Chemical Fingerprint and Source Identification of Atmospheric Fine Particles Sampled at Three Environments at the Tip of Southern Taiwan

ABSTRACTThe spatiotemporal variation, chemical fingerprints, transportation routes, and source apportionment of atmospheric fine particles (PM2.5) along the coastal region of southern Taiwan were investigated at three environments in the tip of southern Taiwan. Three representative sampling sites at Chien-Chin (urban site), Siao-Gang (industrial site) and Che-Cheng (background site) were selected for simultaneous PM2.5 sampling from December 2014 to May 2015. Regular sampling of 24-h PM2.5 was conducted for continuous 6–9 days in each month. After sampling, the chemical composition, including water-soluble ions, metallic elements and the carbonaceous content of PM2.5, was further analyzed within two weeks. The levoglucosan concentration was further compared to OC and K+ in PM2.5 originating from biomass burning. Moreover, the potential sources of PM2.5 and their respective contribution were further resolved by backward trajectory simulation, combined with chemical mass balance (CMB) receptor modeling. The field sampling results indicated that the PM2.5 concentrations at the urban and industrial sites were always higher than those at the background site. The most abundant water-soluble ionic species of PM2.5 are SO42–, NO3– and NH4+, implying that PM2.5 is mainly composed of secondary ammonium sulfate and ammonium nitrate. The most abundant metallic elements of PM2.5 included crustal elements (Al, Fe and Ca) and anthropogenic (generated by humans) elements (V, Ni, As, Cd, Zn and Pb). Moreover, the concentrations of OC and EC at the Chien-Chin and Siao-Gang sites were generally higher than those at the Che-Cheng site, mainly due to the emissions from urban and industrial anthropogenic sources. Vehicular exhausts and industrial emissions were the main sources of PM2.5 at the Chien-Chin and Siao-Gang sites, respectively, while biomass burning and soil dusts were the dominant sources of PM2.5 at the Che-Cheng site.