0.26 0.22 99.53 5.81 0.32 3025 025-v1a-082106 0.25 0.13 0.24 0.21 7.01 1.66 0.30 1025 025-v1b-022107 0.83 1.64 0.23 0.14 1.10 8.16 0.28 32026 026-v1a-082106 0.25 0.14 0.24 0.21 33.83 5.03 0.31 1026 026-v2a-082106 0.25 0.13 0.24 0.21 1.15 0.27 0.30 1027 027-v1a-082106 1.24 2.87 0.23 0.20 34.04 5.02 1.86 1029 029-v1a-082206 0.40 5.44 0.23 0.20 6.29 18.21 0.76 1029 029-v2a-082206 0.28 0.15 0.27 0.23 1.29 0.11 0.33 0030 030-v1a-082206 4.28 3.87 0.24 0.21 3.23 11.02 7.64 3030 030-v1ad-082206 3.96 4.76 0.23 0.20 5.37 10.73 7.11 2031 031-v1b-082306 2.0 3.2 0.2 0.2 1.2 11.3 4.5 4032 032-v1b-082306 1.0 0.1 0.2 0.2 34.8 2.2 2.3 032 032-v2b-082306 0.3 0.1 0.3 0.2 1.2 0.1 0.3 033 033-v1a-082406 0.3 2.9 0.2 0.2 1.1 13.4 1.0 033 033-v1a-082506 0.1 2.5 0.2 0.2 1.1 12.0 0.8 033 033-v1a-082606 1.4 5.7 0.2 0.2 1.2 21.3 3.0 3
E-6

Volatile organic compound, sample IDs and concentrations. 

Home 

ID 

Sample ID Naph 

(μg/m3) 

Phen 

(μg/m3) 

alP 

(μg/m3) 

Styr 

(μg/m3) 

TChlr 

(μg/m3) 

Tolu 

(μg/m3) 

Clr 

(μg/m3) 

124T 

(μg/m3) 

Viny 

(μg/m3) 

014 014-v1b-081406 0.14 1.11 0.34 0.22 0.32 0.83 0.34 0.23 0.39 014 014-v2b-081406 0.14 0.67 0.21 0.22 0.33 0.57 0.34 0.23 0.39 015 015-v1a-081406 0.14 0.90 0.11 0.22 0.32 0.34 0.34 0.23 0.39 016 016-v1b-081506 0.13 0.58 1.33 0.21 0.31 1.44 0.32 0.22 0.37 017 017-v1a-081506 0.14 0.46 0.50 0.23 0.34 2.43 0.35 0.24 0.40 017 017-v2b-081506 0.14 0.68 0.21 0.22 0.32 0.64 0.34 0.23 0.39 017 017-v1a-022107 0.16 0.45 2.42 0.16 0.20 4.09 0.65 0.26 0.44 017 017-v2a-022107 0.15 0.67 0.23 0.24 0.36 0.30 0.37 0.25 0.43 018 018-v1a-081506 0.13 0.41 1.46 0.20 0.29 1.44 0.31 0.21 0.35 018 018-v1bd-081506 0.13 0.72 1.66 0.20 0.30 2.02 0.32 0.21 0.36 018 018-v1b-022107 0.15 0.31 2.12 0.68 27.93 1.86 1.30 0.17 0.41 019 019-v1a-081606 0.16 0.91 0.50 0.25 0.37 1.04 0.39 0.26 0.44 019 019-v1b-102406 0.27 0.86 8.77 0.32 0.30 12.89 0.32 1.83 0.36 019 019-v1b-022007 0.23 2.12 12.02 1.36 0.70 11.52 0.43 2.08 0.39 019 019-v1bd-022007 0.23 1.88 11.91 1.45 0.70 11.84 0.53 2.07 0.41 020 020-v1b-081606 0.57 5.32 25.18 4.47 0.30 50.79 0.31 9.65 0.36 020 020-v2b-081606 0.15 0.54 0.22 0.23 0.34 1.07 0.36 0.24 0.41 021 021-v1a-081606 0.25 5.41 35.29 2.42 2.08 12.26 0.34 0.60 0.39 022 022-v1b-081706 0.16 1.40 13.55 1.59 0.37 5.87 0.38 0.18 0.44 023 023-v1b-081706 0.15 3.82 33.02 2.13 5.03 9.52 0.71 0.25 0.43 023 023-v2a-081706 0.14 1.15 0.22 0.23 0.34 1.26 0.35 0.24 0.40 024 024-v1b-081706 0.15 1.39 18.52 0.61 0.35 4.16 0.37 0.25 0.42 025 025-v1a-082106 0.14 1.06 1.60 0.69 0.33 4.98 0.34 0.23 0.39 025 025-v1b-022107 0.13 1.39 6.30 0.61 0.31 12.94 1.01 0.47 0.37 026 026-v1a-082106 0.14 2.09 6.33 0.44 0.33 5.72 0.35 0.24 0.40 026 026-v2a-082106 0.14 1.54 0.21 0.12 0.33 0.94 0.34 0.23 0.39 027 027-v1a-082106 0.09 2.41 7.18 1.28 0.32 8.01 0.33 0.57 0.38 029 029-v1a-082206 0.15 1.82 39.37 1.48 0.32 5.65 0.22 3.47 0.38 029 029-v2a-082206 0.16 0.83 0.24 0.25 0.37 1.82 0.38 0.26 0.44 030 030-v1a-082206 0.39 2.26 19.45 0.86 0.33 43.81 0.34 4.78 0.39 030 030-v1ad-082206 0.37 2.04 18.60 1.22 0.32 41.67 0.33 4.66 0.38 031 031-v1b-082306 0.15 3.42 19.51 0.78 0.33 21.11 0.34 2.42 0.39 032 032-v1b-082306 0.09 1.33 3.52 0.63 0.34 10.97 0.36 1.69 0.41 032 032-v2b-082306 0.15 1.55 0.23 0.31 0.35 2.10 0.37 0.25 0.42 033 033-v1a-082406 0.13 1.77 15.92 0.92 0.30 9.78 2.17 0.82 0.36 033 033-v1a-082506 0.11 1.78 11.41 0.23 0.32 8.07 0.66 0.45 0.39 033 033-v1a-082606 0.18 2.40 26.21 0.79 0.28 16.81 5.40 1.15 0.41 
E-7

Volatile organic compound, sample IDs and concentrations. 

Home 

ID 

Sample ID Benz 

(μg/m3) 

2Bto 

(μg/m3) 

Capr 

(μg/m3) 

Dchl 

(μg/m3) 

Ethy 

(μg/m3) 

Hxan 

(μg/m3) 

nHex 

(μg/m3) 

d

(μ

034 034-v1a-082406 0.28 0.15 0.27 0.23 1.29 2.70 0.33 0034 034-v2b-082406 0.26 0.14 0.25 0.21 1.20 0.17 0.31 0037 037-v1a-090506 0.26 24.61 0.25 0.23 6.87 6.65 0.80 4038 038-v1a-090506 0.25 8.46 0.24 0.23 24.74 49.18 0.82 1038 038-v2a-090506 0.24 0.13 0.16 0.13 1.12 0.19 0.35 0038 038-v1b-012407 0.51 1.35 0.25 0.22 1.21 4.00 0.26 5039 039-v1a-090506 0.28 7.46 0.24 0.21 12.41 30.38 1.05 1039 039-v1a-012407 1.19 5.60 0.23 0.20 1.14 6.21 0.29 1040 040-v1a-090606 2.05 7.00 0.24 0.41 17.51 5.85 0.73 9041 041-v1b-090606 0.23 2.45 0.22 0.10 26.85 13.26 0.96 7041 041-v2a-090606 0.26 0.67 0.24 0.12 1.19 0.37 0.68 0041 041-v1a-012507 1.22 31.78 0.26 0.23 8.48 7.55 0.33 7041 041-v2b-012507 1.00 0.14 0.26 0.22 1.25 0.33 1.05 0041 041-v1a-012607 1.27 4.42 0.25 0.21 11.77 8.72 1.24 5041 041-v1a-012707 1.22 3.25 0.25 0.22 15.49 10.54 0.90 7042 042-v1a-090606 4.58 3.40 0.23 2.56 32.64 22.00 6.88 1043 043-v1a-090706 0.29 1.60 0.28 1.66 12.25 7.00 0.59 3044 044-v1a-090706 0.24 3.56 0.23 0.13 4.39 2.57 0.69 0044 044-v2b-090706 0.26 0.83 0.24 0.14 1.19 0.35 0.68 0044 044-v1a-012607 1.68 2.82 0.24 0.21 1.18 8.30 0.72 2044 044-v1ad-012607 1.63 2.55 0.26 0.23 1.26 7.79 0.68 2045 045-v1a-090706 3.39 36.24 0.23 0.20 41.39 26.96 2.50 1045 045-v1ad-090706 3.76 34.22 0.23 0.20 49.49 27.63 2.89 1045 045-v1b-012307 NA NA NA NA NA NA NA 046 046-v1a-090806 0.36 20.62 0.22 0.19 44.70 23.47 1.01 1047 047-v1b-090806 4.53 13.99 0.23 0.20 21.00 20.41 5.23 7047 047-v2b-090806 0.27 0.14 0.26 0.23 1.26 0.28 0.38 0048 048-v1b-090806 1.43 10.95 0.23 0.20 17.16 10.85 1.72 3049 049-v1a-091206 0.25 13.36 0.24 0.35 19.94 29.66 0.68 1049 049-v1a-013007** 0.92 0.14 0.25 0.22 1.21 12.31 0.55 2049 049-v2a-013007 0.98 0.12 0.22 0.19 1.09 0.32 0.25 0050 050-v1b-091206 0.26 1.74 0.24 0.16 1.19 1.91 0.84 0050 050-v2b-091206 0.25 0.73 0.24 0.19 1.15 0.22 0.30 0050 050-v1b-013007 3.88 1.48 0.23 0.20 6.11 11.84 6.72 4053 053-v1a-091306 0.25 2.51 0.24 0.21 1.18 2.55 0.31 0053 053-v2b-091306 0.27 0.14 0.26 0.22 1.24 0.37 0.32 0054 054-v1b-091306 0.23 4.79 0.22 0.19 4.49 5.23 0.28 0054 054-v1bd-091306 0.22 5.45 0.21 0.18 3.55 5.24 0.27 0
E-8

Volatile organic compound, sample IDs and concentrations.

Home 

ID 

Sample ID Naph 

(μg/m3) 

Phen 

(μg/m3) 

alP 

(μg/m3) 

Styr 

(μg/m3) 

TChlr 

(μg/m3) 

Tolu 

(μg/m3) 

Clr 

(μg/m3) 

124T 

(μg/m3) 

Viny 

(μg/m3) 

m

(μg

034 034-v1a-082406 0.16 0.91 2.35 0.13 0.37 4.41 0.38 0.26 0.44 1034 034-v2b-082406 0.15 0.42 0.22 0.23 0.34 0.36 0.35 0.24 0.41 0037 037-v1a-090506 0.49 1.83 14.81 2.86 0.56 8.44 0.36 1.50 0.41 3038 038-v1a-090506 0.66 4.67 57.45 9.30 0.33 7.09 0.54 1.04 0.39 5038 038-v2a-090506 0.16 1.34 0.21 0.51 0.32 2.25 0.33 0.60 0.38 1038 038-v1b-012407 0.08 0.80 10.12 1.71 0.34 2.71 0.23 0.30 0.41 1039 039-v1a-090506 0.30 2.44 25.63 3.72 3.64 8.24 0.35 1.12 0.40 9039 039-v1a-012407 0.14 1.08 8.03 1.79 1.26 5.31 0.34 0.69 0.39 7040 040-v1a-090606 0.26 2.26 12.65 1.96 0.33 6.92 0.43 0.96 0.40 4041 041-v1b-090606 0.18 2.98 41.74 1.67 0.30 8.65 0.31 0.74 0.36 2041 041-v2a-090606 0.17 0.87 0.22 0.75 0.34 3.13 0.35 0.75 0.40 2041 041-v1a-012507 0.16 2.42 16.31 2.21 0.36 8.46 0.30 0.95 0.43 3041 041-v2b-012507 0.15 0.96 0.23 0.27 0.36 2.93 0.37 0.42 0.42 1041 041-v1a-012607 0.15 1.65 18.37 1.17 0.34 21.00 0.35 0.90 0.41 2041 041-v1a-012707 0.15 2.45 19.60 1.21 0.35 13.87 0.19 1.05 0.41 3042 042-v1a-090606 0.40 5.35 29.26 2.03 0.32 70.43 0.44 4.48 0.38 2043 043-v1a-090706 0.25 1.35 10.31 0.47 0.38 5.32 0.40 0.64 0.46 1044 044-v1a-090706 0.42 1.44 3.54 1.14 0.32 5.91 0.33 1.57 0.38 3044 044-v2b-090706 0.19 0.68 0.22 0.18 0.34 3.59 0.35 0.90 0.40 2044 044-v1a-012607 0.39 1.43 6.44 1.32 0.33 8.11 0.35 2.82 0.40 4044 044-v1ad-012607 0.39 1.56 6.39 0.90 0.36 7.90 0.37 2.69 0.43 4045 045-v1a-090706 2.51 6.46 49.26 4.42 0.31 23.43 0.33 4.13 0.38 1045 045-v1ad-090706 2.40 6.38 51.61 4.42 0.32 24.02 0.33 4.08 0.38 1045 045-v1b-012307 NA NA NA NA NA NA NA NA NA 046 046-v1a-090806 0.30 4.70 35.35 2.91 0.31 10.90 0.22 1.03 0.37 3047 047-v1b-090806 0.77 5.14 47.83 2.53 0.31 30.21 0.33 5.43 0.38 2047 047-v2b-090806 0.18 0.02 0.23 0.24 0.36 2.69 0.37 0.68 0.43 1048 048-v1b-090806 0.50 1.54 19.74 1.85 0.32 12.72 0.34 3.01 0.39 7049 049-v1a-091206 0.40 3.93 31.24 2.83 0.33 13.26 0.26 0.86 0.40 3049 049-v1a-013007 0.13 0.48 12.44 1.08 0.34 8.12 0.36 0.70 0.41 2049 049-v2a-013007 0.13 0.53 0.20 0.17 0.31 3.75 0.32 0.61 0.37 2050 050-v1b-091206 0.23 1.27 1.32 1.19 0.34 6.00 0.35 1.31 0.40 5050 050-v2b-091206 0.18 0.54 0.21 0.62 0.33 2.17 0.34 0.68 0.39 2050 050-v1b-013007 0.30 1.74 14.09 2.19 0.48 24.98 0.67 5.24 0.38 1053 053-v1a-091306 0.13 0.61 0.22 0.21 0.33 0.96 0.35 0.30 0.40 0053 053-v2b-091306 0.10 0.44 0.23 0.17 0.35 0.37 0.37 0.27 0.42 0054 054-v1b-091306 0.16 0.80 1.91 0.76 0.30 4.15 0.32 0.48 0.36 2054 054-v1bd-091306 0.15 1.03 1.92 0.44 0.29 4.36 0.30 0.48 0.35 1
E-9

Volatile organic compound, sample IDs and concentrations. 

Home 

ID 

Sample ID Benz 

(μg/m3) 

2Bto 

(μg/m3) 

Capr 

(μg/m3) 

Dchl 

(μg/m3) 

Ethy 

(μg/m3) 

Hxan 

(μg/m3) 

nHex 

(μg/m3) 

(μ

055 055-v1a-091406 0.25 11.37 0.24 0.21 2.48 4.34 0.30 056 056-v1b-091406 0.27 3.65 0.26 0.22 0.85 8.11 0.32 056 056-v2a-091406 0.24 0.13 0.23 0.20 1.12 0.40 0.29 058 058-v1a-091506 0.26 23.86 0.25 0.22 11.61 6.12 0.26 058 058-v1a-013107 0.99 2.73 0.24 0.21 10.60 12.82 2.24 2059 059-v1a-091506 0.25 0.94 0.23 0.20 1.14 2.26 0.32 059 059-v2b-091506 0.26 0.53 0.24 0.21 1.19 0.16 0.31 059 059-v1a-091606 0.29 1.12 0.27 0.24 1.33 3.40 1.03 059 059-v1b-091706 0.27 1.37 0.29 0.24 3.09 1.15 1.79 059 059-v1b-012907 3.85 0.98 0.25 0.21 1.20 4.12 3.48 059 059-v2b-012907 0.37 0.13 0.24 0.21 1.17 0.45 0.30 061 061-v1a-091806 1.55 4.90 0.27 0.81 36.06 13.13 1.77 1062 062-v1b-091806 0.42 7.76 0.26 0.23 43.74 3.65 1.30 1062 062-v2a-091806 0.26 0.14 0.25 0.22 1.21 0.10 0.90 062 062-v2ad-091806 0.25 0.13 0.24 0.21 1.17 0.10 0.51 062 062-v1a-012507 1.35 1.27 0.20 0.18 11.55 2.37 1.11 2064 064-v1a-091906 1.79 1.61 0.26 0.23 1.27 4.40 4.73 064 064-v1ad-091906 1.77 2.20 0.27 0.24 1.31 4.80 5.21 065 065-v1a-091906 2.81 1.53 0.26 0.19 3.18 6.25 3.79 065 065-v2a-091906 0.27 0.15 0.26 0.23 1.27 0.49 0.33 066 066-v1a-091906 0.25 2.60 0.24 0.21 6.39 4.23 0.73 067 067-v1a-092006 0.26 1.45 0.25 0.21 1.20 2.36 0.71 068 068-v1a-092006 0.28 2.47 0.27 0.23 2.52 6.17 1.19 068 068-v2b-092006 0.25 0.14 0.24 0.40 1.18 0.58 0.24 069 069-v1a-092006 5.34 23.48 0.24 0.21 19.74 11.41 8.19 3070 070-v1a-092106 0.28 2.25 0.26 0.23 1.28 2.57 0.87 071 071-v1a-092106 0.21 3.07 0.24 33.50 10.88 4.51 0.69 071 071-v2a-092106 0.26 0.14 0.25 0.21 1.20 0.48 0.33 072 072-v1a-092106 0.26 4.73 0.25 0.22 9.57 2.35 1.66 073 073-v1b-012307 0.69 0.60 0.24 0.21 1.19 2.34 0.66 2073 073-v2a-012307 0.41 0.14 0.26 0.22 1.25 0.11 0.32 074 074-v1b-012307 2.41 0.25 0.24 0.21 1.15 3.42 4.09 1075 075-v1a-012407 1.08 1.49 0.23 0.20 15.70 5.19 0.83 2075 075-v2b-012407 0.68 0.11 0.20 0.18 0.99 0.21 0.19 076 076-v1b-012507 0.43 10.60 0.26 1.65 1.27 2.84 0.22 077 077-v1a-012607 1.20 0.14 0.24 0.21 12.43 8.49 1.09 1077 077-v2b-012607 0.72 0.14 0.24 0.21 1.19 0.10 0.21 078 078-v1b-012907 1.13 0.45 0.24 0.21 1.15 4.20 0.90 1078 078-v1bd-012907 1.31 0.58 0.24 0.21 1.15 4.64 1.00 1
E-10

Volatile organic compound, sample IDs and concentrations.

Home 

ID 

Sample ID Naph 

(μg/m3) 

Phen 

(μg/m3) 

alP 

(μg/m3) 

Styr 

(μg/m3) 

TChlr 

(μg/m3) 

Tolu 

(μg/m3) 

Clr 

(μg/m3) 

124T 

(μg/m3) 

Viny 

(μg/m3) 

m

(μg

055 055-v1a-091406 0.17 0.76 1.05 0.72 0.33 2.07 0.34 0.62 0.39 2056 056-v1b-091406 0.20 1.30 6.35 0.59 0.36 1.81 0.37 0.57 0.42 1056 056-v2a-091406 0.11 0.23 0.21 0.03 0.32 0.34 0.33 0.30 0.38 0058 058-v1a-091506 0.26 2.39 7.52 1.28 0.88 2.33 0.36 0.52 0.41 2058 058-v1a-013107 0.27 1.52 23.94 0.72 3.47 13.25 0.83 1.08 0.39 6059 059-v1a-091506 0.15 0.32 0.33 0.14 0.32 2.91 0.34 0.85 0.39 2059 059-v2b-091506 0.10 0.20 0.22 0.23 0.34 0.36 0.35 0.24 0.40 0059 059-v1a-091606 0.28 1.06 0.41 0.60 0.38 7.02 0.39 2.00 0.45 5059 059-v1b-091706 0.39 1.01 0.67 0.68 0.42 8.53 0.44 2.16 0.52 6059 059-v1b-012907 1.06 0.72 1.64 1.21 0.34 29.22 0.35 17.92 0.41 3059 059-v2b-012907 0.14 0.54 0.22 0.16 0.33 1.53 0.35 0.23 0.40 1061 061-v1a-091806 0.59 4.49 25.65 3.51 0.40 8.28 0.42 1.89 0.49 6062 062-v1b-091806 0.20 1.85 11.86 2.05 0.36 7.16 1.03 1.69 0.43 3062 062-v2a-091806 0.15 0.31 0.22 0.71 0.34 2.30 0.36 1.01 0.41 2062 062-v2ad-091806 0.14 0.39 0.22 0.33 0.33 2.00 0.35 0.59 0.40 1062 062-v1a-012507 0.08 1.05 7.13 1.48 0.28 5.71 0.17 1.07 0.33 4064 064-v1a-091906 0.28 0.97 7.79 0.67 0.36 16.85 0.38 3.13 0.43 1064 064-v1ad-091906 0.32 1.13 8.33 1.86 0.40 18.51 0.39 3.94 0.44 1065 065-v1a-091906 0.27 1.09 6.87 0.74 0.48 15.46 0.45 2.30 0.43 1065 065-v2a-091906 0.14 0.21 0.23 0.16 0.36 0.97 0.38 0.54 0.43 1066 066-v1a-091906 0.21 1.32 6.40 0.66 0.63 3.02 0.35 1.11 0.40 2067 067-v1a-092006 0.14 0.60 3.88 0.29 0.29 3.39 0.35 1.04 0.41 3068 068-v1a-092006 0.15 0.74 10.57 1.18 0.37 3.73 0.38 0.79 0.44 2068 068-v2b-092006 0.14 0.43 0.22 0.71 0.33 2.14 0.35 0.72 0.40 2069 069-v1a-092006 0.31 2.64 14.62 2.54 0.45 115.15 1.22 6.11 0.40 2070 070-v1a-092106 0.16 1.17 4.03 0.57 0.36 6.68 0.38 1.31 0.43 5071 071-v1a-092106 0.14 2.17 5.14 0.33 0.34 4.59 0.35 0.52 0.40 1071 071-v2a-092106 0.15 0.42 0.22 0.23 0.34 0.89 0.35 0.55 0.41 0072 072-v1a-092106 0.15 0.20 4.62 0.16 0.35 4.40 0.36 1.01 0.41 2073 073-v1b-012307 0.07 1.41 7.58 0.26 3.61 4.80 0.35 0.38 0.40 1073 073-v2a-012307 0.15 0.50 0.23 0.24 0.36 0.60 0.37 0.25 0.42 0074 074-v1b-012307 0.14 0.59 8.04 61.95 0.39 13.98 0.34 0.72 0.39 3075 075-v1a-012407 0.84 1.72 9.83 0.83 22.59 8.29 0.72 1.80 0.37 3075 075-v2b-012407 0.12 0.50 0.18 0.19 0.28 1.38 0.29 0.28 0.33 1076 076-v1b-012507 0.16 0.72 4.96 0.59 0.36 3.60 0.94 2.49 0.43 6077 077-v1a-012607 0.65 1.74 22.33 2.15 0.33 6.34 0.35 2.11 0.40 3077 077-v2b-012607 0.14 0.41 0.22 0.23 0.34 1.66 0.35 0.21 0.40 0
E-11

Volatile organic compound, sample IDs and concentrations. 

Home 

ID 

Sample ID Benz 

(μg/m3) 

2Bto 

(μg/m3) 

Capr 

(μg/m3) 

Dchl 

(μg/m3) 

Ethy 

(μg/m3) 

Hxan 

(μg/m3) 

nHex 

(μg/m3) 

d

(μg

079 079-v1b-012907 NA NA NA NA NA NA NA 080 080-v1a-013007 3.70 4.27 0.23 0.24 1.13 11.63 2.96 2081 081-v1a-013107 15.14 0.68 0.24 0.21 9.74 10.97 24.03 14081 081-v2b-013107 0.30 0.14 0.25 0.22 1.23 0.11 0.32 0083 083-v1b-020107 1.87 0.27 0.25 0.22 1.21 6.09 0.96 14083 083-v1ad-020107 1.84 0.27 0.23 0.20 1.13 4.80 0.82 1084 084-v1b-020107 1.31 2.21 0.26 0.22 7.04 9.53 0.58 1084 084-v2a-020107 0.87 0.13 0.22 0.20 1.09 0.09 0.18 0085 085-v1b-020107 2.04 0.87 0.24 0.21 13.53 4.56 0.76 14086 086-v1a-020507 4.66 10.03 0.25 0.22 1.22 12.40 6.47 4086 086-v1ad-020507 4.76 11.68 0.25 0.22 1.22 13.10 7.54 5087 087-v1a-020507 3.46 0.41 0.24 0.21 1.18 1.41 4.69 8087 087-v2a-020507 1.40 0.14 0.25 0.22 1.21 0.10 0.92 0088 088-v1a-020507 0.98 0.13 0.24 0.21 1.17 9.34 0.74 5089 089-v1b-020607 1.23 0.21 0.24 7.91 7.31 1.44 1.07 5090 090-v1b-020607 2.47 1.07 0.24 0.11 1.15 3.08 3.50 1090 090-v2b-020607 2.06 0.14 0.25 0.21 1.20 0.31 1.03 0091 091-v1b-020607 3.48 1.95 0.23 0.20 1.12 7.82 3.11 7092 092-v1b-020707 2.71 3.59 0.24 0.22 16.01 7.86 2.50 6092 092-v2b-020707 1.75 0.13 0.34 0.21 1.17 0.12 1.10 0092 092-v2ad-020707 1.85 0.14 0.24 0.21 1.18 0.10 1.34 0093 093-v1a-020707 7.20 1.83 0.26 0.22 14.93 6.80 3.66 8093 093-v1bd-020707 8.15 2.01 0.24 0.21 17.03 7.15 3.98 9094 094-v1b-020807 1.62 4.21 0.24 75.60 1.18 4.05 1.11 1095 095-v1a-020807 3.24 10.22 0.27 0.24 1.31 11.38 4.03 3095 095-v2b-020807 1.36 0.15 0.27 0.24 1.32 0.18 0.82 0096 096-v1a-020807 5.32 0.45 0.24 0.21 1.18 10.76 4.85 1097 097-v1a-022007 0.80 1.24 0.24 218.95 1.17 4.28 0.33 2098 098-v1a-022007 1.06 5.79 0.24 0.37 26.42 15.58 1.23 2098 098-v2b-022007 0.68 0.14 0.25 0.21 1.20 0.10 0.31 0099 099-v1a-022207 2.45 6.33 0.23 0.26 14.16 29.89 2.97 24099 099-v2a-022207 0.75 0.13 0.23 0.20 1.12 0.10 0.17 0099 099-v1a-022307 3.03 4.75 0.20 0.12 10.73 27.65 4.38 2099 099-v1a-022407 2.77 4.83 0.24 0.12 12.86 28.73 4.47 2101 101-v1b-022207 0.80 1.56 0.26 0.23 1.28 12.95 0.22 14102 102-v1a-022307 1.37 2.82 0.23 0.20 1.13 24.68 0.64 1104 104-v1b-022307 1.10 1.13 0.24 0.21 8.80 3.54 0.80 6104 104-v2b-022307 0.93 0.13 0.23 0.20 1.11 0.31 0.24 0
E-12

Volatile organic compound, sample IDs and concentrations. 

Home 

ID 

Sample ID Naph 

(μg/m3) 

Phen 

(μg/m3) 

alP 

(μg/m3) 

Styr 

(μg/m3) 

TChlr 

(μg/m3) 

Tolu 

(μg/m3) 

Clr 

(μg/m3) 

124T 

(μg/m3) 

Viny 

(μg/m3) 

m

(μ

078 078-v1b-012907 0.10 0.44 12.01 0.31 0.33 7.25 0.56 0.53 0.39 078 078-v1bd-012907 0.12 1.09 13.22 0.76 0.33 8.29 0.54 0.70 0.39 079 079-v1b-012907 NA NA NA NA NA NA NA NA NA 080 080-v1a-013007 0.57 1.06 22.55 2.52 0.48 29.96 0.72 3.06 0.38 1081 081-v1a-013107 0.38 2.59 20.68 1.18 0.33 53.78 0.35 8.36 0.40 3081 081-v2b-013107 0.15 0.40 0.23 0.24 0.35 0.37 0.36 0.25 0.42 083 083-v1b-020107 0.14 0.84 10.79 1.48 0.34 8.20 1.78 1.32 0.41 083 083-v1ad-020107 0.13 0.58 10.95 0.77 0.32 8.28 2.09 1.18 0.38 084 084-v1b-020107 0.18 1.50 11.71 1.58 0.35 7.73 0.37 1.05 0.42 084 084-v2a-020107 0.13 0.25 0.33 0.21 0.31 1.78 0.32 0.34 0.37 085 085-v1b-020107 0.20 1.63 11.59 0.94 0.34 8.45 0.30 1.34 0.40 086 086-v1a-020507 0.35 1.08 37.65 0.89 0.35 43.88 1.17 6.62 0.41 2086 086-v1ad-020507 0.33 1.30 40.05 0.93 0.35 44.78 1.21 6.86 0.41 2087 087-v1a-020507 0.18 0.59 6.99 0.87 0.28 26.84 0.35 1.95 0.40 087 087-v2a-020507 0.15 0.25 0.18 0.23 0.34 4.51 0.36 0.69 0.41 088 088-v1a-020507 0.18 1.47 22.57 0.87 0.33 8.34 0.35 1.44 0.40 089 089-v1b-020607 0.14 1.49 6.64 0.58 0.46 4.20 0.32 0.80 0.40 090 090-v1b-020607 0.18 0.52 7.18 0.60 0.32 18.64 0.34 2.11 0.39 090 090-v2b-020607 0.15 0.37 0.15 0.05 0.41 5.06 0.35 0.81 0.41 091 091-v1b-020607 0.26 2.64 11.09 1.67 0.28 30.26 0.74 2.39 0.38 1092 092-v1b-020707 0.22 1.79 11.77 1.21 0.44 94.47 1.16 1.58 0.39 092 092-v2b-020707 0.11 0.40 0.22 0.25 0.44 6.33 0.35 0.95 0.40 092 092-v2ad-020707 0.11 0.25 0.22 0.10 0.47 6.57 0.35 0.99 0.40 093 093-v1a-020707 0.22 1.66 18.76 1.35 0.41 20.00 0.18 2.75 0.42 1093 093-v1bd-020707 0.27 1.43 20.99 1.57 0.49 22.96 0.20 3.13 0.40 1094 094-v1b-020807 0.17 1.71 5.35 0.98 1.00 13.82 0.35 1.10 0.40 095 095-v1a-020807 0.10 0.88 12.49 1.52 0.37 18.29 0.39 2.05 0.44 095 095-v2b-020807 0.16 0.70 0.24 0.17 0.22 4.28 0.39 0.68 0.45 096 096-v1a-020807 0.32 1.76 43.15 1.78 0.27 19.62 0.89 2.28 0.40 097 097-v1a-022007 0.13 1.61 6.76 0.36 0.33 5.74 0.35 0.60 0.40 098 098-v1a-022007 0.28 2.00 11.21 0.84 0.33 16.04 0.35 3.11 0.40 1098 098-v2b-022007 0.15 0.36 0.22 0.23 0.34 0.99 0.35 0.14 0.41 099 099-v1a-022207 0.63 2.24 14.93 0.81 0.22 16.10 4.34 4.24 0.38 099 099-v2a-022207 0.14 0.36 0.21 0.21 0.32 1.06 0.33 0.16 0.38 099 099-v1a-022307 0.60 2.49 15.21 1.09 0.21 20.58 4.51 4.31 0.32 1099 099-v1a-022407 0.62 2.38 14.61 1.06 0.33 18.90 3.60 5.62 0.40 1101 101-v1b-022207 0.15 2.00 9.12 0.39 0.36 7.30 2.31 0.35 0.43 102 102-v1a-022307 0.64 1.95 39.13 2.46 0.32 17.81 5.65 3.76 0.38 104 104-v1b-022307 0.09 0.76 6.62 0.57 0.33 12.76 2.11 0.47 0.39 
E-13

Volatile organic compound, sample IDs and concentrations. 

Home 

ID 

Sample ID Benz 

(μg/m3) 

2Bto 

(μg/m3) 

Capr 

(μg/m3) 

Dchl 

(μg/m3) 

Ethy 

(μg/m3) 

Hxan 

(μg/m3) 

nHex 

(μg/m3) 

d

(μg

105 105-v1b-022707 1.50 4.50 0.23 0.20 4.86 17.13 2.26 1106 106-v1a-022807 1.77 9.83 0.23 0.48 6.65 10.93 1.77 1107 107-v1b-022807 1.02 0.57 0.21 0.13 1.04 13.98 0.52 2107 107-v2b-022807 0.86 0.13 0.24 0.21 1.15 0.10 0.30 0107 107-v2ad-022807 0.86 0.13 0.24 0.21 1.15 0.10 0.19 0108 108-v1b-022807 11.94 14.32 0.25 0.21 1.20 13.23 20.48 1109 109-v1a-030207 1.37 4.28 0.24 0.21 17.25 22.00 0.86 1110 110-v1a-030207 2.22 0.76 0.21 1.63 1.04 5.16 0.74 1110 110-v2b-030207 0.60 0.13 0.22 0.20 1.09 0.33 0.28 0112 112-v1b-030507 0.79 2.20 0.23 1.03 1.12 5.47 0.42 5112 112-v2b-030507 0.46 0.14 0.25 0.22 1.22 0.61 0.32 0113 113-v1a-030507 3.37 7.97 0.23 0.63 1.12 14.03 6.32 15114 114-v1b-030607 2.51 49.43 0.25 0.22 1.21 32.80 1.56 3115 115-v1b-030607 1.88 179.68 0.24 0.21 1.16 20.03 0.70 7115 115-v2b-030607 0.49 0.13 0.24 0.21 1.15 0.50 0.30 0116 116-v1a-030607 0.93 3.34 0.23 0.20 1.14 11.56 0.84 2116 116-v1bd-030607 0.82 4.27 0.25 0.21 1.20 11.22 0.73 22117 117-v1a-030707 1.99 7.91 0.24 0.21 1.15 27.88 18.90 10118 118-v1b-030707 1.18 4.09 0.24 0.21 1.18 23.94 1.31 24118 118-v2b-030707 0.37 0.14 0.25 0.21 1.20 0.47 0.31 0119 119-v1a-030707 1.65 4.97 0.26 0.22 1.24 21.25 2.49 12120 120-v1b-030807 0.79 14.17 0.25 0.21 1.20 18.73 0.26 1121 121-v1b-030807 0.69 0.14 0.25 0.22 1.21 19.62 0.40 9121 121-v2a-030807 0.55 0.13 0.23 0.20 1.10 0.09 0.28 0121 121-v2ad-030807 0.49 0.14 0.25 0.22 1.21 0.10 0.31 0
E-14

Volatile organic compound, sample IDs and concentrations. 

Home 

ID 

Sample ID Naph 

(μg/m3) 

Phen 

(μg/m3) 

alP 

(μg/m3) 

Styr 

(μg/m3) 

TChlr 

(μg/m3) 

Tolu 

(μg/m3) 

Clr 

(μg/m3) 

124T 

(μg/m3) 

Viny 

(μg/m3) 

m

(μg

104 104-v2b-022307 0.14 0.85 0.20 0.21 0.31 1.76 0.33 0.29 0.38 1105 105-v1b-022707 0.13 2.74 10.35 0.60 0.31 11.25 0.33 1.80 0.38 5106 106-v1a-022807 0.47 2.72 7.99 0.85 2.26 13.82 1.46 2.38 0.38 1107 107-v1b-022807 0.24 2.25 6.86 0.90 0.29 13.81 1.56 1.49 0.35 2107 107-v2b-022807 0.14 0.48 0.21 0.22 0.33 1.14 0.34 0.17 0.39 0107 107-v2ad-022807 0.14 0.35 0.21 0.22 0.33 1.13 0.34 0.17 0.39 0108 108-v1b-022807 0.47 1.18 9.47 0.65 0.34 99.92 0.82 13.16 0.41 6109 109-v1a-030207 1.06 2.49 20.33 1.33 0.59 33.89 0.35 2.22 0.26 1110 110-v1a-030207 0.12 1.41 8.89 0.69 0.29 16.17 0.31 0.79 0.35 4110 110-v2b-030207 0.13 0.34 0.20 0.21 0.31 1.13 0.32 0.14 0.37 0112 112-v1b-030507 4.85 1.21 8.70 0.63 0.32 4.71 0.78 0.73 0.38 2112 112-v2b-030507 0.15 0.73 0.23 0.23 0.35 0.96 0.36 0.25 0.41 0113 113-v1a-030507 0.32 1.53 12.56 2.43 3.37 41.19 2.09 3.54 0.38 1114 114-v1b-030607 0.33 3.20 20.18 1.73 0.34 22.55 1.56 1.68 0.41 5115 115-v1b-030607 0.14 2.77 8.40 1.46 0.36 10.99 3.09 0.81 0.39 5115 115-v2b-030607 0.14 0.62 0.21 0.22 0.33 1.06 0.34 0.23 0.39 0116 116-v1a-030607 0.10 2.47 13.31 1.89 0.59 4.78 1.22 0.61 0.39 5116 116-v1bd-030607 0.08 2.59 12.58 1.78 0.53 4.26 1.39 0.51 0.41 5117 117-v1a-030707 0.14 2.78 23.45 3.66 0.33 41.62 2.44 2.82 0.39 2118 118-v1b-030707 0.14 1.87 23.89 3.64 0.33 14.73 2.75 1.29 0.40 4118 118-v2b-030707 0.15 0.61 0.22 0.23 0.34 0.77 0.35 0.24 0.41 0119 119-v1a-030707 0.18 1.26 10.01 3.24 0.35 13.06 0.44 1.82 0.42 5120 120-v1b-030807 0.26 4.87 16.36 1.23 0.34 9.74 11.82 0.68 0.41 3121 121-v1b-030807 0.24 3.27 15.99 0.88 0.34 6.82 0.68 1.02 0.41 2121 121-v2a-030807 0.13 0.50 0.20 0.21 0.31 0.78 0.33 0.22 0.37 0121 121-v2ad-030807 0.15 0.52 0.22 0.23 0.34 0.69 0.36 0.24 0.41 0
E-15

Formaldehyde and acetaldehyde, sample IDs and concentrations.

Home 

ID 

Sample ID Acetaldehyde 

(μg/m3) 

Formaldehyde 

(μg/m3) 

Home 

ID 

Sample ID Acetaldehyde 

(μg/m3) 

Formaldehyde 

(μg/m3) 

001 001-f1-080706 NA NA 017 017-f2-022107 0.19 2.00 002 002-f1-080706 2.83 7.99 018 018-f1-081506 3.86 11.73 002 002-f2-080706 3.14 1.33 018 018-f1d-081506 6.19 18.58 002 002-f1-030107 27.56 52.78 018 018-f1-022107 10.02 23.29 003 003-f1-080706 11.46 35.94 019 019-f1-081606 2.97 4.77 004 004-f1-080806 16.61 39.04 019 019-f1-102406 15.21 24.22 004 004-f1-030107 62.05 62.83 019 019-f1-022007 22.50 35.65 005 005-f1-080806 64.13 111.28 019 019-f1d-022007 21.57 33.26 005 005-f2-080806 NA NA 020 020-f1-081606 27.07 92.69 005 005-f1-102306 48.52 71.61 020 020-f2-081606 3.31 2.23 005 005-f1-022707 20.84 43.84 021 021-f1-081606 58.98 45.42 006 006-f1-080806 43.10 61.31 022 022-f1-081706 23.16 58.46 006 006-f1-102306 14.13 22.85 023 023-f1-081706 44.15 92.46 006 006-f2-102306 4.48 3.00 023 023-f2-081706 3.59 2.40 006 006-f2d-102306 4.57 3.17 024 024-f1-081706 16.00 53.00 006 006-f1-022707 21.83 32.58 025 025-f1-082106 8.43 22.41 006 006-f2-022707 0.25 2.31 025 025-f1-022107 16.25 33.87 008 008-f1-080906 63.43 108.55 026 026-f1-082106 13.20 36.70 008 008-f2-080906 4.95 3.90 026 026-f2-082106 2.87 2.10 008 008-f1-030107 67.82 79.20 027 027-f1-082106 13.05 34.16 008 008-f2-030107 0.86 0.71 029 029-f1-082206 39.44 81.48 009 009-f1-080906 24.23 58.56 029 029-f2-082206 3.82 2.64 009 009-f1d-080906 24.59 56.90 030 030-f1-082206 25.27 56.66 010 010-f1-081006 50.67 135.52 030 030-f1d-082206 22.41 48.98 011 011-f1-081006 51.08 102.00 031 031-f1-082306 22.12 77.28 011 011-f2-081006 3.13 2.28 032 032-f1-082306 11.75 26.80 011 011-f1-030207 21.60 45.40 032 032-f2-082306 4.31 3.91 012 012-f1-081006 NA NA 033 033-f1-082406 74.54 58.15 013 013-f1-081406 72.61 100.13 033 033-f1-082506 54.89 50.23 013 013-f1-102406 15.29 45.17 034 033-f1-082606 108.67 63.60 013 013-f2-102406 3.12 53.26 034 034-f1-082406 7.26 14.37 014 014-f1-081406 1.90 7.72 037 034-f2-082406 3.16 2.28 014 014-f2-081406 1.38 0.72 038 037-f1-090506 25.42 40.66 015 015-f1-081406 2.52 10.49 038 038-f1-090506 52.85 105.76 016 016-f1-081506 4.51 10.07 038 038-f2-090506 2.30 2.10 017 017-f1-081506 2.90 7.80 039 038-f1-012407 11.27 27.09 017 017-f2-081506 2.32 1.04 039 039-f1-090506 45.97 42.43 017 017-f1-022107 6.29 18.55 040 039-f1-012407 32.25 21.59  040 040-f1-090606 22.00 47.44 
E-16

Formaldehyde and acetaldehyde, sample IDs and concentrations.

Home 

ID 

Sample ID Acetaldehyde 

(μg/m3) 

Formaldehyde 

(μg/m3) 

Home 

ID 

Sample ID Acetaldehyde 

(μg/m3) 

Formaldehyde 

(μg/m3) 

041 041-f1-090606 31.30 35.94 059 059-f1-012907 12.67 17.67 041 041-f2-090606 4.82 4.08 061 061-f1-091806 59.51 33.48 041 041-f1-012507 14.62 13.65 062 062-f1-091806 18.85 34.98 041 041-f2-012507 1.73 1.20 062 062-f2-091806 4.02 3.46 041 041-f1-012607 18.49 16.68 062 062-f2d-091806 4.17 3.50 041 041-f1-012707 22.95 22.54 062 062-f1-012507 9.92 15.46 042 042-f1-090606 30.08 58.71 064 064-f1-091906 14.05 48.84 043 043-f1-090706 22.32 65.52 064 064-f1d-091906 13.66 46.88 044 044-f1-090706 10.99 20.07 065 065-f1-091906 11.67 25.21 044 044-f2-090706 4.55 3.22 065 065-f2-091906 2.59 1.25 044 044-f1-012607 15.04 18.96 066 066-f1-091906 12.17 20.67 044 044-f1d-012607 14.07 17.15 067 067-f1-092006 8.72 12.41 045 045-f1-090706 33.42 125.72 068 068-f1-092006 14.54 15.99 045 045-f1d-090706 39.18 143.70 068 068-f2-092006 2.46 2.05 045 045-f1-012307 NA NA 069 069-f1-092006 55.12 63.58 046 046-f1-090806 28.59 105.13 070 070-f1-092106 7.86 25.33 047 047-f1-090806 34.70 96.48 071 071-f1-092106 7.28 24.46 047 047-f2-090806 3.50 2.89 071 071-f2-092106 2.77 8.04 048 048-f1-090806 20.96 62.48 072 072-f1-092106 8.60 16.73 049 049-f1-091206 36.26 77.44 073 073-f1-012307 17.86 15.22 049 049-f1-013007 14.18 31.17 073 073-f2-012307 0.78 0.34 049 049-f2-013007 1.16 1.11 074 074-f1-012307 15.25 17.21 050 050-f1-091206 4.59 21.55 075 075-f1-012407 19.64 30.94 050 050-f2-091206 1.71 1.00 075 075-f2-012407 1.22 0.61 050 050-f1-013007 30.83 38.90 076 076-f1-012507 17.55 17.87 053 053-f1-091306 3.59 13.40 077 077-f1-012607 13.44 30.68 053 053-f2-091306 0.16 1.01 077 077-f2-012607 1.21 1.75 054 054-f1-091306 6.76 29.97 078 078-f1-012907 19.56 23.21 054 054-f1d-091306 4.92 24.32 078 078-f1d-012907 19.45 22.54 055 055-f1-091406 4.40 17.94 079 079-f1-012907 NA NA 056 056-f1-091406 7.59 25.72 080 080-f1-013007 22.38 45.98 056 056-f2-091406 1.00 1.68 081 081-f1-013007 27.81 30.05 058 058-f1-091506 10.08 34.62 081 081-f2-013107 0.30 0.30 058 058-f1-013107 33.75 35.90 083 083-f1-020107 25.43 33.99 059 059-f1-091506 4.02 10.68 083 083-f1d-020107 18.24 25.24 059 059-f2-091506 0.68 3.14 084 084-f1-020107 12.44 39.56 059 059-f1-091606 5.81 14.30 084 084-f2-020107 NA NA 059 059-f1-091706 6.70 13.53 085 085-f1-020107 16.80 34.11 
E-17

Formaldehyde and acetaldehyde, sample IDs and concentrations.

Home 

ID 

Sample ID Acetaldehyde 

(μg/m3) 

Formaldehyde 

(μg/m3) 

Home 

ID 

Sample ID Acetaldehyde 

(μg/m3) 

Formaldehyde 

(μg/m3) 

086 086-f1-020507 27.17 47.52 112 112-f1-030507 15.20 38.72 086 086-f1d-020507 NA NA 112 112-f2-030507 2.29 1.58 087 087-f1-020507 12.69 19.96 113 113-f1-030507 36.29 40.28 087 087-f2-020507 3.67 3.02 114 114-f1-030607 96.70 59.61 088 088-f1-020507 13.79 31.80 115 115-f1-030607 49.91 45.72 089 089-f1-020607 5.78 12.84 115 115-f2-030607 2.16 2.02 090 090-f1-020607 14.73 18.25 116 116-f1-030607 37.72 44.65 090 090-f2-020607 2.78 2.43 116 116-f1d-030607 37.07 45.05 091 091-f1-020607 15.46 40.65 117 117-f1-030707 33.46 71.18 092 092-f1-020707 31.04 39.51 118 118-f1-030707 43.76 65.56 092 092-f2-020707 3.41 2.88 118 118-f2-030707 0.60 1.23 092 092-f2d-020707 4.03 3.72 119 119-f1-030707 53.27 56.21 093 093-f1-020707 13.84 36.83 120 120-f1-030807 38.62 118.67 093 093-f1d-020707 9.49 25.98 121 121-f1-030807 28.80 34.63 094 094-f1-020807 21.39 28.48 121 121-f2-030807 0.35 2.46 095 095-f1-020807 16.94 28.54 121 121-f2d-030807 0.57 2.94 095 095-f2-020807 2.78 1.96 017 017-AA-022107 1.62 1.95 096 096-f1-020807 58.75 34.10 017 017-FAA-081706 7.58 9.18 097 097-f1-022007 11.62 48.55 017 017-FRA-081706 6.66 8.57 098 098-f1-022007 36.85 31.55 017 017-FSA-081506 7.70 10.20 098 098-f2-022007 0.69 2.87 017 017-RA-022107 5.90 15.26 099 099-f1-022207 56.53 85.97 017 017-SA-022107 5.38 13.65 099 099-f2-022207 1.83 3.06 033 033-FAA-082406 NA NA 099 099-f1-022307 85.95 94.50 033 033-FRA-082406 NA NA 099 099-f1-022407 57.25 86.43 033 033-FSA-082406 NA NA 101 101-f1-022207 25.23 57.81 120 120-AA-030807 10.42 4.65 102 102-f1-022307 45.26 75.56 120 120-RA-030807 74.05 22.76 104 104-f1-022307 17.06 35.01 120 120-SA1-030807 69.98 20.90 104 104-f2-022307 2.18 1.68 120 120-SA2-030807 65.75 21.36 105 105-f1-022707 89.07 28.36 106 106-f1-022807 28.49 69.85 107 107-f1-022807 27.06 38.11 107 107-f2-022807 1.22 0.70 107 107-f2d-022807 1.50 1.19 108 108-f1-022807 19.81 37.92 109 109-f1-030207 101.48 85.71 110 110-f1-030207 15.42 70.73 110 110-f2-030207 1.37 3.21 
E-18

Nitrogen dioxide sample IDs and concentrations.

Home 

ID 

Sample ID Concentration 

(μg/m3) 

Home 

ID 

Sample ID Concentration 

(μg/m3) 

002 002-N1-030107 5.97 106 106-N1-022807 6.07 004 004-N1-030107 9.41 107 107-N1-022807 5.66 005 005-N1-022707 5.65 107 107-N2-022807 5.74 006 006-N1-022707 5.57 107 107-N2D-022807 5.96 006 006-N2-022707 5.49 108 108-N1-022807 5.55 008 008-N1-030107 10.39 109 109-N1-030207 5.48 008 008-N2-030107 6.2 110 110-N1-030207 9.27 011 011-N1-030207 5.29 110 110-N2-030207 6.09 017 017-N1-022107 6.09 112 112-N1-030507 22.95 017 017-N2-022107 6.32 112 112-N2-030507 5.59 018 018-N1-022107 12.74 113 113-N1-030507 9.28 019 019-N1-022007 5.37 114 114-N1-030607 5.71 019 019-N1D-022007 5.55 115 115-N1-030607 6.43 025 025-N1-022107 5.63 115 115-N2-030607 5.66 097 097-N1-022007 19.56 116 116-N1-030607 15.95 098 098-N1-022007 5.34 116 116-N1D-030607 15.61 098 098-N2-022007 5.70 120 120-N1-030807 22.05 099 099-N1-022407 6.13 121 121-N1-030807 20.50 099 099-N1-022307 5.24 121 121-N2-030807 5.87 099 099-N1-022207 49.72 121 121-N2D-030807 6.03 099 099-N2-022207 14.28 101 101-N1-022207 5.93 102 102-N1-022307 5.85 104 104-N1-022307 26.34 104 104-N2-022307 5.33 105 105-N1-022707 5.70 
E-19

PM2.5 particulate matter sample IDs and concentrations. 

Home 

ID 

Sample ID Concentration 

(μg/m3) 

Home 

ID 

Sample ID Concentration 

(μg/m3) 

002 002-P1-030107 9.14 104 104-P1-022307 8.54 004 004-P1-030107 11.40 104 104-P2-022307 150.04 005 005-P1-022707 10.94 105 105-P1-022707 6.19 006 006-P1-022707 33.99 106 106-P1-022807 21.75 006 006-P2-022707 145.76 107 107-P1-022807 9.92 008 008-P1-030107 8.30 107 107-P2-022807 139.41 008 008-P2-030107 129.13 107 107-P2D-022807 9.38 011 011-P1-030207 3.79 108 108-P1-022807 11.88 017 017-P1-022107 5.88 109 109-P1-030207 7.87 017 017-P2-022107 126.59 110 110-P1-030207 5.82 018 018-P1-022107 NA 110 110-P2-030207 131.30 019 019-P1-022007 10.15 112 112-P1-030507 8.57 019 019-P1D-022007 6.76 112 112-P2-030507 143.15 025 025-P1-022107 6.06 113 113-P1-030507 8.69 097 097-P1-022007 32.35 114 114-P1-030607 6.06 098 098-P1-022007 13.53 115 115-P1-030607 29.88 098 098-P2-022007 140.46 115 115-P2-030607 141.39 099 099-P1-022407 6.72 116 116-P1-030607 35.51 099 099-P1-022307 17.09 116 116-P1D-030607 38.02 099 099-P1-022207 16.12 120 120-P1-030807 11.55 099 099-P2-022207 140.10 121 121-P1-030807 12.54 101 101-P1-022207 12.43 121 121-P2D-030807 10.52 102 102-P1-022307 15.81 
E-20 

Carbon monoxide and carbon dioxide concentrations, and temperature and relative 

humidity sample IDs. 

Home 

ID 

Sample 

Type Date 

24 Hr CO2

(ppm) 

24 Hr 

CO 

(ppm) 

24 Hr 

Temp 

(F) 

24 Hr 

RH 

(%) 

Max 1 

Hr CO 

(ppm) 

Max 8 

Hr CO 

(ppm) 

1 CC1 8/7/06 764.55 0.14 76.83 50.51 2.33 0.42 

2 CC1 8/7/06 379.10 0.29 72.84 50.39 0.49 0.35 

2 CC2 8/7/06 298.85 1.70 68.97 62.19 3.42 2.71 

2 C1 3/1/07 745.15 0.58 65.90 44.41 1.17 0.82 

3 CC1 8/7/06 440.70 0.02 76.78 46.70 0.44 0.06 

4 CC1 8/8/06 504.45 0.45 75.48 51.57 2.24 0.96 

4 C1 3/1/07 1156.03 3.92 67.29 52.18 7.28 5.40 

5 CC1 8/8/06 795.82 1.62 74.58 54.86 2.02 1.79 

5 C1 10/23/06 1023.12 1.94 71.52 52.22 2.17 2.09 

5 CC2 8/8/06 349.59 0.73 82.72 45.81 1.86 1.50 

5 C1 2/27/07 664.99 0.00 67.25 43.16 0.02 0.00 

6 C2 2/27/07 319.94 2.77 44.93 80.60 3.77 3.66 

6 CC1 8/8/06 631.93 0.83 75.04 53.21 1.04 0.92 

6 C1 2/27/07 563.73 0.54 63.65 47.05 1.12 0.66 

6 C2D 10/23/06 390.70 1.53 64.50 52.48 3.65 2.78 

6 C2 10/23/06 383.90 1.50 64.63 53.10 3.20 2.46 

6 C1 10/23/06 453.79 0.26 73.09 39.02 0.91 0.32 

8 C1 3/1/07 832.66 0.00 74.66 38.78 0.00 0.00 

8 C2 3/1/07 316.92 2.31 50.41 67.49 3.29 3.14 

8 CC1 8/9/06 863.53 2.32 81.67 50.90 6.75 2.61 

8 CC2 8/9/06 337.50 1.13 82.39 43.59 2.13 1.66 

9 CC1 8/9/06 614.29 1.72 78.88 46.46 3.22 2.01 

9 CC1D 8/9/06 616.04 2.12 78.83 46.25 3.44 2.43 

10 CC1 8/10/06 753.49 0.61 78.35 49.73 1.04 0.91 

11 C1 3/2/07 431.74 0.20 62.71 49.08 0.40 0.32 

11 CC1 8/10/06 874.73 1.25 77.28 54.26 1.96 1.52 

11 CC2 8/10/06 343.22 0.31 82.84 36.08 1.50 0.73 

12 CC1 8/10/06 460.17 0.52 80.51 41.36 1.71 0.73 

13 CC1 8/14/06 1108.16 1.84 73.91 54.03 3.03 2.44 

13 C1 10/24/06 525.64 0.56 74.23 37.03 1.64 1.41 

13 C2 10/24/06 340.24 1.05 64.18 40.05 3.40 2.49 

14 CC2 8/14/06 318.39 1.39 67.59 68.42 2.39 2.13 

14 CC1 8/14/06 351.58 0.85 71.72 55.43 1.28 1.00 

15 CC1 8/14/06 334.20 0.42 73.26 52.78 0.62 0.53 

16 CC1 8/15/06 406.98 2.00 69.08 62.32 2.34 2.31 

17 CC1 8/15/06 386.85 0.79 73.82 54.11 1.35 1.15 

17 CC2 8/15/06 293.24 1.74 70.58 63.59 2.82 2.56 

17 C2 2/21/07 314.89 2.49 52.50 78.52 3.80 3.44 

17 C1 2/21/07 478.17 0.01 72.26 40.09 0.06 0.02 

18 CC1 8/15/06 430.06 0.01 76.27 47.89 0.13 0.02 

18 CC1D 8/15/06 443.13 1.28 76.54 48.31 1.87 1.50 

18 C1 2/21/07 541.10 0.00 70.78 42.27 0.02 0.00 

19 CC1 8/16/06 392.10 1.08 71.93 46.91 1.99 1.49 

19 C1D 2/20/07 572.85 1.14 NA NA 2.71 1.84 

19 C1 2/20/07 564.84 1.22 67.08 44.87 1.79 1.54 

19 C1 10/24/06 463.54 0.46 70.59 42.29 0.78 0.63 

20 CC1 8/16/06 459.73 0.48 79.38 43.20 0.84 0.66 

20 CC2 8/16/06 323.43 0.13 73.04 48.27 1.13 0.38 

21 CC1 8/16/06 639.20 0.92 76.55 50.27 2.02 1.09 

22 CC1 8/17/06 558.52 0.20 78.37 44.01 0.38 0.26 

23 CC1 8/17/06 720.85 0.01 76.62 48.19 0.04 0.01 

23 CC2 8/17/06 299.56 0.35 78.77 46.32 1.00 0.70 
E-21 

Carbon monoxide and carbon dioxide concentrations, and temperature and relative 

humidity sample IDs. 

Home 

ID 

Sample 

Type Date 

24 Hr CO2

(ppm) 

24 Hr 

CO 

(ppm) 

24 Hr 

Temp 

(F) 

24 Hr 

RH 

(%) 

Max 1 

Hr CO 

(ppm) 

Max 8 

Hr CO 

(ppm) 

24 CC1 8/17/06 395.57 0.32 77.41 46.19 0.62 0.45 

25 C1 2/21/07 501.90 0.13 68.87 44.39 0.76 0.22 

25 CC1 8/21/06 393.03 1.29 73.98 52.60 1.62 1.52 

26 CC2 8/21/06 314.00 0.36 74.48 56.62 1.26 0.75 

26 CC1 8/21/06 440.28 0.32 74.36 51.12 0.64 0.57 

27 CC1 8/21/06 393.72 0.18 77.78 46.74 0.34 0.24 

29 CC2 8/22/06 337.75 0.01 79.35 38.83 0.21 0.03 

29 CC1 8/22/06 555.82 1.62 78.08 49.25 2.07 2.02 

30 CC1D 8/22/06 613.08 1.44 74.09 42.60 2.49 1.99 

30 CC1 8/22/06 595.67 0.73 73.72 42.68 2.29 1.53 

31 CC1 8/23/06 541.44 1.37 80.87 38.91 2.17 1.47 

32 CC2 8/23/06 359.53 0.55 75.63 45.33 2.14 1.43 

32 CC1 8/23/06 468.78 0.00 80.89 37.62 0.00 0.00 

33 CC1 8/25/06 548.44 0.96 74.71 48.12 1.36 1.11 

33 CC1 8/24/06 616.43 1.16 75.02 46.05 1.49 1.34 

33 CC1 8/26/06 852.46 1.19 74.61 48.09 1.61 1.45 

34 CC1 8/24/06 452.96 0.73 67.56 63.51 1.69 1.16 

34 CC2 8/24/06 286.97 1.47 71.09 57.82 3.08 2.40 

37 CC1 9/5/06 577.59 1.77 76.80 44.87 2.29 2.06 

38 C1 1/24/07 487.08 0.03 72.39 19.48 0.08 0.04 

38 CC1 9/5/06 511.22 0.04 76.40 44.63 0.32 0.12 

38 CC2 9/5/06 304.35 -0.31 84.37 35.85 2.14 1.43 

39 C1 1/24/07 838.14 1.57 67.47 31.85 3.13 2.01 

39 CC1 9/5/06 723.77 2.56 77.56 42.58 3.02 2.97 

40 CC1 9/6/06 575.58 0.64 82.80 37.61 1.23 0.98 

41 C1 1/25/07 641.70 0.82 67.98 25.50 1.12 0.85 

41 C1 1/26/07 721.65 1.00 66.45 28.14 1.57 1.04 

41 C1 1/27/07 773.38 1.08 66.15 32.92 1.81 1.27 

41 C2 1/25/07 258.40 0.40 52.84 33.62 1.33 0.92 

41 CC2 9/6/06 301.08 -0.05 81.57 36.57 2.10 1.28 

41 CC1 9/6/06 750.76 0.25 75.47 39.75 0.59 0.47 

42 CC1 9/6/06 593.41 0.29 79.25 39.21 0.58 0.34 

43 CC1 9/7/06 402.85 0.43 74.76 44.13 1.08 0.92 

44 CC1 9/7/06 513.74 0.21 78.19 45.75 0.39 0.28 

44 CC2 9/7/06 317.53 2.32 71.26 67.04 3.65 3.45 

44 C1D 1/26/07 801.25 0.75 67.20 28.20 1.88 1.51 

44 C1 1/26/07 785.67 1.55 67.25 27.96 2.09 1.96 

45 C1 1/23/07 599.72 0.12 70.44 21.67 1.76 0.36 

45 CC1 9/7/06 773.83 1.63 80.33 41.50 2.45 2.26 

45 CC1D 9/7/06 789.00 0.15 81.06 40.85 1.13 0.45 

46 CC1 9/8/06 522.90 0.28 78.68 40.95 0.62 0.56 

47 CC1 9/8/06 549.76 1.24 76.12 43.98 2.29 1.58 

47 CC2 9/8/06 342.06 0.96 70.28 66.67 1.80 1.62 

48 CC1 9/8/06 515.75 0.48 78.51 44.00 0.95 0.65 

49 C2 1/30/07 320.36 3.57 50.98 93.26 4.39 4.21 

49 C1 1/30/07 772.59 1.65 65.73 45.84 2.50 2.10 

49 CC1 9/12/06 720.86 0.24 75.62 79.80 0.77 0.54 

50 CC1 9/12/06 384.43 1.52 76.85 59.52 2.01 1.70 

50 CC2 9/12/06 348.35 1.21 72.71 72.82 2.28 1.90 

50 C1 1/30/07 817.48 0.34 69.88 42.21 1.19 0.45 

53 CC1 9/13/06 365.48 0.93 74.58 60.97 1.26 1.03 

53 CC2 9/13/06 297.72 1.13 69.49 72.21 1.81 1.62 

54 CC1 9/13/06 404.58 0.80 74.87 60.98 1.12 0.98 
E-22 

Carbon monoxide and carbon dioxide concentrations, and temperature and relative 

humidity sample IDs. 

Home 

ID 

Sample 

Type Date 

24 Hr CO2

(ppm) 

24 Hr 

CO 

(ppm) 

24 Hr 

Temp 

(F) 

24 Hr 

RH 

(%) 

Max 1 

Hr CO 

(ppm) 

Max 8 

Hr CO 

(ppm) 

54 CC1D 9/13/06 397.28 1.48 74.55 60.72 1.74 1.64 

55 CC1 9/14/06 436.81 1.08 75.31 56.79 1.66 1.37 

56 CC1 9/14/06 416.94 0.04 73.68 59.09 0.24 0.10 

56 CC2 9/14/06 339.39 1.53 67.83 69.47 1.78 1.68 

58 CC1 9/15/06 443.37 1.53 74.60 55.69 1.72 1.58 

58 C1 1/31/07 541.70 1.44 70.28 42.69 1.68 1.52 

59 CC1 9/17/06 353.03 NA 72.05 46.04 NA NA 

59 C1 1/29/07 390.41 1.75 62.07 55.93 2.85 2.12 

59 CC2 9/15/06 323.01 2.33 63.81 76.72 3.47 3.09 

59 CC1 9/15/06 368.43 1.43 69.49 61.23 1.62 1.58 

59 C2 1/29/07 330.39 3.44 51.70 94.05 3.88 3.67 

59 CC1 9/16/06 376.15 0.91 70.21 63.67 1.61 1.41 

61 CC1 9/18/06 703.31 1.00 75.51 40.94 1.45 1.30 

62 C1 1/25/07 586.68 0.06 69.20 24.26 0.31 0.09 

62 CC2D 9/18/06 307.89 0.02 72.55 30.74 0.47 0.07 

62 CC2 9/18/06 302.07 0.02 72.41 31.66 0.35 0.06 

62 CC1 9/18/06 573.18 0.12 77.21 36.16 0.23 0.15 

64 CC1D 9/19/06 486.16 0.40 77.35 28.29 1.11 0.64 

64 CC1 9/19/06 475.71 0.02 77.18 28.60 0.20 0.06 

65 CC2 9/19/06 322.59 0.36 69.66 37.47 1.74 0.99 

65 CC1 9/19/06 545.48 0.83 75.65 33.18 2.00 1.17 

66 CC1 9/19/06 451.87 0.01 73.67 39.13 0.07 0.04 

67 CC1 9/20/06 484.10 0.52 71.86 27.60 1.63 0.84 

68 CC1 9/20/06 452.88 0.24 74.06 27.58 0.67 0.42 

68 CC2 9/20/06 327.15 0.07 66.97 39.20 0.61 0.20 

69 CC1 9/20/06 892.81 0.83 78.77 30.06 2.08 1.26 

70 CC1 9/21/06 445.14 0.70 75.73 36.83 1.35 1.16 

71 CC2 9/21/06 322.50 1.89 68.97 43.85 2.81 2.10 

71 CC1 9/21/06 430.25 0.00 76.26 29.67 0.03 0.00 

72 CC1 9/21/06 484.27 0.01 77.47 31.40 0.30 0.04 

73 C1 1/23/07 555.53 0.00 70.57 22.65 0.04 0.01 

73 C2 1/23/07 315.33 0.35 57.69 25.10 1.35 0.72 

74 C1 1/23/07 706.92 0.22 68.69 25.31 0.95 0.41 

75 C1 1/24/07 617.95 0.01 71.93 22.79 0.09 0.03 

75 C2 1/24/07 280.50 0.00 56.80 25.49 0.01 0.00 

76 C1 1/25/07 563.85 0.06 64.65 24.39 0.12 0.08 

77 C1 1/26/07 557.28 0.08 NA NA 0.19 0.12 

77 C2 1/26/07 333.75 3.03 50.17 76.02 3.86 3.57 

78 C1 1/29/07 561.37 1.67 69.23 41.39 2.60 1.80 

78 C1D 1/29/07 582.28 0.23 68.87 42.05 1.45 0.39 

79 C1 1/29/07 523.34 0.92 64.56 47.77 2.29 1.23 

80 C1 1/30/07 927.60 1.20 68.06 45.18 2.82 2.00 

81 C2 1/31/07 312.89 2.11 51.15 82.63 2.76 2.57 

81 C1 1/31/07 581.16 NA 68.78 44.68 NA NA 

83 C1 2/1/07 616.15 0.80 65.09 48.40 2.09 0.94 

83 C1D 2/1/07 572.75 1.08 64.73 49.04 3.26 1.28 

84 C1 2/1/07 557.29 1.34 NA NA 2.36 1.61 

84 C2 2/1/07 336.98 3.40 52.09 75.16 4.89 4.40 

85 C1 2/1/07 660.90 1.60 65.72 48.95 2.85 1.90 

86 C1D 2/5/07 912.76 0.17 72.49 32.13 1.26 0.32 

86 C1 2/5/07 911.02 1.13 NA NA 3.05 1.45 

87 C1 2/5/07 657.18 0.71 72.51 28.14 1.94 0.85 

87 C2 2/5/07 354.01 0.14 66.82 28.67 1.26 0.28 
E-23 

Carbon monoxide and carbon dioxide concentrations, and temperature and relative 

humidity sample IDs. 

Home 

ID 

Sample 

Type Date 

24 Hr CO2

(ppm) 

24 Hr 

CO 

(ppm) 

24 Hr 

Temp 

(F) 

24 Hr 

RH 

(%) 

Max 1 

Hr CO 

(ppm) 

Max 8 

Hr CO 

(ppm) 

88 C1 2/5/07 509.37 1.78 69.63 33.18 1.90 1.83 

92 C1 2/7/07 1027.85 1.64 70.40 43.12 2.58 2.13 

93 C1 2/7/07 561.80 1.10 64.78 37.50 1.41 1.33 

93 C1D 2/7/07 547.92 0.24 64.30 37.88 0.40 0.35 

94 C1 2/8/07 930.72 2.41 70.27 29.80 4.69 3.70 

95 C1 2/8/07 751.66 0.41 67.86 34.48 0.83 0.44 

95 C2 2/8/07 344.37 1.91 57.51 36.99 3.03 2.62 

96 C1 2/8/07 632.60 1.43 66.95 31.50 2.77 2.48 

97 C1 2/20/07 552.90 0.17 74.29 35.34 1.21 0.27 

98 C1 2/20/07 875.54 1.92 64.18 51.69 2.33 2.15 

98 C2 2/20/07 335.11 1.51 52.15 73.39 2.39 2.21 

99 C1 2/22/07 754.63 1.12 67.80 47.90 2.23 1.72 

99 C1 2/23/07 813.78 1.35 67.91 46.72 1.95 1.81 

99 C1 2/24/07 715.09 1.91 67.43 46.83 2.13 1.99 

99 C2 2/22/07 315.92 2.41 45.20 82.06 3.52 3.07 

102 C1 2/23/07 1020.33 1.88 68.05 46.80 2.43 2.11 

104 C1 2/23/07 663.34 1.22 69.68 38.14 2.05 1.80 

104 C2 2/23/07 325.49 1.93 47.57 61.59 2.87 2.66 

105 C1 2/27/07 656.01 1.64 62.73 52.16 1.99 1.89 

106 C1 2/28/07 748.66 1.64 67.05 51.38 2.32 1.94 

107 C2 2/28/07 349.19 1.53 48.10 65.87 3.16 2.52 

107 C2D 2/28/07 280.70 1.51 NA NA 3.35 2.65 

107 C1 2/28/07 631.57 0.69 68.71 45.28 1.52 0.96 

108 C1 2/28/07 562.91 1.85 65.49 46.92 3.07 2.27 

109 C1 3/2/07 838.49 1.61 69.41 45.46 2.25 1.91 

110 C1 3/2/07 723.12 0.73 66.36 45.90 3.15 1.90 

110 C2 3/2/07 334.54 1.70 53.40 67.35 2.50 2.31 

112 C1 3/5/07 582.87 0.52 68.61 45.14 1.28 0.92 

112 C2 3/5/07 327.21 0.25 64.25 44.08 0.53 0.40 

113 C1 3/5/07 663.02 1.51 67.44 50.60 2.54 2.02 

114 C1 3/6/07 890.43 NA 67.51 54.03 NA NA 

115 C2 3/6/07 367.05 1.05 58.49 57.92 1.82 1.62 

115 C1 3/6/07 1013.39 2.32 68.67 51.94 2.77 2.41 

116 C1 3/6/07 627.57 1.73 69.79 46.13 2.01 1.88 

116 C1D 3/6/07 612.52 2.06 69.61 46.62 2.39 2.26 

117 C1 3/7/07 754.28 0.45 NA NA 0.64 0.55 

118 C1 3/7/07 925.97 2.09 72.24 47.17 2.40 2.20 

118 C2 3/7/07 312.60 2.22 58.54 71.60 3.31 3.10 

119 C1 3/7/07 763.51 1.43 66.91 52.53 1.51 1.47 

120 C1 3/8/07 1084.66 1.30 74.46 47.17 1.98 1.46 

121 C2D 3/8/07 316.99 2.40 54.63 69.15 3.11 2.88 

121 C1 3/8/07 438.56 1.14 67.18 51.35 2.43 1.62 
E-24

Outdoor air exchange rate PFT measurements. 

Home 

ID 

Test Day 

24 hour 

Sample ID

Test Day 

ach 

Test Day 

Duplicate Sample 

ID 

Test Day 

Duplicate 

ach 

Long Term 

2 Week 

 Sample ID 

Long 

Term 

ach 

Long Term 

Duplicate 

Sample ID

001 001-T1-080706 0.25002 002-T1-030107 0.21 002-T1L-030107 0.24002 002-T1-080706 6.47 002-T1L-080706 1.37 002-T1LD-080706 003 003-T1-080706 0.71004 004-T1-080806 0.45004 004-T1-030107 0.13005 005-T1-080806 0.17005 005-T1-102306 0.15005 005-T1-022707 0.27006 006-T1-080806 0.16 006-T1L-080806 0.22006 006-T1-022707 0.23006 006-T1-102306 0.63008 008-T1-080906 0.21008 008-T1-030107 0.23009 009-T1-080906 0.34 009-T1D-080906 0.33010 010-T1-081006 0.10011 011-T1-081006 0.11011 011-T1-030207 0.09012 012-T1-081006 0.58013 013-T1-081406 0.16013 013-T1-102406 0.81 013-T1L-102406 0.27014 014-T1-081406 5.34 014-T1L-081406 1.51015 015-T1-081406 5.19016 016-T1-081506 1.43017 017-T1-081506 4.28017 017-T1-022107 0.66018 018-T1-081506 1.25 018-T1D-081506 1.25018 018-T1-022107 0.61019 019-T1-022007 0.11 019-T1D-022007 0.10019 019-T1-081606 NA
E-25

Outdoor air exchange rate PFT measurements. 

Home 

ID 

Test Day 

24 hour 

Sample ID

Test Day 

ach 

Test Day 

Duplicate Sample 

ID 

Test Day 

Duplicate 

ach 

Long Term 

2 Week 

 Sample ID 

Long 

Term 

ach 

Long Term 

Duplicate 

Sample ID

019 019-T1-102406 0.29020 020-T1-081606 0.21021 021-T1-081606 0.16022 022-T1-081706 0.41023 023-T1-081706 0.17024 024-T1-081706 0.45 024-T1L-081706 0.27025 025-T1-022107 0.35025 025-T1-082106 0.95 025-T1L-082106 0.83026 026-T1-082106 0.33027 027-T1-082106 1.25029 029-T1-082206 0.19 029-T1L-082206 0.24030 030-T1-082206 0.30 030-T1D-082206 0.31031 031-T1-082306 0.44 031-T1-082306 0.27032 032-T1-082306 0.73033 033-T1-082406 0.23033 033-T1-082606 0.13033 033-T1-082506 0.29034 034-T1-082406 0.59037 037-T1-090506 0.29038 038-T1-090506 0.13 038-T1L-090506 0.16038 038-T1-012307 0.27 038-T1L-012307 0.14039 039-T1-012407 0.17039 039-T1-090506 0.20040 040-T1-090606 0.39041 041-T1-090606 0.21 041-T1L-090606 0.17041 041-T1-012507 0.18041 041-T1-012607 0.19041 041-T1-012707 0.20042 042-T1-090606 0.21043 043-T1-090706 0.38044 044-T1-012607 0.22 044-T1D-012607 0.22 044-T1L-012607 0.21 044-T1LD-012607 
E-26

Outdoor air exchange rate PFT measurements. 

Home 

ID 

Test Day 

24 hour 

Sample ID

Test Day 

ach 

Test Day 

Duplicate Sample 

ID 

Test Day 

Duplicate 

ach 

Long Term 

2 Week 

 Sample ID 

Long 

Term 

ach 

Long Term 

Duplicate 

Sample ID

044 044-T1-090706 0.86045 045-T1-090706 0.19 045-T1D-090706 0.20045 045-T1-012307 0.24046 046-T1-090806 0.28047 047-T1-090806 0.15048 048-T1-090806 0.33049 049-T1-091206 0.14049 049-T1-013007 0.13050 050-T1-091206 3.17 050-T1L-091206 0.47050 050-T1-013007 0.17053 053-T1-091306 0.35054 054-T1-091306 0.41 054-T1D-091306 0.38055 055-T1-091406 1.04056 056-T1-091406 0.66058 058-T1-013107 0.15058 058-T1-091506 0.48059 059-T1-091706 1.25059 059-T1-091606 1.79059 059-T1-091506 2.25 059-T1L-091506 2.30059 059-T1-012907 0.59061 061-T1-091806 0.18062 062-T1-091806 0.32062 062-T1-012507 0.45064 064-T1-091906 0.33 064-T1D-091906 0.36 064-T1L-091906 0.26065 065-T1-091906 0.51066 066-T1-091906 0.46067 067-T1-092006 0.85 067-T1L-092006 0.78068 068-T1-092006 0.33069 069-T1-092006 0.20070 070-T1-092106 0.85071 071-T1-092106 0.57
E-27

Outdoor air exchange rate PFT measurements. 

Home 

ID 

Test Day 

24 hour 

Sample ID

Test Day 

ach 

Test Day 

Duplicate Sample 

ID 

Test Day 

Duplicate 

ach 

Long Term 

2 Week 

 Sample ID 

Long 

Term 

ach 

Long Term 

Duplicate 

Sample ID

072 072-T1-092106 0.77073 073-T1-012307 0.32074 074-T1-012307 0.17075 075-T1-012407 0.25076 076-T1-012507 0.25077 077-T1-012607 0.11078 078-T1-012907 0.39 078-T1D-012907 0.40 078-T1L-012907 0.42 078-T1LD-012907 079 079-T1-012907 0.38080 080-T1-013007 0.20081 081-T1-013107 0.29083 083-T1-020107 0.41 083-T1D-020107 0.40 083-T1L-020107 0.32 083-T1LD-020107 084 084-T1-020107 0.25085 085-T1-020107 0.26086 086-T1-020507 0.09 086-T1D-020507 0.09087 087-T1-020507 0.32088 088-T1-0250507 0.13089 089-T1-020607 0.50090 090-T1-020607 0.18 090-T1L-020607 0.12091 091-T1-020607 0.20092 092-T1-020707 0.25093 093-T1-020807 0.14 093-T1D-020807 0.13094 094-T1-020807 0.20095 095-T1-020807 0.17 095-T1L-020807 0.16096 096-T1-020807 0.12097 097-T1-022007 0.64098 098-T1-022007 0.20099 099-T1-022307 0.17099 099-T1-022207 NA 099-T1L-022207 0.15 099-T1LD-022207 099 099-T1-022407 0.16101 101-T1-022207 0.26102 102-T1-022307 0.11 102-T1L-022307 0.11104 104-T1-022307 0.66105 105-T1-022707 0.23 105-T1L-022707 0.23
E-28

Outdoor air exchange rate PFT measurements. 

Home 

ID 

Test Day 

24 hour 

Sample ID

Test Day 

ach 

Test Day 

Duplicate Sample 

ID 

Test Day 

Duplicate 

ach 

Long Term 

2 Week 

 Sample ID 

Long 

Term 

ach 

Long Term 

Duplicate 

Sample ID

106 106-T1-022807 0.33 106-T1L-022807 0.24107 107-T1-022807 0.23108 108-T1-022807 0.24109 109-T1-030207 0.13110 110-T1-030207 0.30112 112-T1-030507 0.31113 113-T1-030507 0.13114 114-T1-030607 0.09115 115-T1-030607 0.18116 116-T1-030607 0.22 116-T1D-030607 0.16117 117-T1-030707 0.11118 118-T1-030707 0.19 118-T1L-030707 0.19119 119-T1-030707 0.11120 120-T1-030807 0.12 120-T1L-030807 0.23121 121-T1-030807 0.18
F-1 

APPENDIX F 

Home and Mechanical Ventilation System Characteristics 
F-2 

Appendix Key 

Label Description 

ad Automatic Damper 

DOA Ducted Outdoor Air Mechanical Outdoor Air Ventilation System 

EC Evaporative Cooler 

fc Fan Cycler 

ELA Effective Leakage Area @ 10 pascals 

Fl Floor 

G Garage 

gd Gravity Damper 

H Home 

HRV Heat Recovery Ventilator Mechanical Outdoor Air Ventilation System 

md Manual Damper 

na Not Applicable / Not Available 

OA Outdoor Air 

Occ Occupants 

RAD Forced Air Unit Return Air Damper Nighttime Cooling System 

t-stat Thermostat 

WD Window 

WDF Window Fan 

WHF Whole House Fan Nighttime Cooling System 
Home characteristics and air leakage data. 

Home 

ID Date 

Home 

Age # Occ Fl Area Volume 

WD Area/ 

Fl Area ACH50 SLA 

Home to 

OA 

ELA 

Home to 

Garage 

ELA 

001 8/8/06 3.27 2 1742 16624 0.08 4.49 3.18 141.90 10.90 002 3/4/07 3.93 2 1813 17328 0.07 4.23 2.94 137.50 23.16 003 8/8/06 3.02 4 2244 19584 0.06 4.92 3.00 176.20 22.95 004 8/9/06 2.77 2 2005 19136 0.05 3.78 2.45 129.80 22.53 005 2/28/07 2.85 5 3147 28391 0.08 6.14 3.26 285.60 35.95 006 2/28/07 3.27 4 3806 35404 0.07 5.37 2.69 294.70 27.25 008 8/10/06 2.86 2 1283 10918 0.07 5.64 3.04 105.80 10.69 009 8/10/06 2.27 1 1283 10667 0.04 6.14 3.70 122.70 14.57 010 8/11/06 2.86 1 1887 18047 0.07 4.28 2.81 139.70 11.00 011 3/3/07 2.28 1 1616 13821 0.08 5.97 NA NA NA 012 8/11/06 3.11 2 1894 18107 0.05 4.37 2.61 134.60 10.06 013 8/15/06 4.12 4 2241 19901 0.06 5.16 2.98 179.50 14.25 014 8/15/06 3.12 3 3403 31320 0.03 4.59 2.88 258.50 29.87 015 8/15/06 3.21 2 2883 27340 0.06 5.20 2.86 231.10 46.53 016 8/16/06 3.13 1 2273 21580 0.07 4.93 2.08 145.70 51.67 017 2/22/07 3.29 2 2038 19556 0.05 4.58 2.83 155.40 10.69 018 8/16/06 3.54 2 1718 16304 0.06 5.30 3.51 158.00 18.44 019 8/17/06 2.88 4 4205 38916 0.05 4.46 2.15 262.90 16.35 020 8/17/06 3.30 1 2152 20748 0.05 5.56 3.31 194.80 20.12 021 8/17/06 3.13 2 1968 19764 0.07 4.14 2.88 148.80 8.80 022 8/18/06 3.05 2 1659 14223 0.08 6.45 4.04 172.70 27.04 023 8/18/06 3.38 5 3321 33317 0.05 4.88 2.63 251.60 42.23 024 8/18/06 1.96 2 2851 27414 0.07 4.63 2.66 210.20 17.29 025 8/22/06 3.31 2 2531 24128 0.07 4.21 2.62 177.90 15.30 026 8/22/06 3.72 2 2439 23416 0.06 4.32 2.41 164.50 5.34 027 8/22/06 1.80 5 2197 16615 0.06 4.00 2.10 120.80 13.52 029 8/23/06 2.14 3 3119 28910 0.04 3.61 1.66 153.50 29.76 030 8/23/06 3.64 5 2311 20497 0.06 6.35 3.34 214.60 29.76 031 8/24/06 2.90 3 2719 23294 0.05 3.45 2.01 144.40 0.00 032 8/24/06 3.40 5 2374 22909 0.06 5.91 3.24 217.10 6.39 033 8/27/06 3.40 4 2214 21182 0.07 4.23 2.61 155.70 5.76 

F-3
Home characteristics and air leakage data. 

Home 

ID Date 

Home 

Age # Occ Fl Area Volume 

WD Area/ 

Fl Area ACH50 SLA 

Home to 

OA 

ELA 

Home to 

Garage 

ELA 

034 8/25/06 5.48 4 5064 55613 0.03 4.62 3.31 450.50 0.00 037 9/6/06 3.27 4 3413 31772 0.07 4.40 2.71 246.70 28.51 038 1/24/07 2.35 2 3413 31772 0.08 4.75 2.98 269.60 34.58 039 1/24/07 3.10 4 3413 31772 0.07 4.60 2.83 258.30 9.54 040 9/7/06 3.93 4 2858 22276 0.05 3.93 2.12 159.20 13.83 041 1/28/07 3.02 3 2147 17661 0.06 6.33 3.40 195.90 12.79 042 9/7/06 3.02 3 3108 25522 0.05 3.64 2.02 166.20 18.13 043 9/8/06 4.19 4 2838 26996 0.05 NA NA NA NA 044 9/8/06 2.77 5 2765 25606 0.06 5.74 3.69 267.60 9.64 045 9/8/06 2.85 4 2301 19970 0.06 6.19 3.47 215.00 7.13 046 9/8/06 2.69 3 3212 26836 0.06 5.27 2.92 250.20 10.58 047 9/8/06 3.02 2 2226 18290 0.06 4.77 2.96 167.60 26.62 048 9/9/06 3.02 3 2515 20920 0.07 4.22 2.53 164.70 39.61 049 1/31/07 3.28 4 2952 27489 0.06 3.84 2.40 188.00 11.32 050 9/13/06 4.20 6 3327 32043 0.07 4.02 2.33 214.10 1.05 053 9/14/06 4.95 6 3647 34210 0.07 3.85 2.18 219.80 15.41 054 9/14/06 4.04 4 3753 34414 0.07 5.32 3.20 321.60 23.89 055 9/15/06 4.38 5 2537 24865 0.08 5.25 3.06 213.10 14.04 056 9/15/06 3.79 3 3338 32662 0.09 5.13 2.71 259.90 21.27 058 2/1/07 4.21 3 3659 34641 0.06 3.23 1.39 155.60 17.82 059 9/18/06 4.30 5 3756 32829 0.07 8.38 4.82 484.10 20.54 061 9/19/06 3.30 3 2935 24579 0.05 4.72 2.71 209.60 15.51 062 9/19/06 3.30 4 2790 22909 0.06 3.87 2.37 169.10 14.78 064 9/20/06 3.97 3 3144 28888 0.06 4.69 2.70 231.30 17.92 065 9/20/06 2.88 4 3113 26598 0.06 4.85 2.61 221.00 9.22 066 9/20/06 3.97 2 2942 27207 0.05 5.94 3.54 280.40 18.03 067 9/21/06 3.47 2 2442 21042 0.07 4.73 1.78 134.70 5.87 068 9/21/06 2.64 2 3532 32848 0.06 3.63 2.12 204.00 35.95 069 9/21/06 3.47 5 2916 25618 0.05 3.73 2.98 206.50 23.48 070 9/22/06 2.81 2 2521 24411 0.06 7.28 5.61 352.70 12.68 071 9/22/06 3.64 2 3072 27170 0.06 4.95 2.50 216.40 7.65 072 9/22/06 3.48 6 2935 26057 0.04 4.43 2.67 207.10 7.13 

F-4
Home characteristics and air leakage data. 

Home 

ID Date 

Home 

Age # Occ Fl Area Volume 

WD Area/ 

Fl Area ACH50 SLA 

Home to 

OA 

ELA 

Home to 

Garage 

ELA 

073 1/24/07 5.06 3 2857 26252 0.06 4.75 2.50 200.70 4.09 074 1/24/07 4.15 5 2855 28356 0.07 5.27 3.17 249.40 NA 075 1/25/07 NA 6 3156 37463 0.09 6.64 5.05 430.40 24.42 076 1/26/07 3.24 2 3754 30752 0.05 4.51 2.33 237.70 18.65 077 1/27/07 3.49 2 3590 33599 0.08 4.20 2.38 235.70 7.02 078 1/30/07 4.83 3 3116 26172 0.06 4.11 2.19 184.80 11.84 079 1/30/07 2.08 3 2180 17949 0.06 4.87 2.65 154.20 16.56 080 1/30/07 3.67 6 3066 27626 0.07 5.14 2.82 237.90 9.85 081 2/1/07 2.25 3 2258 18989 0.10 4.83 2.90 169.90 13.73 083 2/2/07 3.34 3 1864 16223 0.08 6.20 3.88 187.30 1.05 084 2/2/07 3.93 2 2348 20537 0.07 4.67 3.01 181.20 11.95 085 2/2/07 4.09 4 2389 21224 0.07 4.87 2.71 176.00 9.01 086 2/6/07 4.27 2 1879 16187 0.06 5.31 3.43 164.50 13.73 087 2/6/07 NA 4 1902 17392 0.07 4.36 3.28 143.90 21.38 088 2/6/07 4.10 1 3257 26735 0.06 4.76 2.63 227.30 17.61 089 2/7/07 2.35 2 2828 23064 0.06 5.18 2.62 202.70 24.21 090 2/7/07 4.27 4 1902 17439 0.07 4.25 3.01 144.40 16.24 091 2/7/07 4.02 5 2686 21534 0.05 4.10 1.96 145.90 35.11 092 2/8/07 4.27 8 3327 27570 0.06 4.49 2.41 215.50 27.77 093 2/8/07 3.69 3 2324 20276 0.08 5.12 2.99 184.70 22.32 094 2/9/07 4.27 2 1667 12996 0.08 6.27 3.73 157.50 31.65 095 2/9/07 2.86 4 2790 26729 0.06 4.97 3.05 229.70 22.22 096 2/9/07 1.69 3 3443 33276 0.06 4.72 2.84 266.80 17.50 097 2/21/07 5.05 2 2258 21788 0.06 5.49 3.30 203.30 45.06 098 2/21/07 4.14 4 2205 21098 0.06 5.78 3.60 213.00 23.89 099 2/25/07 3.65 4 3404 34194 0.06 3.52 2.03 194.40 13.62 101 2/23/07 3.56 2 1677 16010 0.07 4.87 3.29 143.60 19.91 102 2/24/07 2.48 1 1940 16663 0.07 4.55 2.57 133.30 13.41 104 2/24/07 2.98 2 1771 15158 0.08 7.32 3.73 183.20 90.34 105 2/28/07 3.49 5 3923 34840 0.05 4.72 2.55 275.10 42.97 106 3/1/07 3.33 6 2301 21273 0.07 4.68 2.81 173.90 6.92 107 3/1/07 4.58 3 2752 25399 0.06 2.83 1.77 128.80 80.80 

F-5
Home characteristics and air leakage data. 

Home 

ID Date 

Home 

Age # Occ Fl Area Volume 

WD Area/ 

Fl Area ACH50 SLA 

Home to 

OA 

ELA 

Home to 

Garage 

ELA 

108 3/1/07 3.41 2 2878 26961 0.08 6.05 3.68 284.90 69.90 109 3/3/07 3.67 2 2226 21330 0.07 3.97 2.67 155.30 14.04 110 3/3/07 3.17 2 1616 13821 0.08 5.62 3.50 145.80 11.95 112 3/6/07 4.01 4 4457 40371 0.04 5.61 2.66 344.70 74.62 113 3/6/07 4.93 5 2785 27450 0.08 5.21 3.02 234.50 13.10 114 3/7/07 3.68 5 3451 30164 0.06 6.06 3.11 299.30 6.29 115 3/7/07 3.85 4 2028 17462 0.07 7.11 4.01 217.80 20.75 116 3/7/07 4.60 4 4182 40288 0.05 4.23 2.48 258.60 96.52 117 3/8/07 2.43 2 2319 22231 0.08 5.23 3.24 202.10 3.88 118 3/8/07 2.93 3 1548 13296 0.07 5.18 3.14 126.70 14.67 119 3/8/07 NA 1 1532 13144 0.07 5.34 3.29 130.60 10.58 120 3/9/07 4.02 2 1361 12459 0.06 5.94 3.27 123.00 96.21 121 3/9/07 4.94 3 2261 20499 0.04 4.41 2.89 168.90 26.10 

F-6
F-7 

Forced air unit (FAU) duct leakage data. 

Home ID Date System #1 

Duct Leakage 

(%) 

System #2 

Duct Leakage 

(%) 

System #3 

Duct Leakage 

(%) 

001 8/8/06 8.9 

002 3/4/07 6.1 

003 8/8/06 11.3 

004 8/9/06 7.4 

005 2/28/07 15.8 16.7 

006 2/28/07 7.4 13.1 

008 8/10/06 4.2 

009 8/10/06 8.0 

010 8/11/06 5.4 

011 3/3/07 7.2 

012 8/11/06 3.8 

013 8/15/06 8.5 

014 8/15/06 9.4 

015 8/15/06 9.2 

016 8/16/06 11.2 

017 2/22/07 4.8 

018 8/16/06 7.5 

019 8/17/06 29.3 

020 8/17/06 13.4 

021 8/17/06 12.5 

022 8/18/06 4.8 

023 8/18/06 9.0 

024 8/18/06 10.2 

025 8/22/06 11.1 

026 8/22/06 12.8 

027 8/22/06 12.6 

029 8/23/06 3.5 

030 8/23/06 27.8 

031 8/24/06 6.8 

032 8/24/06 12.7 

033 8/27/06 8.8 

034 8/25/06 73.5 34.0 17.2 

037 9/6/06 8.3 9.2 

038 1/24/07 4.1 4.2 

039 1/24/07 9.5 3.9 

040 9/7/06 11.4 6.8 

041 1/28/07 9.2 

042 9/7/06 10.5 

043 9/8/06 32.8 38.4 

044 9/8/06 7.2 

045 9/8/06 14.3 

046 9/8/06 11.3 9.7 

047 9/8/06 6.0 

048 9/9/06 8.7 

049 1/31/07 16.2 

050 9/13/06 10.4 13.0 

053 9/14/06 9.3 9.7 

054 9/14/06 16.9 12.8 

055 9/15/06 17.1 

056 9/15/06 13.4 14.1 

058 2/1/07 9.7 10.4 

059 9/18/06 9.4 8.5 
F-8 

Forced air unit (FAU) duct leakage data. 

Home ID Date System #1 

Duct Leakage 

(%) 

System #2 

Duct Leakage 

(%) 

System #3 

Duct Leakage 

(%) 

061 9/19/06 8.9 

062 9/19/06 NA 

064 9/20/06 14.0 8.6 

065 9/20/06 11.1 6.9 

066 9/20/06 7.8 

067 9/21/06 8.8 10.4 

068 9/21/06 11.6 13.0 

069 9/21/06 13.2 

070 9/22/06 6.2 

071 9/22/06 20.7 

072 9/22/06 9.2 

073 1/24/07 10.6 14.6 

074 1/24/07 10.9 10.2 

075 1/25/07 16.8 14.2 

076 1/26/07 8.5 9.5 

077 1/27/07 9.0 12.2 

078 1/30/07 11.6 8.4 

079 1/30/07 7.3 

080 1/30/07 10.1 10.2 

081 2/1/07 NA 

083 2/2/07 17.0 

084 2/2/07 11.3 

085 2/2/07 14.8 

086 2/6/07 8.8 

087 2/6/07 6.3 

088 2/6/07 10.4 7.5 

089 2/7/07 16.0 

090 2/7/07 NA 

091 2/7/07 1.9 

092 2/8/07 9.9 6.7 

093 2/8/07 11.5 

094 2/9/07 11.8 

095 2/9/07 8.8 

096 2/9/07 7.2 7.3 

097 2/21/07 4.8 

098 2/21/07 21.8 

099 2/25/07 5.6 

101 2/23/07 6.4 

102 2/24/07 8.9 

104 2/24/07 46.6 

105 2/28/07 10.6 14.3 

106 3/1/07 14.6 

107 3/1/07 15.8 

108 3/1/07 10.4 11.0 

109 3/3/07 4.8 

110 3/3/07 5.8 

112 3/6/07 36.7 

113 3/6/07 10.7 

114 3/7/07 5.2 7.9 

115 3/7/07 10.1 

116 3/7/07 31.9 

117 3/8/07 16.8 
F-9 

Forced air unit (FAU) duct leakage data. 

Home ID Date System #1 

Duct Leakage 

(%) 

System #2 

Duct Leakage 

(%) 

System #3 

Duct Leakage 

(%) 

118 3/8/07 4.4 

119 3/8/07 5.1 

120 3/9/07 5.7 

121 3/9/07 6.0 
F-10 

Window usage and mechanical exhaust and outdoor air exchange rate data. 

Home 

ID Date 

 

Test Day 

Window Usage 

(ft2

-hrs) 

 

Week Average 

Window Usage 

(ft2

-hrs) 

 

Exhaust Air 

24-hr Air 

Exchange Rate 

 

Outdoor Air 

24-hr Air 

Exchange Rate 

 

001 8/8/06 94.57 143.89 0.01 na 

002 8/8/06 833.62 988.85 0.03 0.000 

002 3/2/07 28.85 46.98 0.02 0.000 

003 8/8/06 299.79 153.07 0.01 0.000 

004 3/2/07 0.00 1.14 0.03 0.004 

004 8/9/06 753.54 829.51 0.03 0.010 

005 8/9/06 0.00 0.00 0.01 0.000 

005 2/28/07 0.00 0.00 0.02 0.000 

005 10/24/06 0.00 0.00 0.01 0.000 

006 10/24/07 527.67 506.02 0.00 0.000 

006 8/9/06 13.00 176.19 0.01 0.000 

006 2/28/07 0.00 0.37 0.01 0.000 

008 8/10/06 91.91 186.29 0.00 0.032 

008 3/2/07 1.71 1.71 0.01 0.048 

009 8/10/06 198.76 169.99 0.03 0.070 

010 8/11/06 42.29 71.89 0.00 0.021 

011 3/3/07 0.00 0.00 0.00 na 

011 8/11/06 0.00 0.00 0.00 na 

012 8/11/06 362.40 319.56 0.00 0.002 

013 8/15/06 45.18 42.33 0.06 0.000 

013 10/25/07 609.74 424.14 0.04 0.000 

014 8/15/06 1305.96 808.79 0.00 0.000 

015 8/15/06 833.24 718.86 0.00 0.408 

016 8/16/06 497.36 341.46 0.51 0.442 

017 8/16/06 1113.70 925.33 0.35 0.469 

017 2/22/07 0.00 0.00 0.36 0.469 

018 8/16/06 0.00 8.20 0.00 1.816 

018 2/22/07 0.00 0.00 0.01 0.622 

019 2/21/07 0.00 0.00 0.00 0.534 

019 10/25/06 364.27 277.03 0.00 0.013 

019 8/17/06 2447.54 1180.63 0.00 0.595 

020 8/17/06 0.00 2.79 0.00 0.000 

021 8/17/06 0.83 3.78 0.02 0.054 

022 8/18/06 203.76 173.98 0.03 na 

023 8/18/06 34.71 33.56 0.00 0.000 

024 8/18/06 299.56 235.45 0.17 0.191 

025 2/22/07 0.00 0.00 0.16 0.224 

025 8/22/06 118.43 95.96 0.16 2.021 

026 8/22/06 290.44 452.04 0.17 0.123 

027 8/22/06 421.27 520.33 0.01 0.000 

029 8/23/06 104.41 464.54 0.02 0.000 

030 8/23/06 49.21 75.68 0.00 0.000 

031 8/24/06 200.60 315.46 0.00 0.000 

032 8/24/06 530.71 411.65 0.04 0.000 

033 8/27/06 47.50 17.81 0.02 0.000 

033 8/25/06 29.69 17.81 0.02 0.000 

033 8/26/06 47.50 17.81 0.02 0.000 

034 8/25/06 457.51 500.22 0.02 3.696 

037 9/6/06 169.01 130.87 0.00 0.000 

038 9/6/06 58.47 12.54 0.00 0.000 

038 1/24/07 27.08 27.32 0.00 0.000 
F-11 

Window usage and mechanical exhaust and outdoor air exchange rate data.

Home 

ID Date 

 

Test Day 

Window Usage 

(ft2

-hrs) 

 

Week Average 

Window Usage 

(ft2

-hrs) 

 

Exhaust Air 

24-hr Air 

Exchange Rate 

 

Outdoor Air 

24-hr Air 

Exchange Rate 

 

039 1/25/07 0.00 0.00 0.02 0.000 

039 9/6/06 23.44 72.24 0.01 0.000 

040 9/7/06 303.95 453.75 0.01 0.000 

041 1/27/07 0.00 9.59 0.00 0.000 

041 1/26/07 5.39 9.59 0.00 0.000 

041 1/28/07 0.81 9.59 0.00 0.000 

041 9/7/06 38.96 59.21 0.02 0.000 

042 9/7/06 132.10 122.06 0.01 0.000 

043 9/8/06 298.26 242.44 0.00 0.012 

044 9/8/06 301.41 351.76 0.01 2.182 

044 1/27/07 0.55 3.06 0.00 0.000 

045 1/24/07 0.00 4.02 0.00 0.000 

045 9/8/06 1.04 2.07 0.02 0.000 

046 9/9/06 61.11 21.01 0.00 0.000 

047 9/9/06 0.00 0.32 0.02 0.000 

048 9/9/06 415.70 151.32 0.01 0.000 

049 1/31/07 0.00 25.80 0.00 0.000 

049 9/13/06 67.22 320.16 0.00 0.000 

050 1/31/07 0.00 0.04 0.00 0.000 

050 9/13/06 937.65 521.17 0.01 0.000 

053 9/14/06 1216.58 1260.36 0.01 0.000 

054 9/14/06 785.13 837.38 0.01 0.000 

055 9/15/06 335.42 265.60 0.10 0.000 

056 9/15/06 770.76 740.41 0.00 0.000 

058 9/16/06 1267.94 1049.77 0.00 0.000 

058 2/1/07 0.00 3.14 0.01 0.008 

059 9/16/06 999.14 1099.41 0.01 0.000 

059 9/17/06 1260.87 1099.41 0.00 0.000 

059 9/18/06 1158.90 1099.41 0.01 0.000 

059 1/30/07 103.35 88.26 0.00 0.000 

061 9/19/06 0.00 157.32 0.00 0.000 

062 9/19/06 353.84 359.42 0.00 0.000 

062 1/26/07 263.77 102.44 0.02 0.000 

064 9/20/06 263.46 337.52 0.00 0.000 

065 9/20/06 622.58 620.05 0.03 0.000 

066 9/20/06 0.00 33.66 0.00 0.000 

067 9/21/06 1258.77 648.13 0.00 0.000 

068 9/21/06 179.77 186.06 0.00 0.000 

069 9/21/06 112.67 309.52 0.00 0.000 

070 9/22/06 98.39 169.34 0.00 0.000 

071 9/22/06 313.17 247.99 0.01 0.000 

072 9/22/06 392.62 220.73 0.00 0.000 

073 1/24/07 23.49 16.00 0.00 0.000 

074 1/24/07 0.64 0.40 0.01 0.000 

075 1/25/07 22.52 3.22 0.00 0.000 

076 1/26/07 92.36 109.90 0.01 0.000 

077 1/27/07 0.00 10.89 0.00 0.000 

078 1/30/07 83.37 144.69 0.01 0.000 

079 1/30/07 44.35 24.60 0.04 0.000 

080 1/30/07 0.00 186.70 0.01 0.000 

081 2/1/07 21.17 49.82 0.02 0.000 
F-12 

Window usage and mechanical exhaust and outdoor air exchange rate data.

Home 

ID Date 

 

Test Day 

Window Usage 

(ft2

-hrs) 

 

Week Average 

Window Usage 

(ft2

-hrs) 

 

Exhaust Air 

24-hr Air 

Exchange Rate 

 

Outdoor Air 

24-hr Air 

Exchange Rate 

 

083 2/2/07 13.77 30.43 0.03 0.083 

084 2/2/07 0.00 0.00 0.00 0.000 

085 2/2/07 5.28 14.10 0.02 0.000 

086 2/6/07 1.92 6.79 0.00 0.000 

087 2/6/07 320.57 110.27 0.02 0.000 

088 2/6/07 32.99 8.20 0.00 0.000 

089 2/7/07 512.19 248.23 0.01 0.000 

090 2/7/07 169.13 87.13 0.00 0.000 

091 2/7/07 72.48 43.30 0.02 0.000 

092 2/8/07 0.00 1.11 0.01 0.000 

093 2/8/07 0.00 0.00 0.00 0.000 

094 2/9/07 31.73 251.24 0.00 0.000 

095 2/9/07 0.00 86.97 0.03 0.000 

096 2/9/07 0.00 5.13 0.01 0.000 

097 2/21/07 0.00 0.00 0.53 0.333 

098 2/21/07 0.00 0.00 0.00 0.000 

099 2/23/07 0.00 0.00 0.01 0.013 

099 2/25/07 0.00 0.00 0.01 0.013 

099 2/24/07 0.00 0.00 0.00 0.013 

101 2/23/07 0.00 0.00 0.00 0.000 

102 2/24/07 0.00 0.00 0.00 0.029 

104 2/24/07 0.00 0.00 0.31 0.259 

105 2/28/07 0.00 1.15 0.00 0.000 

106 3/1/07 0.00 0.00 0.02 0.000 

107 3/1/07 13.01 9.45 0.00 0.000 

108 3/1/07 4.34 1.62 0.04 0.000 

109 3/3/07 0.00 0.00 0.11 0.002 

110 3/3/07 140.15 67.91 0.08 0.002 

112 3/6/07 324.71 154.74 0.01 0.000 

113 3/6/07 0.00 101.42 0.04 0.000 

114 3/7/07 0.00 0.00 0.02 0.000 

115 3/7/07 20.26 53.19 0.01 0.000 

116 3/7/07 50.49 58.01 0.02 0.000 

117 3/8/07 0.00 0.00 0.00 0.000 

118 3/8/07 0.00 53.07 0.01 0.000 

119 3/8/07 0.00 36.85 0.00 na 

120 3/9/07 0.00 55.86 0.02 0.000 

121 3/9/07 159.84 121.24 0.01 0.000 
F-13 

Mechanical outdoor air ventilation system characteristics. 

Home ID System Type Damper 

Type 

Control Location System Operational Status 

001 DOA ad fc/attic not operational 

004 DOA md t-stat/home operational 

008 DOA md t-stat/home operational 

009 DOA md t-stat/home operational 

010 DOA md t-stat/home operational 

011 DOA md t-stat/home not operational 

012 DOA md t-stat/home operational 

015 WHF gd switch/home operational 

016 HRV na switch/attic operational 

017 HRV na switch/attic operational 

018 HRV na switch/attic operational 

018 RAD ad t-stat/home operational 

019 RAD ad t-stat/home operational 

021 DOA ad fc/attic operational 

022 HRV na switch/home not operated 

024 HRV na timer/home operational 

024 WHF gd switch/home operational 

025 HRV na switch/attic operational 

025 RAD ad t-stat/home operational 

026 HRV na switch/home operational 

034 WHF gd switch/home operational 

043 DOA (FAU1) ad t-stat/home operational 

043 DOA (FAU2) ad t-stat/home operational 

044 WD fan na switch/home operational 

044 WHF gd switch/home operational 

058 DOA (FAU1) md t-stat/home operational 

070 EC ad t-stat/home operational 

083 DOA md t-stat/home operational 

088 WHF gd switch/home operational 

097 HRV na switch/attic operational 

099 DOA ad fc/attic operational 

102 DOA ad fc/attic operational 

104 HRV na timer/home operational 

109 DOA md t-stat/home operational 

110 DOA md t-stat/home operational 

112 RAD ad t-stat/home operational 

116 RAD ad t-stat/home operational 

117 RAD ad fc t-stat/home operational 

118 DOA md fc/attic operational 

119 DOA md fc/attic not operational 
F-14 

Mechanical outdoor air ventilation system outdoor air flow rates and operational on-times 

during the 24-hour Test Day. 

Home ID Date System Type Outdoor Air 

Flow Rate 

(cfm) 

Test Day 

On-time 

(hours) 

1 8/8/06 DOA na na 

4 3/2/07 DOA 28 1.22 

4 8/9/06 DOA 28 2.81 

8 3/2/07 DOA 71 2.98 

8 8/10/06 DOA 71 1.95 

9 8/10/06 DOA 48 6.20 

10 8/11/06 DOA 27 5.63 

11 3/3/07 DOA na na 

11 8/11/06 DOA na na 

12 8/11/06 DOA 31 0.38 

15 8/15/06 WHF 6591 0.68 

16 8/16/06 HRV 159 24.00 

17 2/22/07 HRV 153 24.00 

17 8/16/06 HRV 153 24.00 

18 8/16/06 RAD 700 12.81 

18 2/22/07 RAD 635 1.85 

18 2/22/07 HRV 120 24.00 

18 8/16/06 HRV 120 24.00 

19 2/21/07 RAD 880 0.00 

19 8/17/06 RAD 880 10.52 

19 10/25/06 RAD 880 0.24 

21 8/17/06 DOA 44 9.68 

22 8/18/06 HRV 209 na 

24 8/18/06 WHF 5067 0.00 

24 8/18/06 WHF 7486 0.00 

24 8/18/06 HRV 135 15.52 

25 2/22/07 RAD 830 0.00 

25 2/22/07 HRV 90 24.00 

25 8/22/06 HRV 90 24.00 

25 8/22/06 RAD 1110 15.63 

26 8/22/06 HRV 149 7.75 

34 8/25/06 WHF 7272 11.31 

43 9/8/06 DOA (2) 27 4.45 

43 9/8/06 DOA (1) 8 1.61 

44 1/27/07 WDF 201 0.00 

44 1/27/07 WHF 3856 0.00 
F-15 

Mechanical outdoor air ventilation system outdoor air flow rates and operational on-times 

during the 24-hour Test Day. 

Home ID Date System Type Outdoor Air 

Flow Rate 

(cfm) 

Test Day 

On-time 

(hours) 

44 9/8/06 WDF 201 18.50 

44 9/8/06 WHF 3856 4.83 

58 2/1/07 DOA 49 2.19 

58 9/15/06 DOA 49 0.00 

70 9/22/06 EC 2450 0.00 

83 2/2/07 DOA 355 1.51 

88 2/6/07 WHF 3589 0.00 

88 2/6/07 WHF 3250 0.00 

97 2/21/07 HRV 121 24.00 

99 2/24/07 DOA 10 17.94 

99 2/25/07 DOA 10 17.91 

99 2/23/07 DOA 10 17.78 

102 2/24/07 DOA 9 1.63 

104 2/24/07 HRV 66 23.75 

109 3/3/07 DOA 52 0.38 

110 3/3/07 DOA 63 0.14 

112 3/6/07 RAD 1175 0.00 

116 3/7/07 RAD 945 0.00 

117 3/8/07 RAD 775 0.00 

118 3/8/07 DOA 31 3.69 

119 3/8/07 DOA na na 
F-16 
G-1 

APPENDIX G 

Difficulties Encountered in the Field Study 

The following are difficulties that we encountered during the study, followed by the corrective 

action that was taken. Unless otherwise noted, we have deleted from the database and the 

associated data analyses the data noted below that was unable to be collected as a result of 

constraints encountered in the field or were associated with shortened sample periods (thus not 

representative of the standard 24-hour samples), failed analytical analyses, or yielded unrealistic 

data. 

1. During the Summer-North field session, three formaldehyde/acetaldehyde samples, 001-

F1-080706, 005-F2-080806, and 012-F1-081006 had fallen off from the air sampling rig. 

To ensure that the samples did not fall off in the future, an extra one-inch piece of 

Masterflex Norprene tubing was added to the top of the charcoal scrubber to secure the 

samples. 

2. During the Winter-South field session, there were two pump failures that occurred in 

homes that affected the formaldehyde/acetaldehyde sample 045-F1-012307 and 079-F1-

012907 and VOC samples 045-V1-012307 and 079-V1-012907. Team 3 found the pumps 

off upon arrival but were able to recover the elapsed time. It was unknown what had 

caused the pump malfunctions, but to ensure that samples were not shortened in the 

future we minimized the use of these pumps. 

3. During the analyses of the formaldehyde/acetaldehyde measurements, 084-F2-020107 

and 086-F1D-020507, a laboratory error occurred and the analyses for these two samples 

were lost. 

4. For the formaldehyde/acetaldehyde measurements in the FAU in Home 033 during the 

Summer-North field session, all three samples, 033-FSA-082406 (supply air sample), 

033-FRA-082406 (return air sample), and 033-FAA-082406 (attic) suffered a sampling 

error. The field technician inadvertently installed the Anasorb CSC, coconut charcoal 

sorbent tube in front of the DNPH sampler. This scrubber was supposed to be placed 

downstream of the sampler to scrub the emissions of residual acetonitrile released by the 

DNPH sample cartridge. The net result of this was that the formaldehyde and 

acetaldehyde mass concentrations were either below the method mass detection limit or 

unrealistically low. 

5. For the PM2.5 samples there was one sample lost. Sample 018-P1-022107, yielded an 

unrealistically low mass gain of -1 μg indoor concentration. An examination of the air 

sample flow rates indicated proper air sampling rates. Re-weighing the filter resulted in 

confirmation of the laboratory post-sampling weighing. Thus, the cause of this sample 

error is either that the filter was not installed into the air sampler or there was an error 

associated with the pre-sampling weighing. We examined with a microscope at 100x 

filter 018-P1-022107, filters with normal mass loadings, and field blanks, and could not 
G-2 

discern any visible difference. We thus cannot say one way or another whether the filter 

018-P1-022107 was ever installed. 

6. For the PFT samplers there were two samples lost. Sample 099-T1-022207 was lost 

during the laboratory analyses. Sample 019-T1-081606 yielded an unrealistically low 

outdoor air exchange rate, 0.03 ach. 

7. There was a malfunction with IAQ Calc #1, where Team 3 had found it off on two 

occasions—one in Winter North Home 108 and Winter South Home 039. It was 

unknown what had caused the malfunction, but to ensure that samples were not shortened 

in the future we minimized the use of IAQ Calc #1 in the future, resulting in no further 

failures. Both homes had samples sets representing more than 63% of the 24-hour 

sampling period (i.e., Home 039 with 63% of 24 hours from 16:16 to 07:30 and Home 

108 data with 84% of 24 hours from 16:08 to 12:24), thus we elected to retain these data 

(i.e., CO, CO2, T, and RH) in both the database and the associated population statistics. 

8. We also observed that IAQ Calc #6 had a malfunction when recording temperature and 

relative humidity. The results were observed to be erratic and unrealistic at four homes 

(019-C1D-022007, 077-C1-020507, 107-C2D-022807, and 117-C1-030707) in the 

Winter-North field session and two homes (084-C1-020107 and 086-C1-020507) in the 

Winter-South field session. To reduce any future problems, the use of IAQ Calc #6 was 

reduced as much as possible. 

9. During the QA/QC review of the carbon monoxide data we discovered three homes with 

erratic indoor data. The homes were Home 059 (Summer-South), Home 081 (WinterSouth), and Home 114 (Winter-North). The cause of these erratic results could not be 

determined. 

10. During the Summer and Winter South Regions, Team 1 did not specify which type of 

PFT sources had been used, for homes 037, 039, 041 for the summer and 041 for the 

winter. It was assumed that the A type sources were used when entering data and doing 

the analyses. We note that the small difference between these two sources is 12 nanoliters 

per hour (nL/h). For the A source the emission rate is 1584 nL/h and for the X source, the 

emission rate is 1572 nL/h. As this error is very low (i.e., a 0.76% difference) we elected 

to retain these data for the population statistics. 

11. The building envelope and garage-home air leakage measurements were not performed in 

Home 043, as a result of insufficient time provided by the homeowner to complete these 

tests, which represents the last set of tests conducted at each home. Additionally in Home 

011, wind conditions allowed only for a CFM50 measurement, and thus only an ACH 50 

is calculated and no SLA is calculated, and just a house-to-garage pressure and coupling 

factor is calculated and no house-to-garage leakage area is calculated. 

12. The FAU duct air leakage measurements were not performed in Homes 061, 081, and 

090, as a result of the inspectors not being able to seal one or more supply air diffusers in 
G-3 

bedrooms where access was not possible at the time of our inspection (e.g., sleeping 

occupant). 

13. During the Winter South Field Session, Team 1 had distributed the window/door and fan 

logs using a different adhesive on the back of the logs. When Team 3 arrived to remove 

the logs, they could not do so without ripping the log sheets. To ensure that the data was 

not lost, Team 3 copied the information from the logs onto a separate sheet of paper. To 

prevent this from happening in the future, Team 1 was notified of the adhesive problem 

and was directed to use the original selected non-residue adhesive. 

14. In Home 043 the research team was unable to collect information regarding the area of 

different types of floor finishes, the area of moisture staining or fungal growth, and the 

area of composite wood from floors, walls, ceiling, and furniture/cabinetry due to a lack 

of time provided by the homeowner to complete this task. 

The following paragraphs summarize the number and percentage of air contaminant and outdoor 

air exchange rate samples lost during this study and as described above. 

Formaldehyde. A total of 10 of the 221 field samples (4%) were lost, representing a 4% loss 

percentage. The most common cause of these losses were failures in the sample pumps and 

tubing connections. 

Volatile Organic Compounds. A total of 2 of the 208 field samples were lost, representing a loss 

percentage of less than 1%. The most common cause of these losses was failure in the sample 

pumps. 

Carbon Monoxide. A total of 3 of the 206 field samples were lost, representing a loss percentage 

of less than 2%. The cause of these failures is unknown but some type of failure in the 

electrochemical sensor electronics is suspected. 

Outdoor Air Exchange Rate PFT Samples. A total of 2 of the 167 field samples were lost, 

representing a loss percentage of 1%. The most common cause of these losses was laboratory 

analytical error.