SO2

Also: sulfur dioxide, Sulfur dioxide

Sulphur dioxide is a pollutant released by fossil fuel burning and volcanic eruptions. SO₂ produces aerosols that reflect sunlight back to space, causing cooling and contributing to acid rain (low-pH rain). At ground level, SO₂ harms air quality by irritating the nose, throat, and airways. Over time, air quality standards have reduced global SO₂ concentrations except in China. Sulfate aerosols normally dissipate after only 3-5 days, but last about one year when injected into the stratosphere by a volcanic eruption.

• Emissions graph by Smith et al. 2011