Oxidant generation capacity of source-apportioned PM2.5.

While many studies found associations between ambient particulate matter (PM) and morbidity or mortality outcomes, it is unclear whether these associations were dependent on the composition of PM, which varies with the source of that PM. We address this knowledge gap by conducting a time-series PM-health effects assessment that specifically investigates the role of source-apportioned fine PM (PM2.5) on the oxidant generation capacity that might be responsible for respiratory and cardiovascular health outcomes. Daily PM2.5 composition speciation and black carbon (BC) measurements, conducted in rural New York for 303 days between March 2003 and January 2005, were analyzed using factor analysis source-apportionment model, and five source categories (transported aerosol/secondary sulfate, resuspended soil, metals, residual oil combustion, and industrial/incineration) were identified. After the exposure of human epithelial cells (BEAS-2B) to these PM2.5 samples, cellular nuclear factor-κB (NF-κB) activation showed a relatively significant association Ni (concentration averaging 38 ng/m(3)), and weaker but still significant correlations with Ba (13 ng/m(3)), Mn (9 ng/m(3)), and Fe (500 ng/m(3)). The single-source regression analysis of NF-κB signal showed significant association with metal source only. Our results showed that metals in PM2.5 were the important source for cellular oxidant generation and may be responsible for subsequent health effects associate with particle air pollution.