ABSTRACT
The aim of this study was to determine how COVID-19 pandemic influenced air quality in the chosen Polish cities. Data on nitrogen oxides, carbon monoxides, fine and coarse particulate matter concentrations from air quality monitoring stations was used to compare pollutants levels during the pandemic and in the 5-year pre-pandemic period. The impact of the pandemic on the air quality has been analysed using linear mixed effect models, adjusting for long-term, seasonal and weekly trends and meteorological conditions. Results showed that during the pandemic, until the second lockdown only nitrogen oxides levels were significantly reduced (up to 20%), while when again loosening restrictions the rebound effect led to 20-30% increase of all analysed pollutants. © Institute of Geography and Spatial Organization.