TY - JOUR
T1 - Double-Edged Role of VOCs Reduction in Nitrate Formation
T2 - Insights from Observations during the China International Import Expo 2018
AU - Zhang, Yingnan
AU - Wang, Hongli
AU - Huang, Liubin
AU - Qiao, Liping
AU - Zhou, Min
AU - Mu, Jiangshan
AU - Wu, Can
AU - Zhu, Yujiao
AU - Shen, Hengqing
AU - Huang, Cheng
AU - Wang, Gehui
AU - Wang, Tao
AU - Wang, Wenxing
AU - Xue, Likun
N1 - Publisher Copyright:
© 2023 American Chemical Society.
PY - 2023/10/24
Y1 - 2023/10/24
N2 - Aerosol nitrate (NO3-) constitutes a significant component of fine particles in China. Prioritizing the control of volatile organic compounds (VOCs) is a crucial step toward achieving clean air, yet its impact on NO3- pollution remains inadequately understood. Here, we examined the role of VOCs in NO3- formation by combining comprehensive field measurements conducted during the China International Import Expo (CIIE) in Shanghai (from 10 October to 22 November 2018) and multiphase chemical modeling. Despite a decline in primary pollutants during the CIIE, NO3- levels increased compared to pre-CIIE and post-CIIE─NO3- concentrations decreased in the daytime (by −10 and −26%) while increasing in the nighttime (by 8 and 30%). Analysis of the observations and backward trajectory indicates that the diurnal variation in NO3- was mainly attributed to local chemistry rather than meteorological conditions. Decreasing VOCs lowered the daytime NO3- production by reducing the hydroxyl radical level, whereas the greater VOCs reduction at night than that in the daytime increased the nitrate radical level, thereby promoting the nocturnal NO3- production. These results reveal the double-edged role of VOCs in NO3- formation, underscoring the need for transferring large VOC-emitting enterprises from the daytime to the nighttime, which should be considered in formulating corresponding policies.
AB - Aerosol nitrate (NO3-) constitutes a significant component of fine particles in China. Prioritizing the control of volatile organic compounds (VOCs) is a crucial step toward achieving clean air, yet its impact on NO3- pollution remains inadequately understood. Here, we examined the role of VOCs in NO3- formation by combining comprehensive field measurements conducted during the China International Import Expo (CIIE) in Shanghai (from 10 October to 22 November 2018) and multiphase chemical modeling. Despite a decline in primary pollutants during the CIIE, NO3- levels increased compared to pre-CIIE and post-CIIE─NO3- concentrations decreased in the daytime (by −10 and −26%) while increasing in the nighttime (by 8 and 30%). Analysis of the observations and backward trajectory indicates that the diurnal variation in NO3- was mainly attributed to local chemistry rather than meteorological conditions. Decreasing VOCs lowered the daytime NO3- production by reducing the hydroxyl radical level, whereas the greater VOCs reduction at night than that in the daytime increased the nitrate radical level, thereby promoting the nocturnal NO3- production. These results reveal the double-edged role of VOCs in NO3- formation, underscoring the need for transferring large VOC-emitting enterprises from the daytime to the nighttime, which should be considered in formulating corresponding policies.
KW - multiphase chemical box model
KW - nitrogen oxides
KW - oxidants
KW - particulate nitrate
KW - volatile organic compounds
UR - https://www.scopus.com/pages/publications/85175585835
U2 - 10.1021/acs.est.3c04629
DO - 10.1021/acs.est.3c04629
M3 - 文章
C2 - 37821356
AN - SCOPUS:85175585835
SN - 0013-936X
VL - 57
SP - 15979
EP - 15989
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 42
ER -