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Gu R, Wang W, Peng X, Xia M, Zhao M, Zhang Y, Wang Y, Liu Y, Shen H, Xue L, Wang T, Wang W. Nitrous acid in the polluted coastal atmosphere of the South China Sea: Ship emissions, budgets, and impacts. Sci Total Environ 2022; 826:153692. [PMID: 35182648 DOI: 10.1016/j.scitotenv.2022.153692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 02/01/2022] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
Nitrous acid (HONO) can significantly contribute to hydroxyl radicals (OH) and thus regulate atmospheric oxidation chemistry; however, ambient HONO sources are not well quantified and vary in different environments. In this study, we conducted comprehensive field observations at a coastal site in the South China Sea and performed chemical box modelling to demonstrate contrasting budgets and impacts of diurnal atmospheric HONO derived from the sea, coastline and continent. The ship emission ratio of HONO/nitrogen oxides (NOx) (1.21 ± 0.99%) was calculated from hundreds of night-time fresh plume measurements. Offshore marine air was frequently influenced by ship exhausts, and the sea acted as an HONO sink. Heterogeneous conversions of nitrogen dioxide (NO2) on underlying surfaces and photolysis of adsorbed nitric acid (HNO3(ads)) were the major HONO sources in coastal air, when heterogeneous NO2 conversions on the ground surface and the homogeneous NO + OH reaction dominated HONO formation in continental air. HONO photolysis was a significant source of reactive radicals (ROx = OH + HO2 + RO2) in these air masses. Atmospheric box model including only homogeneous HONO source of the NO + OH reactions significantly underpredicted the OH concentration and atmospheric oxidising capacity in coastal and continental air. This study provides new insights into the complex sources and significant impacts of HONO in the polluted coastal boundary layer.
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Affiliation(s)
- Rongrong Gu
- Environment Research Institute, Shandong University, Qingdao 266237, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Weihao Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China; Hangzhou PuYu Technology Development Co., Ltd, Hangzhou 311300, China
| | - Xiang Peng
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China; Department of Ambient Air Quality Monitoring, China National Environmental Monitoring Center, Beijing 100012, China
| | - Men Xia
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Min Zhao
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Yingnan Zhang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Ya'nan Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Yiming Liu
- School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai 519082, China
| | - Hengqing Shen
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Likun Xue
- Environment Research Institute, Shandong University, Qingdao 266237, China; Collaborative Innovation Center for Climate Change, Nanjing, Jiangsu 210023, China.
| | - Tao Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China; Environment Research Institute, Shandong University, Qingdao 266237, China.
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Qingdao 266237, China
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