Does air pollution upsurge in megacities after Covid-19 lockdown? A spatial approach

Area of Science:

• Environmental Science
• Atmospheric Chemistry
• Public Health

Background:

• The COVID-19 pandemic led to widespread lockdowns, significantly altering human activities.
• India implemented strict lockdown policies to curb the virus's spread, creating a unique scenario for environmental assessment.

Purpose of the Study:

• To analyze the impact of COVID-19 lockdown measures on air quality in Delhi and Mumbai.
• To assess changes in concentrations of seven key pollutants (PM2.5, PM10, NH3, CO, NO2, O3, SO2) before, during, and after the lockdown.

Main Methods:

• A spatial analysis approach was used to examine pollutant concentrations.
• Data collected covered periods before, during, and after the lockdown in Delhi and Mumbai.
• Seven criteria pollutants were analyzed: Particulate Matter (PM2.5, PM10), Ammonia (NH3), Carbon Monoxide (CO), Nitrogen Dioxide (NO2), Ozone (O3), and Sulfur Dioxide (SO2).

Main Results:

• Significant declines in PM2.5 (42%), PM10 (50%), NH3 (21%), CO (37%), NO2 (53%), and SO2 (41%) were observed during the lockdown compared to previous years.
• A 2% increase in Ozone (O3) concentration was noted during the lockdown period.
• Analysis of the National Air Quality Index (NAQI) indicated no long-term improvement in air quality.

Conclusions:

• While the COVID-19 lockdown temporarily reduced certain air pollutants, it did not lead to sustained air quality improvements in Delhi and Mumbai.
• Findings offer crucial data for urban administrators to formulate effective air quality management strategies.