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94-22:
Half
of the Mutagenic Activity of Ambient Air is from Derivatives of Emitted PAHs
Polycyclic aromatic hydrocarbons (PAHs) are combustion products of organic fuels such as diesel, coal, and wood,
and are under examination by the State for classification as toxic air contaminants. This study, which examined
ambient particulate matter, ambient vapor-phase samples, and urban dust, determined that roughly half of direct-acting
ambient air mutagenicity could be ascribed to atmospheric transformation products of PAHs. The research adds significantly
to the knowledge of the chemical nature of mutagens in ambient air. The resulting data provide a basis for determining
the effects of various PAH emissions control options on public health in California. The study was performed by
the Statewide Air Pollution Research Center at the University of California, Riverside.
94-21:
Assessing
Pollution Transport Aloft with 915-MHz Radar Wind Profiles
This study demonstrated the feasibility of remotely monitoring air movement aloft with radar wind profiles operating
at 915 MHz. The primary objective was to collect data to describe air movement aloft and to relate those data to
the potential for the transport of pollutants in air layers aloft between air basins. The data collected indicate
continuous air flow, limited to shallow layers at times, through the major transport routes between various air
basins in California. This study was performed by the Environmental Technologies Laboratory of the National Oceanic
and Atmospheric Administration.
94-20:
On-Road
Remote Sensing and In-Use Emissions of Motor Vehicles
The University of Denver's automobile emissions remote sensor was tested for accuracy and precision under
controlled and field conditions. The sensor, accurate within plus or minus 5 percent for carbon monoxide
and plus or minus 15 percent for hydrocarbon when compared to simultaneous measurements made by an instrumented
vehicle, successfully identified high-emitting vehicles to be pulled over for further examination. The results
indicate that the remote sensor can be used to identify high-emitting motor vehicles on the state's roadways and
target them for cleanup actions. This study was performed by the University of Denver.
94-19:
Key
Organic Compounds in Particulate Matter from Air Pollution Sources
Organic compounds present in fine particulate matter emitted from 18 urban source types and in ambient air
were identified and quantified. The results were used, where possible, to determine appropriate tracer compounds
for each source type in order to better understand their contributions to the amount of fine particulate matter
in the Los Angeles area. This information can be used by districts and the ARB to develop informed control
strategies for this portion of the ambient fine particulate matter. This study was performed by the California
Institute of Technology.
94-18:
Estimated
Cost of Ozone Damage to California Crops
Under the Atmospheric Acidity Protection Program, the Air Resources Board conducted this special study of
the effects of ozone and acidic deposition on agriculture in the San Joaquin Valley. Although acidic deposition
at current levels was not projected to adversely affect crop yields, ambient levels of ozone were postulated to
cause significant yield losses in a variety of species. The California Agricultural Resources Model was used
to estimate the economic impact of ozone on crop yields in the State. It was estimated that total benefits to consumers
and producers would be $490 million per year if long-term average ozone levels were reduced to 0.04 parts per million
during the growing season. The results of this project indicate that economic impacts of ozone are significant
and that ozone poses a threat to the profitability of the agricultural industry in the State and can impose
additional costs on consumers. This study was performed by the University of California, Davis.
94-17:
Does
Bioremediation of Hazardous Waste Sites Lead to Significant Airborne Emissions?
This project quantified airborne emissions of volatile organic compounds (VOCs) and toxic air contaminants
(TACs) from bioremediation processes used to clean up hazardous waste sites and compiled a list of all sources
of existing data on airborne emissions of VOCs and TACs from bioremediation operations. Critical reviews of the literature
were conducted on current practices in bioremediation. A variety of conclusions can be drawn from the results of
this study. Two important conclusions are that (1) some bioremediation processes can result in emissions of
significant amounts of ambient VOCs and (2) in a well designed bioremediation operation, anaerobic conditions should
be short-lived and of minor importance to the process. This study was performed by the University of California,
Davis.
94-16:
Sources
of PM10 and Volatile Organic Gases in the South Coast Air Basin
The chemical mass balance receptor model was applied to the data collected on chemically speciated diurnal particulate
matter and volatile organic compounds during the 1987 Southern California Air Quality Study. The model showed that
suspended dust was the main contributor to PM10 during the summer, and that secondary ammonium nitrate and primary
motor vehicle exhaust contributions were high in the fall. Motor vehicle exhaust was the main contributor to nonmethane
hydrocarbons, ranging from 30 to 70 percent of the total. Liquid fuel, gasoline vapor, and natural gas leaks
were also significant contributors; contributions from architectural coatings and other emitters were negligible.
This study was performed by the Desert Research Institute.
94-15:
Generation,
Characterization, and Transport of Owens Lake Dust
This study investigated the sources and the generation mechanisms of windblown PM10 dust on the dry bed of Owens
Lake. The dust is transported to nearby populated areas, including the towns of Keeler and Lone Pine, and to the
Naval Air Weapons Center at China Lake. The levels of dust in this area are among the highest ever measured in
the United States. The largest dust storms are generated primarily by abrasion of the surface by fine sand particles.
This suggests that the intense nearby dust storms could be reduced by effectively controlling the movement of sand
on the lake bed playa. This study was performed by the University of California, Davis.
94-14:
California
Indoor Exposure Database
A database for evaluating Californians' long-term indoor and personal exposures to 30 volatile organic compounds
(VOCs) is now available. The database consolidates datasets from six field studies that obtained VOC measurements
and questionnaire information from residents of several California cities. Statistical analyses using the
new database indicate that indoor and personal exposures are higher in winter than in summer for
common VOCs. In addition, exposure levels correlate positively with the presence of indoor emission sources
and human activities in the home. This study was performed by the Research Triangle Institute.
94-13:
Does the Presence of Gasoline in Methanol/Gasoline Mixtures Enhance the Dermal Absorption of Methanol?
Methanol and methanol / gasoline mixtures were tested on rat skin to determine whether gasoline in the mixtures
enhanced the skin absorption of methanol. While methanol / gasoline mixtures with greater than 50 percent gasoline
content did enhance the relative degree to which methanol was absorbed, the total amount of methanol absorbed from
these mixtures was less than that from the same amount of pure methanol because of the lower content of methanol
in the mixtures. Thus, from a public health perspective, accidental spills of methanol / gasoline mixtures on the
skin will not produce greater absorption of methanol than spills of pure methanol itself. This study was performed
by the University of California, Davis.
94-12:
Young
Adult Females Experience Menstrual Cycle Disruptions Following Ozone Exposure
Healthy young adult women and men were exposed to filtered air, 0.18 parts per million ozone, and 0.30 parts
per million ozone while exercising for one hour on bicycle ergometers. There were no statistically significant
differences between the male and female groups' pulmonary responses to ozone. A significant number of women, however,
experienced menstrual cycle disruptions following exposure to 0.30 parts per million ozone. This study was performed
by the University of California, Davis.
94-11:
How
Much Air Do We Breathe?
This was the first large systematic study to measure the amount of air people breathe during their normal
activities. The amount of air breathed and related physiological factors were measured on 160 normally active
males and females ranging from 6 to 77 years of age. Measurements were taken both during actual work
and play conditions and in laboratory settings. Results indicate that adult males from adolescents through seniors
breathe similar amounts of air during similar activities, as do adult females across those age groups. Children
inhale more air than do adults, relative to body surface area. The amount of air breathed during certain activities
can be predicted from body surface area, breathing frequency, and heart rate. However, the investigator found
that widely used estimation methods based on treadmill heart rate measurements tend to overpredict the amount of
air breathed during field activities by 10-20 percent. This study provides actual measurements obtained during
real activities, and will significantly improve population estimates of the amount of air pollutants inhaled,
thereby reducing some of the uncertainty in air pollution risk assessment. This study was performed by
the University of California, Davis.
94-10:
Indoor
Air Concentrations of Phthalates and PAHs in Southern California Homes
This study was the first to measure indoor air levels of phthalates and polynuclear aromatic hydrocarbons (PAHs)
in a large, representative sample of homes. Phthalates, which are commonly used plasticizers, and PAHs, which are
combustion by-products, are toxic air pollutants. Several phthalates are known to cause birth defects in animals,
and many PAHs are known or suspected carcinogens. Both groups of compounds are emitted from a number of indoor
sources. Measurements were made in 125 homes in the fall of 1990 in Riverside. Indoor concentrations
of phthalates were, on average, about 2 to 15 times higher than outdoor concentrations. Average indoor PAH levels
ranged from about one-half to two times average outdoor levels, and levels were higher in homes in which cigarettes
were smoked. This study was performed by the Research Triangle Institute.
94-9:
Organic
Gases in Los Angeles Area Air: Analysis of the SCAQS Database
The ambient nonmethane organic gas (NMOG) database from the 1987 Southern California Air Quality Study (SCAQS)
is one of the most complete ever collected in an urban area. Ground and aircraft-based samples were taken
during summer and fall. In each sample, over one hundred hydrocarbon species and ten carbonyl species
were determined. Analysis of the data greatly increased our understanding of NMOG behavior in the South Coast
Air Basin (SoCAB), and will ultimately lead to more effective ozone control strategies. The main findings
of this study were that: (1) the variation of NMOG composition throughout the Basin during the day, and from
day to day, was less than expected; (2) ambient NMOG measurements did not agree well with expected levels calculated
from the emissions inventories (most likely due to underestimation of emissions from motor vehicles); (3) there
appears to be a large amount of carbonyl species formation from the photochemical oxidation of organic gases; and
(4) carbonyl compounds having more than four carbons were more abundant than expected. This study was performed
by Sonoma Technology, Inc.
94-8:
Application
of Models to Predict Acidity Changes in Alpine Watersheds in the Sierra Nevada
The objective of this project was to determine whether the Alpine Lake Forecaster could be applied to four
watersheds in the Sierra Nevada for data collected between 1986 and 1988. The analysis showed that the forecaster
can be applied to three of the four watersheds. It was determined that it may be possible to use one of the
coefficients in the model to assess the sensitivity of other Sierra watersheds to acidic deposition. The results
of a multivariate mixing model indicate that two soil environments - the bench meadow and the inlet meadow - may
explain most of the observed variation in stream chemistry. This study was performed by the U.S. Geological
Survey.
94-7:
Dioxin
and P AH Levels in California's Ambient Air
Ambient air was collected in three areas, based on concern about exposures to toxics from nearby sources: in Sutter
and Colusa Counties while rice straw was being burned nearby, in Fresno during a period of heavy wood burning,
and in an industrial area of Richmond. These samples were analyzed for polycyclic aromatic hydrocarbons (PAHs)
and PAH derivatives, and for polychlorinated dibenzo-dioxins and furans (dioxins); samples were also assayed for mutagenicity.
In general, the highest concentrations of PAHs and dioxins were found in the samples taken near wood burning,
and the lowest concentrations were found in those samples taken near rice straw burning. This study was performed
by ENSR Consulting and Engineering.
94-6:
California's
Children: How and Where They Can Be Exposed to Air Pollution
Information from this statewide study of the amount of time California's children spend in various activities and
locations will be used to develop more accurate estimates of children's exposures to air pollution. Children spend
about 85 percent of their time indoors, 11 percent outdoors, and 4 percent in enclosed transit. The time spent
in some locations and activities, and the time spent near some pollutant sources, differs markedly among individuals
and population subgroups. This study was performed by the University of California, Berkeley.
94-5:
Species
Profiles for Selected Organic Gas Emissions
Regulating the emissions of smog-forming hydrocarbons and other organic gases in California requires
identifying the specific types and amounts of hydrocarbon compounds emitted by various sources. In this study,
profiles of hydrocarbon emissions were developed for selected petroleum production equipment and for
utility and heavy-duty internal combustion engines. Information from this study will be used to improve emissions
inventories for organic gases and to improve modeling analyses used for the development of ozone control strategies.
This study was performed by California Polytechnic State University, San Luis Obispo.
94-4:
Preliminary
Findings of the California Acid Deposition Monitoring Program
This study was initiated to build on the early acid deposition work developed under the Kapiloff Acid Deposition
Act of 1982. The objective was to design a monitoring network to measure parameters needed to estimate the
dry deposition flux of acidic gases and particles. Development of methods for measuring dry deposition resulted
in establishment of the California Dry Deposition Monitoring Network, which consists of ten sites throughout
California. This study describes the network and the measurements made in the first one-and-a-half years
of operation. This study was performed by the Desert Research Institute, University of Nevada, Reno.
94-3:
Indoor
and Personal Exposures to Toxic Air Pollutants
This is the first study to measure residential levels of a large number of pollutants in a non-metropolitan inland
community in California. Results confirm consistently higher indoor than outdoor levels of most volatile organic
compounds (VOCs) in different geographic regions of California; thus outdoor measurements alone are likely to underestimate
individuals' overall exposures to VOCs. Results also indicate that average indoor and personal exposures
to many VOCs are similar in different geographic regions, although some show a trend toward higher levels in the
southern areas of the state. The findings will improve estimates of Californians' exposures to toxic pollutants.
This study was performed by the Research Triangle Institute.
94-2:
Ambient
Ozone Concentrations in Mid-Elevation Conifer Forests in the Sierra Nevada: Status Report.
In response to the need for air quality data, the four-year Sierra Cooperative Ozone Impact Assessment Study (SCOIAS)
was initiated in 1990 to determine the levels to which ozone-sensitive pine tree species at middle elevations
in the Sierra Nevada are exposed to ozone during the growing season (May through October). The SCOIAS consists
of a network of six monitoring stations in five national forests. From June through September 1991, peak hourly
average ozone concentrations were greater than 60 ppb at all sites in the network and frequently exceeded
80 ppb. These levels have been found to cause needle injury in laboratory studies and in forests in southern California.
This study was performed by the University of California, Davis.
94-1:
Several
Sources of Dioxins, PAHs, and Toxic Metals
Emissions of three types of toxic air pollutants -- dioxins, PAHs and heavy metals -- from two waste oil burners
and two drum reconditioning facilities were sampled and analyzed as part of the Air Resources Board's program
to reduce levels of toxic pollutants in the atmosphere. Data from this research will be used in the development
of ARB's toxic emissions control measures. This study was performed by the Midwest Research Institute.
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