Sulfur dioxide emissions in the U.S. 1970-2023

Sulfur dioxide (SO₂) emissions in the United States decreased by roughly 94 percent between 1970 and 2023, to 1.7 million tons. There are numerous factors for these reductions, such as the implementation of the Acid Rain Program and the installation of air pollution controls at coal power plants. 

Sources of sulfur dioxide

SO₂ is largely used as an indicator for gaseous sulfur oxides (SOx) as these gases are found in low concentrations in the atmosphere. There are a number of sources of SO₂ emissions in the U.S., though it is mostly emitted into the atmosphere through the burning of fossil fuels. Roughly half of SO₂ emissions in the U.S. are produced by electric utilities. The Labadie Power Station is the U.S. power sector's worst SO₂ polluter.  

Air pollutants in the U.S.

In 1970, annual SO₂ emissions were considerably higher than those of other key air pollutants in the U.S. But the reductions observed over the past decades have seen SO₂ emissions drop below PM10 and nitrogen dioxide emissions.