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This page last reviewed June 11 , 2009

Air Pollution Research Reports/Studies - Indoor Air Pollution

Completed Projects are listed under the following sub-categories:


Exposure Assessment
Monitors
Toxic Air Contaminants

Exposure Assessment

VENTILATION AND INDOOR AIR QUALITY IN NEW HOMES. Principal Investigator: Francis J. Offermann. Indoor Environmental Engineering.  2009. 04-310

WORKSHOP ON INTERFACIAL CHEMISTRY IN INDOOR ENVIRONMENTS July 17--18, 2007. Principal Investigator: Glen Morrison. University of Missouri-Rolla.  2007. SA07--3002

SURVEY OF THE USE OF OZONE GENERATING AIR CLEANERS BY THE CALIFORNIA PUBLIC. Principal Investigator: Thomas Piazza. University of California, Berkeley.  2007. 05-301

STUDY OF VENTILATION PRACTICES AND HOUSEHOLD CHARACTERISTICS IN NEW CALIFORNIA HOMES. Principal Investigator: Thomas Piazza and Robert Lee. University of California, Berkeley. 2007. 03-326

INDOOR AIR CHEMISTRY: CLEANING AGENTS, OZONE AND TOXIC AIR CONTAMINANTS. Principal Investigator: William W. Nazaroff. University of California, Berkeley. 2006. 01-336

Four journal papers from this study have been published. Please go to Board Meeting Health Updates - Citations and scroll down to the September 28, 2006 entry for the citations.


DETAILED CHARACTERIZATION OF INDOOR AND PERSONAL PARTICULATE MATTER CONCENTRATIONS. Principal Investigator: Helen Suh. Harvard School of Public Health.  2004. 00-302

CALIFORNIA PORTABLE CLASSROOMS STUDY. Principal Investigator: Roy Whitmore. Research Triangle Park, NC.2003. 00-317.

CHARACTERIZATION OF THE COMPOSITION OF PERSONAL, INDOOR, AND OUTDOOR PARTICULATE EXPOSURES. Principal Investigator: Helen Suh. Harvard School of Public Health. 2003. 98-330.

Objectives:  To: 1)obtain detailed chemical speciation of personal, indoor, and outdoor PM2.5 samples; 2) examine the relationships among personal, indoor, and outdoor levels of the PM2.5 components; and 3) identify the relative contributions of different indoor and outdoor sources to personal PM2.5 exposures.  Monitoring will be conducted in conjunction with an U.S. EPA-funded exposure study of chronic obstructive pulmonary disease patients in Los Angeles.  The pollutants will be sampled for 24 hours on seven consecutive days in the summer and winter, for a total of 210 sampling days.

Importance to ARB’s Program:  This study will provide the first California data on personal and indoor pollutant exposures for one of the population groups most susceptible to particulate matter (PM) health effects.  Results from this study will improve the ARB’s identification and understanding of the exposure impacts of various outdoor and indoor sources of PM.  We will also use the data to improve the accuracy of its estimates of Californians’ exposures to PM2.5, metals, and related toxic air pollutants.

CHARACTERIZING THE RANGE OF CHILDREN'S POLLUTANT EXPOSURE DURING SCHOOL BUS COMMUTES. Principal Investigator: Dennis R. Fitz. UC Riverside. 2003. 00-322.

INTERIM REPORT FOR THE FRESNO ASTHMATIC CHILDREN'S ENVIRONMENT STUDY (FACES). University of California, Bekerley. 2002. 99-322 & 99-323

UPDATE AND REFINEMENT OF AN INDOOR EXPOSURE ASSESSMENT METHODOLOGY. Principal Investigator: Arlene S. Rosenbaum. ICF Kaiser Consulting Group – System Applications International, Incorporated.2002. 98-327.

Objectives:  To update and refine the population indoor exposure assessment methodology and verify the accuracy of the improved method.  This method is currently used to estimate Californians’ indoor and total exposures to air pollution.  This project will update the data used to estimate exposure and improve the methodology’s efficiency and ease of use.  It will also develop and refine estimation processes, including processes to account for indoor pollutant removal mechanisms, and better characterize the uncertainty and variability of the modeled estimates.

Importance to ARB’s Program:   The California Health and Safety Code Section 39660.5 requires the ARB to consider indoor exposures to TACs when assessing risks posed by these pollutants.  To fully consider the impact indoor exposures have on total TAC exposure risks, the ARB needs accurate estimates of both indoor and total exposures to air pollutants and an effective and accurate means of measuring and evaluating these data.  By updating and improving the existing assessment methodology and informational database, this project will assist the ARB in accurately assessing and reducing the risks associated with both indoor and total exposures to TACs.

User's Guide

INDOOR AIR QUALITY:  RESIDENTIAL COOKING EXPOSURES. Principal Investigator: Roy Fortmann. ARCADIS Geraghty & Miller, Inc. 2001. 97-330.

Objectives:  To: 1) characterize emissions rates and resultant personal exposures and indoor concentrations for PM, carbon monoxide, and nitrogen dioxide produced by residential cooking, under typical conditions and realistic worst-case scenarios; 2) characterize emissions rates and resultant indoor concentrations of other cooking pollutants, such as polycyclic aromatic hydrocarbons (PAHs), elements, and potential marker compounds; and 3) measure the effectiveness of selected exposure reduction practices.

Importance to ARB’s Program:  This study focuses on one of the main causes of increased personal exposure to particles and several other indoor pollutants – residential cooking.  ARB will use the data from this study to improve the accuracy of exposure models used to determine human exposure estimates and to further explore the correlation between personal exposure levels and cooking activities. The data on PAH and metals will be used to improve estimates of indoor exposures to TACs, as required by Health and Safety Code Section 39660.5.  Results from this study will also be used to provide guidance to the public for reducing their pollutant exposure.

MEASURING CONCENTRATIONS OF SELECTED AIR POLLUTANTS INSIDE CALIFORNIA VEHICLES.  Principal Investigator: Charles Rodes PhD. Research Triangle Institute.1999. 95-339.

Objectives:  To determine the concentrations of PM, toxic gases, metals, carbon monoxide, and other pollutants inside vehicles as they are driven, under various conditions, on California roadways.  Also, to simultaneously measure the pollutants just outside the vehicle, along the roadway, and at nearby ambient monitoring stations to determine how pollutant concentrations in those locations differ from and affect in-vehicle exposure levels.

Findings:  Measurements of PM2.5 and PM10 were made in two sedans, a sport utility vehicle, and a school bus under various types of traffic conditions, roadways, and cabin ventilation.  Investigators also measured PM-associated metals and 13 VOCs, including methyl tertiary butyl ether (MTBE), benzene, and formaldehyde, and took real-time measurements of black carbon (soot), particle counts, and carbon monoxide.  In general, VOC and PM levels inside or just outside the vehicles were higher than those measured at the roadside sites and the ambient air stations.  In a comparison of carpool lane vs. right-hand lane exposure levels, pollutant levels measured inside vehicles traveling in a carpool lane were notably lower than those in the right-hand, slower lanes.  Factors such as roadway type, freeway congestion level, and time-of-day were also found to have some influence on the in-vehicle pollutant levels.  Under the conditions of the study, factors such as vehicle type and ventilation settings were found to have little effect on the in-vehicle pollutant levels.  In-vehicle levels of fine particles were especially high when following a diesel or gross-emitting gasoline vehicle, and the increase occurred very rapidly.

Importance to ARB’s Program:  Although Californians spend an average of seven percent of their time traveling inside vehicles, few in-vehicle measurements of particles, VOCs, and toxic metals have been made.  The results of this project will be used to improve estimates of Californians’ current in-vehicle exposures to particles, diesel exhaust, MTBE, and other pollutants.  They will also help determine the relative contribution of in-vehicle exposures to the total air exposures for these pollutants.  Additionally, the results will be used to identify actions that drivers and passengers can take to reduce their in-vehicle exposures to air pollutants.  The ARB plans to follow up this study by investigating PM levels and related factors in school buses and other vehicles in a future research project.

DEVELOPMENT OF A MODEL FOR ASSESSING INDOOR EXPOSURE TO AIR POLLUTANTS. Principal Investigator: Michael D. Koontz. Geomet Technologies, Incorporated. 1998. A933-157.

Objectives:  To develop a user-friendly model to estimate the population's average and high-end exposures to both gaseous and particulate pollutants.  The model will use indoor concentration data, California activity patterns data, indoor source emission data, air exchange rate data, and other information. 

Findings:  Researchers on this project succeeded in developing a unique California Population Indoor Exposure Model (CPIEM).  CPIEM can incorporate detailed human activity information, pollutant concentration data, and other California-specific data to provide improved indoor and total exposure estimates for the California population.  The model is flexible; it provides population exposure and inhaled dose estimates for different exposure times, up to eight different types of indoor environments, the outdoor environment, and the total exposure across all environments.  The exposure module allows the user to specify the population characteristics, such as age, gender, and county of residence. The model estimates the central tendency of exposure distributions well, but, like other population exposure models, is less reliable in estimating the extremes (high and low ends) of the distributions. 

Importance to ARB’s Program:  The improved estimates of exposure will improve the accuracy of risk estimates, which will help the ARB identify and design more effective methods of risk management.  It will especially improve indoor assessments required for ARB Toxic Air Contaminants Program actions under the California Health and Safety Code, section 39660.5. 

RESIDENTIAL MICROENVIRONMENTAL AND PERSONAL SAMPLING FOR EXPOSURE  CLASSIFICATION. Principal Investigator: Edward Avol. University of Southern California.1996 92-317.

Objectives:  To measure residential exposures to ozone, particles, formaldehyde, and airborne acids in a representative sample of children's homes in the ARB/USC Epidemiology Study (A033-186, see Health Effects section, 1996).  Also, to examine the relationships between indoor ozone levels and outdoor ozone levels, house characteristics, occupants' activities, and air exchange rates. 

Importance to ARB’s Program:  The results will be used to improve estimates of Californians' exposures to ozone, PM, and formaldehyde and develop effective strategies for reducing the resultant health risks.  They will also be used to refine the exposure model used in the epidemiology study and improve estimates of the participants' exposures to these pollutants. 

MEASUREMENT OF BREATHING RATE AND VOLUME IN ROUTINELY PERFORMED DAILY ACTIVITIES. Principal Investigator: William C. Adams, Ph.D. University of California, Davis.1993. A033-205.

Objectives:  To measure the amount of air breathed during routine activities in the first comprehensive study of males and females of all ages, in order to fill a major data gap in exposure/dose calculations. 

Findings:  The amount of air breathed during defined activities and for various age groups is now known.  Adult males of all ages breathe similar amounts of air during similar activities.  Likewise, adult females of all ages breathe similar amounts of air during similar activities.  This study confirmed that, relative to body size, children breathe more air than adults during similar activities.  Contrary to other studies, the investigator found that heart rate is not a good predictor of pulmonary ventilation at all exercise levels. 

Importance to ARB’s Program:  The ARB and other groups are using these breathing measurements to refine estimates of the amount of air pollutants inhaled.  This study eliminates much of the uncertainty of estimating inhaled dose from laboratory measurements by actually measuring the amount of air breathed by a wide variety of individuals during actual activities.

PTEAM: PARTICLE TOTAL EXPOSURE ASSESSMENT METHODOLOGY STUDY.  Principal Investigator: L Sheldon. Research Triangle Institute. 1992. A933-144.

Objectives:  To measure exposures to inhalable particles and some associated elements.  ARB participation ensured that the study was conducted in California and provided funding for measuring indoor and outdoor levels of two classes of toxic air pollutants: PAHs, which are combustion by-products, and phthalates, which are commonly used plasticizers. 

Findings:  Personal monitoring showed that people are exposed to about 50% more PM during the day than would have been predicted using stationary monitors.  Indoor PAH levels ranged from about one-half to two times outdoor levels.  Phthalates were ubiquitous, and average indoor levels were 2 to 15 times higher than outdoor levels. 

Importance to ARB’s Program:  The ARB is using the data to assess Californians' indoor and personal exposures to inhalable particles and a number of toxic air pollutants, including benzo(a)pyrene, phthalates, lead, and other metals.

ACTIVITY PATTERNS OF CALIFORNIA RESIDENTS. Principal Investigator: James A. Wiley. University of California, Berkeley. 1991. A6-177-33.

Objectives:  To obtain representative data on the time spent by California adults and adolescents in different activities and locations, with the focus on potential exposure to harmful air pollutants.  Also, to examine regional, seasonal, and socioeconomic/demographic differences. 

Findings:  Adults and adolescents spend, on average, 62% of their time indoors at home, 25% indoors at other locations, about 6% outdoors, and 7% in enclosed transit.  The frequency, duration, and time of day of potential exposures to various indoor and outdoor air pollutants varied greatly across the population. 

Importance to ARB’s Program:  The findings improved the ARB’s understanding of how and where Californians are exposed to air pollution.  The results are being used to improve the indoor exposure assessments for TACs required by the California Health and Safety Code. The ARB, other agencies, and researchers are using the data in models to more accurately estimate people's exposures to pollutants.

STUDY OF CHILDREN'S ACTIVITY PATTERNS. Principal Investigator: James A. Wiley. University of California, Berkeley. 1991. A733-149.

Objectives:  To obtain representative data on the time spent by California children in different activities and locations, with the focus on potential exposure to harmful air pollutants.  To examine regional, seasonal, and socioeconomic/demographic differences to the extent possible. 

Findings: Children spend, on average, 76% of their time indoors at home, 10% indoors at other locations, about 10% outdoors, and 4% in enclosed transit.  Potential exposure to pollutants as a result of activity patterns was quite variable. 

Importance to ARB’s Program:  The findings improved our understanding of how and where children are exposed to air pollution and how to most effectively reduce the resultant health risks.  The ARB, other agencies, and researchers are using the data in models to more accurately estimate people's exposures to pollutants.

Monitors

REFINEMENT AND DEMONSTRATION OF A NEW INDOOR CONTINUOUS NITROGEN DIOXIDE MONITOR. Principal Investigator:Jeffrey D. Myers. Battelle. 2003. 99-327.

A CONTINUOUS, REAL-TIME MINIATURE OZONE MONITOR.  University of California, Berkeley.  Principal Investigator: Robert A. Harley. University of California, Berkeley. 1999. 94-342.

Objectives:  To develop and test a miniature ozone monitor for continuous real-time measurements of ozone in indoor and outdoor microenvironments, with potential for future adaptation as a personal monitor.  The primary performance objective for the prototype monitor is the ability to accurately and precisely measure 30 to 300 parts per billion (ppb) ozone for periods of 30 minutes or less.

Findings:  The investigators developed a prototype portable ozone monitor that uses a piezoelectric quartz crystal coated with polybutadiene.  The monitor meets the performance objectives in laboratory tests for interferences and in field tests at homes, offices, and a photocopy room.  It appears to be well-suited for indoor and outdoor monitoring studies, but requires further refinement to improve its ease of use and further testing under high ozone conditions and more diverse field conditions.  Further development of this technology will be needed to make it suitable for personal monitoring applications. 

Importance to ARB’s Program:  This monitor performs accurate ozone measurements over periods of one hour or less, recording and displaying the ozone level immediately.  This permits measurements of short-term peak exposures to ozone, allowing real-life exposures to be compared to health-based standards.  In addition, data obtained using this monitoring technology will be used to improve exposure and risk assessments and identify populations with high ozone exposures. 

DEVELOPMENT OF A SHORT-AVERAGING-TIME INDOOR NITROGEN DIOXIDE MONITOR.  Principal Investigator: Thomas J. Kelly. Battelle.1999. 96-312.

Objectives:  To develop and test a small, quiet, economical nitrogen dioxide (NO2) monitor capable of measuring concentrations indoors for short averaging times of one hour or less.  The monitor must be able to accurately measure NO2 across the full range of expected indoor levels, including the very high levels sometimes seen during operation of gas appliances.  Testing will include trials in residences and public buildings.

Findings:  Investigators developed a monitor that can determine NO2 and nitrous acid concentrations using a commercial electrochemical sensor that responds to both species, but with different sensitivities.  There appears to be no significant interference from other compounds.  Measurement accuracy is within 10-20% of reference methods when sensors are new.  The monitor samples continuously, and is portable and fully self-contained.  This is the first portable, real-time NO2 monitor with an operational range that encompasses indoor NO2 levels.

Importance to ARB’s Program:  This project will provide ARB with a fully characterized, economical, portable NO2 sampler suitable for use in indoor air quality studies.  The monitor will enable us to measure the full range of levels inside buildings, and thus provide data for improved population exposure estimates.  The short averaging time will allow for comparison of measured levels to the one-hour ambient air quality standard for NO2, an indicator of safe versus potentially harmful levels of NO2.

Toxic Air Contaminants

COMMON INDOOR SOURCES OF VOLATILE ORGANIC COMPOUNDS: EMISSION RATES AND TECHNIQUES FOR REDUCING CONSUMER EXPOSURES.  Principal Investigator: Alfred T Hodgson. University of California, Lawrence Berkeley Laboratory. 1999. 95-302.

Objectives:  To characterize and quantify the emissions rates of VOCs, including TACs, from three general categories of common indoor building and decorating materials.  Also, to measure the effectiveness of various practical measures that consumers can take to reduce their exposures to the VOCs emitted from these products during and after home remodeling activities. Materials studied included carpets, carpet pads, adhesives, vinyl flooring, and interior latex paint.

Findings:  The investigators characterized the VOC emissions from three groups of materials: carpets and vinyl flooring (including associated installation material), and latex paints.  Fifteen TACs were identified in the emissions from these products. Evaluation of methods for reducing exposure to related VOCs determined that use of low emitting products is the most effective means for limiting exposure to emissions from all categories of materials, and airing out carpet and carpet cushion before installation is effective for reducing exposure from carpet compounds.  Additionally, using a high rate of mechanical ventilation (exhaust fans) for at least three days, and for as long afterward as is practical, should lower occupant exposure to VOCs from paint and carpet.

Importance to ARB’s Program:  Results from this study will provide a scientific basis for future indoor air quality guidelines that advise Californians on ways to reduce their exposure to indoor pollutants in new or remodeled homes.  Emissions data will be used in models to improve estimates of indoor exposures to TACs, as required by the California Health and Safety Code.

ASSESSING EXPOSURE TO AIR TOXICANTS FROM ENVIRONMENTAL TOBACCO SMOKE. Principal Investigator: William W. Nazaroff. University of Colorado, Boulder.1998. 94-344.

Objectives:   To estimate the proportion of Californians' exposures to 17 selected TACs that is attributable to ETS and the proportion that is attributable to other sources.  In addition, the study estimated the potential future reduction in exposure to these ETS chemicals that is likely to result from changes in Californians' smoking habits, new smoking laws, and other factors.

Findings: ETS was found to contribute significantly to the exposure of nonsmokers to TACs. For example, in the mid-to-late 1980s, the estimated average contribution of ETS to benzene exposures was 3-10% of the total benzene exposure; benzene is a potent carcinogen.  Because of legislation prohibiting smoking in enclosed workspaces and other factors, ETS-caused exposures to the VOCs is predicted to be reduced in the late 1990s by 60-80% for adults, 45-55% for adolescents, and 30-35% for children.  The smaller reduction for adolescents and children is due to the fact that these groups spend a greater portion of their time in unregulated indoor environments such as private residences. 

Importance to ARB’s Program:  Results from this project can be used in conjunction with other recently available data to estimate the relative contributions of indoor and outdoor sources of these TACs to Californians' current exposures and risks.  This information will help the ARB identify effective mitigation strategies for reducing the residual public health risks from these TACs.

DETERMINATION OF FORMALDEHYDE AND TOLUENE DIISOCYANATE EMISSIONS FROM INDOOR RESIDENTIAL SOURCES.  Principal Investigator: Thomas J. Kelly. Battelle. 1996. 93-315.

Objectives:  To measure the emissions of formaldehyde and toluene diisocyanate from their indoor sources.  Measurements were made in medium and large chambers under conditions that reflect typical indoor conditions as well as conditions approximating extreme but realistic indoor conditions that would cause higher emissions. 

Findings:  Major residential sources of formaldehyde generally emit less formaldehyde than in the past, but some products, including pressed wood products, permanent press fabric, and a wood floor finish, still emit significant amounts of formaldehyde.  Toluene diisocyanate was not emitted in measurable amounts from any of the residential sources tested. 

Importance to ARB’s Program:  Formaldehyde and toluene diisocyanate can cause adverse health effects at low levels and are used in the manufacture of products widely found and used inside residences and offices.  The results will be used to better estimate Californians' exposures to these compounds and to provide guidance to California citizens on steps they can take to reduce their exposures to them.

TOXIC VOLATILE ORGANIC COMPOUNDS IN ENVIRONMENTAL TOBACCO SMOKE:  EMISSION FACTORS FOR MODELING EXPOSURE OF CALIFORNIA POPULATIONS.  Principal Investigator: J. M. Daisey. Lawrence Berkeley Laboratory. 1994. A133-186.

Objectives:  To measure the levels of over 20 toxic air pollutants in aged second-hand smoke (ETS) from the brands of cigarettes most smoked in California.  In order to compare the results with existing data, emissions of the same pollutants from fresh sidestream smoke (smoke from the burning end of the cigarette, or SS) were also measured. 

Findings:  Most of the target compounds were present in levels high enough to be measured in both ETS and SS.  ETS emissions were highest for particles, aldehydes, nicotine, and the aromatic hydrocarbons.  The ETS emissions were fairly consistent among the different cigarette brands, even when "regular" cigarettes were compared to mentholated and "light" cigarettes.  ETS emissions were generally higher than emissions measured in SS, apparently due to chemical losses in the SS apparatus.  The ETS emission factors agree with other literature values and the investigators recommend their use in exposure modeling. 

Importance to ARB’s Program:  Cigarettes are a major indoor source of many toxic air pollutants.  This study provides unique information to help estimate Californians' exposures to many toxic components of ETS.

DATABASE DEVELOPMENT AND DATA ANALYSIS FOR CALIFORNIA INDOOR EXPOSURE STUDIES.  Principal Investigator: C.A. Clayton. Research Triangle Institute.1993. A133-187.

Objectives:  To combine data from six California indoor exposure studies into a unified database to facilitate further analysis of the data from all the studies.  Also, to demonstrate the usefulness of the consolidated database by conducting several analyses, such as examining   differences in exposure across seasons and location.

Findings: Data from six California exposure studies are now compatible and can be easily accessed through the database.  The analytical results suggest that indoor and personal exposures are higher in winter than in summer for common volatile organic compounds.  Some indoor exposures to chemicals correlate with the presence of indoor emission sources and human activities in the home. 

Importance to ARB’s Program:  The ARB will use the database to more fully analyze the large body of exposure information collected by the ARB and the U.S. EPA in California over the last decade.  The database has already been used to estimate Californians' exposures to about 20 toxic pollutants for the California Comparative Risk Project.

INDOOR CONCENTRATIONS OF POLYCYCLIC AROMATIC HYDROCARBONS IN CALIFORNIA RESIDENCES.  Principal Investigator: L Sheldon. Research Triangle Institute. 1993. A033-132.

Objectives:   To measure the levels of selected toxic combustion by-products (PAHs and carbon monoxide) in California homes and evaluate the relative contributions of sources -- such as cigarette smoking, wood-burning stoves, and gas heaters -- to indoor levels of those pollutants. 

Findings:  Cigarette smoking, wood stoves, fireplaces, and kerosene heaters were major sources of PAHs in the homes where they were used.  Infiltration of polluted outdoor air also contributed significantly to indoor levels.  Only a few homes showed elevated levels of carbon monoxide, associated mostly with the use of gas heat and fireplaces. 

Importance to ARB’s Program:  The findings will be used to estimate Californians' indoor exposures to PAHs and carbon monoxide and to provide guidance to the public on how they can avoid unhealthful exposures.

ASSESSMENT OF INDOOR CONCENTRATIONS, INDOOR SOURCES, AND EMISSIONS OF SELECTED ORGANIC COMPOUNDS.  Principal Investigator: Joan M Daisey. Lawrence Berkeley Laboratory. 1991. A933-063.

Objectives:  To survey and summarize available information on indoor concentrations and sources of 47 toxic air pollutants and identify data gaps that could be filled by conducting indoor source emissions tests. 

Findings:  Except for four of the compounds, available data are generally not sufficient for estimating indoor exposures.  The investigators  identified compounds for which it would be useful to conduct indoor source emission tests and outlined a general plan for conducting such tests. 

Importance to ARB’s Program: The information compiled on indoor concentrations and sources has been used to estimate indoor exposures for the Toxic Air Contaminants Program.  This project prompted two further ARB studies to measure emissions from indoor pollutant sources.

INDOOR POLLUTANT CONCENTRATIONS AND EXPOSURES. Principal Investigator: L. Sheldon. A. Research Triangle Institute. 1991. A833-156.

Objectives:  To measure indoor air levels of pollutants to be addressed in the Toxic Air Contaminants Program; to determine whether indoor/personal air levels in a small, inland Northern California community are similar to those in Los Angeles; and to attempt to measure for the first time the indoor concentrations of certain semi-volatile pollutants. 

Findings:  This study confirmed findings of previous California studies that personal exposure levels to VOCs are somewhat higher than indoor air levels and that indoor levels of many VOCs are higher than outdoor levels.  The indoor and personal VOC levels were similar to those measured in other northern California homes, but lower than those found in southern California homes.  Semi-volatile chemicals were difficult to measure, but appeared to be low indoors. 

Importance to ARB’s Program:  The data have been used to estimate indoor exposures to several pollutants for the Toxic Air Contaminants Program, as required under the California Health and Safety Code.  The results are also being used to estimate Californians' indoor and total exposure to air pollution for the Comparative Risk Project and to provide guidance to help the public reduce their exposures to these pollutants.

SAMPLING, ANALYSIS, AND DATA VALIDATION OF INDOOR CONCENTRATIONS OF POLYCYCLIC AROMATIC HYDROCARBONS (PAH). Principal Investigator: F.J. Offermann. Indoor Environmental Engineering; Lawrence Berkeley Laboratory. 1990. A732-106.

Objectives:  To develop sampling and analytical methods in the laboratory for monitoring indoor concentrations of PAHs, which are toxic by-products of combustion, and field test these methods to determine their feasibility for use in larger studies. 

Findings:  The investigators successfully developed methods to measure gas phase PAHs indoors.  They concluded that methods for measuring particle-phase PAHs and gas phase nitro-PAHs required further development prior to field use. 

Importance to ARB’s Program:  Results from this project were used during the development of the monitors for two large-scale ARB residential PAH studies (A933-144, 1992 and A033-132, 1993).

STUDY OF RESIDENTIAL INDOOR AND OUTDOOR RADON CONCENTRATIONS IN CALIFORNIA.  Principal Investigator: Kai-Shen Liu, Ph.D., M.P.H. California Public Health Foundation; California Department of Health Services. 1990. A6-194-53.

Objectives:  To characterize the magnitude of the radon problem in California through the first statewide study of radon levels in air, soil, and water in randomly selected residences.

Findings:  The statewide annual average indoor radon concentration was about 60% of the national average and well below the U.S. Environmental Protection Agency’s (EPA’s) recommended action level.  The radon concentrations in the Sierra foothills and Ventura County were elevated relative to those in the rest of California. 

Importance to ARB’s Program:  Results from this study have been used by the ARB and the Department of Health Services (DHS) to estimate Californians' exposures to radon, and by DHS and the U.S. EPA to guide additional monitoring efforts for further characterizing possible problem areas in the state.

PTEAM PILOT:  EVALUATION OF METHODS FOR MONITORING PAHs, PHTHALATES, NITROSAMINES, AND ACIDS.  Research Triangle Institute. 1990. A833-060.

Objectives:  To field test indoor sampling and analysis methods for four classes of air pollutants (PAHs; phthalates; nitrosamines; and acids) in nine southern California homes to ensure that resources would be properly focused in a proposed, larger field study.

Findings:  The investigators demonstrated the feasibility of measuring PAHs and phthalates indoors and refined the methods for use in the larger study.  They determined that the methods for monitoring indoor levels of nitrosamines and acids required further improvement and testing prior to use in the field.

Importance to ARB’s Program:  The methods for PAHs and phthalates were used in the subsequent large field study (A933-144, 1992).  Nitrosamines and acids were dropped from the sampling plan.  The PAH and phthalate methods were also used in another residential study sponsored by ARB (A033-132, 1993).

DEVELOPMENT AND IMPLEMENTATION OF EXPOSURE ASSESSMENT PROCEDURES FOR TOXIC AIR POLLUTANTS IN SEVERAL LOS ANGELES COUNTY (CALIFORNIA) COMMUNITIES (also called the 1987 TEAM study).  Principal Investigator: E. D. Pellizari. Research Triangle Institute. 1989. A5-174-33.

Objectives:  To determine similarities and differences in air levels of VOCs in 50 Los Angeles homes monitored three years earlier.  Also, to identify possible indoor sources of the pollutants and estimate the rate of pollutant emissions from those sources.

Findings:  The personal and indoor air levels were higher than outdoor levels for most of the pollutants.  These findings were similar to those of the previous study.  Indoor source strengths were successfully calculated for 12 prevalent compounds.  A few were notably high. 

Importance to ARB’s Program:  The results have been used extensively to develop estimates of Californians' exposures to toxic VOCs from inhalation of indoor air, as required by the California Health and Safety Code.  The results also have been used in the Comparative Risk Project and to provide guidance to the public on ways to reduce their exposures to these pollutants.

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