Efficient determination of vehicle emission factors by fuel use category using on-road measurements: downward trends on Los Angeles freight corridor I-710
Open Access
- 11 January 2013
- journal article
- research article
- Published by Copernicus GmbH in Atmospheric Chemistry and Physics
- Vol. 13 (1), 347-357
- https://doi.org/10.5194/acp-13-347-2013
Abstract
To evaluate the success of vehicle emissions regulations, trends in both fleet-wide average emissions as well as high-emitter emissions are needed, but it is challenging to capture the full spread of vehicle emission factors (EFs) with chassis dynamometer or tunnel studies, and remote sensing studies cannot evaluate particulate compounds. We developed an alternative method that links real-time on-road pollutant measurements from a mobile platform with real-time traffic data, and allows efficient calculation of both the average and the spread of EFs for light-duty gasoline-powered vehicles (LDG) and heavy-duty diesel-powered vehicles (HDD). This is the first study in California to report EFs under a full range of real-world driving conditions on multiple freeways. Fleet average LDG EFs were in agreement with most recent studies and an order of magnitude lower than observed HDD EFs. HDD EFs reflected the relatively rapid decreases in diesel emissions that have recently occurred in Los Angeles/California, and on I-710, a primary route used for goods movement and a focus of additional truck fleet turnover incentives, HDD EFs were often lower than on other freeways. When freeway emission rates (ER) were quantified as the product of EF and vehicle miles traveled (VMT) per time per mile of freeway, despite a two- to three-fold difference in HDD fractions between freeways, ERs were found to be generally similar in magnitude. Higher LDG VMT on low HDD fraction freeways largely offset the difference. Therefore, the conventional assumption that freeways with the highest HDD fractions are significantly worse sources of total emissions in Los Angeles may no longer be~true.Keywords
This publication has 28 references indexed in Scilit:
- Emission Changes Resulting from the San Pedro Bay, California Ports Truck Retirement ProgramEnvironmental Science & Technology, 2011
- Reactive nitrogen compounds (RNCs) in exhaust of advanced PM–NOx abatement technologies for future diesel applicationsAtmospheric Environment, 2011
- Higher than expected NOx emission from trucks may affect attainability of NO2 limit values in the NetherlandsAtmospheric Environment, 2011
- Inter-community variability in total particle number concentrations in the eastern Los Angeles air basinAtmospheric Chemistry and Physics, 2010
- On-Road Emission Measurements of Reactive Nitrogen Compounds from Three California CitiesEnvironmental Science & Technology, 2010
- Comparison of emissions from on-road sources using a mobile laboratory under various driving and operational sampling modesAtmospheric Chemistry and Physics, 2009
- Measurements and predictors of on-road ultrafine particle concentrations and associated pollutants in Los AngelesAtmospheric Environment, 2008
- Controlled generation of black carbon particles from a diffusion flame and applications in evaluating black carbon measurement methodsAtmospheric Environment, 2007
- Diurnal and seasonal characteristics of particle volatility and chemical composition in the vicinity of a light-duty vehicle freewayAtmospheric Environment, 2005
- Freeway Performance Measurement System: Operational Analysis ToolTransportation Research Record: Journal of the Transportation Research Board, 2002