Air quality index variation before and after the onset of COVID-19 pandemic: a comprehensive study on 87 capital, industrial and polluted cities of the world.

Environ Sci Eur · 2021 · PMC8645297 · PMID 34900511

Europe PMC DOI

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a decreasing trendno p-value reported

The results show that only 25% (17/67) and 13% (7/55) of the cities that had lower AQI-PM 2.5 and AQI-PM 10 in 2020 than in 2019 had also a decreasing trend in 2021, but in other cases, AQI values have increased during 2021.

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