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

Received: May 31, 2008
Revised: May 31, 2008
Accepted: May 31, 2008
Download Citation: RIS|BibTeX|https://doi.org/10.4209/aaqr.2007.09.0039  

Cite this article:
Wang, W.C., Chen, K.S., Chen, S.J., Lin, C.C., Tsai, J.H., Lai, C.H. and Wang, S.K. (2008). Characteristics and Receptor Modeling of Atmospheric PM2.5 at Urban and Rural Sites in Pingtung, Taiwan. Aerosol Air Qual. Res. 8: 112-129. https://doi.org/10.4209/aaqr.2007.09.0039

ABSTRACT

Suspended particles of PM_2.5 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 PM_2.5) are 59.2 (47.4) μg/m³ at Pingtung (urban) site, and 63.6 (45.7) μg/m³ 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 PM_2.5 masses, the mean PM_2.5/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 PM_2.5 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 PM_2.5 mass at Pingtung are vehicle exhaust (49.3–62.4%) and secondary aerosols (SO₄^2–, NO₃^– and NH₄⁺) (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.

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