EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

OH reactivity in three major city clusters of China in ozone seasons: insights for regional ozone formation

Shengrong Lou1, Xiangsen Shen1, Xin Li2, Qian Wang1, and Shuoying Liu2
Shengrong Lou et al.
  • 1Shanghai Academy of Environment Sciences, Atmospheric Research Department, Shanghai 201103, China (
  • 2State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China

OH radical is the key driver of the photochemical process and closely related to ozone formation. OH reactivity is the quantification of OH radical sink in ambient air. In this study, in-situ OH reactivity measurements are carried out in Shenzhen, Chengdu and Changzhou, three typical cities in major city clusters of China, during their ozone pollution seasons. The measured OH reactivity is ranging from 5~35 s-1 under various meteorological conditions and trace gas concentrations. Aldehydes such as HCHO and acetaldehyde, mainly from the secondary formation of VOCs, are the principal contributors at day time. Primary VOCs such as toluene and biogenic VOCs such as isoprene play different roles in three measurement locations. The missing OH reactivity, which is defined as the OH reactivity that cannot be explained by trace gas measurements, are evaluated by in-situ measurement results as well as an observation-based model. Gas-phase secondary pollutants could be the main source of the missing OH reactivity. The sensitivity tests by the OBM model show ozone production in all areas is mainly VOC-limited but the key precursors of ozone are not identical, leading to different control strategies.

How to cite: Lou, S., Shen, X., Li, X., Wang, Q., and Liu, S.: OH reactivity in three major city clusters of China in ozone seasons: insights for regional ozone formation, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12898,, 2020