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Exposure Assessment
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 click HERE 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 – Systems 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.
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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