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This page updated July 30, 2007.
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Research Notes
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Abstracts of 1990
Research Notes
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NOTE:
Research Notes from 1990 through 1992 are not available on the Web at this time. However, the abstracts are presented
below.
You may request a paper copy of Research Notes listed below by email.
Be sure to include the Note number and title and your name and address.
90-13: Effects of Ozone on Fruit Trees
In a study conducted in California's San Joaquin Valley,
nine fruit tree species were exposed to various levels of ozone in open top field chambers for one growing
season. Trees were grown in purified air, ambient air, and air with twice ambient ozone levels. The species
differed in their sensitivity to air pollution. Five of the nine species exhibited reduced photosynthetic rates
reflected in lower accumulation of starch reserves and smaller trunk cross-sectional areas. This study was
performed by the University of California, Davis.
90-12: Organic Emissions from Vegetation in California's
Central Valley
Hydrocarbon compounds emitted by more than 30 of the
most common agricultural and natural plants found in California's Central Valley were separated and measured. Nearly
50 hydrocarbons were identified, including isoprene, monoterpenes, acetates, alcohols, aldehydes, alkanes,
alkenes, aromatics, esters, ethers, ketones, and sesquiterpenes. All of the plant species tested
emitted some of these hydrocarbons at rates suggesting a potential effect upon air quality. This study was
performed by the University of California, Riverside.
90-11: Air Pollution from Burning Agricultural Wastes
A test system was designed and constructed to simulate
the open burning of agricultural and forestry wastes. The system maintains a steady-state flame front with
continuous waste feed and uses state-of-the-art measurement methods for criteria air pollutants and toxic air
pollutants. Pilot tests, using rice straw as fuel, demonstrated that the system can provide reproducible emissions
data. This study was performed by the University of California, Davis.
90-10: Measuring Polycyclic Aromatic Hydrocarbons (PAHs)
Indoors
Some polycylic aromatic hydrocarbons (PAHs) have been
found to directly or indirectly cause cancer. A sampling system and analytical methods for measuring indoor
concentrations of airborne particles and vapors of PAHs were developed and tested in this study.
The sampling system was reliable, quiet, and small enough to be used in large field studies. The analytical
methods proved satisfactory for PAH vapors but the methods for analyzing PAH particles and nitro-PAHs require
further development. Concurrent samples and analyses of indoor and outdoor concentrations of PAHs were also obtained.
In general, indoor concentrations of PAH vapors were higher than those outdoors. The highest indoor concentrations
of PAHs were found where sources of wood smoke and tobacco smoke were present. Some of the data resulting
from this study are to be used in the ARB's review of PAHs as toxic air contaminants. This study was performed
by Indoor Environmental Engineering.
90-9: Ambient Concentrations of Dioxins in the South
Coast Air Basin
Ambient concentrations of dioxin and furan compounds
(both types are often referred to as dioxins) were measured at several sites in the South Coast Air Basin
(SoCAB). Monitoring sites were chosen to represent the influence of a variety of urban sources and to supply
background measurements. Concentrations of dioxins in the SoCAB were similar to those found in urban areas
in the northeastern and midwestern parts of the United States. Certain dioxin and furan compounds have
been identified as toxic air contaminants and associated with cancer in humans. This study was performed by
ENSR Consulting and Engineering.
90-8: Development and Evaluation of a Polymer Membrane
Preconcentrator
A bench-scale polymeric membrane system was developed
to concentrate dilute gas streams containing low concentrations of solvent vapors. The system removed
about 60 percent of the incoming solvent and generated a "permeate" stream about three times
as concentrated as the original feed stream. At this time, however, the membrane-augmented technology does not
appear to be an economic alternative to conventional carbon adsorption or other classical control options for low
concentration vapor streams. This study was performed by the Radian Corporation.
90-7: Health Risks Due to Diesel Exhaust Particles
and Acids
The toxicity of carbon particles from diesel engine
exhaust in the presence of acids -- a common ambient pollutant mixture in the Los Angeles area -- was evaluated.
Short-term, low-level exposures of rats to various combinations of test atmospheres resulted in accumulation
of soot (carbon) and depression of some immune functions in macrophages, an important cell population involved
in defending lungs from infection. This study was performed by the University of California, Irvine.
90-6: Multi-Day Storage Patterns for Gasoline-Fueled
Vehicles in the South Coast Air Basin
Current inventories of hydrocarbon emissions include
only an estimate of the contribution of evaporative emissions from vehicles stored for periods longer than
one day. Surveys of actual vehicle storage patterns in the South Coast Air Basin found that 25 percent of
privately owned and 37 percent of commercially owned vehicles are stored for more than one day at
a time. This study was performed by the Valley Research Corp.
90-5: An Economic Assessment of Crop Losses Due to
Air Pollution
The economic impact of alternative ambient air quality
standards for ozone on important California field crops was estimated using a regional economic model of production
and sales. Statewide benefits of achieving the alternate standards ranged from a high of $333 million
to a low of $50 million per year. The benefits were divided approximately equally between farmers and consumers
but varied significantly among crops and regions. San Joaquin Valley farmers would receive over ninety percent
of the producers' estimated economic benefits from ozone reductions. This study was performed by the University
of California, Davis.
90-4: Evaporative Emissions from Vehicles on the Road
The Air Resources Board's emissions inventory does
not adequately estimate the magnitude of evaporative emissions from vehicles as they are being driven. To
improve estimates of these emissions, two representative gasoline- fueled vehicles were tested. The limited
test data from this pilot study indicate that for one of the vehicles, the running loss emissions were higher
than the exhaust hydrocarbon emissions as measured by the Federal Test Procedure. This study was performed
by the National Institute for Petroleum and Energy Research.
90-3: The Southern California Air Quality Study
A comprehensive, representative air quality and meteorological
database for the South Coast Air Basin was developed to test, evaluate, and improve elements of air quality simulation
models for oxidants, NOx, PM10, fine particles, visibility, toxic air contaminants, and acidic species. Measurement
methods for PM10, fine particles, acidic species, and important nitrogen and carbon species also were evaluated.
The study enhanced understanding of the relationship between emissions and the spatial and temporal distributions
of pollutants, so that air quality simulation models and air quality control strategies could be improved.
This project was performed by several contractors.
90-2: Characterization of Particulate Emissions from
Selected Sources in
California
Fine particulate (PM10) emissions from 40 sources
in three air basins that have not attained compliance with State standards were collected to relate source
contributions to ambient particulate concentrations. Chemical profiles for seven-particle size categories and total
suspended particulate matter were developed for each of the sources. The 40 sources were then combined
into ten emissions categories. Results will be used to support development of strategies for attainment
of the air quality standards in these areas. This project was performed by OMNI Environmental Services,
Inc.
90-1:
Toxic Emissions from Gasoline-Powered Light-Duty Vehicles
The largest source of motor vehicle emissions in California
is gasoline-powered passenger cars. However, few data are available on toxic air contaminants (TACs) emitted from
these vehicles. This study measured emissions from two popular vehicles. Toxic compounds detected in
the exhaust of the vehicles included benzene, toluene, xylenes, styrene, 1,3-butadiene, aldehydes, ketones,
phenols, halogenated hydrocarbons, and trace metals. The results confirm known emissions of toxic compounds and
provide measurements for some additional compounds. Criteria pollutants were also measured to assess the status
of the vehicles' emissions control systems. This study was performed by Southwest Research Institute. |
Research Notes
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