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

Journal metrics

IF value: 5.414
IF 5-year value: 5.958
IF 5-year
CiteScore value: 9.7
SNIP value: 1.517
IPP value: 5.61
SJR value: 2.601
Scimago H <br class='widget-line-break'>index value: 191
Scimago H
h5-index value: 89
© 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.

  26 Oct 2020

26 Oct 2020

Review status
This preprint is currently under review for the journal ACP.

Using satellite measurements and mesoscale modelling to understand the contribution to an extreme air pollution event in India

Ashique Vellalassery1, Dhanyalekshmi Pillai1,a, Julia Marshall2,b, Christoph Gerbig2, Michael Buchwitz3, and Oliver Schneising3 Ashique Vellalassery et al.
  • 1Indian Institute of Science Education and Research Bhopal (IISERB), Bhopal, India
  • 2Max Planck Institute for Biogeochemistry, Jena, Germany
  • 3Institute of Environmental Physics (IUP), University of Bremen, Bremen, Germany
  • aalso at: Max Planck Partner Group (IISERB) affiliated with the Max Planck Society Munich, Germany
  • bnow at: Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany

Abstract. Several ambient air quality records corroborate severe and persistent degradation of air quality over North India during the winter months with evidence of a continued increasing trend of pollution across the Indo-Gangetic Plain (IGP) over the past decade. A combination of atmospheric dynamics and uncertain emissions, including the post-monsoon agricultural stubble burning, make it challenging to resolve the role of each individual factor. Here we demonstrate the potential use of an atmospheric transport model, the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) to identify and quantify the role of transport mechanisms and emissions on the occurrence of the pollution events. The investigation is based on the use of CO observations from TROPOspheric Monitoring Instrument (TROPOMI), onboard the Sentinel 5-Precursor satellite, and the surface measurement network as well as WRF-Chem simulations to investigate the factors contributing to CO enhancement over India during November 2018. We show that the simulated column-averaged dry air mole fraction (XCO) is largely consistent with TROPOMI observations with a spatial correlation coefficient of 0.87. The surface-level CO concentrations show larger sensitivities to boundary layer dynamics, wind speed, and diverging source regions, leading to a complex concentration pattern and reducing the observation-model agreement with a correlation coefficient ranging from 0.41 to 0.60 for measurement locations across the IGP. We find that daily satellite observations can provide a first-order inference of the CO transport pathways during the enhanced burning period, and this transport pattern is reproduced well in the model. By using the observations and employing the model at a comparable resolution, we confirm the significant role of atmospheric dynamics as well as residential, industrial and commercial emissions in the production of the exorbitant level of air pollutants in North India. We find that biomass burning plays only a minimal role in both column and surface enhancements of CO, except for in the state of Punjab during the high pollution episodes. While the model reproduces observations reasonably well, a better understanding of the factors controlling the model uncertainties is essential to relate the observed concentrations to the underlying emissions. Overall, our study emphasizes the importance of undertaking rigorous policy measures, mainly focusing on reducing residential, commercial and industrial emissions in addition to actions already underway in the agricultural sectors.

Ashique Vellalassery et al.

Interactive discussion

Status: open (until 26 Dec 2020)
Status: open (until 26 Dec 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

Ashique Vellalassery et al.

Ashique Vellalassery et al.


Total article views: 120 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
87 32 1 120 2 3
  • HTML: 87
  • PDF: 32
  • XML: 1
  • Total: 120
  • BibTeX: 2
  • EndNote: 3
Views and downloads (calculated since 26 Oct 2020)
Cumulative views and downloads (calculated since 26 Oct 2020)

Viewed (geographical distribution)

Total article views: 200 (including HTML, PDF, and XML) Thereof 196 with geography defined and 4 with unknown origin.
Country # Views %
  • 1



No saved metrics found.


No discussed metrics found.
Latest update: 24 Nov 2020
Publications Copernicus
Short summary
We investigate the factors contributing to severe and persistent degradation of air quality in North India that worsens during every winter over the last decade. This is achieved by implementing atmospheric modelling and using recently available Sentinel-5P satellite data for carbon monoxide. We see a minimal role of agricultural burning except for the state of Punjab. The imperative is to focus on residential and industrial emission reduction strategy to tackle air pollution over North India.
We investigate the factors contributing to severe and persistent degradation of air quality in...