COVID-19 Lockdown Effects on Air Quality: Case Study Oulu and Helsinki vs. SARS-CoV-2 Hotspots

Abstract

In response to the global COVID-19 pandemic, nations implemented lockdown measures to con-tain the virus. This study assessed air pollution levels during and after lockdowns, focusing on heavily affected locations: Oulu and Helsinki in Finland, Paris in France, Madrid in Spain, Milan in Italy, and Wuhan in China. Air Quality Index (AQI) data from these areas over two years were analyzed to understand lockdown effects. COVID-19 lockdowns in six cities were compared with SARS-CoV-2 measures using statistical methods. Pollutant variations were evaluated via tests, showing significant differences. Parametric analyses and regression studied lockdown impacts on pollution and relationships. The study comprehensively analyzed COVID-19 lockdowns' ef-fects on air quality, identifying differences, quantifying changes, and exploring patterns in Oulu and Helsinki. Pollutant correlations varied among cities during lockdowns. Regression analysis highlighted independent variables' impact on pollutants. Decreases in NO2 were seen in Helsinki, Madrid, Oulu, Paris, and Milan, reflecting reduced traffic and industry. PM2.5 and PM10 reduc-tions occurred in these cities and also Wuhan, except for O3 levels which increased. Reduced human activities improved air quality, especially for NO2 and PM10. Regional variations necessi-tate tailored interventions. The study emphasizes addressing urban PM2.5 and NO2 pollution influenced by transportation and industry. COVID-19 lockdowns significantly reduced pollution, highlighting environmental measures for better air quality.