Average PM2.5 levels in the most populated cities in Europe 2021-2022
Milan had the highest average PM2.5 concentration among Europe's most populated cities in 2021 and 2022, with 19.7 µg/m3. Milan sits in the Po Valley of Northern Italy, which is one of Europe's most polluted regions due to its geographical location and proximity to industrial activities. Poland's capital Warsaw ranked second, with average PM2.5 concentrations of 16.1 µg/m3 based on levels measured in 2021 and 2022. Warsaw is prone to poor air quality due to factors such as burning solid fuels for household heating. Around 97 percent of the European Union's urban population is exposed to PM2.5 concentrations above World Health Organization guidelines.