Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 5.668 IF 5.668
  • IF 5-year value: 6.201 IF 5-year
  • CiteScore value: 6.13 CiteScore
  • SNIP value: 1.633 SNIP 1.633
  • IPP value: 5.91 IPP 5.91
  • SJR value: 2.938 SJR 2.938
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 174 Scimago H
    index 174
  • h5-index value: 87 h5-index 87
Discussion papers
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 07 Jan 2020

Submitted as: research article | 07 Jan 2020

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Atmospheric Chemistry and Physics (ACP).

Significant production of ClNO2 and possible source of Cl2 from N2O5 uptake at a suburban site in eastern China

Men Xia1, Xiang Peng1, Weihao Wang1, Chuan Yu1, Peng Sun2, Yuanyuan Li2, Yuliang Liu2, Zhengning Xu2, Zhe Wang1,a, Zheng Xu2, Wei Nie2, Aijun Ding2, and Tao Wang1 Men Xia et al.
  • 1Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
  • 2Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing, 210023, China
  • anow at: Division of Environment and Sustainability, Hong Kong University of Science and Technology, Hong Kong, China

Abstract. ClNO2 and Cl2 can affect atmospheric oxidation and thereby the formation of ozone and secondary aerosols, yet their sources and production mechanisms are not well understood or quantified. In this study we present field observations of ClNO2 and Cl2 at a suburban site in eastern China during April 2018. Persistent high levels of ClNO2 (maximum ~ 3.7 ppbv; 1 min average) were frequently observed at night, due to the high ClNO2 yield (φ(ClNO2), 0.56 ± 0.20) inferred from the measurements. The φ(ClNO2) value showed a positive correlation with the [Cl]/[H2O] ratio, and its parameterization was improved by the incorporation of [Cl]/[H2O] and the suppression effect of aerosol organics. ClNO2 and Cl2 showed a significant correlation on most nights. We show that the Cl2 at our site was likely a co-product with ClNO2 from N2O5 uptake on aerosols that contain acidic chloride, rather than being produced by ClNO2 uptake, as previously suggested. The Cl2 yield (φ(Cl2)) derived from the N2O5 uptake hypothesis exhibited significant correlations with [Cl] and [H+], based on which a parameterization of φ(Cl2) was developed. The derived parameterizations of φ(ClNO2) and φ(Cl2) can be used in models to quantify the nighttime production of ClNO2 and Cl2 and their impact on the next day’s photochemistry.

Men Xia et al.
Interactive discussion
Status: open (until 03 Mar 2020)
Status: open (until 03 Mar 2020)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
Men Xia et al.
Total article views: 212 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
154 56 2 212 16 0 2
  • HTML: 154
  • PDF: 56
  • XML: 2
  • Total: 212
  • Supplement: 16
  • BibTeX: 0
  • EndNote: 2
Views and downloads (calculated since 07 Jan 2020)
Cumulative views and downloads (calculated since 07 Jan 2020)
Viewed (geographical distribution)  
Total article views: 106 (including HTML, PDF, and XML) Thereof 106 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
No saved metrics found.
No discussed metrics found.
Latest update: 24 Jan 2020
Publications Copernicus
Short summary
ClNO2 and Cl2 can be photolyzed by sunlight to produce highly reactive Cl atom which affects air quality and climate. We observed high concentrations of ClNO2 and Cl2 during a recent field study in East China. We analyzed the data and proposed a new hypothesis on Cl2 production mechanism. The yields of ClNO2 and Cl2 from N2O5 uptake were parameterized using observational constraints, and they can be used in air quality models to improve simulations of atmospheric photochemistry and air quality.
ClNO2 and Cl2 can be photolyzed by sunlight to produce highly reactive Cl atom which affects air...