Passive air sampling for determining the levels of ambient PCDD/Fs and their seasonal and spatial variations and inhalation risk in Shanghai, China.

The seasonal and spatial variations, compositional profiles, and possible sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in ambient air samples in Shanghai of China were investigated by passive air samplers, and the potential inhalation risks posed by these chemicals were evaluated. The following results were obtained: (1) The World Health Organization (WHO) toxic equivalency (TEQ) values for PCDD/Fs were in the range of 10.8-259 fg m(-3) (mean 63.4 fg m(-3)) in summer and 24.1-154 fg m(-3) (mean 83.4 fg m(-3)) in winter. Atmospheric PCDD/F levels were in the following order: industrial areas > commercial and residential areas > rural areas. (2) 2,3,4,7,8-PeCDF (24 %), 2,3,7,8-TeCDD (16 %), 1,2,3,7,8-PeCDD (13 %), and 2,3,7,8-TeCDF (12 %) were the predominant contributors to the TEQ of PCDD/Fs. (3) There was a slight seasonal trend with higher TEQ values in winter than in summer, which could be related to seasonal variations in the dispersion of PCDD/Fs in ambient air. (4) The children's daily intake was at the lower end of the range for the tolerable daily intake of PCDD/Fs recommended by WHO, which indicates that the inhalation risk of PCDD/Fs for local residents in Shanghai is relatively low.