Volume 13, No. 2, April 2013, Pages 436-449 PDF(3.71 MB)
Inorganic Chemical Characterization of Aerosols in Four Asian Mega-Cities
Tomoaki Okuda1, Hideshige Takada2, Hidetoshi Kumata3, Fumiyuki Nakajima4, Shiro Hatakeyama2, Masao Uchida5, Shigeru Tanaka1, Kebin He6, Yongliang Ma6
1 Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
2 Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8509, Japan
3 Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
4 The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
5 National Institute for Environmental Studies, 16-2 Onogawa Tsukuba Ibaraki, 305-8506, Japan
6 School of Environment, Tsinghua University, Beijing 100084, China
This study is a systematic field observation campaign that examines the chemical characteristics of aerosols in four different mega-cities in Asia, namely Beijing (China), Hanoi (Vietnam), Kolkata (India), and Tokyo (Japan). The unity of the analytical method and the synchronicity of the sampling periods are quite important, especially when developing a comparative risk assessment in different places. Sampling was thus carried out in each city continuously for a one-year period between 2008 and 2010, as this enabled consideration of the seasonal variations that are associated with the Asian monsoon system that governs the climate of this region. The study found that the sum of the concentrations of measured elements decreased in the order of BJ > KK > HA > TY, while the sum of the concentrations of measured ions decreased in the order of BJ > HA > KK > TY. The concentration level of chemical species in aerosols in Beijing was one order of magnitude higher than that in Tokyo. The risks associated with carcinogenic metals in the four cities have also been calculated. We conclude that the calculated carcinogenic risks to humans by chromium were higher than the risks caused by nickel in all four cities.
Beijing; Hanoi; Kolkata; Tokyo; Hazardous metals; EDXRF.