Research Screening Committee Meeting
December 17, 2001

This page updated June 28, 2005.

State of California


Research Screening Committee Meeting

Cal/EPA Headquarters Building
1001 I Street
Conference Room 530
Sacramento, CA 95814
(916) 445-0753

December 17, 2001
9:30 a.m.



"Keeping Tahoe Blue through Ambient Air Quality Modeling: Aircraft and Boat Measurements of Air Quality and Meteorology Over Lake Tahoe," University of California, Davis, $133,382
  To protect Lake Tahoe's famous clarity, the Tahoe Regional Planning Agency (TRPA) has determined it is necessary to understand how the lake's nutrient balance is being enriched so they can reduce the enrichment of nutrients including nitrogen and phosphorous to the lake. Through dry and wet deposition, phosphorus and nitrogen from the atmosphere may enrich the nutrient balance in the lake. To understand the effect of air pollution on Lake Tahoe, the Board's staff will conduct Lake Tahoe air quality modeling exercises. This proposal by the University of California at Davis will provide input and validation databases for these modeling exercises by developing and delivering vertical profiles. These will include wind and relative humidity, aerosol concentrations (less than 0.3 and between 0.3 and 3 micrometer in equivalent optical diameter), and concentrations of ozone, nitric oxide and the total reactive nitrogen species (~1 ppbv detection limits). Gas phase ammonia and nitric acid and particulate phosphorous, nitrate and ammonium will be collected through an annular denuder-filter system. In the spring, summer and fall, these instruments will be flown on board a Cessna airplane flown over and across Lake Tahoe. In the winter, these instruments will be installed in a research vessel which will make dedicated cruises on the lake. The results of this proposal will be used to validate the ARB's modeling exercises, which will characterize the amount and sources of nitrogen and phosphorus deposited from the atmosphere to the lake. This project will gather the information the ARB needs to help TRPA set standards that will protect Lake Tahoe's clarity.


"Keeping Tahoe Blue: Quantifying Atmospheric Nitrogen Oxides in the Lake Tahoe Basin," University of California, Berkeley, $175,036
  To protect Lake Tahoe's famous clarity, the Tahoe Regional Planning Agency (TRPA) has determined it is necessary to understand how the lake's nutrient balance is being enriched so they can reduce the enrichment of nutrients including nitrogen and phosphorous to the lake. Through dry and wet deposition, atmospheric nitrogen oxides including nitrogen oxides, nitric acid and organic nitrates may be contributing to increases in the nitrogen available as a nutrient in the lake. Sources of atmospheric nitrogen oxides may include emissions from forest fires, transported pollutants from the Sacramento Valley and the Bay Area, and direct emissions within the Basin from vehicles and home wood burning as well as natural sources. To understand the contribution of atmospheric sources to enrichment of nitrogen in the lake, this proposal will measure nitric acid, nitrogen dioxide, and two separate classes of organic nitrates: total peroxynitrates (such as PAN), and total organic nitrates at Lake Tahoe using a state-of-the-art thermal dissociation laser induced fluorescence instrument. These measurements, along with other data collected by ARB, will be used by the University of California at Berkeley to quantify the different sources of atmospheric nitrogen in the Tahoe basin. These analyses will also focus on understanding the rate at which different classes of nitrogen oxides are deposited to the different types of surfaces (trees, snow, soils, the lake itself) in the basin. The measurements will also be used by the ARB as inputs for initialization and evaluation of their Tahoe Basin Air Quality Model. These model's combined with observations will be used by the ARB to evaluate the quantity of atmospheric nitrogen deposited to the lake. This project will gather the information the ARB needs to help TRPA set standards that will protect the clarity of the lake.


"Determination of Asbestos Content of Current Automotive Dry Friction Materials, and the Potential Contribution of Asbestos to Particulate Matter Derived from Brake Wear," California Department of Health Services, $99,969
  In 1991, the U.S. EPA allowed the use of asbestos in disc brake pads, drum brake linings, and clutch facings. Recent reports show that asbestos is widely used in after-market brakes. To determine the need to control emissions of this carcinogen, ARB staff need to estimate the possible extent of asbestos emissions due to brake wear from vehicles used in California. First, the contractor will develop an inventory of asbestos contained in brakes, and also develop an asbestos analysis scheme. Next, the contractor will institute a sampling program at brake repair shops focusing on brakes with high asbestos content, and perform laboratory analysis of the brakes and brake-wear dust. Finally, the contractor will characterize the form, size, and levels of asbestos present in brake dust. The results should help the ARB assess the potential health threat from public exposure to asbestos emissions generated from brake wear and thereby determine the need for regulatory control.


"Incidence of Malfunctions and Tampering in Heavy-Duty Vehicles," University of California, Riverside, $199,103
  Insufficient data is available on the number of component malfunctions or tampering with in-use heavy-duty vehicles. This data is needed to estimate the in-use fleet emissions and to identify the most significant occurrences. The objective of this project is to estimate the incidence of malfunctions and tampering that can increase PM or NOX emissions from on-road heavy-duty diesel vehicles. According to old information, such faults have been common among on-road vehicles and can seriously augment emissions. The contractor will obtain data from several different sources, including a literature review, warranty information, analysis of existing data from the ARB's heavy-duty
on-road inspection program, surveys of records at repair facilities, and road-side inspections to be carried out in concert with staff from Enforcement Division. Another project, sponsored by the Coordinating Research Council, will measure the emission effects of many of the malfunctions whose occurrence rates will be estimated in the
ARB-sponsored project. ARB will use the information from both projects to improve the emissions inventories for diesel vehicles and to design an inspection-and-maintenance program.


"Improving Accuracy of Ship Emissions Estimates for Inventory and Modeling Methodologies," University of Delaware, $50,000
  The current ships are primarily powered by diesel engines and are a significant source of air pollution in heavily traveled port regions such as coastlines as well as on a global scale. However, ship emissions have not been addressed in a coherent manner in any existing inventories and methodologies used. To improve our understanding of ship emissions impacts and address some of the most significant questions, the National Oceanic and Atmospheric Administration (NOAA) has launched a larger scientific study of air pollution transport, called International Transport and Chemical Transformation 2002 (ITCT 2k2), scheduled for the Spring of 2002.
  As part of this field study, the proposed project will augment the planned atmospheric monitoring of ship plumes by aircraft and other means. It will perform analyses to help interpret ITCT-related field observations. Specific tasks of this project include (1) development of a spreadsheet model to estimate each vessel's emissions under current operating conditions, (2) prediction of the emissions from vessels operating within the study area, and (3) comparison of emissions predictions with monitoring results and concurrent ship-stack plume observations for predetermined vessels. The methodologies developed in this research will contribute to ARB's efforts to establish accurate ship emissions inventories and improved modeling of their impacts.


"Health Benefits of Incremental Improvements in Air Quality," $200,000
  This Request for Proposal is designed to answer questions regarding the relationship between improvements in air quality and possible improved health outcomes. Air quality has improved in the South Coast Air Basin over the past 30 years. An assumption has been made that this improvement in air quality should result in measurable improved health outcomes for the public, however no statistical analysis has been performed to test this assumption. The proposals requested will evaluate the collection of available ambient air quality data for the South Coast Air Basin and will generate an exposure database for the Basin using U.S. Census data. The Census data will be used to incorporate demographic factors such as age, sex, race, access to health care, employment, and average family income into the analysis of various disease and health care outcomes by type, race, age, sex and other demographic factors at Census tracks in the South Coast Air Basin and will evaluate specific air pollutants with respect to health outcomes. The cost of reduction in emissions for the South Coast Air Basin should be offset by the cost saving to the public from reduced health outcomes as a result of the improved air quality.


"Historical-Scale Biochemical Markers of Oxidant Injury and Exposure in Pines," University of California, Davis, $145,075, Contract No. 97-309
  Due to the precursor sources and transport dynamics of California, injury to forests has been of concern in regard to photochemical oxidant effects for over 40 years. The objective of this project was to conduct biochemical analyses on increment cores from pine trees in California that have been exposed to different concentrations of ambient ozone. Because long-term ozone impacts on tree growth occur over multi-decade timeframes, the biochemical basis for growth declines can only be determined through analyses of tree-wood. In Phase I, tree cores from the San Bernardino Mountains were examined. Analyses of 50-biochemical markers were conducted using pyrolysis gas chromatography-mass spectrometry to evaluate wood samples from pre- and post-1945 growth periods. Trees exhibiting ozone damage were found to have an H:G lignin ratio that increased, and a stilbene level that decreased in post-1945 wood relative to wood formed pre-1945. In Phase II, tree cores from the Sierra Nevada were examined. Responses were consistent with the results found for ozone-damaged and undamaged pines in Phase I. At the southernmost sites in the Sierra Nevada, where ambient ozone levels are highest, H:G lignin ratios were highest and stilbene levels lowest relative to trees in northern and central sites. The results of this study suggest that selected biochemical markers in wood may qualitatively corroborate visual analyses of foliar injury in native pines. Further work is needed to affirm the findings observed in this project, that are based on a relatively small number of tree cores.


"Thermodynamics of Organic Atmospheric Aerosols," California Institute of Technology, $299,122,
Contract 98-314 
  Particulate matter has been implicated in human morbidity and mortality and many researchers suspect that the organic fraction is more potent in terms of adverse health effects. It is now well recognized that primary and secondary organic matter contribute significantly to the particulate burden in the urban atmosphere. The earliest attempts to model the organic fraction of the ambient aerosol assumed that primary emitted organic compounds are inert, totally nonvolatile, and do not interact with other species in the aerosol. The results of more recent studies show that many primary organics are semi-volatile, and interact with other species in the aerosol or gas phases.
  This air quality-modeling project includes, for the first time, treatment of inorganic and organic components simultaneously. It addresses the effects of organic constituents on the hygroscopic behavior of aerosols as well as the gas-aerosol equilibrium of secondary organic aerosol components. The basic thermodynamics was formulated based on information in the literature and on data from detailed outdoor smog chamber experiments at Caltech that were incorporated into the current state-of-the-art inorganic equilibrium model known as "SCAPE2." The sensitivity of the model to variations in key atmospheric parameters was also investigated, as was issues of computational efficiency. The two three-dimensional models were tested individually on two episodes in the South Coast Air Basin: Models-3 / CMAQ on the August 27-28, 1987 SCAQS episode and CIT on the September 8, 1993 episode. The two components of secondary organic aerosol (SOA), hydrophilic and hydrophobic, were predicted to exhibit quite different behavior. The formation of aqueous-phase SOA was probably limited by partitioning during the day; higher concentrations were predicted at night when relative humidity is high. Despite the formation of secondary species, primary organic carbon represents the dominant component of organic carbon in the South Coast Air Basin. The results of this project are absolutely crucial to our ability to model both the inorganic and organic fractions of PM2.5 and therefore to construct comprehensive gas/aerosol photochemical models for SIP applications. Information of this type plays a vital role in the design of emissions control programs that reduce airborne particle concentrations in California.


"Determination of Non-registration Rates for On-Road Vehicles in California," University of California, Riverside, $210,000, Contract No. 99-318
  Accurate estimation of the contributions of on-road motor vehicles to the emissions inventory requires estimation of the actual number of vehicles in use. In addition to the known population of registered vehicles, there are an unknown number of unregistered vehicles. To better understand the population and use characteristics of the
in-use California fleet, the College of Engineering, Center for Environmental Research and Technology
(CE-CERT) completed a statewide survey of vehicle registration. This study estimated percentage of registered vehicles, unregistered vehicles, and out-of-state vehicles. In total, digital photographic records were obtained for over 120,000 vehicles, including vehicles in every county in the state. For each survey target, vehicle make, model, license plate number, registration status and date, time, location (city, county, zip code), and description of site were obtained. This represents the most comprehensive study of vehicle non-registration rates to date and encompasses all regions in California. An estimate of approximately 3.4 percent for the vehicle non-registration rate was obtained in the field study in California. This included vehicles unregistered for less than three months (2.4 percent), vehicles unregistered between three months and two years (1 percent), and chronic non-registration for more than two years (0.03 percent). The unregistered vehicle population had a significant contribution from older model vehicles in comparison with the overall fleet. These results are consistent with unregistered vehicles being older and high emitter vehicles that would make a disproportionate contribution to the emissions inventory.


"Ambient Ozone Patterns and Ozone Injury Risk to Ponderosa and Jeffrey Pines in the Sierra Nevada," USDA, Forest Service, $77,569, Contract 98-305 
  The objectives of the project were: (1) to deploy a network of passive samplers to collect ambient ozone data throughout the Sierra Nevada; (2) to produce mapped distributions of ambient ozone using the data from active monitors and passive ozone samplers; and (3) to develop spatial estimates of high ozone risk of needle injury to ponderosa and Jeffrey pine. The present project involved collecting air quality and tree response data in National Forests and Parks throughout the Sierra Nevada in summer 1999. Ozone data were collected for ten two-week periods, using 94 passive samplers and nine active monitors. Tree injury amounts were evaluated in 25-plots at the end of summer. Spatial analyses of the ozone data were performed by three teams of analysts to generate maps of summer ozone concentration in the Sierra Nevada, although only two analyses have been released to date. The maps generated by the two analytical teams yielded similar results with respect to average summertime ozone levels in the Sierra Nevada from 220 to 2,800 m elevation. It was postulated that reliable estimates of ambient ozone were developed for 94 percent of the study area (i.e., 488 km2 out of 514 km2), and improvements could be achieved through the incorporation of additional variables in the interpolation model, and / or deploying a larger network of passive samplers. Estimates of total summertime ozone exposure (SUM0) were calculated to identify areas of highest tree injury risk. Assessments of ozone injury were generally consistent with projected levels of ozone exposure risk on the western slope of the Sierra Nevada.

Research Screening Committee