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Meta-Analysis on Near-Road Air Pollutants Concentrations for Developing Traffic Indicators for Exposure Assessment
Chen, F., S. Liu, AND J. Xue. Meta-Analysis on Near-Road Air Pollutants Concentrations for Developing Traffic Indicators for Exposure Assessment. Presented at ISES Conference, Cincinatti, OH, October 12 - 16, 2014.
The National Exposure Research Laboratory (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA mission to protect human health and the environment. HEASD research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA 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.
Near-road air pollution has been associated with various health risks in human populations living near roadways. To better understand relationship between vehicle emissions and spatial profiles of traffic-related air pollutants we performed a comprehensive and systematic literature survey on publications containing measurement data for air pollutants with distance information from roads. 8169 publications matched to the initial wide-scope keywords search and 3799 publications were retained after excluding publications related to models, health effects, and land use. 1879 publications were collected into an Endnote library after screening the 3799 publications for containing information on black carbon (BC), carbon monoxide (CO), nitrogen oxides (NO, NO2, or NOx), and particulate matter (PM). Three researchers independently read the abstracts of these 1879 publications to find those containing actual data for the selected air pollutants near major roads with distance profiles. Analyses were performed on concentration data of the selected air pollutant from 65 publications meeting the final criteria. These analyses showed no apparent distance decay relationship for PM but a clear distance-decay for BC. NOx also showed distance gradients which are more obvious than that shown for CO. These initial observations suggest that some near-road air pollutants bear closer relationship with the vehicle emissions than the others. Further analysis of original data obtained from EPA near-road study projects will refine these spatial-distance-decay patterns. Thus it is possible to develop traffic density-defined parameters for serving as surrogate pollution indexes for these air pollutants.