Sulphur dioxide (SO₂) and air quality
Learn where sulphur dioxide comes from, how it can contribute to particle pollution and how to read an hourly result.
Sources of sulphur dioxide
Burning fuels that contain sulphur can release sulphur dioxide. Power generation, some industrial processes, ships and other equipment can contribute where they burn sulphur-containing fuels. Volcanoes can also release the gas.
Some sulphur dioxide reacts in the atmosphere to form sulphate particles. A station reporting low SO₂ at one moment can still record particulate matter from sources or reactions farther away.
Reading SO₂ near a source
An instrument near an industrial or port area can report short peaks as wind carries emissions across the site. A model grid estimate represents a wider area and can smooth such a peak. Use the station type and valid time to understand what each result represents.
Sulphur dioxide has its own hourly bands in the European AQI. Some stations measure other pollutants only, so check the actual list of available values.