Volume 2, No. 1, June 2002, Pages 9-22 PDF(1.45 MB)
Developing Strategies for Improving Urban Visual Air Quality
Chung-Shin Yuan1, Chang-Gai Lee1,2, San-Ho Liu1, Ching Yuan3, Horng-Yu Yang4, Chen-Tung Arthur Chen5
1 Institute of Environmental Engineering, National Sun Yat-Sen Univerity, Kaohsiung, Taiwan, Republic of China
2 Department of Environmental Engineering, Rajen Institute of Technlongy, Pindong, Taiwan, Republic of China
3 Department of Civil and Environmental Engineering, National Universiry of Kaohsiung, Kaohsiung, Taiwan, Republic of China
4 Department of General Science, Air Force Institute of Aeronautical Technology, Gang-Shan, Kaoshiung, Taiwan, Republic of China
5 Institute of Marine Geology and Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan, Republic of China
This study examined the feasibility of adopting various strategies for improving urban air quality using atmospheric visibility as an indicator. Atmospheric visibility was regularly observed twice daily with unaided eyes at two sites since November 1998 in metropolitan Kaohsiung, which was selected as the study area because of having the worst ambient air quality in Taiwan. In addition to regular observation, intensive field monitoring of atmospheric visibility and aerosol particles was conducted in January and March of 2000. Aerosol particles were sampled by using two dichotomous samplers and the analyzed for various metallic constituents, carbon content, and water-soluble ions including major anions (F-, Cl-, SO4-2, and NO3-) and cations (NH4+, K+, Na+, Ca+2, and Mg+2). The apportioning of emission sources to impairing atmospheric visibility was conducted with receptor models based on chemical mass balance (CMB) and principal component factor analysis (PCA). Receptor modeling results were then applied to establish multiple regression models for atmospheric visibility, chemical composition of aerosol particles, and apportioned emission sources. The multiple regression models were further used to determine strategies for improving urban visual air quality in metropolitan Kaohsiung. Receptor modeling results indicated that motor vehicle exhaust and secondary aerosols were major sources of fine particles as well as major contributors to the reduction of atmospheric visibility in metropolitan Kaohsiung. Further investigation of the chemical component of fine particles indicated that ammonium sulfate, ammonium nitrate, and elemental carbon contributed 46%, 17%, and 17%, respectively, of the atmospheric visibility logarithm. Consequently, this study concluded that the most effective strategy for improving visual air quality in metropolitan Kaohsiung is to reduce the formation o secondary aerosols containing ammonium sulfate and ammonium nitrate.
Visual air quality; Atmospheric visibibity; Source apportionment; Receptor modeling.