Study on the characteristics of black carbon during atmospheric pollution conditions in Beijing

Xiaochuan Zhang; Tianhai Cheng; Hong Guo; Fangwen Bao; Shuaiyi Shi; Wannan Wang; Xin Zuo

doi:10.1016/j.scitotenv.2020.139112

Study on the characteristics of black carbon during atmospheric pollution conditions in Beijing

Sci Total Environ. 2020 Sep 1:733:139112. doi: 10.1016/j.scitotenv.2020.139112. Epub 2020 May 5.

Authors

Xiaochuan Zhang¹, Tianhai Cheng², Hong Guo³, Fangwen Bao⁴, Shuaiyi Shi⁵, Wannan Wang¹, Xin Zuo¹

Affiliations

¹ State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100049, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100049, China. Electronic address: chength@radi.ac.cn.
³ State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100049, China. Electronic address: guohong@radi.ac.cn.
⁴ Center for Oceanic and Atmospheric Science at SUSTech (COAST), Department of Ocean Sciences and Engineering, Southern University of Science and Technology, Shenzhen, China.
⁵ State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100049, China.

PMID: 32470715
DOI: 10.1016/j.scitotenv.2020.139112

Abstract

Black carbon (BC), not only has a negative impact on human health, but also contributes to visibility degradation and the attenuation of solar radiation due to light absorption. In this paper, we investigated the variations of BC concentration, BC optical characteristics and its effects on the physical and optical properties of atmospheric aerosols based on AERONET data during atmospheric pollution conditions in Beijing from 2012 to 2017. The results indicated that the average annual ground-level BC concentration and BC/PM_2.5 were 8.9 μg m^-3 and 6.7%, respectively, from 2012 to 2017 during atmospheric pollution conditions in Beijing. The annual mean ground-level BC concentration showed weak variation, but the monthly variation was pronounced during atmospheric pollution conditions. Moreover, the BC column concentration had a higher correlation with absorptive aerosol optical thickness (AAOT) at 870 nm (R² = 0.93) than 440 nm (R² = 0.73). The difference in AAOT between 440 nm and 870 nm was more significant under high BC column concentration. The seasonal variation of the BC column concentration that contributed to the AAOT at 870 nm displayed a consistent monthly average variation tendency. The BC column concentrations were divided into three segments of low, moderate, and high according to the results of the approximately normal distribution of the BC column concentration. Compared with high BC concentration, the single scattering albedo (SSA) and asymmetry parameter were enhanced by 0.05 and 0.04 in low BC concentrations, respectively. On the contrary, the fine mode fraction (FMF) was dropped by 12.5% in low BC concentrations. A higher BC concentration contributed to the enhancement in the AAOT and the extinction ratio of the fine mode aerosol. Meanwhile, the atmospheric particles' forward scattering ability was also attenuated under a high BC concentration.

Keywords: AAOT, Physical and optical properties; Atmospheric pollution condition; BC concentration; Beijing.