WHO Ambient Air Quality Database (Update Jun 2026)

Overview

The WHO Ambient Air Quality Database compiles ground-level measurements of annual mean concentrations for nitrogen dioxide (NO₂), and particulate matter with a diameter equal to or smaller than 10 μm (PM₁₀) and 2.5 μm (PM_2.5). These measurements aim to represent an average for the city or town, rather than for individual monitoring stations.

Both groups of pollutants originate mainly from human activities related to fossil fuel combustion. To ensure the data accurately reflects population exposure, the database primarily utilizes urban measurements, encompassing urban background, residential, commercial, and mixed areas, as well as rural and industrial zones close to urban settlements.

• Frequency: Updated regularly every 2–3 years since 2011.
• Impact: This data serves as the primary input to derive Sustainable Development Goal (SDG) Indicator 11.6.2 (Air quality in cities), for which WHO is the custodian agency.
• Primary Sources: Official national and subnational datasets provided by countries upon request, official reports, and government websites. For European Union members, data is sourced from the European Environment Agency (EEA).