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Determining Source Impacts Near Roadways using Wind Regression and Organic Source Markers
Citation:
OLSON, D. A., R. VEDANTHAM, G. A. NORRIS, S. G. Brown, AND P. Roberts. Determining Source Impacts Near Roadways using Wind Regression and Organic Source Markers. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 47(February):261-268, (2012).
Impact/Purpose:
The National Exposure Research Laboratory′s (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA′s mission to protect human health and the environment. HEASD′s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA′s strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Description:
Concentrations of 13 organic source markers (10 polycyclic aromatic hydrocarbons and 3 hopanes) are reported from time-integrated samples (24-hr and sub-daily) collected near an highway in Las Vegas, NV. Sample selection for assessing source impacts from the roadway was completed using the wind regression mod Air Pollution Transport to Receptor (EPA APTR 1.0). The model uses a kernel smoothing method for estimating source sectors (sector apportionment) of chemicals across wind speeds and wind directions. The model was applied using semi-continuous (5-min averaging time) pollutant data (black carbon (BC), CO, NO2, and NOx) and meteorological data. Using simple screening criteria to identify source impacts (>30% sector apportionment from the roadway and errors in the estimated sector apportionment <30%), sector apportionment results were consistent with organic source marker concentrations representative of motor vehicle exhaust (e.g., benzo(g,h,i)perylene and hopane). Results demonstrated the use of APTR to identify source-impacted time intervals when compared with filter samples analyzed for organic source markers.