Using Transit Vehicles as Probes to Monitor Community Air Quality and Exposure

Abstract

This project evaluates the feasibility of using transit vehicles traveling on fixed routes in a well-controlled residential community in El Paso for near-road exposure assessment. Continuous on-road measurements of four pollutants (PM2.5 , PM10, NO2, and O3) were recorded using U.S. EPA FEM-designated monitors in conjunction with a GPS device for coordinates and vehicle speed. Concurrent near-road measurements of the same air pollutants at two near-road stationary sites were used to develop relationships with the mobile data. It was found that pollutant concentrations measured by mobile air monitors agree well with that collected at stationary sites. On-road PM2.5 and PM10 concentrations closely resemble that measured at stationary sites. O3 concentration was found to be ubiquitous in the community whether it’s on-road, near-road, or in the community. On-road measurements of NO2 showed slightly higher values compared to near-road sites. Furthermore, concentrations of transportation related air pollutants at traffic intersections in an environment with less traffic and topological features were found to be indistinguishable from that measured on road segments away from the traffic intersections. This study demonstrates that mobile air monitoring in a less traveled community can accurately detect the exposure concentrations that are representative of the community and near-road receptors. Further research should focus on how the mobile data can be used in exposure and health assessment and how the technique can be applied to characterize exposure concentrations at locations that stationary monitoring is not allowed or possible.