Developing Strategies for Improving Urban Visual Air Quality

Chung-Shin Yuan；Chang-Gai Lee；San-Ho Liu；Ching Yuan；Horng-Yu Yang；Chen-Tung Arthur Chen

visual air quality ； atmospheric visibility ； source apportionment ； receptor modeling

Aerosol and Air Quality Research

2卷1期（2002 / 06 / 01）

9 - 22

英文

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 then analyzed for various metallic constituents, carbon content, and water-soluble ions including major anions (Fˉ, Clˉ, S04＾-2, and NO3ˉ) and cations (NH(superscript +)4, K(superscript +), Na(superscript +), Ca(superscript +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 of secondary aerosols containing ammonium sulfate and ammonium nitrate.