Characteristics and Receptor Modeling of Atmospheric PM2.5 at Urban and Rural Sites in Pingtung, Taiwan

W. C. Wang ； K. S. Chen ； S. J. Chen ； C. C. Lin ； J. H. Tsai ； C. H. Lai ； S. K. Wang

《Aerosol and Air Quality Research》 8卷2期 (2008/06) Pp. 112-129

並列摘要

Suspended particles of PM2.5 in air were sampled concurrently at an urban site and a rural site in Pingtung County in southern Taiwan, in the spring, the summer and the fall of 2005. All samples were analyzed to identify eight water-soluble ions, carbonaceous contents, and 19 metal elements. Measurements reveal that the overall means of PM10 (and PM2.5) are 59.2 (47.4) μg/m^3 at Pingtung (urban) site, and 63.6 (45.7) μg/m^3 at Chao-Chou (rural) site. Although both sites exhibited strong correlations (R = 0.98 at Pingtung, and R=0.78 at Chao-Chou) between PM10 and PM2.5 masses, the mean PM2.5/PM10 ratio was 0.81 at Pingtung, higher than 0.68 at Chao-Chou, suggesting that relatively large bare lands and outdoor burning on farms may have caused more coarse particles to be present in PM2.5 at a rural site (Chao-Chou) than at an urban site (Pingtung). Results of CMB (chemical mass balance) modeling show that the main contributors to PM2.5 mass at Pingtung are vehicle exhaust (49.3-62.4%) and secondary aerosols (SO4(superscript 2-), NO3(superscript –) and NH4(superscript +) (31.2-37.8%), while those at Chao-Chou are the outdoor burning (25.3-50.4%) of agricultural waste, secondary aerosols (27.2-34.3%) and vehicle exhaust (12.0-26.9%), depending on the seasons.

並列關鍵字

PM2.5 ； Water-soluble ions ； Carbonaceous species ； Receptor modeling ； CMB analysis