Spatio-Temporal Distributions of Particulate Matter and Heavy Metal Exposures in Washington, DC

The District of Columbia ranks seventh highest as one of the unhealthiest places to live due to poor air quality (EPA Report, 1999). Particulate matter is one of the major contributors to pollution in the Washington, DC environment. Quite often ambient airborne toxics are closely associated with particulate matter. Fine aerosols are characterized as particles with diameters smaller than 1m and are easily deposited into the alveolar regions of the human lungs, which can impose severe health risks. In this study, high-resolution aerosol measurements of PM2.5 and heavy metals like chromium, lead, cadmium and arsenic, in four wards of Washington, DC have been performed. Spatial distributions of both aerosols and heavy metals are characterized as a function of size and mass properties. This paper presents results of the spatial analysis of aerosol number and mass distribution for PM2.5.