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

Jinning Zhu ； Jin Xing ； Haiyan Tang ； Wen-Jhy Lee ； Ping Yan ； Kangping Cui ； Qianli Huang

《Aerosol and Air Quality Research》 17卷8期 (2017/08) Pp. 2027-2040

https://doi.org/10.4209/aaqr.2017.06.0217

摘要

Monitoring atmospheric deposition fluxes (dry and wet deposition) is of great importance in tracing the environmental fate and behavior of PCDD/Fs. To further understand the characteristics of both dry and wet PCDD/F deposition in Northern China, two cities, namely Harbin and Shijiazhuang were investigated. During 2014, in Harbin, the monthly dry deposition fluxes of total-PCDD/Fs-WHO_(2005)-TEQ ranged between 308 and 1290 pg WHO_(2005)-TEQ m^(-2) month^(-1), with an annual flux of 8240 pg WHO_(2005)-TEQ m^(-2) year^(-1); however, in Shijiazhuang, the dry deposition fluxes ranged from 699 to 2230 pg WHO_(2005)-TEQ m^(-2) month^(-1), with an annual 15400 pg WHO_(2005)-TEQ m^(-2) year^(-1). Monthly dry deposition velocities of particle phase total-PCDD/Fs-WHO_(2005)-TEQ are similar, ranging between 0.42 and 0.94 cm s^(-1) (average 0.59 cm s^(-1)) and between 0.42 and 0.92 cm s^(-1) (average 0.6 cm s^(-1)) in Harbin and Shijiazhuang, respectively. Due to the low level of rainfall in Northern China, the monthly wet deposition fluxes were in the range of 3-79.9 (369 pg WHO_(2005)-TEQ m^(-2) year^(-1)) and 0-140 pg WHO_(2005)-TEQ m^(-2) month^(-1) (622 pg WHO_(2005)-TEQ m^(-2) year^(-1)) in Harbin and Shijiazhuang, respectively. In addition, the average scavenging ratios of total-PCDD/Fs-WHO_(2005)-TEQ were 31900 and 30700 in Harbin and Shijiazhuang, respectively. Combined with dry and wet deposition, the annual total (dry + wet) deposition flux in Shijiazhuang (16100 pg WHO_(2005)-TEQ m^(-2) year^(-1)) is 1.9 times of magnitude higher than that in Harbin (8610 pg WHO_(2005)-TEQ m^(-2) year^(-1)). The results indicated that the dry deposition flux was the major mechanism for removal of PCDD/Fs from the atmosphere in Northern China. By examining both the PM_(2.5) level and total-PCDD/Fs-WHO_(2005)-TEQ deposition in Northern China, and comparing the values with those found in other places, it is clear that there is an urgent need to control the particulate emissions in this area.

關鍵字

Dry deposition ； Wet deposition ； PCDD/Fs ； PM_(10) ； PM_(2.5) ； Northern China