Comparing physicochemical properties of ambient particulate matter of hot spots in a highly polluted air quality zone

Abstract

The SURFER model is seldom used in combination with the CMB model to look for hot spots and estimate the contribution of various sources, and this is the aim of the current study. In addition, the hot spots of ambient particulate matter (PM) and their physicochemical characteristics in a highly polluted zone in southern Taiwan were further investigated and compared. The experimental results show that PM10 concentration in the fall was higher than in spring and summer. Moreover, northern monsoons transported suspended particles from the upwind emission sources to the sampling sites, causing an increase in secondary aerosols such as sulfate and nitrate. The contribution of secondary aerosols in rural areas such as Dai-liao and Chao-zhou (32.1% and 29.9%) and suburban areas like Ren-wu and Lin-yuan (28.7% and 29.0%) were higher than those in urban areas such as Hsiao-kang (20.3%). The higher Fe concentration in Hsiao-kang was attributed to PM emission from steel factories (6.9-7.8%). In this study, the organic carbon/elemental carbon (OC/EC) in PM2.5 and PM10 for the five sites were all in the order of Hsiao-kang > Ren-wu > Lin-yuan > Chao-zhou > Da-liao. In fall, farm burns are very common in both Dai-liao and Chao-zhou, and this source contributed approximately 7.3% and 6.3%, respectively, to these results. The seasonal variation of the contribution from vehicle exhausts to PM10 (13.9-27.5%) at Hsiao-kang was always higher than those at other sites, especially in the fall. The results could provide important information for cost-effective control strategies to improve ambient air quality in hot spot areas. Copyright © Taiwan Association for Aerosol Research.