Research Screening Committee Meeting
April 26, 2002

This page updated June 28, 2005.

State of California
AIR RESOURCES BOARD

BOARD MEMBERS' ADVANCE AGENDA

Research Screening Committee Meeting

Cal/EPA Headquarters Building
1001 I Street
Conference Room 550
Sacramento, CA 95814
(916) 445-0753

April 26, 2002
9:30 a.m.

REQUEST FOR PROPOSAL RESPONSE

1.

"Alternatives to Automotive Consumer Products that use Volatile Organic Compounds (VOC) and / or Chlorinated Organic Compound Solvents," $200,000, Proposal No. 2518-225
  About 4.5 million aerosol spray cans and spray bottles of automotive cleaning and degreasing products are sold in California each year. These automotive products are estimated to emit 16.4 tons per day (tpd) of volatile organic compounds (VOC)s and 5.2 tpd of chlorinated toxic air contaminants (TACs). Automotive products include brake cleaners, carburetor cleaners, engine degreasers, and general-purpose degreasers. Screening tests will be used to identify the most promising near-zero-VOC alternatives to traditional automobile consumer products. These alternatives will be evaluated and compared to the currently used automotive products in automotive maintenance and repair facilities. The ARB has statewide responsibilities to reduce TAC emissions through its Air Toxics Program, and to reduce VOC emissions through its Consumer Products Program. The work proposed in this RFP could lead to feasible alternative formulations that would reduce emissions of VOCs and TACs from automotive products. Therefore, the proposed research would support two important ARB programs.
INTERAGENCY PROPOSALS

2.

"Health Benefits of Incremental Improvements in Air Quality," University of California, Berkeley, $296,261, Proposal No. 2519-225
  This pilot project 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 project will collect 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 as a function of air pollution levels. 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.

3.

"Design and Construction of an Engine Testing Facility for Controlled Human Exposure Studies," University of California, San Francisco, $350,000, Proposal No. 2511-224
  Several recent nasal instillation studies suggest that diesel exhaust particulate matter (PM) may exacerbate
pre-existing allergies, and may facilitate development of new allergies. However, there is very little published information on effects of diesel exhaust exposure in human subjects because no exposure facilities exist anywhere. This proposal has two objectives: (1) design, construct and test an engine dynamometer system for generation of diesel exhaust for use in a human exposure chamber, and (2) design a human exposure chamber for use with the exhaust generation system. The dynamometer system will be capable of operating with multiple types of engines (i.e., diesel, CNG or gasoline). Funding of this facility will make it possible to perform human studies that have been impossible to date. The results of this research will provide the Board with scientific information on biological mechanisms of engine emission health effects, the role of engine emissions in allergy and asthma, and the acute effects of engine exhaust. The facility will also allow comparisons between the acute health effects of various fuel and engine controls. Availability of the facility will likely attract funding from other sources interested in health effects of engine emissions, such as U.S. EPA, the National Institutes of Health, and the Health Effects Institute.
SOLE SOURCE PROPOSAL

4.

"Initial Exploration of Advanced Data Analysis Methods to Assist in Air Quality Management," Clarkson University, $40,440, Proposal No. 2520-225
  In-house research by ARB has used the chemistry of large dust events to identify "typical" Asian transport events recorded in routine particulate matter (PM) samples and to analyze those events to estimate the frequency and intensity of PM transport from Asia to North America. This project would extend that work with an analysis of existing PM data to analyze combustion products accompanying the dust to link them to general source categories (e.g., coal, oil, biomass, motor vehicles). Such data will permit ARB to better quantify Asian influences on California air quality and to track changes due to Asian economic growth and/or implementation of controls on Asian sources. The second component of the project will analyze both filter and single-particle data from southern California to attempt to distinguish gasoline and diesel PM in ambient air.
CONTRACT AUGMENTATION

5.

"Collection of Evaporative Emissions Data from Off-Road Equipment," Automotive Testing Laboratories, $24,968.43, Contract No. 00-315
  This contract would be augmented by about $25,000 to collect information needed in support of an upcoming regulatory proposal. The work to be performed would be a direct extension of the tasks already performed in the original contract, whose budget has been expended. Automotive Testing Laboratories (ATL) would measure diurnal and hot-soak emissions from six pieces of equipment and running loss from a mower. The tests would be performed before and after the retrofit of sealed tanks that ARB Staff plan to propose as regulatory requirements.
REQUEST FOR PROPOSALS

6.

"Development of Low Cost, User Friendly Air Monitoring Devices," $1,500,000
  Routine air quality measurement devices are expensive and typically require skilled technicians to assure proper operation. Additionally, levels of some air pollutants can vary substantially over a given region, requiring multiple measurements to accurately measure the levels to which the population is exposed. There is a demand for low
cost, easy-to-use devices for deployment indoors and outdoors in communities where disproportionate impacts from air pollution are suspected. There is also a need for portable, economical, devices that can be used for
short-term measurements in locales under consideration for siting of power plants and other sources, so that the potential impacts of proposed plants can be better understood and mitigated.
  The objective of this Request for Proposals is to develop at least two, low cost, user-friendly air pollutant measurement devices that can be used by homeowners, communities, local governments, and others to readily assess air quality in many locales in their area. Devices that measure particulate pollutants and / or toxic air contaminants, and that have good potential for future commercialization, are of greatest interest. It is anticipated that two new or newly-adapted devices will be developed in two to three years under this project; assistance with future commercialization where appropriate can be achieved through our Innovative Clean Air Technologies Program. These devices will be used to meet the needs of members of the public, communities and others for quick, economical measurements of air quality.
INTERIM REPORT

7.

"The Physical and Chemical Characteristics of Ultrafine and Nanoparticle Particulate Matter Emissions from Gasoline and Diesel On-Road Motor Vehicles: Phase I - Scoping Study," University of California, Davis, $501,874, Contract No. 98-335
  Recently, there has been heightened concern about the emission of ultrafine (<0.1mm) and smaller particles from internal combustion engine (ICE) sources. While not very significant by mass, ultrafine particles account for the majority of the number of particles emitted by ICE sources. Diesel and gasoline engines are known emitters of ultrafine particles. Currently, all standards (ambient and engine) are mass-based. However, some evidence now links adverse health effects to particle number (and/or surface area) more strongly than to mass. Recent observations by researchers in the U.S. and abroad support a strong correlation between local traffic patterns and ambient particle number levels. This project was designed to characterize the ultrafine particles found near roadways. The project is divided into two phases: 1) A Phase I proof-of-concept study to characterize ultrafine particles at a single test site, and 2) Phase II, which is a more comprehensive study to determine the physical and chemical makeup of ultrafine particles due to roadway traffic on different types of roads. This interim report presents the results for Phase I as required by the RSC for consideration of deployment of the full Phase II roadside study. Phase I found that average particle number levels measured downwind of a Northern California freeway were at least one order of magnitude greater than background concentrations (defined upwind of the freeway). However, particle numbers were not significantly correlated to traffic volume.
FINAL REPORTS

8.

"A Critical Review of the Particulate Matter Toxicology Literature for Senate Bill 25 Review of the Particulate Matter Standard," Kent Pinkerton, $31,500, Contract No. 00-327
  California is currently reviewing its Ambient Air Quality Standards for particulate matter (PM) and sulfate in light of the requirements set forth by the Children's Environmental Health Protection Act (SB 25 - Escutia, 1999). Based on available evidence, which draws mainly from epidemiological studies, the current PM and sulfate standards were deemed inadequate for the protection of public health, including that of infants and children. In support of the PM and sulfate standard review, the objectives of this project were the following: 1) prepare a focused review of the PM toxicology literature; 2) provide an overview of what information from animal toxicology may be useful in the standard setting process; 3) examine the toxicology of fine versus coarse particles; and 4) review the differences among children, adults, and compromised individuals with regard to adverse health effects and toxicology of PM exposure. Overall, the review of the toxicology literature provides support for the conclusion that different components of PM, acting by different biological mechanisms, cause a variety of short-term health effects in animals and humans. However, it is clear that much more work is needed to understand the precise mechanisms by which components of PM exert their toxicological effects.

9.

"Particulate Air Pollution and Morbidity in the California Central Valley: a High Particulate Pollution Region," Kaiser Foundation Research Institute, $264,654, Contract No. 97-303
  Particulate air pollution and its continued impact on public health is a major focus of current research efforts. Understanding the impact of particulate matter (PM) pollution is important to guide future regulations to protect sensitive populations at risk. Assigning specific health effects to individual air pollutants is a difficult task and few studies have examined the effects of different size fractions and chemical components of PM. This study was designed to address these issues and examine the relationship between PM and other pollutants and acute cardiopulmonary morbidity. This investigation examined the relationship of daily ambient measures for PM2.5, PM10, the coarse fraction of PM, selected chemical components of PM, NO2, and ozone with daily hospital admissions and emergency room visits for cardiopulmonary disease. The study population used was the Kaiser Permanente, Northern California membership residing in the San Joaquin Valley of California from 1996 through 2000. Strong positive associations were found between PM10, PM2.5, and carbon monoxide and acute and chronic respiratory hospitalizations in Kaiser Permanente members. Studies such as these can provide the information needed to determine levels at which air pollutants contribute to adverse health impacts and will aid the ARB in setting ambient air quality standards to protect the public health.

10.

"Health Effects of PM Components on Sensitive Animal Models," University of California, Irvine, $439,890, Contract No. 96-311
  The primary goal of this study, which was part of a collaborative program between the University of California, Davis and the University of California, Irvine was to examine how the physical and chemical characteristics of particles affected the cardiopulmonary systems in sensitive animal models. A model of California particles consisting of ammonium nitrate and elemental carbon was used in this exposure study. These particles represent a major fraction of ambient PM2.5. These particles are often in the presence of ozone, and therefore ozone was included in the atmospheres. This investigation focused on determining the importance of particle size in eliciting responses in young adult and old (senescent) Fischer 344 rats. The particle size ranges used in the exposures were identified as ultrafine (dp £ 0.2 mm), fine (0.5mm £ dp £ 1.0 mm) and coarse (1.0 mm £ dp £ 3.0 mm). Lung injury and heart responses were measured in the exposed animals using measurements of blood pressure, heart rate, expired nitric oxide, protein in bronchoalveolar lavage fluid, and functional assays of macrophages isolated from bronchoalveolar lavage samples. Inflammatory responses were seen in both adult and senescent rats. Senescent rats had reduced immune functions with exposure, indicating that these animals may be more susceptible to respiratory infection. Senescent rats were more sensitive to particle induced changes in both heart rate and blood pressure with significant effects seen at exposure levels that were half of those used in adult rats. The greatest effects were seen with exposure to ultrafine particles. However, if one corrects the responses for the dose that each atmosphere could potentially deliver under the conditions of this experiment (computed using a rat lung deposition model), the distinction by particle size seen is most likely to be a function of delivered dose. These studies can aid ARB in understanding the mechanisms of PM toxicity and the effects of particles on sensitive groups.

11.

"Mechanisms of Particulate Toxicity: Effects on the Respiratory System," University of California, Davis, $895,000, Contract No. 96-310
  The health effects caused by exposure to ambient levels of particulate matter (PM) continue to be of primary concern to scientists, regulators, and the general public. There is a substantial body of evidence to indicate that exposure to particulate air pollutants can cause cardiopulmonary heath effects, including premature death, although the mechanisms by which PM exert their effects are largely unknown. This study was designed to examine possible mechanisms of particulate toxicity. The effect of short-term exposures to two common components of California particules, ammonium nitrate and carbon, were studied in the respiratory tract of rats. Young, adult, and old rats were exposed to three different concentration ranges of the particulate components. The responses demonstrated the ability of PM exposures to cause inflammation and alterations in cytotoxicity and cellular proliferation in the respiratory tract of healthy rats. The information provided by this study will increase our understanding of the mechanisms of PM toxicity and help identify potentially sensitive populations that are particularly at risk from exposure to common constituents of California particulate matter. Such information is vital to the development of effective regulatory measures to protect public health from California particles.

12.

"Update and Refinement of an Indoor Exposure Assessment Methodology," ICF Kaiser / Systems Applications International, $245,074.61, Contract No. 98-327
  The ARB is required to consider indoor exposures to toxic air contaminants in assessing risks posed by those pollutants. To meet this need, and to fully consider indoor exposures in assessing and reducing risk, the ARB needs accurate estimates of Californians' indoor and total exposures to air pollutants, especially exposures of the most sensitive groups in the population, such as children. One key tool in assessing Californians' exposures has been the California Population Indoor Exposure Model (CPIEM). In this project, the contractor updated and improved CPIEM, which was developed in the early 1990s. This included converting the model to a user-friendly, Windows interface and improving the efficiency of the methodology; expanding and refining estimation calculations; reviewing and incorporating new data into the model; and verifying the accuracy of the improved method. The contractor also added the valuable capability of characterizing the uncertainty and variability of the exposure estimates. The work completed under this project further improves and broadens ARB's ability to estimate Californians' exposures to air pollutants.

13.

"Processing and Validation of Data Collected by Radar Wind Profilers, Radio Acoustic Sounding Systems, and Sodars During the 1997 Southern California Ozone Study," National Oceanic Atmospheric Administration, Parsons Engineering Science, Inc. and the South Coast Air Quality Management District, Total Budget: $237,647, Contract Nos. 99-305, 99-306, 99-307
  A wide variety of agencies and their contractors operated rawinsondes, profiling radars, and SODARs to represent the meteorological conditions aloft during SCOS97-NARSTO. Providing an integrated database required evaluation of a variety of system operations and quality control practices. It included centralized quality assurance audits, data management, and subsequent data review and processing. A series of interdependent tasks were undertaken by three groups, the National Oceanic and Atmospheric Administration (NOAA), Parsons ES, and Sonoma Technology, Inc. to produce an integrated and fully validated database of the meteorological observations. Prior to this project use of the available data required choices by the data users lacking complete information regarding the most appropriate processing methods and resulting sets of data. The draft final report provides a description of the actions taken by the three contractors and the resulting database, which has been delivered. The product is a database with higher quality, validated data. It provides a single recommended data set that can be used by modelers and analysts without need for further judgements regarding choice of data streams or data validity.

14.

"An Investigation of the Relationship Between Total Non-Methane Organic Carbon and the Sum of Speciated Hydrocarbons and Carbonyls Measured by Standard GC/FID: Validation and Refinement of a New Instrument, and Measurements in the South Coast Air Basin," University of California, Los Angeles, $111,576, Contract No. 98-323
  Volatile organic compounds (VOCs) are one of the critical precursors to the formation of urban smog. To understand the ozone formation, it is necessary to assess ambient concentrations of reactive organic compounds. However, some ambient VOCs such as oxygenated compounds are not detected by the standard method used in the California VOC monitoring network. The objective of this project was to apply a new instrument, developed under the ARB's sponsorship, to determine the magnitude of the VOCs not measured by the standard method at several sites in Los Angeles. The results obtained indicate that the measurements by the new analyzer agree well (within 5 to 20 percent) with those measured by the standard method for fresh emission sources including gasoline and diesel exhaust. Approximately 10 percent of "excess" VOCs were observed at the Burbank site, which is surrounded by freeways and light industrial sources and at the UCLA site during wintertime when photochemistry is minimal. In contrast, between 25 and 45 percent of the VOCs were not measured by the standard technique at the UCLA and Azusa sites during the summer when photochemistry is more important. The results are expected to be incorporated into air quality models for devising successful VOC control strategies.

15.

"Evaluation of NOy and Nitric Acid Measurement Methods and Collection of Ambient Data," University of California, Riverside, $128,638, Contract No. 98-341
  Nitrogen containing compounds are of great interest to the ARB. Ambient nitrogen dioxide (NO2) is a health hazard and plays a critical role in ozone formation. Results from the Children's Heath Study indicate that ambient nitric acid can possibly have a negative impact on the development of children's lung function. Using the current measurement technique (chemi-luminescence), reported concentrations of NO2 may also reflect nitric acid, organic nitrates, and nitrous acid, in addition to NO2. This project's method for separating NO2 and nitric acid relied on immediate conversion of these compounds in one channel at the entrance of the inlet using a forward converter, and removal of nitric acid before a similar conversion for the other channel. The difference was an indication of nitric acid. Measurements were conducted at Azusa and at Riverside. Investigators also tested a thermal-evolution denuder (TED) method to provide a second approach for nitric acid measurement. Nitric acid by difference has now shown promise in delineating NO2 from nitric acid and two channel chemi-luminescent instruments may be deployed in areas where high nitric acid concentrations are expected. The TED method still needs substantial methodological development. Proper determination of NO2, through measurements of nitric acid, will help us with photochemical modeling and assessments critical to the State Implementation Plans.

16.

"Flux Measurements of Ammonia to Estimate Emission Factors for Area Sources," University of California, Riverside, $50,092, Contract No. 98-340
  Particulate matter (PM) has been implicated in human morbidity and mortality. In many areas of California, ammonium nitrate is a significant fraction of PM. For that reason, accurate and updated ammonia emission inventories are a key requirement for the triennial emission inventory and the 2005 PM State Implementation Plans (SIP). To collect the data needed to improve the emission inventory, a passive sampler that would be easier and less expensive to operate than active samplers currently in use was needed. Such a sampler was built and tested alongside an active sampler at a dairy, a dairy lagoon, a lagoon slurry fertilized field, a pig farm, and an urea-fertilized citrus grove. The passive sampler proved to deliver repeatable, consistent, and useful results. Active and passive sampling data are well correlated; however, active sampling produces much higher emission factors (by a factor of 20). The recommendations suggest a new passive sampler configuration may be much simpler and produce a lower level of discrepancy. This configuration should be tested and a more robust standard operating procedure developed for local air quality districts and impacted commerce to develop emission factors and inventories on their own. This projected developed information which will lead to a more accurate and up-to-date statewide ammonia emission inventory would fully comply with the 2005 SIP and our triennial emission inventory obligations.

17.

"Development and Application of Improved Methods for Measurement of Ozone Formation Potentials of Volatile Organic Compounds," University of California, Riverside, $299,720, Contract No. 97-314
  The ozone forming potential or reactivity of volatile organic compounds (VOCs) has been incorporated into the California Low Emission Vehicle/Clear Fuel regulation and aerosol coatings regulation. Reactivity-based regulations can potentially provide added cost-effectiveness and flexibility for the more stringent VOC control strategies of the future. To develop reactivity scales such as the Maximum Incremental Reactivity (MIR), both chamber experiments and computer simulations are needed for selected VOCs and this is very costly. The objective of this project was to improve existing methods for evaluating reactivity and develop new methods with lower costs and greater sensitivity. Unfortunately, this project was not entirely successful in achieving the stated objective. The major effort in this project was focused on investigating the use of nitrous acid + VOC irradiation experiments to provide alternative reactivity measurements that can reduce ambiguities in mechanism evaluations and that can potentially be applied to a wider variety of VOCs than is practical for chamber experiments. However, further improvements to the injection system are needed and a new analysis system needs to be integrated into the experiment before the nitrous acid flow method can reliably be applied to reactivity assessments of low volatile compounds or complex mixtures such as petroleum distillates. Work on improving this method is underway as part of a new project funded by the ARB. The final product is expected to be a new technique for reactivity assessment.

18.

"Linkages Between Measurements of Multifunctional and Polar Organics in Chamber Studies and the Ambient Environment," University of California, Davis, $107,150, Contract No. 98-311
  Photooxidation of hydrocarbon emissions produces multifunctional and polar organic compounds. In the ambient atmosphere, these compounds may undergo further oxidation or partition to particles and generate secondary aerosols. The polarity of these compounds gives increased reactivity in biological systems. In fact, the mutagenicity of particles has been linked to the polarity of the organic fraction. Existing knowledge on the identities of these multifunctional photooxidation products has been derived primarily from chamber studies. This project improved and validated a technique to measure multifunctional carbonyls in ambient air and established a linkage between these measurements and chamber studies. Specifically, the researchers optimized and validated a new analytical method, which utilizes a mist chamber, to collect trace levels (ppt detection limits) of multifunctional organic compounds with short sampling times (~10 min.). As part of this project, the researchers also characterized multifunctional compounds in air samples collected in Azusa, CA (as part of the 1997 Southern California Ozone Study) and in fine particulate matter collected from the Caldecott tunnel. The ambient air studies provided insight into the composition of gas-phase multifunctional carbonyls and characterized many polar organics in fine particulate matter that originated from heavy- and light-duty vehicle emissions. The new analytical method is a rugged tool that provides quantitative measurements of the distributions, yields and lifetimes of primary and secondary photooxidation products. Data obtained with this method will help in the formulation and validation of photochemical models and in the investigation of oxygenated multifunctional compounds as markers for stationary and mobile sources.

19.

"Development of Reactivity Scales via 3-D Grid Modeling of California Ozone Episodes," University of California, Berkeley, $240,524, Contract No. 98-309
  Reactivity scales (e.g., Maximum Incremental Reactivity: MIR) of volatile organic compounds (VOCs) have been developed under the Air Resources Board (ARB)'s sponsorship and incorporated into the California Low Emission Vehicle / Clear Fuel regulation and aerosol coatings regulation. This is because the reactivity-based regulations can be cost-effective and add flexibility in complying with the more stringent VOC control strategies of the future. However, a concern has been raised regarding the level of physical detail because the MIR scale has been developed using a box and based on 10-hour simulations, whereas some VOCs may remain in an urban airshed for two to three days. The objectives of this project were to: 1) use state-of-the-science models to assess the reactivity of selected compounds with respect to ozone formation in the South Coast Air Basin and in Central California, 2) compare incremental reactivities computed using 3-D models with the MIR values computed using a box model, and 3) perform sensitivity and uncertainty analysis of incremental reactivity. The incremental scales developed using 3-D models resulted in similar rankings to those developed using a box model. Relative measures of reactivity varied less than absolute measures as a function of location. Different measures of reactivity including MIR, Maximum Ozone Incremental Reactivity, population exposure, and 1-hour versus 8-hour average ozone gave similar results. Uncertainties in relative reactivity of selected compounds were dominated by uncertainties in the rate parameters of their primary oxidation reactions. These findings can help address the concerns regarding the model performance and reactivity applicability in different regions.

20.

"Chlorine Emissions from Activated Sea-Salt Aerosols and Their Potential Impact on Ozone," University of California, Irvine, $15,000, Contract No. 00-324
  A variety of laboratory, field, and modeling studies strongly suggests that heterogeneous reactions of sea salt particles can generate photochemically active halogen species such as chlorine radicals in marine areas. There is also evidence that chlorine radicals can take part in the tropospheric gas-phase chemical reactions that lead to the formation or destruction of ozone. Although gas-phase reaction mechanisms involving chlorine radicals are available, a chlorine emissions inventory does not exist. This research project developed a spatially and temporally distributed chlorine gas emissions inventory for the South Coast Air Basin. The chlorine emissions inventory was generated by combining the most recent knowledge of gas-phase and aqueous-phase (aerosol phase) chemistry with a state-of-the-science wind-driven sea-salt emissions model. A photochemical modeling study was performed to determine whether urban photochemical models simulating sea-salt particle chemistry can predict observed chlorine levels and how such chlorine levels affect the ozone formation. A host urban airshed model, employing a rich chemical mechanism and simulating aerosol dynamics, was augmented with current sea-spray generation functions, a comprehensive gas-phase chlorine chemistry mechanism and several heterogeneous / multiphase chemical reactions considered key processes leading to reactive chlorine formation. Modeling results adequately reproduce regional sea-salt particle concentrations. The results suggest that inclusion of sea-salt derived chlorine chemistry could increase morning ozone predictions by as much as ~12 ppb in coastal regions and by ~4 ppb to the peak domain ozone in the afternoon. Peak ozone concentrations at most monitoring sites increase by
2 - 4 ppb and even higher ozone increases, up to 7 ppb, are predicted at other times not coinciding with the peak. An emissions inventory of anthropogenic sources of chlorine is recommended as these may enhance ozone formation even further by emitting chlorine gases directly into polluted regions. The information gained in this project will improve our understanding of the processes involved in the formation of photochemical smog in California, particularly the significance of chlorine radicals.

21.

"Refinement, Calibration, and Field Studies Involving Transportable Aerosol Time-of-Flight Mass Spectrometers (ATOFMS)," University of California, Riverside and San Diego, $596,059,
Contract No. 96-307
  California needs to develop controls to reduce ambient concentrations of aerosols to attain the National Ambient Air Quality Standards for Particulate Matter. Developing a scientific foundation for future PM controls requires research on two fronts: characterizing directly emitted "primary" aerosols in sufficient detail to link them to particular sources, and studies of the dynamics of particle aging and the formation of "secondary" particles from gaseous precursors. Dr. Prather's development work with Aerosol Time-of-Flight Mass Spectrometry (ATOFMS) under ARB contract demonstrated that these instruments can provide real-time data with high specificity for particle size and composition in ambient air, while eliminating the problems of long-time sample integration, time lags between sample collection and data availability, and positive and negative chemical artifacts associated with filter methods. The work under this Interagency Agreement has produced: 1) Data and analysis of field experiments during the Southern California Ozone Study (SCOS97-NARSTO); 2) Long-term characterization of the Riverside aerosol; 3) Analysis of aerosol evolution during transport from Los Angeles to Azusa; 4) Source characterization studies for motor vehicle particle emissions; 5) Application of ART-2A neural network methods to aerosol classification; and 6) Calibration / quantitation studies of ATOFMS comparing particle size and chemical composition results with established sampling and analytical methods. The reported results not only prove the utility of ATOFMS as a field research tool, but also advance general understanding of the dynamics of aerosol aging and the formation of secondary aerosols in southern California. These data will support refinement of aerosol air quality models and lead to better identification of aerosol source contributions to ambient air quality. Together, these advances will facilitate more specific PM control programs and add confidence in predicting the air quality benefits of PM controls.

22.

"Heavy-Duty Truck Evaporative Emissions Testing for Emissions Inventory," Automotive Testing Laboratories, $128,691, Contract No. 98-303
  Historically, gasoline light-duty vehicles (LDV) were the most significant sources of evaporative emissions. But improvements in emissions control technology for light-duty vehicles (LDV) have translated into significant reductions in the contributions from these sources to the motor vehicle emissions inventories. Consequently, the relative contributions of other vehicle classes, including heavy-duty gasoline trucks (HDGT), have increased. Currently, the evaporative emissions from HDGTs are extrapolated from emissions data for light- and medium-duty gasoline trucks. However, as the fleet penetration of this class of vehicles increases due to the popularity of trucks, vans, and sport utility vehicles, it has become necessary to enhance the emissions inventory with actual test data.
  The objective of this study was to determine evaporative emissions from HDGTs for the ARB's emissions inventory. Automotive Testing Laboratories (ATL) procured a fleet of nine HDGTs and tested them for evaporative and exhaust emissions. Evaporative emissions of interest were running losses, hot soak, and diurnal emissions. The project consisted of three tasks: 1) vehicle selection and procurement; 2) fuel procurement; and 3) emissions testing. Results suggest that, similar to light-duty vehicles, age and the resulting emission control device failures have the greatest impact on evaporative emissions. Also shown were the potential benefits offered by repairs of malfunctioning equipment.

23.

"Testing for Exhaust Emissions of Diesel Powered Off-Road Engines," West Virginia University, $272,525, Contract No. 98-317
  This study was initiated to fill the current void in off-road diesel equipment testing cycles and to provide some
of the "real-world" emissions data that are needed for accurately modeling emissions inventories. The off-road
diesel-powered equipment targeted for this study was selected to be representative of the major off-road diesel emissions contributors in California. Onboard engine data (engine speed and CO2 as a surrogate for load) were logged from four off-road vehicles in field operation, for use in generating transient test cycles that could simulate
real-world operating conditions for exhaust emissions research. The engines were removed from three of the vehicles and tested for emissions on a dynamometer according to the transient test cycles developed from the
recorded in-field data. These engines were also tested on the standard steady-state 8-mode test cycle. Exhaust emissions from the fourth vehicle were measured in the field as it performed its normal operating activities. Project results indicate that the current steady-state, ISO 8178, 8-mode test cycle does not accurately represent the actual emissions produced by off-road, diesel-powered equipment during day-to-day operations. Furthermore, the exhaust emission levels produced by the vehicles are highly vehicle- and task-specific. These data will be useful in improving current off-road vehicle emission inventory models.

24.

"Investigation of Low Reactivity Solvents," California Polytechnic State University, San Luis Obispo, $84,315, Contract No. 98-310
  The ARB is interested in lowering emissions of VOCs due to their role in the formation of ambient ozone. Due to evaporation of the solvents they contain, consumer products represent a significant emission source for VOCs. These solvents and solvent mixtures consist of a wide range of organic compounds, which have widely varying
ozone-formation potentials. Having a single source of information on the properties of solvents used in these products would encourage manufacturers to consider replacing conventional solvents that are highly reactive with newer, less reactive solvents.
  A database of physical and chemical properties for common solvents was prepared. Consideration was given to products which are representative of the California marketplace, and special attention was given to solvents that have low reactivity. The ARB plans to make this database available to the public, through its web site. The purpose of this database is to allow rapid evaluation of solvent properties, with an ultimate goal of encouraging the conversion to less reactive solvents, where feasible.
  The contractor also performed chemical analysis on several solvent mixtures used in consumer products, in order to identify and quantify the VOCs present. The ARB will use these data to refine the emission inventory.

25.

"Microscale Emissions Modeling System," California Polytechnic State University, San Luis Obispo, $179,547, Contract No. 96-316
  Prior to recommending emissions controls from mobile sources, the ARB needs to quantify these emissions. For this purpose, the ARB must know the emissions from specific vehicles driven in California, the number of vehicles of each type in use, and also their activity and use patterns. The objective of this project was to develop modeling techniques that lend themselves to estimating vehicle emissions for a section of roadway. CalPoly developed the "Microscale Emissions Modeling System" that uses laser range-finders to estimate vehicle speed and acceleration and trigger a license plate reader for vehicles passing through a traffic lane. The resulting data is combined with ARB vehicular emissions tables that relate vehicle emissions to speed, acceleration, and vehicle technology type. This enables the system to estimate the emissions of each vehicle moving past the system.


Research Screening Committee

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