Sulfate aerosols

Sulfate aerosols are produced by chemical reactions in the atmosphere from gaseous precursors (with the exception of sea salt sulfate and gypsum dust particles). The two main sulfate precursors are sulfur dioxide (SO2) from anthropogenic sources and volcanoes, and dimethyl sulfide (DMS) from biogenic sources, especially marine plankton. These aerosols can cause a cooling affect on earth.
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Particulate matter that consists of compounds of sulfur formed by the interaction of sulfur dioxide and sulfur trioxide with other compounds in the atmosphere. Sulfate aerosols are injected into the atmosphere from the combustion of fossil fuels and the eruption of volcanoes like Mt. Pinatubo. Recent theory suggests that sulfate aerosols may lower the earth's temperature by reflecting away solar radiation (negative radiative forcing). General Circulation Models which incorporate the effects of sulfate aerosols more accurately predict global temperature variations. See particulate matter, aerosol, General Circulation Models.