When a volcano erupts, along with the ash and lava, there is another element that it gives out. It is the gas emitted. This gas is made up of water vapour laced with heavy metals. Volcanoes continuously exhale water vapour which is laced with heavy metals, co2, hydrogen sulphide and sulphur dioxide etc. Out of all these, the easiest one to detect is sulphur dioxide.
With a decrease in human emissions, the problem of volcanic emission has surfaced again. This is leading to health concerns for people living in areas with active volcanoes.
Researchers from the Michigan Technological University created a global inventory for volcanic sulphur dioxide. They compiled the emissions data from 2005 to 2015 to produce annual estimates for all the presently emitting volcanoes. It was found that the daily emissions went unnoticed but the cumulative data recorded was quite significant. This data will help them to refine climate and atmospheric chemistry models and provide a hint of the human and environmental risks.