Black carbon concentrations in California vehicles and estimation of in-vehicle diesel exhaust particulate matter exposures (original) (raw)
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Little is known about particulate elemental carbon (EC) personal exposure levels, a key component of diesel exhaust, specifically in transport microenvironments. A method utilizing the optical properties of EC particles has been applied to personal exposure measurement filter samples. In a series of field studies carried out in London, UK, during 1999-2000 over 400 fine particle (PM 2.5 ) personal exposure level measurements were taken for journeys in bicycle, bus, car and underground rail transport microenvironments, along three main fixed routes. The particulate EC contribution to the PM 2.5 personal exposure was assessed indirectly by means of an optical technique and with the development and use of a size fraction specific and site-specific calibration curve. In this first EC personal exposure study of transport users geometric mean exposure levels in the summer field campaign were 11.2 mg m À3 (GSD=2.7) for cyclists, 13.6 mg m À3 (GSD=1.9) for bus passengers and 21.6 mg m À3 (GSD=2.1) for car drivers; corresponding exposure levels in the winter were 16.4 mg m À3 (GSD=1.8), 18.6 mg m À3 (GSD=2.3) and 27.3 mg m À3 (GSD=2.0), respectively. EC/PM 2.5 ratios were approximately 0.5-0.6 for bicycle and bus modes and 0.7-0.8 for the car mode. EC/PM 2.5 ratios for different routes ranged from approximately 0.7 for Route 1 to 0.4 for Route 3. Cyclists had the lowest exposure to EC, and car occupants the highest exposure. A large difference in exposure levels between a central high traffic density route and the other less central routes was observed. Particulate EC was a very significant proportion of the total PM 2.5 personal exposure and EC personal exposure levels were considerably higher than reported fixed site monitor EC concentrations. r
Environmental science & technology, 2015
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Environmental Science & Technology, 2003
People driving in a vehicle might receive an enhanced dose of mobile source pollutants that are considered a potential risk for cardiovascular diseases. The exposure to components of air pollution in highway patrol vehicles, at an ambient, and a roadside location was determined during 25 work shifts (3 p.m. to midnight) in the autumn of 2001, each day with two cars. A global positioning system and a diary provided location and activity information. Average pollutant levels inside the cars were low compared to ambient air quality standards: carbon monoxide 2.7 ppm, nitrogen dioxide 41.7 µg/m 3 , ozone 11.7 ppb, particulate matter smaller 2.5 µm (PM 2.5 ) 24 µg/m 3 . Volatile organic compounds inside the cars were in the ppbrange and showed the fingerprint of gasoline. PM 2.5 was 24% lower than ambient and roadside levels, probably due to depositions associated with the recirculating air conditioning. Levels of carbon monoxide, aldehydes, hydrocarbons, and some metals (Al, Ca, Ti, V, Cr, Mn, Fe, Cu, and Sr) were highest in the cars, and roadside levels were higher than ambient levels. Elevated pollutant levels were related to locations with high traffic volumes. Our results point to combustion engine emissions from other vehicles as important sources of air pollutants inside the car.
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Science of The Total Environment, 2013
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The Ports of Los Angeles and Long Beach are the entry point for almost half of all cargo containers entering the United States. The use of diesel trucks to move Port-related goods has raised significant public health concerns associated with black carbon and other air pollutants. It is difficult to reliably estimate people's exposure to vehicle-related pollutants due to the narrow impact zone of traffic, usually within 200-300 m downwind of major roadways. Previous studies suffer from the lack of traffic count data on surface streets and the lack of neighborhood-level population data. We examined seasonal and annual average exposures of particulate matter less than 2.5 mm (PM 2.5 ) and elemental carbon (EC) at a neighborhood scale for communities heavily impacted by diesel trucks near these ports. We assembled a traffic-activity database that distinguishes gasoline and diesel vehicles on both freeways and surface streets, by consolidating information from several sources, including our own field measurements. The CALINE4 model was used to estimate residential exposure of the study population to PM 2.5 and EC. Parcel property data were used to allocate Census block group (BG) population to increase spatial resolution.
WIT Transactions on the Built Environment, 2013
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Articles Elemental Carbon and PM 2.5 Levels in an Urban Community Heavily Impacted by Truck Traffic
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is a hub in the tristate (New York, New Jersey, and Connecticut) freight transportation system. This study was carried out in response to community concerns about potential health effects of exposure to diesel exhaust particulate (DEP). We measured particulate matter < 2.5 µm in aerodynamic diameter (PM 2.5) and elemental carbon (EC) on sidewalks and tested whether spatial variations in concentrations were related to local truck traffic density. Ten-hour integrated air samples for EC and PM 2.5 were collected for 9 days over a 3-week period in the summer of 1999 at seven geographically distinct intersections. Simultaneous traffic counts were carried out for each sampling event. Traffic was classified into three classes: passenger cars, small trucks, and large trucks (diesel vehicles). Mean diesel vehicle volumes ranged from 9.3 to 276.5 vehicles/hr across sites. Mean EC concentrations by site ranged from 2.6 µg/m 3 at the control site to 7.3 µg/m 3 along a designated truck route....