Norwegian Environment Agency air quality

Norwegian air quality via the Environment Agency's open portal — no API key.

The Norwegian Environment Agency operates the public air-quality portal (luftkvalitet.miljodirektoratet.no) with station metadata and hourly aggregated measurements sourced from NILU. The portal's open data surface is stable without authentication — we use it as a business fallback when no NILU API key is configured (#3093, #3178). Same component coverage as NILU (PM10/PM2.5/NO2/O3/SO2). AQI classification against the Norwegian Institute of Public Health's air-quality criteria.