Vertical distributions of wintertime atmospheric nitrogenous compounds and the corresponding OH radicals production in Leshan, southwest China

Chengzhi Xing; Cheng Liu; Qihou Hu; Qingyan Fu; Shanshan Wang; Hua Lin; Yizhi Zhu; Shuntian Wang; Weiwei Wang; Zeeshan Javed; Xiangguang Ji; Jianguo Liu

doi:10.1016/j.jes.2020.11.019

Vertical distributions of wintertime atmospheric nitrogenous compounds and the corresponding OH radicals production in Leshan, southwest China

J Environ Sci (China). 2021 Jul:105:44-55. doi: 10.1016/j.jes.2020.11.019. Epub 2021 Jan 14.

Authors

Chengzhi Xing¹, Cheng Liu², Qihou Hu¹, Qingyan Fu³, Shanshan Wang⁴, Hua Lin⁵, Yizhi Zhu¹, Shuntian Wang¹, Weiwei Wang⁶, Zeeshan Javed⁷, Xiangguang Ji⁵, Jianguo Liu⁸

Affiliations

¹ Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China.
² Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei 230026, China; Anhui Province Key Laboratory of Polar Environment and Global Change, USTC, Hefei 230026, China. Electronic address: chliu81@ustc.edu.cn.
³ Shanghai Environmental Monitoring Center, Shanghai 200235, China.
⁴ Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Shanghai Institute of Eco-Chongming (SIEC), No.3663 Northern Zhongshan Road, Shanghai 200062, China.
⁵ School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei 230026, China.
⁶ Chongqing Key Laboratory of Catalysis and New Environmental Materials, College of Environment and Resources, Chongqing Technology and Business University, Chongqing 400067, China.
⁷ School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
⁸ Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.

PMID: 34130838
DOI: 10.1016/j.jes.2020.11.019

Abstract

Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations were operated from 02 to 21 December 2018 in Leshan, southwest China, to measure HONO, NO₂ and aerosol extinction vertical distributions, and these were the first MAX-DOAS measurement results in Sichuan Basin. During the measurement period, characteristic ranges for surface concentration were found to be 0.26-4.58 km^-1 and averaged at 0.93 km^-1 for aerosol extinction, 0.49 to 35.2 ppb and averaged at 4.57 ppb for NO₂ and 0.03 to 7.38 ppb and averaged at 1.05 ppb for HONO. Moreover, vertical profiles of aerosol, NO₂ and HONO were retrieved from MAX-DOAS measurements using the Heidelberg Profile (HEIPRO) algorithm. By analysing the vertical gradients of pollutants and meteorological information, we found that aerosol and HONO are strongly localised, while NO₂ is mainly transmitted from the north direction (city center direction). Nitrogen oxides such as HONO and NO₂ are important for the production of hydroxyl radical (OH) and oxidative capacity in the troposphere. In this study, the averaged value of OH production rate from HONO is about 0.63 ppb/hr and maximum value of ratio between OH production from HONO and from (HONO+O₃) is > 93% before12:00 in Leshan. In addition, combustion emission contributes to 26% for the source of HONO in Leshan, and we found that more NO₂ being converted to HONO under the conditions with high aerosol extinction coefficient and high relative humidity is also a dominant factor for the secondary produce of HONO.

Keywords: HONO; Hydroxyl radical; MAX-DOAS; Secondary source; Verticle distribution.

MeSH terms

Air Pollutants* / analysis
China
Cities
Nitrogen Compounds
Nitrogen Dioxide / analysis
Nitrous Acid / analysis

Substances

Air Pollutants
Nitrogen Compounds
Nitrogen Dioxide
Nitrous Acid