Air quality monitoring sites and annual nitrogen dioxide (NO2) averages in the Helsinki metropolitan area

Monitoring site data includes permanent monitoring sites, mobile monitoring sites and passive samplers, as well as the annual average concentrations (μg/m3) of nitrogen dioxide (NO2) measured at these sites in 2004-2023.

The data is produced annually. New monitoring locations and results are added to the map annually. Passive sampler monitoring started in 2004.

Coordinate system of the data is ETRS-GK25.

The data can be viewed and downloaded in HSY’s open map service.