Atmospheric Wet Deposition of PCDD/Fs in the Ambient Air

Abstract

Wet deposition is an important mechanism for removing air pollutants from the atmosphere. The total PCDD/Fs-WHO2005-TEQ wet deposition from 2018-2020 was investigated for Beijing and Tianjin City in this study. In addition, the gas-particle partitioning of wet deposition, the total PCDD/Fs-WHO2005-TEQ concentrations in the rain, the PM2.5-bound total PCDD/Fs-WHO2005-TEQ content, and the PM2.5 concentration were also studied for Beijing and Tianjin City, respectively. Between 2018 to 2020, as a whole, the average seasonal variations in PCDD/F wet deposition fluxes in spring, summer, fall, and winter were 50.50, 41.47, 23.03 and 16.76 pg WHO2005-TEQ m -2 month -1 , respectively, while in Tianjin, they were 35.30, 42.40, 13.37, and 14.77 pg WHO2005-TEQ m -2 month -1 , respectively. Because the two cities have more rainfall in spring and summer than they do in fall and winter, rainfall has a significant influence on the wet deposition flux. In regard to PCDD/Fs-WHO2005-TEQ in the rain, in Beijing, the average total PCDD/Fs-WHO2005-TEQ concentration in the rain in spring, summer, fall, and winter were 1.70, 0.39, 1.42, and 1.52 pg WHO2005-TEQ L -1 , respectively, while those in Tianjin, were 1.73, 0.42, 1.35, and 1.88 pg WHO2005-TEQ L -1 , respectively. The above results show that the total PCDD/Fs-WHO2005-TEQ concentrations in the rain are significantly lower in summer, which is mainly due to the fact that in summer, the total PCDD/Fs-WHO2005-TEQ concentrations in the air are lower, and the proportion of the gas phase is increased. When the total PCDD/Fs-WHO2005-TEQ concentrations in the air are washed away by a heavy rainfall, the PCDD/F concentrations are diluted.

Effects of Precipitation on the Air Quality Index, PM2.5 Levels and on the Dry Deposition of PCDD/Fs in the Ambient Air

“…According to previous studies, precipitation can effectively improve air quality because rainwater can take away PM2.5 and other pollutants in the air and carry away some of the particulate matter to some extent, reducing the concentration of PCDD/Fs, and thus purifying the air and improving air quality (Tian et al, 2021a;Yu et al, 2021).…”

Study on Air Quality Index, Atmospheric Pollutants and Dry Deposition of PCDD/Fs in the Ambient Air near Southwest China

“…PCDD/Fs have been shown to be a risk causative factor for cancer, immune deficiencies, reproductive and developmental abnormalities, autism spectrum disorder, and endocrine disruption (Guo et al, 2018;Schecter et al, 2006). It was shown that the distribution behavior of both gas and particle phases was the main determinant of the environmental trends of PCDD/Fs, while the PCDD/Fs entering the ecosystem mainly originated from the gravitational sedimentation of the particle phase (Tian et al, 2021a). Therefore, attention should be focused on the relationship between particulate matter and PCDD/Fs.…”