A Source Apportionment of U.S. Fine Particulate Matter Pollution for Health Effects Analysis

P-067 Introduction: Long-term exposure to fine particulate matter (PM2.5) air pollution is associated with increased risk of mortality (Pope et al., 2002). However, the question remains regarding which pollution source emissions are most damaging. In 1999, the U.S. EPA instituted a nationwide PM2.5 mass and composition Speciation Network that provides the PM2.5 characteristics needed to conduct a statistical apportionment of air pollution impacts for cities across the U.S. In addition, a recent EPA workshop has indicated source apportionment methods to be reliable for apportioning the health effects of PM2.5 (Thurston et al., 2005). Methods: Using the 2000–2003 EPA Speciation Network data (considering 201 sites in 125 cities), we conducted a factor analysis (FA) of the entire nation. Quarterly mean site averages were used. We applied the Absolute Principal Components method developed by Thurston and Spengler (1985), in which FA is conducted, absolute zero values calculated and applied to give absolute FA scores, followed by a regression of the mass to apportion PM2.5 to source categories and locations around the U.S. Results: The sources identified (their key elements), and their mean nationwide PM2.5 impacts (with 95% Confidence Intervals) were: Metals Industry (Pb, Zn) 0.2 ug/m3 (0.1–0.3); Soil Particles (Ca, Si) 0.6 ug/m3 (0.4 –0.8); Motor Vehicles (OC, EC, NO3) 5.5 ug/m3 (5.1–5.9); Steel Industry (Fe, Mn) 0.1 ug/m3 (0.0–0.2); Coal Combustion (As, Se) 1.9 ug/m3 (1.6–2.1); Oil Combustion (V, Ni) 0.3 ug/m3 (0.2–0.4); Salt Particles (Na, Cl) 0.5 ug/m3 (0.3–0.6); Other Sulfate (S) 2.9 ug/m3 (2.7–3.2). This accounts for over 80% of the U.S. mean PM2.5 (14.4 ug/m3). Spatial plots of the impacts confirm the factor interpretations: Motor Vehicle impacts highest in Southern California; Soil impacts highest in the desert Southwest; Steel impacts highest in cities with major steel works (e.g., Detroit, MI); and, Coal impacts highest in the Ohio Valley region (e.g., Pittsburgh, PA). Residual oil burning impacts were highest in cities with deep ports (e.g., LA, CA; Savannah, GA, and Newark, NJ-NYC, NY) indicating a major impact by from cargo ships burning “bunker fuel”. Discussion: This reveals U.S. source factors similar to those reported for the 1979–1983 IP Network (Ozkaynak and Thurston, 1987). Results indicate that applying source apportionment methods to the EPA Speciation Network can provide a useful avenue to identify sources impacting the Nation, and for the determination of source-specific health effects to allow more efficient regulation of PM2.5. Research supported by NYU's National Institute of Environmental Health Sciences (NIEHS) Center Grant (ES00260) and the NYU-U.S. EPA Particulate Matter Health Research Center (R827351).