Atmospheric Deposition of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Two Cities of Southern China

ABSTRACT

Atmospheric deposition is an important pathway for air pollutants entering the environment. In order to better understand both dry and wet deposition of PCDD/Fs in ambient air, two cities – Guangzhou and Nanjing in Southern China, were investigated. The monthly dry deposition fluxes of total-PCDD/Fs-WHO₂₀₀₅-TEQ were in the range of 60.6–560 and 104–1160 pg WHO₂₀₀₅-TEQ m^–2 month^–1 during 2014 in Guangzhou and Nanjing, respectively. In addition, it was found that the monthly dry deposition velocities of particle phase PCDD/Fs-TEQ ranged between 0.49 and 0.98 cm s^–1 (averaged 0.69 cm s^–1) and between 0.44 and 0.8 cm s^–1 (averaged 0.52 cm s^–1) in Guangzhou and Nanjing, respectively. The average scavenging ratios of total-PCDD/Fs-WHO₂₀₀₅-TEQ were 20480 and 30947 in Guangzhou and Nanjing, respectively. The total (dry + wet) deposition fluxes in Nanjing ranged between 135 and 1250, and averaged 643 pg WHO2005-TEQ m^–2 month^–1, approximatedly1.38–2.23 times of magnitude higher than those in Guangzhou, which ranged between 97.7 to 559 pg WHO2005-TEQ m^–2 month^–1 and averaged 254 pg WHO2005-TEQ m^–2 month^–1. The results of this study provide useful information for both further studies and environmental control strategies aimed at persistent organic compounds (POPs).