Reduced light absorption of black carbon (BC) and its influence on BC-boundary-layer interactions during “APEC Blue”

Atmospheric chemistry and physics

article

Gao, Meng¹  Wang, Yuesi⁴  Zhang, Qiang⁵  Carmichael, Gregory R.⁶  Hu, Jianlin¹  Yang, Yang¹  Liao, Hong¹  Zhu, Bin⁷  Zhang, Yuxuan⁸  Liu, Zirui⁴  Lu, Xiao⁹  Wang, Chen⁶  Zhou, Qiming² 

[1] Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control (AEMPC), Nanjing University of Information Science & Technology;Department of Geography, State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University;Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou);State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences;Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University;Department of Chemical and Biochemical Engineering, The University of Iowa;Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science & Technology;School of Atmospheric Sciences, Nanjing University;School of Atmospheric Sciences, Sun Yat-Sen University

DOI  :  10.5194/acp-21-11405-2021

学科分类：医学（综合）

来源: Copernicus Publications

【 摘 要 】

Light absorption and radiative forcing of black carbon (BC) is influenced by both BC itself and its interactions with other aerosol chemical compositions. Although the changes in BC concentrations in response to emission reduction measures have been well documented, the influence of emission reductions on the light absorption properties of BC and its influence on BC-boundary-layer interactions has been less explored. In this study, we used the online coupled WRF-Chem model to examine how emission control measures during the Asia-Pacific Economic Cooperation (APEC) summit affect the mixing state and light absorption of BC, and the associated implications for BC-PBL interactions. We found that both the mass concentration of BC and the BC coating materials declined during the APEC week, which reduced the light absorption and light absorption enhancement ( E ab ) of BC. The reduced absorption aerosol optical depth (AAOD) during APEC was caused by both the decline in the mass concentration of BC itself (52.0 %), and the lensing effect of BC (48.0 %). The reduction in coating materials (39.4 %) contributed the most to the influence of the lensing effect, and the reduced light absorption capability ( E ab ) contributed 3.2 % to the total reduction in AAOD. Reduced light absorption of BC due to emission control during APEC enhanced planetary boundary layer height (PBLH) by 8.2 m. PM 2.5 and O 3 were found to have different responses to the changes in the light absorption of BC. Reduced light absorption of BC due to emission reductions decreased near-surface PM 2.5 concentrations but near-surface O 3 concentrations were enhanced in the North China Plain. These results suggest that current measures to control SO 2 , NO x , etc. would be effective in reducing the absorption enhancement of BC and in inhibiting the feedback of BC on the boundary layer. However, enhanced ground O 3 might be a side effect of current emission control strategies. How to control emissions to offset this side effect of current emission control measures on O 3 should be an area of further focus.

【 授权许可】

CC BY