Components of particulate air pollution and mortality in Chile.

To determine the association between several elements of fine particulate air pollution (PM2.5) and mortality in a general population sample, daily time-series analysis was used to test the association between daily mortality and components of PM2.5 measured in downtown Santiago, Chile between 1998 and 2006. The strongest individual effect was seen for elemental carbon. A 5.28 ug/m3 increase in elemental carbon was associated with a relative risk (RR) of 1.08 (95% CI = 1.07-1.09) for total non-accidental mortality. Using factor analysis, a group of elements consistent with a mobile combustion source (carbon monoxide, nitrogen dioxide, elemental and organic carbon) was significantly associated with total mortality (RR 1.11; 95% CI = 1.083-1.138). Soil-sourced particles had a weaker but statistically significant mortality effect. Of the many sources of particulate air pollution, those from motor vehicle exhaust had the greatest observed effect on mortality.