Acid Rain

Acidic deposition, or acid rain as it is commonly known, occurs when emissions of sulfur dioxide (SO₂) and oxides of nitrogen (NO_x) react in the atmosphere with water, oxygen, and oxidants to form acidic compounds. These compounds are then deposited on the earth’s surface in either dry form (gases or particles) or wet form (rain, snow, or fog). Prevailing winds transport the compounds, sometimes hundreds of miles, across state and national borders before they are deposited on the surface.

Acid rain can cause acidification of lakes and streams, with the potential to harm aquatic life, and it can contribute to damage to trees.

In addition, acid rain can accelerate the decay of paints and building materials, including buildings, statues, and sculptures that are part of our cultural heritage.

Acid rain occurs in Florida, but the degree of acidity of the state’s rainfall is much less than that of the Northeast U.S., where most of the ecological damage associated with acid rain has been found. However, Florida does have a number of lakes that are potentially sensitive to acidification by rainfall.

The federal Clean Air Act limits the emissions of acid-forming pollutants from electric power plants by requiring that sulfur dioxide emissions (in tons) for a given plant in a given calendar year be less than or equal the number of allowances granted them by the EPA Clean Air Markets Division for that year.  Shortages must be covered by using banked allowances, or significant fines will be imposed on the plant.  Allowances can be banked by saving prior years’ allocations, and/or purchase on the open market through the Chicago Board of Trade.

The Emissions Monitoring Section performs quality assurance activities on monitoring systems required by the federal Acid Rain Program.