We have developed a machine learning tool to find emission plumes of sulphur dioxide (SO₂) observed in satellite data. SO₂ is an atmospheric pollutant from fuel combustion, metal smelting, and volcanic degassing, impacting health, acid deposition, and climate forcing. Over 6 years we find over 50 000 plumes, most of which are clustered around known sources (e.g. volcanoes or industrial hotspots). We show how this tool can be used to rapidly detect emissions across the globe.