Japan Geoscience Union Meeting 2023

Presentation information

[J] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS07] Atmospheric Chemistry

Mon. May 22, 2023 3:30 PM - 4:45 PM Exhibition Hall Special Setting (2) (Exhibition Hall 8, Makuhari Messe)

convener:Yosuke Sakamoto(Kyoto University Graduate School of Global Environmental Studies), Risa Uchida(Japan Automobile Research Institute), Shigeyuki Ishidoya(Advanced Industrial Science and Technology), Yoko Iwamoto(Graduate School of Integrated Sciences for Life, Hiroshima University), Chairperson:Satoshi Inomata(National Institute for Environmental Studies), Yosuke Sakamoto(Kyoto University Graduate School of Global Environmental Studies), Risa Uchida(Japan Automobile Research Institute)

4:15 PM - 4:30 PM

[AAS07-18] Rapid hydrolysis of NO2 at high ionic strengths of deliquesced aerosol particles

*Gen Masao1, Haotian Zheng2,3,4, Yele Sun5, Wanyun Xu6, Nan Ma7, Hang Su8, Yafang Cheng8, Shuxiao Wang2,3, Jia Xing2,3, Shuping Zhang2,3, Likun Xue9, Chaoyang Xue10, Yujing Mu11, Xiao Tian12, Atsushi Matsuki13, Shaojie Song4,12,14 (1.Tohoku University, 2.Tsinghua University, 3.State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, 4.CMA-NKU Cooperative Laboratory for Atmospheric Environment Health Research, 5.Institute of Atmospheric Physics, Chinese Academy of Sciences, 6.Chinese Academy of Meteorological Sciences, 7.Jinan University, 8.Max Planck Institute for Chemistry, 9.Shandong University, 10.CNRS – Université Orléans – CNES, 11.Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, 12.Nankai University, 13.Kanazawa University, 14.Harvard University)

Keywords:NO2 hydrolysis, Aerosol, Ionic strength, Multiphase reactions

Nitrogen dioxide (NO2) hydrolysis in deliquesced aerosol particles forms nitrous acid and nitrate and thus impacts air quality, climate, and nitrogen cycle. Traditionally, it is considered to proceed far too slowly in the atmosphere. However, the significance of this process is highly uncertain because kinetic studies have only been made in dilute aqueous solutions, and not under high ionic strength conditions of the aerosol particles. Here, we use laboratory experiments, air quality models, and field measurements to examine the effect of ionic strength on the reaction kinetics of NO2 hydrolysis. We find that high ionic strengths (I) enhance the reaction rate constants (kI) by more than two orders of magnitude compared to that at infinite dilution (kI=0), yielding log10(kI/kI=0) = 0.058I. A state-of-the-art air quality model shows that the enhanced NO2 hydrolysis reduces the negative bias in the simulated concentrations of nitrous acid by 27% on average when compared to field observations over the North China Plain. Rapid NO2 hydrolysis also enhances the levels of nitrous acid in other polluted regions such as North India and further promotes atmospheric oxidation capacity. This study highlights the need to evaluate various reaction kinetics of atmospheric aerosols with high ionic strengths.