PM2.5 particles include both directly emitted dust, smoke, soot, pollen and soil particles and particles that form directly in the atmosphere. They are responsible for adverse health effects. In 2019, they were estimated to have caused about 307,000 premature deaths in the EU.

The Atlas gives a detailed picture of how transport, agriculture, industry, residential heating and shipping emissions affect PM2.5 pollution. It also clarifies the role that cities, regions, Member States and the EU can have in the reduction of air pollution, as locally specific circumstances are relevant to design effective air quality plans. The results have been produced using a simplified air quality model developed by the JRC called SHERPA.