PM2.5 sources affecting particle radioactivity in Boston, Massachusetts

Abstract Recent studies have found associations between particle radioactivity and various human health outcomes. The aim of this study is to identify sources contributing to PM2.5 (particulate matter with the aerodynamic diameter less than 2.5 μm) gross α- and β-activity levels. We used positive matrix factorization (PMF) to identify and apportion sources of PM2.5 in Boston during the period of one year in Boston. Toward this end, we used daily concentrations of elements, black carbon (BC), and PM2.5 mass. We identified six source types: regional pollution, motor vehicles, oil combustion, crustal, biomass burning, and sea salt. Subsequently, we performed multiple linear regression (MLR) analysis to examine the association between individual source contributions and PM2.5 gross α- and β-activities. Our analysis suggested that regional pollution had the highest impact on both PM2.5 α- and β-activities, followed by motor vehicles. Biomass burning and sea salt were not significantly associated with PM2.5 β-activity.