The abundance and inter-relationship of atmospheric peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), O3, and NOy during the wintertime in Beijing, China

Gen Zhang; Lingjun Xia; Kunpeng Zang; Wanyun Xu; Fang Zhang; Linlin Liang; Bo Yao; Weili Lin; Yujing Mu

doi:10.1016/j.scitotenv.2020.137388

The abundance and inter-relationship of atmospheric peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), O₃, and NO_y during the wintertime in Beijing, China

Sci Total Environ. 2020 May 20:718:137388. doi: 10.1016/j.scitotenv.2020.137388. Epub 2020 Feb 19.

Authors

Gen Zhang¹, Lingjun Xia², Kunpeng Zang³, Wanyun Xu⁴, Fang Zhang⁵, Linlin Liang⁴, Bo Yao⁶, Weili Lin⁷, Yujing Mu⁸

Affiliations

¹ State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing 100081, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control (AEMPC), Nanjing University of Information Science & Technology, Nanjing 210044, China.
² Jiangxi Ecological Meteorology Center, Nanchang 330096, Jiangxi, China.
³ Key Laboratory for Ecological Environment in Coastal Areas, National Marine Environmental Monitoring Center, Ministry of Ecology and Environment, Dalian 116023, China.
⁴ State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing 100081, China.
⁵ College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China.
⁶ Meteorological Observation Centre (MOC), China Meteorological Administration (CMA), Beijing 100081, China.
⁷ Minzu University of China, Beijing 100081, China.
⁸ Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: yjmu@rcees.ac.cn.

PMID: 32105937
DOI: 10.1016/j.scitotenv.2020.137388

Abstract

Although atmospheric peroxyacetyl nitrate (PAN) and O₃ have been extensively measured in Beijing during the summertime, the abundances of PAN, peroxypropionyl nitrate (PPN) and the total odd-reactive nitrogen budget (NO_y) and their inter-relationship have been studied comparatively less in the winter. Here we measured atmospheric PAN, PPN, O₃, NO_x, and NO_y in Beijing from Nov. 2012 to Jan. 2013. Compared with our previous results in the summertime, much lower levels were observed in the winter, with the mean and maximum values of 311.8 and 1465 pptv for PAN, 52.8 and 850.6 pptv for PPN, and 11.6 and 36.7 ppbv for O₃. In contrast, high levels were found as 94.2 and 374.9 ppbv for NO_y, with a major constituent of NO_x (75.9%). The source to the west and northwest made the significant contribution to the relatively high O₃ concentrations during nighttime. PAN concentrations were highly related with the PAN-rich air mass transported from the southeast during the nighttime, whereas predominated by local photochemical production during the daylight. The distributions of NO_x and NO_y were dominated by local emission and photochemical production during daylight but also influenced by air masses transported from south direction during nighttime. Significant positive correlation (R² = 0.9, p < 0.0001) between PAN and PPN with a slope (∆PPN/∆PAN) of 0.17 indicated that anthropogenic volatile organic compounds (AVOCs) dominated the photochemical formation of PANs in Beijing, and the independent relationship between the PPN/PAN ratio and PAN (>500 pptv) implied a steady state between PAN and PPN achieving rapidly in the polluted air masses. Negative correlation and slopes between PAN and O₃ likely resulted from their weak photochemical productions in the winter, coupled with the large NO sources which acted as a local sink for O₃, but much less so for PAN due to its enhanced thermal stability under low temperature.

Keywords: NO(y); Ozone; Peroxyacetyl nitrate; Peroxypropionyl nitrate; Photochemical pollution; Regional transport.