OMI Mission Objective 3:
What are the sources of aerosols and trace gases that affect global air quality and how are they transported?

OMI, in conjunction with other Aura instruments (particularly HIRDLS and TES), will provide global mapping of several key tropospheric constituents including aerosols and some EPA (Environmental Protection Agency) criteria pollutants and other radicals. These include tropospheric ozone, NO₂, SO₂, BrO, and HCHO in the planetary boundary layer.

Air quality change has now become a major environmental issue because of intercontinental transport of urban pollution and biomass burning products. It has been shown that satellite measurements in conjunction with photochemical models can provide knowledge on the sources, sinks and transport of these gases and of aerosols.

OMI will certainly be able to measure SO₂ from volcanic eruptions, but the detection of SO₂ in the boundary layer is more difficult.
If OMI can detect the pre-eruptive release of volcanic SO₂ it might even provide warning of an impending volcanic eruption.