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: 5.509 IF 5.509
  • IF 5-year value: 5.689 IF 5-year 5.689
  • CiteScore value: 5.44 CiteScore 5.44
  • SNIP value: 1.519 SNIP 1.519
  • SJR value: 3.032 SJR 3.032
  • IPP value: 5.37 IPP 5.37
  • h5-index value: 86 h5-index 86
  • Scimago H index value: 161 Scimago H index 161
Volume 17, issue 16 | Copyright
Atmos. Chem. Phys., 17, 9733-9750, 2017
https://doi.org/10.5194/acp-17-9733-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 17 Aug 2017

Research article | 17 Aug 2017

Combined impacts of nitrous acid and nitryl chloride on lower-tropospheric ozone: new module development in WRF-Chem and application to China

Li Zhang1, Qinyi Li1, Tao Wang1, Ravan Ahmadov2,3, Qiang Zhang4, Meng Li4, and Mengyao Lv5 Li Zhang et al.
  • 1Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
  • 2Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, CO, USA
  • 3Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
  • 4Department of Earth System Science, Tsinghua University, Beijing, China
  • 5National Meteorological Center, China Meteorological Administration, Beijing, China

Abstract. Nitrous acid (HONO) and nitryl chloride (ClNO2) – through their photolysis – can have profound effects on the nitrogen cycle and oxidation capacity of the lower troposphere. Previous numerical studies have separately considered and investigated the sources/processes of these compounds and their roles in the fate of reactive nitrogen and the production of ozone (O3), but their combined impact on the chemistry of the lower part of the troposphere has not been addressed yet. In this study, we updated the WRF-Chem model with the currently known sources and chemistry of HONO and chlorine in a new chemical mechanism (CBMZ_ReNOM), and applied it to a study of the combined effects of HONO and ClNO2 on summertime O3 in the boundary layer over China. We simulated the spatial distributions of HONO, ClNO2, and related compounds at the surface and within the lower troposphere. The results showed that the modeled HONO levels reached up to 800–1800ppt at the surface (0–30m) over the North China Plain (NCP), the Yangtze River Delta (YRD), and the Pearl River Delta (PRD) regions and that HONO was concentrated within a 0–200m layer. In comparison, the simulated surface ClNO2 mixing ratio was around 800–1500ppt over the NCP, YRD, and central China regions and was predominantly present in a 0–600m layer. HONO enhanced daytime ROx (OH+HO2+RO2) and O3 at the surface (0–30m) by 2.8–4.6ppt (28–37%) and 2.9–6.2ppb (6–13%), respectively, over the three most developed regions, whereas ClNO2 increased surface O3 in the NCP and YRD regions by 2.4–3.3ppb (or 5–6%) and it also had a significant impact (3–6%) on above-surface O3 within 200–500m. The combined effects increased surface O3 by 11.5, 13.5, and 13.3% in the NCP, YRD, and PRD regions, respectively. Over the boundary layer (0–1000m), the HONO and ClNO2 enhanced O3 by up to 5.1 and 3.2%, respectively, and their combined effect increased O3 by 7.1–8.9% in the three regions. The new module noticeably improved O3 predictions at ∼900 monitoring stations throughout China by reducing the mean bias from −4.3 to 0.1ppb. Our study suggests the importance of considering these reactive nitrogen species simultaneously into chemical transport models to better simulate the formation of summertime O3 in polluted regions.

Download & links
Publications Copernicus
Download
Short summary
Little is known of the integrated impacts of HONO and ClNO2 on lower-tropospheric ozone so far. In this study, we updated WRF-Chem with the CBMZ_ReNOM module, which considers both the sources and chemistry of HONO and ClNO2. The revised model revealed that the two reactive nitrogen compounds significantly affected the oxidation capacity and ozone formation at the surface and within the lower troposphere over polluted regions and noticeably improved summertime O3 predictions over China.
Little is known of the integrated impacts of HONO and ClNO2 on lower-tropospheric ozone so far....
Citation
Share