NILU — the Norwegian Institute for Air Research

Real-time air-quality measurements from Norwegian urban monitoring stations — PM10, PM2.5, NO2, O3, SO2.

An open NILU API delivering hourly aggregated concentration values for particulate matter (PM10, PM2.5), nitrogen dioxide (NO2), ground-level ozone (O3) and sulphur dioxide (SO2) from about 100 monitoring stations across Norway — operated by Statens vegvesen, the Norwegian Environment Agency, local municipalities and industrial actors. Free, no auth, updated hourly. Classification against the Norwegian Institute of Public Health's air-quality criteria (low/moderate/high/very high) is done client-side based on the official thresholds (adjusted 2023).