| Title: | Improving the representation of HONO chemistry in CMAQ and examining its impact on haze over China |
| Author(s): | Zhang S; Sarwar G; Xing J; Chu B; Xue C; Sarav A; Ding D; Zheng H; Mu Y; Duan F; Ma T; He H; |
| Address: | "State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China. University of Chinese Academy of Sciences, Beijing 100049, China. Center for Environmental Measurement and Modeling, U.S. Environmental Protection Agency, 109 T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA. Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China. Institute for the Environment, The University of North Carolina at Chapel Hill, 100 Eurpoa Drive, Chapel Hill, NC 27514, USA" |
| DOI: | 10.5194/acp-21-15809-2021 |
| ISSN/ISBN: | 1680-7316 (Print) 1680-7324 (Electronic) 1680-7316 (Linking) |
| Abstract: | "We compare Community Multiscale Air Quality (CMAQ) model predictions with measured nitrous acid (HONO) concentrations in Beijing, China for December 2015. The model with the existing HONO chemistry in CMAQ severely under-estimates the observed HONO concentrations with a normalized mean bias of -97%. We revise the HONO chemistry in the model by implementing six additional heterogeneous reactions in the model: reaction of nitrogen dioxide (NO(2)) on ground surfaces, reaction of NO(2) on aerosol surfaces, reaction of NO(2) on soot surfaces, photolysis of aerosol nitrate, nitric acid displacement reaction, and hydrochloric acid displacement reaction. The model with the revised chemistry substantially increases HONO predictions and improves the comparison with observed data with a normalized mean bias of -5%. The photolysis of HONO enhances day-time hydroxyl radical by almost a factor of two. The enhanced hydroxyl radical concentrations compare favourably with observed data and produce additional sulfate via the reaction with sulfur dioxide, aerosol nitrate via the reaction with nitrogen dioxide, and secondary organic aerosols via the reactions with volatile organic compounds. The additional sulfate stemming from revised HONO chemistry improves the comparison with observed concentration; however, it does not close the gap between model prediction and the observation during polluted days" |
| Notes: | "PubMed-not-MEDLINEZhang, Shuping Sarwar, Golam Xing, Jia Chu, Biwu Xue, Chaoyang Sarav, Arunachalam Ding, Dian Zheng, Haotian Mu, Yujing Duan, Fengkui Ma, Tao He, Hong eng EPA999999/ImEPA/Intramural EPA/ Germany 2021/11/23 Atmos Chem Phys. 2021 Oct 22; 21(20):15809-15826. doi: 10.5194/acp-21-15809-2021" |
