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) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 01 Aug 2019

Submitted as: research article | 01 Aug 2019

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

Mitigation of PM2.5 and Ozone Pollution in Delhi: A Sensitivity Study during the Pre-monsoon period

Ying Chen1,2, Oliver Wild1,2, Edmund Ryan1,9, Saroj Kumar Sahu4, Douglas Lowe5, Scott Archer-Nicholls6, Yu Wang5, Gordon McFiggans5, Tabish Ansari1, Vikas Singh7, Ranjeet S. Sokhi8, Alex Archibald6, and Gufran Beig3 Ying Chen et al.
  • 1Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
  • 2Data Science Institute, Lancaster University, Lancaster, LA1 4YW, UK
  • 3Indian Institute of Tropical Meteorology, Pune, India
  • 4Environmental Science, Dept. of Botany, Utkal University, Bhubaneswar, India
  • 5Centre for Atmospheric Sciences, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, UK
  • 6NCAS-Climate, Department of Chemistry, University of Cambridge, Cambridge, UK
  • 7National Atmospheric Research Laboratory, Gadanki, AP, India
  • 8Centre for Atmospheric and Climate Physics Research, University of Hertfordshire, Hatfield, Hertfordshire, UK
  • 9School of Mathematics,University of Manchester, Manchester, UK

Abstract. Fine particulate matter (PM2.5) and surface ozone (O3) are major air pollutants in megacities such as Delhi, but the design of suitable mitigation strategies is challenging. Some strategies for reducing PM2.5 may have the notable side-effect of increasing O3. Here, we demonstrate a numerical framework for investigating the impacts of mitigation strategies on both PM2.5 and O3 in Delhi. We use Gaussian process emulation to generate a computationally efficient surrogate for a regional air quality model (WRF-Chem). This allows us to perform global sensitivity analysis to identify the major sources of air pollution, and to generate emission-sector based pollutant response surfaces to inform mitigation policy development. Based on more than 100,000 emulation runs during the pre-monsoon period (peak O3 season), our global sensitivity analysis shows that local traffic emissions from Delhi city region and regional transport of pollutions emitted from the National Capital Region surrounding Delhi (NCR) are dominant factors influencing PM2.5 and O3 in Delhi. They together govern the O3 peak and PM2.5 concentration during daytime. Regional transport contributes about 80 % of the PM2.5 variation during the night. Reducing traffic emissions in Delhi alone (e.g., by 50 %) would reduce PM2.5 by 15–20 % but lead to a 20–25 % increase in O3. However, we show that reducing NCR regional emissions by 25–30 % at the same time would further reduce PM2.5 by 5–10 % in Delhi and avoid the O3 increase. This study provides scientific evidence to support the need for joint coordination of controls on local and regional scales to achieve effective reduction on PM2.5 whilst minimize the risk of O3 increase in Delhi.

Ying Chen et al.
Interactive discussion
Status: final response (author comments only)
Status: final response (author comments only)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Login for Authors/Co-Editors] [Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
Ying Chen et al.
Total article views: 346 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
255 85 6 346 15 6 8
  • HTML: 255
  • PDF: 85
  • XML: 6
  • Total: 346
  • Supplement: 15
  • BibTeX: 6
  • EndNote: 8
Views and downloads (calculated since 01 Aug 2019)
Cumulative views and downloads (calculated since 01 Aug 2019)
Viewed (geographical distribution)  
Total article views: 273 (including HTML, PDF, and XML) Thereof 269 with geography defined and 4 with unknown origin.
Country # Views %
  • 1
No saved metrics found.
No discussed metrics found.
Latest update: 14 Oct 2019
Publications Copernicus
Short summary
PM2.5 and O3 are two major air pollutants. Some mitigation strategies focusing on reducing PM2.5 may lead to substantial increase in O3. We use statistical emulation combined with atmospheric transport model to perform thousands of sensitivity numerical studies to identify the major sources of PM2.5 and O3, and to develop strategies targeted at both pollutants. Our scientific evidence suggests that regional coordinated emission control is required to mitigate PM2.5 whilst prevent O3 increase.
PM2.5 and O3 are two major air pollutants. Some mitigation strategies focusing on reducing PM2.5...