Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/acp-2017-389
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
09 May 2017
Review status
A revision of this discussion paper was accepted for the journal Atmospheric Chemistry and Physics (ACP) and is expected to appear here in due course.
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 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 800–1800 ppt at the surface (0–30 m) over the Northern China Plain (NCP), the Yangtze River Delta (YRD), and the Pearl River Delta (PRD) regions and that HONO was concentrated within a 0–200 m layer. In comparison, the simulated surface ClNO2 mixing ratio was around 800–1500 ppt over the NCP, YRD, and central China regions and was predominantly present in a 0–600 m layer. HONO enhanced daytime ROx (OH + HO2 + RO2) and O3 at the surface (0–30 m) by 2.8–4.6 ppt (28–37 %) and 2.9–6.2 ppb (6–13 %), respectively, over the three most developed regions, whereas ClNO2 increased surface O3 in the NCP and YRD regions by 2.4–3.3 ppb (or 5–6%) and it also had a significant impact (3–6%) on above-surface O3 within 200–500 m. 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 (0–1000 m), 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 ppb to 0.1 ppb. 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.

Citation: Zhang, L., Li, Q., Wang, T., Ahmadov, R., Zhang, Q., Li, M., and Lv, M.: Combined Impacts of Nitrous Acid and Nitryl Chloride on Lower Tropospheric Ozone: New Module Development in WRF-Chem and Application to China, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-389, in review, 2017.
Li Zhang et al.
Interactive discussionStatus: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version      Supplement - Supplement
 
RC1: 'comments', Anonymous Referee #1, 23 May 2017 Printer-friendly Version 
AC1: 'Response to Anonymous Referee #1', Tao Wang, 25 Jun 2017 Printer-friendly Version Supplement 
 
RC2: 'Review of Zhang et al.', Anonymous Referee #2, 26 May 2017 Printer-friendly Version 
AC2: 'Response to Anonymous Referee #2', Tao Wang, 25 Jun 2017 Printer-friendly Version Supplement 
Li Zhang et al.

Viewed

Total article views: 491 (including HTML, PDF, and XML)

HTML PDF XML Total Supplement BibTeX EndNote
341 122 28 491 21 6 31

Views and downloads (calculated since 09 May 2017)

Cumulative views and downloads (calculated since 09 May 2017)

Viewed (geographical distribution)

Total article views: 491 (including HTML, PDF, and XML)

Thereof 485 with geography defined and 6 with unknown origin.

Country # Views %
  • 1

Saved

Discussed

Latest update: 20 Jul 2017
Publications Copernicus
Download
Short summary
Little has been known on 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 that 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 has been known on the integrated impacts of HONO and ClNO2 on lower tropospheric ozone so...
Share