Abstract
The concentration and signature of n-alkanes (n-C10 to n-C33) and 18 PAHs were determined in air filters across a year period (2010) in an urban area of the city of Valdivia, Chile. Filter samples were extracted using sohxlet apparatus and analyzed by GC-MS techniques. Concentrations of total hydrocarbons ranged from 45–352 ng.m−3 and total PAHs ranged from 2.93–78.01 ng.m−3. Concentrations of hydrocarbons during the summer were high (288–352 ng.m-3) and reduced when the autumn began (45–79 ng.m−3) to then increase almost linearly to the next summer. The drop in concentration was attributed in part to the significant reduction of traffic when summer ends as tourists leave the city (about 9–15% of the total cars circulating). Results from the chemometric technique of Polytopic Vector Analysis (PVA) indicated three main sources for the alkanes: biogenic (terrestrial plants), signatures of oil combustion, and an unconfirmed source which is thought to come from non specific organic matter degradation. Total PAHs correlated well with total particulate matter with a R2 = 0.94. Levels of PAHs in the atmosphere were higher during the winter (6.85–78.01 ng.m−3) period than the rest of the year (2.93–36.30 ng.m−3). PVA results indicate three key sources of PAHs and two of those sources derived from oil combustion and biomass burning.
Published Version
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