Unveiling urban air quality dynamics during COVID-19: a Sentinel-5P TROPOMI hotspot analysis

Aneesh Mathew ¹, Padala Raja Shekar ¹, Abhilash T Nair ²

⁰Department of Civil Engineering, National Institute of Technology, Tiruchirappalli, Tamil Nadu, 620015, India.

Scientific Reports +

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September 16, 2024

View abstract on PubMed

Summary

Satellite data reveals India

Area Of Science

Environmental Science
Remote Sensing
Atmospheric Chemistry

Background

Limited ground-based air quality monitoring stations in India create data gaps.
Satellite data offers a viable solution for comprehensive environmental monitoring.
Understanding air pollutant distribution is crucial for public health and environmental protection.

Purpose Of The Study

To investigate the spatial and temporal variations of key air pollutants (SO2, NO2, CO, O3) across India.
To analyze air quality trends from 2019-2022, including pre-COVID, during COVID-19 lockdown, and current periods.
To identify pollution hotspots and their correlation with urban and industrial activities.

Main Methods

Utilized Sentinel-5P TROPOMI satellite imagery for comprehensive air quality analysis.
Conducted spatiotemporal analysis nationwide, with a focus on five major metropolitan cities.
Performed seasonal, monthly, and yearly assessments of pollutant concentrations and identified pollution hotspots.

Main Results

Winter season showed the highest pollutant concentrations (except ozone, which peaked in summer).
Nitrogen dioxide (NO2) hotspots were concentrated in megacities, while sulfur dioxide (SO2) hotspots were linked to industrial areas.
Delhi experienced a 20% rise in NO2, and Kolkata saw an 11% rise in SO2 from 2019-2022; COVID-19 lockdowns significantly reduced NO2 levels.

Conclusions

Satellite data provides critical insights into air pollution dynamics and hotspot identification in India.
The study highlights the significant impact of human activities and lockdowns on air quality.
Findings support evidence-based policymaking for effective air pollution mitigation and public health safeguarding.

Keywords:

Carbon monoxide Nitrogen dioxide Ozone Sentinel-5P Sulphur dioxide TROPOMI