Source Apportionment of PAHs in Airborne Particulates (PM2.5) in Southern Chile

Abstract

ABSTRACTAirborne particulate matter (PM2.5) are known environmental cotaminants. Nevertheless, it is not only the size of particulate matter that influences human health, but also its chemical composition. The chemical composition of the PAH suite in PM2.5 may be indicative of the source materials, typically combustion products. In this study, particulate matter (PM2.5) was collected using portable air samplers during all of 2013 and 2014 at five locations of the Los Rios Region, Valdivia, Chile. The quantity of PM2.5 collected was measured using gravimetric methods. Solvent extracts were analyzed for associated PAHs by means of GC-MS techniques. The concentrations of PM2.5 for all locations ranged from 2.8 to 386 µg/m3 for the autumn/winter periods and from 1.1 to 315 µg/m3 for the spring/summer periods. The mean concentrations of PM2.5 ranged from 11.9 to 112 µg/m3 in summer for all sites. The concentrations of PAHs for all locations ranged from 2.8 to 115 ng/m3 for the autumn/winter periods and from 0.3 to 32 ng/m3 for the spring/summer periods. To determine the possible sources of PM2.5, cross-plots, PCA, and PVA analyses were performed. The results demonstrated that biomass burning was the dominant source of PM2.5 at all locations during autumn/winter periods with PAHs having four to six rings; during the spring/summer periods, PAHs with two to three rings were more abundant and were related to petrogenic sources. The sources of PM2.5 in the different studied areas were similar and were related to season rather than to geography. Analysis of meteorological data for the region demonstrated that the background summer PM2.5 for the years studied was ∼8 µg/m3 while when temperatures decreased below 15°C, there was an exponential increase in the concentration of particles in the air.