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 worldResearch Published on 2021-12-052022-11-01 Journal: Environmental Sciences Europe [Category] COVID-19, [키워드] affecting air quality index Air quality index ambient Analysis Bivariate correlation change changes in conducted Coronavirus disease 2019 correlated correlation country COVID-19 database ecological Factors Health index indicated Linear regression analysis lockdown nitrogen dioxide pandemic parameter parameters Particulate matter provided Quality recognize reduce reduction restriction Result reversed significantly higher t -test temperature tested variable variables Variation was used Wilcoxon signed-rank test with COVID-19 [DOI] 10.1186/s12302-021-00575-y PMC 바로가기 [Article Type] Research