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Click on the Title of any Research Note
below to see the entire Note.
95-29:
Effects
of Ozone on Ponderosa Pine Seedlings in the Southern Sierra Nevada
This study compared the responses of ponderosa pine seedlings to ozone for one vs. two growing seasons in
the southern Sierra Nevada. Seedlings were exposed to clean air, ambient ozone, or twice-ambient ozone in field
chambers in the Sequoia National Forest. After one season, twice-ambient ozone caused minor physiological
disruption, and did not decrease seedling growth. After two seasons, twice-ambient ozone caused severe physiological
disruption and significant decreases in growth. These results suggest that adverse ozone-caused effects may develop
only after two or more years of exposure. Conclusions reached after one season may not be representative of
responses in the long-term. The study was conducted by the University of California, Riverside.
95-28:
Emissions
from Vehicles Using Low-Oxygenate Gasoline Blends
To measure the emissions impacts of Phase 1 oxygenated gasoline, 13 California-smog-certified vehicles were
tested over three emissions test driving cycles for four oxygenated fuels. In general, hydrocarbon and
carbon monoxide emissions were reduced for the oxygenate blends. NOx emissions were varied. This study was
performed by Automotive Testing Laboratories, Inc.
95-27:
Indirect
Sources: Vehicle Trips to Regional Shopping Centers
Travel characteristics for regional shopping centers were determined and a methodology developed for evaluating
improved methods of travel to these indirect sources of air pollution. A significant portion of the variation
found in travel mode to regional shopping centers can be explained by the amount and regional coverage of public
transit service and the density and proximity of the surrounding land uses. This study was performed by JHK &
Associates.
95-26:
Modeling
of Particles and Hydrocarbons in the South Coast Air Basin
Data collected during the Southern California Air Quality Study were analyzed using the chemical mass balance
receptor model to identify the main sources of particulate matter and nonmethane hydrocarbons in the South
Coast Air Basin. The principal source of directly emitted particulate matter at the eastern sites in the summer
was geological material, mostly road dust, followed by motor vehicle emissions. In the fall, and at other
sites during the summer, motor vehicles were the largest source contributing to particulate matter. Motor
vehicle exhaust was the main contributor to nonmethane hydrocarbon concentrations, with lesser contributions
from liquid gasoline and gasoline vapor. This study was performed by the Desert Research Institute.
95-25:
Effects
of Aquatic Acidity on Sierra Nevada Amphibians
Laboratory dose-response studies to determine the sensitivity of aquatic-breeding Sierra Nevada amphibians
to low pH and elevated aluminum content of water showed that, at the pH levels and aluminum concentrations
tested, survival rates were not affected. However, sublethal effects at pH as high as 5.25 or in the presence
of elevated aluminum could represent long-term threats to these amphibian populations. This study was performed
by the University of California, Los Angeles.
95-24:
Leaf
Biomass as a Source of Air Pollution
To update the ARB's San Joaquin Valley Air Basin emissions inventory, emissions of organic gases from conifer
forests on the western slopes of the Sierra Nevada were estimated and the variability of biomass across
plots determined. Elevation, the most consistent predictor of conifer forest biomass, explains about 31 percent
of the variability across plots. The data are available to the public in a GIS-based map, in lookup tables, and
on computer diskette. This study was performed by the University of California, Riverside.
95-23:
Analysis
of PAH Mixtures by Laser-Enhanced Mass Spectrometry
A new technique -- laser desorption/laser photoionization mass spectrometry -- was shown to be effective in the
analysis of polycyclic aromatic hydrocarbons present in mixtures of known compounds and in rice smoke soot. This
technique eliminates the extraction and separation steps required by conventional analytical methods, permitting
analysis of mixtures and greatly reducing the amount of time required for sampling and analysis. This work was
performed by the University of California, Davis.
95-22:
Employee
Responses to Vehicle Trip Reduction Incentives
The effectiveness and costs of employer-sponsored trip-reduction incentives were collected and analyzed. From this
information, predictive software was developed to allow employers and transportation plan reviewers to determine
the likely effectiveness of proposed incentives programs. The most effective incentives were guaranteed ride home,
vanpools, preferential parking, transportation allowance, and carpool subsidies. The annual total cost of all incentives
adopted by California companies averaged $13,000 per employer. This study was performed by COMSIS Corporation.
95-21:
Pleasure
Craft Emissions Inventory
An improved, comprehensive emissions inventory was developed for pleasure craft operations at state and county
levels. Improvements include new and complete data and incorporation of recent industry-developed emissions
factors for more engines than in previous inventories. This study was performed by Systems Applications International.
95-20:
Properties
of Architectural and Industrial Maintenance Coatings
Key chemical, physical, performance, and application properties of commercially available and recently developed
architectural and industrial maintenance coatings were measured. The results will be used in the determination
of reasonably available control technology and best available retrofit control technology for these coatings for
areas of California projecting attainment of the ozone standard in the near future. This study was undertaken by
Harlan Associates, Inc.
95-19:
Effects
of Increased Highway Capacity on Travel Behavior
In this study of actual and estimated travel behavior, investigators determined travellers' preferences as to how
they would respond to changes in travel time and cost as a result of increased highway capacity. The study recommends
adjusting transportation models used for air quality impacts to reflect highway expansion impacts if trip
time savings are greater than five minutes. This study was performed by Dowling Associates.
95-18:
Goals
and Strategies for Indirect-Source Control Programs
Transportation-related land use strategies are identified that can be used by builders, local governments, planning
organizations, and air districts to reduce community-wide vehicle use and emissions from indirect sources.
Information on implementation mechanisms for local governments is presented, and reasonably attainable performance goals
for urban, suburban, and exurban communities are suggested. This study was conducted by JHK and Associates.
95-17:
Atmospheric
Deposition to Agricultural Soil
This study was performed to determine whether atmospheric depositions to the nutritional environment of certain
of California's commercial crops pose a threat to yield or quality and to what extent depositions might contribute
to crop nutrient environments. Aerometric data were used to calculate atmospheric inputs of nitrogen, sulfur, and
calcium to crops and to estimate regional-scale deposition rates for selected agricultural production areas. Only
nitrogen appeared to provide a potential for excessive nutrient loading to California's agricultural soils. This
study was performed by the University of California, Riverside.
95-16:
The
Economic Impacts of Alternatives to Crop Residue Burning
The ARB conducted this research to identify potential alternatives to open-field burning of agricultural residues
in the Sacramento Valley of California, to evaluate the economic viability of alternative uses of residues, and
to quantify the financial and economic impacts of the adoption of these alternatives. The study concludes that,
where a burn restriction policy does not result in a significant yield reduction, adoption of non-burn disposal
methods would have modest impacts on most rice, almond, walnut, and wheat growers and minimal impact on the regional
economy. The most economically viable alternative disposal methods for current economic conditions are soil incorporation
for rice and wheat and offsite use for almond and walnut. This study was performed by Foster Associates, Inc.
95-15:
Architectural
Coatings and Aerosol Paints: Usage and Emissions
During the application of aerosol paints and architectural coatings, significant quantities of solvents are
emitted into the atmosphere. These important emissions contribute to the formation of ground-level ozone, or smog.
For this study, data from ARB surveys on sales of aerosol paint and architectural coatings were summarized
and analyzed, and theoretical emissions from solvent-borne architectural coatings were calculated. The investigators
estimated that roughly 20 to 30 percent of these emissions could be eliminated by implementation of a control measure
proposed in 1989. The research was performed by the Battelle Memorial Institute.
95-14:
Novel
Lidar Technology for Remote Measurements of Ozone Concentrations
A recently developed ground-based instrument employing lidar technology was evaluated and found to accurately
measure ozone concentrations at altitudes of up to 3,000 meters. The novel approach used in this
study provides true vertical distributions of ozone concentrations aloft and better temporal coverage of these
distributions than do other, more common methods such as aircraft and ozonesonde (balloon) measurements. The
ozone and aerosol measurements from this study, in conjunction with temperature and wind measurements,
will be used to better characterize atmospheric conditions aloft and the processes involved in the formation
of the unhealthful ozone concentrations routinely observe in California by traditional ground-based monitors.
This study was performed for the ARB by the Environmental Technology Laboratory of the National Oceanic and Atmospheric
Administration.
95-13:
VOC
and NOx Speciation for Gas-Fired Stationary Combustion Sources
Emissions from gas-fired stationary sources were speciated for volatile organic compounds (VOCs), nitrogen
oxide (NOx) species, and selected air tonics. Eight types of sources using various types of fuel and several different
types of NOx control devices were tested. Twenty-one of the 100 substances tested for were detected. Methane was
the most abundant VOC in the exhaust gases from each source. Reciprocating internal combustion engines produced
the highest levels of total VOC emissions and the greatest number of occurrences of the emissions. Internal combustion
engines also showed the highest NOx concentrations. This study was performed by Energy and Environmental Research
Corporation.
95-12:
Effects
of Compressed Work Week on Employee Travel
The objective of this study was to estimate the net trip and mileage benefits of the compressed work week,
taking into account the possibility that employees engage in driving activities on their days off. Results
showed that employees using a compressed work week take 0.5 to 0.8 fewer trips and travel 13 to 20 fewer
miles per week compared to employees using a regular five-day work week. This study was performed by the University
of Southern California.
95-11:
Neurological
Effects of Low-Level Methanol Exposure
Neurobehavioral, neurophysiological, and visual tests were used to assess neurotoxic effects of methanol inhalation.
The results suggest that neurotoxic effects do not occur, either in a normal population or in a subpopulation
having a propensity for folic acid deficiency, upon exposure to the current industrial methanol limit of 200
ppm. However, possible effects were reported in the normal population when test outcomes were adjusted for factors
such as alcohol consumption and smoking. This study suggests a need for further investigation into the
health effects of methanol exposure, but does not indicate any reason for concern. This study was performed
by the University of California at San Francisco.
95-10:
Ozone
Exposure and Cellular Activity Related to Lung Fibrosis
Collagen deposition in the lungs of animals after chronic ozone exposure indicates that ozone may directly
or indirectly stimulate certain cellular processes related to restructuring of the lung, possibly leading
to fibrosis of lung tissue. This pilot-level study was performed to determine whether ozone exposure can induce
activation of these cells in humans. Exposures were found to result in increased levels of an inflammatory protein
associated with lung fibrosis, implying that ozone may promote secretion of certain pro-fibrotic growth factors.
Other measures of cellular changes related to fibrosis were not found to increase following ozone exposure.
This study was performed by the University of California, San Francisco.
95-9:
On-Road
Motor Vehicle Activity
This work provides data to be used in improving several segments of the database that is used to calculate
the Air Resources Board's mobile source emissions inventory. The types of data collected were vehicle registration
by model and year, by county; mileage accumulation rates for vehicles; and urban bus vehicle miles traveled, by
speed. In addition, methodologies for routine updating of these database segments were developed so that
motor vehicle emissions inventories can be revised more efficiently. The database will also be of value to
agencies that are developing responses to the implementation plan for attainment of Federal air quality standards.
The work was performed by Valley Research Corporation.
95-8:
Data
in Support of Direct Free-Radical Measurements in Polluted Urban Air
This study provides measurements of atmospheric compounds
with ozone-forming potential to be used in prediction and modeling of atmospheric free-radical concentrations.
Comparison of these measurements to those taken for the Southern California Air Quality Study (SCAQS) reveals that
today's photochemical atmosphere is similar to that of 1987. There were also significant differences in the
findings of the two studies. For example, heavy volatile oxygenated organic gases, ubiquitous during the SCAQS,
were not found to contribute significantly to ozone-forming potential. The ratio of carbon monoxide to nitrogen
oxides, used to evaluate the accuracy of ARB's emissions inventory, was also significantly lower than that observed
during the SCAQS. This study was performed by Unisearch Associates.
95-7:
Effects
of Ozone and Acidic Deposition on Gas Exchange Responses in Ponderosa Pine
In California, species of pine that are sensitive to air pollution are exposed to harmful levels of ozone
and to elevated levels of nitrogen-derived pollutants in acidic deposition. Both of these pollutants can disrupt
physiological processes such as gas exchange by leaves. The objectives of the two studies on which this Research
Note is based were to characterize the effects of ozone, in combination with acidic deposition, on growth and physiological
responses in mature branches and seedlings of ponderosa pine grown under conditions representative of north
central California. Exposure to twice-ambient ozone caused moderate reductions in photosynthesis and stomatal
conductance in seedlings and mature branches. Exposure to acidic rain had no consistent impact. The results indicate
that exposure to elevated levels of ozone inhibits pine tree gas exchange rates throughout the growing season.
After several years of exposure, this decrease in gas exchange rates could diminish the ecological and economic
value of forest resources. While acid rain alone had no effect after one year of exposure, its long-term effect,
in combination with ozone, is not well characterized. The studies were performed by the University of California,
Berkeley, and the U.S.D.A. Forest Service.
95-6:
Particle-Size
Test Methods for Sampling High-Temperature and High-Moisture Sources
Source sampling equipment and procedures were developed for determining the particle size distribution of effluents
that are high in temperature or high in moisture. Sources of these types of effluent may be subject to regulation,
but are difficult or impossible to test. Suitable methods for sampling these sources are described in this study,
which was performed by Southern Research Institute.
95-5:
Transfer
of Toxic Air Pollutants Among Environmental Media
The literature concerning seven toxic air pollutants was critically reviewed to obtain estimates of factors affecting
the transfer of these substances between media to which humans are exposed, or which are involved in exposure.
Estimates were provided where data were deficient. The pollutants reviewed are representative of chemical classes
frequently encountered as air pollutants that are especially toxic. The study was performed by the University
of California, Los Angeles.
95-4:
Air
Pollution Mitigation Measures for Airport-Related Activities
This research identifies methods that can be used by airport project planners to evaluate the effectiveness
of proposed measures in reducing emissions from aircraft and airport-related activities. The report for this project
is a useful introduction to emissions inventory development and mitigation for airports, by airport size and type.
This study was performed by Energy and Environmental Analysis.
95-3:
The
Mutagenicity of Vapor-Phase Diesel Exhaust is Greater than Expected
A bioassay-directed chemical analysis procedure was adapted for use in the identification and quantification
of mutagens occurring in the vapor phase of diesel engine exhaust. Application of this method to exhaust emissions
from a heavy-duty diesel vehicle showed that the mutagenicity of the vapor phase is about as high as that of
the particle-associated material. This work was performed by the University of California, Davis.
95-2:
What
is the Fate of Airborne Toxic Emissions?
The Air Resources Board funded this study to provide guidance for developing priorities for its toxic
air contaminant (TAC) regulatory program. The literature was reviewed to obtain quantitative information on
the atmospheric chemistry of several TACs. Atmospheric lifetimes were estimated for 23 TACs and their atmospheric
transformation or removal discussed. Acrolein is discussed as an example of toxic compounds that are formed in
the air. The atmospheric formation of three TACs is also discussed. In an experimental study, gasoline
and terpenes, two major sources of ambient hydrocarbons, were found not to be important sources
of ambient mutagenicity in California. This study was performed by the University of California,
Riverside.
95-1:
Respiratory
Disease and Cancer in Non-Smokers Increase with Higher Long-Term Air Pollution Exposures
A team of researchers, studying a large sample of non-smokers, investigated associations between exposures
to long-term ambient concentrations of seven air pollutants and the occurrence and severity of respiratory
diseases and the occurrence of cancer. Numerous factors modifying the effects of air pollution exposures were
accounted for. Estimated exposures to particulate pollutants were significantly associated with occurrence
and increasing severity of several respiratory conditions in the whole sample and with occurrence of
cancer in women. Estimated exposures to ozone were significantly associated with occurrence and increasing
severity of asthma in men. The results of the study provide some of the most comprehensive information yet about
the adverse health effects of long- term ambient concentrations of these pollutants. The results of this study
will be useful in future revisions of air quality standards. This study was conducted by the Loma Linda Center
for Health Promotion, Loma Linda University.
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