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At least 19 recordsLinked to original sources
PubMed2005

Real-world vehicle emissions: a summary of the 14th coordinating research council on-road Vehicle Emissions Workshop.

The Coordinating Research Council held its 14th Vehicle Emissions Workshop in March 2004, where results of the most recent on-road vehicle emissions research were presented. We summarize ongoing work from researchers who are engaged in improving our understanding of the contribution of mobile sources to ambient air quality and emission inventories. Participants in the workshop discussed efforts to improve mobile source emission models, light- and heavy-duty vehicle emissions measurements, on- and off-road emissions measurements, effects of fuels and lubricating oils on emissions, as well as topics for future research.

Air Pollutants↗
PubMed2004

Real-world vehicle emissions: a summary of the Thirteenth Coordinating Research Council On-Road Vehicle Emissions Workshop.

The Coordinating Research Council held its thirteenth Vehicle Emissions Workshop in April 2003, when results of the most recent on-road vehicle emissions research were presented. Ongoing work from researchers who are engaged in improving understanding of the contribution of mobile sources to ambient air quality and emission inventories is summarized here. Participants in the workshop discussed efforts to improve mobile source emission models, the role of on-board diagnostic systems in inspection and maintenance programs, light- and heavy-duty vehicle emissions measurements, on- and off-road emissions measurements, effects of fuels and lubricating oils on emissions, as well as topics for future research.

Environmental Monitoring↗
PubMed2001

Real-world vehicle emissions: a summary of the tenth coordinating research council on-road vehicle emissions workshop.

The Coordinating Research Council (CRC) held its tenth workshop in March 2000, focusing on results from the most recent real-world vehicle emissions research. In this paper, we summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to emission inventories. Participants in the workshop discussed efforts to improve mobile source emission models and emission inventories, results from gas- and particle-phase emissions studies from spark-ignition and diesel-powered vehicles, new methods for measuring mobile source emissions, improvements in vehicle emission control systems (ECSs), and evaluation of motor vehicle inspection/maintenance (I/M) programs, as well as topics for future research.

Environmental Exposure↗
PubMed2000

Real-world vehicle emissions: a summary of the Ninth Coordinating Research Council On-Road Vehicle Emissions Workshop.

In April 1999, the Coordinating Research Council sponsored a workshop focusing on our understanding of real-world emissions from motor vehicles. This summary presents the latest information on in-use light- and heavy-duty vehicle tailpipe and evaporative emissions, the effects of fuels on emissions, field programs designed to understand the contribution of mobile sources to emission inventories, efforts to evaluate and improve mobile source emission models, progress of vehicle inspection/maintenance programs, and topics for future research. While significant progress has been made in understanding in-use vehicle emissions, further improvements are necessary. Moreover, the impact of current and future changes in emission control technologies and control programs will have to be monitored for effectiveness and incorporated into the emission factor models.

Air Pollutants↗
PubMed2002

Real-world vehicle emissions: a summary of the Eleventh Coordinating Research Council On-Road Vehicle Emissions Workshop.

The Coordinating Research Council (CRC) held its eleventh workshop in March 2001, focusing on results from the most recent real-world vehicle emissions research. We summarize the presentations from researchers engaged in improving our understanding of the contribution of mobile sources to ambient air quality and emission inventories. Participants in the workshop discussed efforts to improve mobile source emission models and emission inventories, the role of on-board diagnostic (OBD) systems in inspection and maintenance (I/M) programs, particulate matter (PM) emissions, contributions of diesel vehicles to the emission inventory, on-road emissions measurements, fuel effects, unregulated emissions, and microscale and modal emission models, as well as topics for future research.

Air Pollution↗
PubMed2003

Real-world vehicle emissions: a summary of the twelfth Coordinating Research Council On-Road Vehicle Emissions Workshop.

The Coordinating Research Council (CRC) held its 12th workshop in April 2002, with nearly 90 presentations on the most recent on-road vehicle emissions research. This paper summarizes the presentations from researchers who are engaged in improving understanding of the contribution of mobile sources to air quality. Participants in the workshop discussed mobile source emission models and emission inventories, results from gas- and particle-phase emissions studies from spark-ignition and diesel-powered vehicles (with an emphasis in this workshop on particle emissions), effects of fuels on emissions, evaluation of in-use emissions control programs, and efforts to improve our capabilities in performing on-board emissions measurements, as well as topics for future research.

Air Pollution↗
PubMed2006

Real-world vehicle emissions: A summary of the 15th coordinating research council on-road vehicle emissions workshop.

The Coordinating Research Council held its 15th workshop in April 2005, with nearly 90 presentations describing the most recent mobile source-related emissions research. In this paper, the authors summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to air quality. Participants in the workshop discussed emission models and emission inventories, results from gas- and particle-phase emissions studies from spark-ignition and diesel-powered vehicles (with an emphasis in this workshop on particle emissions), effects of fuels on emissions, evaluation of in-use emissions control programs, and efforts to improve our capabilities in performing on-board emissions measurements, as well as topics for future research.

Air Pollutants↗
PubMed2000

Development of a microscale emission factor model for CO for predicting real-time motor vehicle emissions.

The U.S. Environmental Protection Agency's (EPA) National Exposure Research Laboratory has initiated a project to improve the methodology for modeling human exposure to motor vehicle emissions. The overall project goal is to develop improved methods for modeling the source through the air pathway to human exposure in significant microenvironments of exposure. This paper presents the technical description of a newly developed model for CO emissions. The sensitivity analysis and evaluation of this emission model is presented in a companion paper titled "Sensitivity Analysis and Evaluation of MicroFacCO: A Microscale Motor Vehicle Emission Factor Model for CO Emissions." The MOBILE models (used in the United States, except California) and EMFAC models (used in California only) used to estimate emissions are suitable for supporting mostly regional (county)-scale modeling and emission inventory because of their dependence on vehicle-miles-traveled aggregate data. These emission models are not designed to estimate real-time emissions needed for human exposure studies near roadways. A number of independent studies have found that current mobile source emission factor models are not very reliable at estimating microscale emissions and are, therefore, inappropriate for use with microscale modeling necessary to estimate human exposures near roadways. A microscale emission factor model for predicting real-world real-time motor vehicle CO emissions (MicroFacCO) has been developed. It uses available information on the vehicle fleet composition. The algorithm used to calculate emission factors in MicroFacCO is disaggregated based on the on-road vehicle fleet. The emission factors are calculated from a real-time fleet rather than from a fleet-wide average estimated by a vehicle-miles-traveled weighting of the emission factors for different vehicle classes. MicroFacCO uses the same database used to develop the MOBILE6 model. As compared with MOBILE emission models, MicroFacCO requires only a few input variables, which are necessary to characterize the real-time fleet being modeled. The main input variables required are on-road vehicle fleet, time and day of year, ambient temperature, and relative humidity.

Carbon Monoxide↗
PubMed2003

Development of a microscale emission factor model for particulate matter for predicting real-time motor vehicle emissions.

The U.S. Environmental Protection Agency's National Exposure Research Laboratory is pursuing a project to improve the methodology for modeling human exposure to motor vehicle emissions. The overall project goal is to develop improved methods for modeling the source through the air pathway to human exposure in significant exposure microenvironments. Current particulate matter (PM) emission models, particle emission factor model (used in the United States, except California) and motor vehicle emission factor model (used in California only), are suitable only for county-scale modeling and emission inventories. There is a need to develop a site-specific real-time emission factor model for PM emissions to support human exposure studies near roadways. A microscale emission factor model for predicting site-specific real-time motor vehicle PM (MicroFacPM) emissions for total suspended PM, PM less than 10 microm aerodynamic diameter, and PM less than 2.5 microm aerodynamic diameter has been developed. The algorithm used to calculate emission factors in MicroFacPM is disaggregated, and emission factors are calculated from a real-time fleet, rather than from a fleet-wide average estimated by a vehicle-miles-traveled weighting of the emission factors for different vehicle classes. MicroFacPM requires input information necessary to characterize the site-specific real-time fleet being modeled. Other variables required include average vehicle speed, time and day of the year, ambient temperature, and relative humidity.

Air Pollutants↗
PubMed2004

Dispersion characteristics of vehicle emission in an urban street canyon.

The dispersion of vehicle emission is limited by various factors existing in an urban environment, which may produce a poor air quality in an urban street canyon environment. This poor air quality has a high potential to be easily delivered into indoor air environment through building ventilation. In this study, the dispersion of vehicle emission was characterized by conducting wind tunnel tests and applying tracer gas techniques. The aspect ratio of a street canyon (i.e. the ratio of the width of a street and the average height of buildings) and the direction of external wind are the major test parameters. In addition to the simple data analysis of the results, a series of statistical analysis was also introduced to formulate the complex effects on the dispersion of vehicle emission. The updated result is presented in this article.

Journal Article↗
PubMed2005

Capillary electrophoresis determinative and GC-MS confirmatory method for water-soluble organic acids in airborne particulate matter and vehicle emission.

Urban fine airborne particulate matter (PM2.5) and vehicle emission samples were studied for water-soluble low-molecular-weight carboxylic acids using CE with indirect UV detection. Further identification of these acids was achieved using GC-MS as their butyl esters (after derivatization with BF3/butanol). Several dicarboxylic acids in the range C2-C10 including straight-chain, branched-chain, cis- and trans-unsaturated, and aromatic acids were confirmed by GC-MS. In addition, aromatic acids such as benzoate, phthalate, terephthalate, isophthalate, and 4-methylphtalate were present in such samples, but some of these were not well resolved by the used CE method. Oxocarboxylic acids (Cn(w) with n > 4) were also identified by GC-MS but not determined by CE due to lack of standards. The rapidity and simplicity of the CE method were clearly demonstrated, and the method was observed to be advantageous for routine monitoring of water-soluble organic acids in airborne PM2.5 and vehicle emission at low microg/L levels.

Air Pollutants↗
PubMed2006

Road grade estimation for on-road vehicle emissions modeling using light detection and ranging data.

Vehicle-specific power (VSP) is useful for explaining a substantial portion of variability in real-world vehicle emissions, such as those measured with portable emissions monitoring systems (PEMS). VSP is a function of vehicle speed, acceleration, and road grade. Road grade is shown to significantly affect estimates of both VSP and of real-world emissions via sensitivity analysis and analysis of empirical data. However, road grade is difficult to measure reliably using PEMS. Therefore, alternative methods for estimating road grade were identified and compared. A preferred method for estimating road grade was explored in more detail based on light detection and ranging (LIDAR) data. The method includes buffering LIDAR data onto roadway maps using a geographic information system tool, defining segments of roadway based on criteria pertaining to vertical curvature, quantification of roadway elevations within the buffered segments, and estimation of road grade and banking by fitting a plane to each segment. Factors influencing errors in road grade estimates are discussed. The method was evaluated by application to selected interstate highways and comparison to design drawing data. The development and application of LIDAR-based road grade data are demonstrated via a case study using PEMS data collected in the Research Triangle Park, NC, area. LIDAR data are shown to be reliable and accurate for road grade estimation for vehicle emissions modeling.

Air Pollutants↗
PubMedDate not supplied

Health effects of occupational exposures to vehicle emissions in Shanghai.

The authors investigated the health effects of occupational exposures to vehicle emissions in 745 bus drivers, conductors, and taxi drivers, compared with 532 unexposed controls, in Shanghai. Logistic regression and general linear models were used to examine the relationship between exposure and respiratory illness. Results showed that the prevalences of some respiratory symptoms and chronic respiratory diseases were significantly higher (p < 0.05) in the exposed group than in the controls. The adjusted odds ratios for throat pain, phlegm, chronic rhinitis, and chronic pharyngitis were 1.95 (95% CI 1.55-2.46), 3.90 (95% CI 2.61-5.81), 1.96 (95% CI 1.11-3.46), and 4.19 (95% CI 2.49-7.06), respectively. Also, there were exposure time response relationships for the prevalences of phlegm and chronic respiratory disease. Pulmonary function and blood lead levels were not significantly correlated with exposure status. The results suggest that occupational exposure to vehicle emissions may induce detectable adverse health effects.

Adult↗
PubMed2004

Contribution of vehicle emissions from an attached garage to residential indoor air pollution levels.

The infiltration of vehicle emissions into a house from the attached garage was studied for 16 homes of differing designs using the same extensively characterized vehicle at each home. Before the in-home measurement program, the cold-start and hot-start tailpipe emissions and hot-soak evaporative emissions from a 1993 Buick Regal were measured using standard vehicle emissions measurement methods. The emissions were chemically characterized for methane, nonmethane hydrocarbons (NMHC), and carbonyl compounds. The in-home measurements occurred over two winter seasons (1997-1998 and 1998-1999) in Ottawa, Ontario, Canada. Samples of indoor air and garage atmosphere were characterized for carbon monoxide, carbon dioxide, methane, NMHC, and carbonyl compounds. During the second year, real-time measurements of carbon, carbon dioxide, and total hydrocarbons were made to determine when and for how long the emissions plume infiltrates the house. Chemical mass balance modeling results using 31 NMHC species suggest that between 9 and 71% of the concentrations measured in the house during the hot-soak test and between 13 and 85% of the concentrations measured in the house during the cold-start test could be attributed to vehicle emissions infiltrating from the garage. In contrast, increases in carbonyl compound concentrations caused by the vehicle were difficult to detect above the already significant levels found in the houses.

Air Movements↗
PubMed2002

Ethical and economic issues in the use of zero-emission vehicles as a component of an air-pollution mitigation strategy.

The air pollution generated by motor vehicles and by static sources is, in certain geographic areas, a very serious problem, a problem that exists because of a failure of the marketplace. To address this marketplace failure, the State of California has mandated that by 2003, 10% of the Light-Duty Vehicle Fleet (LDV) be composed of Zero-Emission Vehicles (ZEVs). However, the policy-making process that was utilized to generate the ZEV mandate was problematic and the resulting ZEV mandate is economically unsound. Moreover, an ethical analysis, based primarily upon the work of John Rawls, suggests that implementation of the California ZEV mandate is--in spite of the wide latitude that ought to be given to policy decision makers--unethical. A more ethical and economically efficient approach to the pollution caused by marketplace failure is one that relies on market incentives and thereby achieves the desired improvement in air quality by appealing both to the self-interest of motorists and to those businesses that are directly or indirectly involved with the automobile industry. Such an approach would take better advantage of the creative forces of the market and improvements in technology over time and avoid the infringements on individual liberty and fairness embodied in the ZEV mandate.

Air Pollution↗
PubMed2001

Tunnel study of on-road vehicle emissions and the photochemical potential in Taiwan.

Motor vehicle emission factors of carbon monoxide (CO) and non-methane volatile organic compounds (NMVOCs) were calculated inside the Chung-Cheng Tunnel of Kaohsiung in Taiwan. The results were compared with those model predictions from the Mobile Taiwan 2.0 model. Individual concentrations of 21 species of NMVOCs were also determined. Photochemical potential of NMVOCs was evaluated by using the maximum incremental reactivity (MIR). Field data showed that the integrated emission factors of CO and NMVOCs for actual fleet were 6.3 and 1.5 g/veh km, respectively. The error range of these factors may be up to 45%. The predicted values by the Mobile Taiwan 2.0 model closely matched the observed data. Concentrations of isopentane, 2-methylpentane, toluene and m,p-xylene were the dominant species of NMVOCs. The ratio of maximum incremental reactivity to NMVOCs concentration was 3.9, similar to those of the studies in the US Fort McHenry and Tuscarora Tunnel.

Carbon Monoxide↗
PubMed2002

Genotoxicity biomonitoring in regions exposed to vehicle emissions using the comet assay and the micronucleus test in native rodent Ctenomys minutus.

Exposure to motor vehicle emissions represents an important concern for possible long-term health effects. The present report describes: 1) the application and verification of the alkaline comet assay in Ctenomys minutus to detect the possible genotoxicity of automobile emissions; 2) a comparison of the comet assay results with peripheral blood micronucleus (MN) assay results performed in the same animals; and 3) the identification of agents involved in the responses and in the seasonal variation of the effects. Ctenomys minutus (Octodontidae-Rodentia) were captured in two different fields from both sides of RS/030, a highway on the coastal plain of the Brazilian state of Rio Grande do Sul. Reference animals were obtained from a nearby field that was about 3 km distant from any road. By the end of this study, 123 rodents (73 females and 50 males) were live-trapped. Our results indicate that there was an increase in cells with DNA damage for C. minutus environmentally exposed to automobile emissions, as demonstrated by the alkaline comet assay, but there was no increase in micronucleated cells. The alkaline comet assay showed age and gender differences in the response. The comet assay results suggest that adult females are the principal population affected by air pollutants from vehicle emissions. Chemical data were also collected from areas exposed to automobile exhaust and these indicated that elevated levels of hydrocarbons, metals, and NO(2) were associated with the elevated levels of damaged cells observed in the wild rodent C. minutus. Our results agree with previous data on engine and fuel components, where weak increases in damage for native rodents exposed to emissions have been observed. Other larger, controlled studies are needed to better understand how the metabolism of C. minutus affects its response to emission exposure.

Animals↗
PubMed2002

Airborne carbonyls from motor vehicle emissions in two highway tunnels.

Carbonyls (aldehydes and ketones) continue to receive scientific and regulatory attention as toxic air contaminants, mutagens, and carcinogens. Vehicle emissions are a major source of carbonyls in outdoor air, but information about the nature and magnitude of carbonyl emissions by motor vehicles is limited. The objective of this study was to identify speciated carbonyls emitted by motor vehicles under real-world, on-road conditions and to calculate on-road carbonyl emission factors. We collected air samples at the inlet and outlet of two highway tunnels, the Caldecott Tunnel near San Francisco and the Tuscarora Mountain Tunnel in Pennsylvania. At the Caldecott Tunnel, the fleet consisted almost entirely of light-duty (LD) vehicles that used California phase 2 reformulated gasoline. Vehicle count, speed and other parameters relevant to carbonyl emissions were nearly the same from one assessment to the next. At the Tuscarora Mountain Tunnel, the fleet included LD vehicles and heavy-duty (HD) diesel trucks. This part of the study was designed to capture differences in percentage of LD and HD vehicles from one assessment to the next. Air downstream of KI oxidant scrubbers was sampled on silica gel cartridges coated with 2,4-dinitrophenylhydrazine (DNPH). Carbonyls were identified as their DNPH derivatives by liquid chromatography (LC) with detection by diode-array, UV-visible spectroscopy and by atmospheric pressure negative-ion chemical ionization mass spectrometry (MS). About 100 carbonyls were identified. For about 30 of these carbonyls, concentrations were measured at the inlet and outlet of both tunnels. This information was used to calculate on-road carbonyl emission factors for LD vehicles (Caldecott Tunnel) and for the overall fleet (Tuscarora Mountain Tunnel). At the Tuscarora Mountain Tunnel, data for the fleet were used to calculate carbonyl emission factors for LD vehicles and for HD diesel trucks, the majority of which were weight class 7-8 trucks. Carbonyl emission factors at the Caldecott Tunnel were calculated as milligrams of emissions per liter of fuel consumed. Those at the Tuscarora Mountain Tunnel were calculated as milligrams of emissions per distance traveled and then converted to milligrams per liter using the fuel economy reported by Gertler et al (2000) for this tunnel (14.75 km/L for LD vehicles and 3.15 km/L for HD vehicles). At the Caldecott Tunnel, the LD vehicles emission factor was 68.4 mg/L for total measured carbonyls; the ten most abundant carbonyls were, in decreasing order, formaldehyde, acetaldehyde, benzaldehyde, acetone, m-tolualdehyde, p-tolualdehyde, methacrolein, o-tolualdehyde, 2,5-dimethylbenzaldehyde, and crotonaldehyde. At the Tuscarora Mountain Tunnel, the LD emission factor was 94.9 mg/L for total measured carbonyls; the ten most abundant carbonyls were formaldehyde, acetone, acetaldehyde, heptanal, crotonaldehyde, 2-butanone, propanal, acrolein, methacrolein, and benzaldehyde. The weight class HD 7-8 vehicle emission factor at the Tuscarora Mountain Tunnel was 82.1 mg/L for total measured carbonyls; the ten most abundant carbonyls were formaldehyde, acetaldehyde, acetone, crotonaldehyde, m-tolualdehyde, 2-pentanone, a C5 saturated aliphatic carbonyl, 2-butanone, benzaldehyde, and methacrolein. The most abundant carbonyl was formaldehyde, which accounted for 45.4% (Caldecott, LD vehicles), 40.1% (Tuscarora Mountain, LD vehicles), and 25.8% (Tuscarora Mountain, HD vehicles) of total measured carbonyl emissions. The three most abundant carbonyls, formaldehyde, acetaldehyde, and acetone, together accounted for 63.0% (Caldecott, LD vehicles), 76.5% (Tuscarora Mountain, LD vehicles), and 50.5% (Tuscarora Mountain, HD vehicles) of total carbonyl emissions. At the Tuscarora Mountain Tunnel, HD vehicles emitted more unsaturated carbonyls, aromatic carbonyls, and dicarbonyls (as a percentage of total carbonyl emissions) than did LD vehicles. For LD vehicles, less acetone and more aromatic carbonyls (as a percentage of total carbonyl emissions) were emitted at the Caldecott Tunnel than at the Tuscarora Mountain Tunnel. The highway tunnel studies described in the main body of the report also offered an opportunity to examine the role of the sampling substrate, a critical aspect of the carbonyl sampling protocol. The results are described in Appendix A. Co-located samples, one collected using a DNPH-coated silica gel cartridge and the other using a DNPH-coated C18 cartridge, were collected downstream of KI oxidant scrubbers at the inlet and outlet of the Caldecott Tunnel. Statistical comparisons of the concentrations measured for about 30 carbonyls indicated good agreement between silica gel cartridges and C18 cartridges for about 25 carbonyls, including formaldehyde and acetaldehyde. Concentrations of acetone and 2-butanone measured using C18 cartridges were lower than those measured using silica gel cartridges.

Air Pollutants↗