TY - JOUR
T1 - Fast near-surface ClNO2 production and its impact on O3 formation during a heavy pollution event in South China
AU - Chen, Xiaorui
AU - Xia, Men
AU - Wang, Weihao
AU - Yun, Hui
AU - Yue, Dingli
AU - Wang, Tao
N1 - Funding Information:
This research has been supported by the National Natural Science Foundation of China (grant no. 91844301 ) and the Hong Kong Research Grants Council (grant no. T24-504/17-N ). The authors thank Qianjie Chen for helpful discussion, Yaru Wang and Yiheng Liang for their help in analysing the oxygenated VOC and aerosol composition, and Naiwen Zhang for her help with the HONO measurements.
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2023/2/1
Y1 - 2023/2/1
N2 - Atmospheric nitryl chloride (ClNO2) acts as a reservoir of both NOx and reactive chlorine radicals and therefore affects atmospheric oxidation chemistry and the production of secondary pollutants such as ozone (O3). However, the factors contributing to ClNO2 production and its impact on O3 formation in the polluted atmosphere are not fully understood. Here, we investigated the causes and impacts of extremely high ClNO2 levels (up to 8.3 ppbv, 1 min average) in a winter pollution episode at a semi-rural surface site in South China. Anthropogenic activities (mainly coal burning) produced an abundant amount of chloride, and high NO3 production rates and efficient N2O5 uptake by aerosols facilitated ClNO2 production at night. We used a chemical box model to assess the ClNO2 impact on next-day O3 production both at the site and in downwind areas. The model results showed that ClNO2 chemistry led to 6.6 % enhancement of net Ox (=NO2 + O3) production at the site, while the enhancement was increased to 11.2 % in the air mass transporting downwind, which resulted in 20 ppbv (38.5 % max) increment of peak O3 concentration. ClNO2 also changed the response of O3 to reduction in the concentration of O3 precursors (NOx and anthropogenic volatile organic compounds (VOCs)), thereby affecting the design of NOx and VOC reduction strategies for O3 pollution mitigation. Reducing chloride emissions can help alleviate the emission reduction burden for NOx and anthropogenic VOCs.
AB - Atmospheric nitryl chloride (ClNO2) acts as a reservoir of both NOx and reactive chlorine radicals and therefore affects atmospheric oxidation chemistry and the production of secondary pollutants such as ozone (O3). However, the factors contributing to ClNO2 production and its impact on O3 formation in the polluted atmosphere are not fully understood. Here, we investigated the causes and impacts of extremely high ClNO2 levels (up to 8.3 ppbv, 1 min average) in a winter pollution episode at a semi-rural surface site in South China. Anthropogenic activities (mainly coal burning) produced an abundant amount of chloride, and high NO3 production rates and efficient N2O5 uptake by aerosols facilitated ClNO2 production at night. We used a chemical box model to assess the ClNO2 impact on next-day O3 production both at the site and in downwind areas. The model results showed that ClNO2 chemistry led to 6.6 % enhancement of net Ox (=NO2 + O3) production at the site, while the enhancement was increased to 11.2 % in the air mass transporting downwind, which resulted in 20 ppbv (38.5 % max) increment of peak O3 concentration. ClNO2 also changed the response of O3 to reduction in the concentration of O3 precursors (NOx and anthropogenic volatile organic compounds (VOCs)), thereby affecting the design of NOx and VOC reduction strategies for O3 pollution mitigation. Reducing chloride emissions can help alleviate the emission reduction burden for NOx and anthropogenic VOCs.
KW - Chloride source
KW - ClNO
KW - O production and mitigation
UR - http://www.scopus.com/inward/record.url?scp=85141924168&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2022.159998
DO - 10.1016/j.scitotenv.2022.159998
M3 - Journal article
C2 - 36368396
AN - SCOPUS:85141924168
SN - 0048-9697
VL - 858
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 159998
ER -