TY - JOUR
T1 - Reduced light absorption of black carbon (BC) and its influence on BC-boundary-layer interactions during “APEC Blue”
AU - Gao, Meng
AU - Yang, Yang
AU - Liao, Hong
AU - Zhu, Bin
AU - Zhang, Yuxuan
AU - Liu, Zirui
AU - Lu, Xiao
AU - Wang, Chen
AU - Zhou, Qiming
AU - Wang, Yuesi
AU - Zhang, Qiang
AU - Carmichael, Gregory R.
AU - Hu, Jianlin
N1 - Funding Information:
Financial support. This work was supported by the Open fund by Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control (grant no. KHK1902), the National Key Research and Development Program of China (grant no. 2016YFA0602003), the National Natural Science Foundation of China (no. 42005084 and no. 92044302), the Ministry of Science and Technology of the People’s Republic of China (Grant no. 2017YFC0210000), the Natural Science Foundation of Guangdong Province (no. 2019A1515011633), and special fund of the State Key Joint Laboratory of Environment Simulation and Pollution Control (grant no. 19K03ESPCT).
Publisher Copyright:
© Copyright:
PY - 2021/7/29
Y1 - 2021/7/29
N2 - 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 (Eab) 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 (Eab) 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. PM2.5 and O3 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 PM2.5 concentrations but near-surface O3 concentrations were enhanced in the North China Plain. These results suggest that current measures to control SO2, NOx, 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 O3 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 O3 should be an area of further focus.
AB - 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 (Eab) 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 (Eab) 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. PM2.5 and O3 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 PM2.5 concentrations but near-surface O3 concentrations were enhanced in the North China Plain. These results suggest that current measures to control SO2, NOx, 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 O3 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 O3 should be an area of further focus.
UR - http://www.scopus.com/inward/record.url?scp=85111734952&partnerID=8YFLogxK
U2 - 10.5194/acp-21-11405-2021
DO - 10.5194/acp-21-11405-2021
M3 - Journal article
SN - 1680-7316
VL - 21
SP - 11405
EP - 11421
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 14
ER -