Air quality change due to COVID-19 lockdown in India and its perception by public

Abstract

In this study, air quality data for 100 days recorded at 193 stations distributed throughout India were analyzed to understand the changes in air quality following the country-wide lockdown imposed from 25th March to 17th May 2020 to contain the spread of the COVID-19 pandemic. The responses from a nationwide online survey conducted to obtain public perceptions of air quality improvement were also analyzed. On average, an approximately 40% improvement in the air quality index was observed, contributed by a reduction in 40% of PM10, 44% of PM2.5, 51% of NO2 and 21% of SO2. There was a significant difference between the levels of all the pollutants before and after the lockdown (p<0.05), except ozone. The Pearson correlation coefficient showed that the correlation between PM10 and PM2.5 with ozone was significant after the lockdown period, indicating that a significant portion of the particulates present in the atmosphere after the lockdown period is secondary. The survey for public perception showed that 60% of the 1750 respondents perceived improvement in air quality. On a scale of 1 to 5, the respondents from Delhi perceived the highest improvement, from 2.2 to 4.5. An odds ratio of 17 indicated a very high dependence of perception on actual air quality. PM10 levels had the highest influence in shaping public perceptions of air quality. The results from Google Trends analysis showed that media had no influence on shaping the perception of improvement in air quality.

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Subtle Changes or Dramatic Perceptions of Air Pollution in Sydney during COVID-19

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Effect of COVID-19-induced lockdown on NO2 pollution using TROPOMI and ground-based CPCB observations in Delhi NCR, India

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