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Urban Scale Variability of PM2.5 Components
Carvin D. Stevens; Ron Williams; Alan Vette and Paul Jones
U.S.EPA, Research Triangle Park, NC, USA
Introduction
An objective of the Detroit Exposure and Aerosol Research Study (DEARS) is to determine the associations between concentrations measured at central site monitors and outdoor residential, indoor residential and personal exposures for selected air toxics, PM constituents, and PM from specific sources.
Purpose
The focus of this poster is to demonstrate that a central site monitor adequately represents ambient concentrations of PM2.5 mass and its secondary constituents over a county-level scale in an urban area. Primary aerosol components, however, are much more spatially variable due to local source contributions in the Detroit urban air shed and more spatially resolved measurements are necessary.
Conclusions
These data suggest that a central site monitor may adequately represent the spatial distribution of secondary components (Nitrates & Sulfates) of PM2.5, but not adequately represent the primary components (primary OC, EC, metals, crustal, etc.) contributed by local sources. Additional source monitoring will be needed with the inclusion of survey, activity, source apportionment and meteorological results to provide better estimates for modeling spatial distributions and exposures to these pollutants across the air shed.
Disclaimer: Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.