How do sulfur oxides contribute to acid rain?

Sulfur oxides, primarily sulfur dioxide (SO₂) and sulfur trioxide (SO₃), are major contributors to acid rain. These gases are released into the atmosphere largely through the combustion of fossil fuels, such as coal and oil, and the smelting of metal ores.123

Once in the atmosphere, these oxides react with water, oxygen, and other chemicals. Sulfur dioxide reacts with water to form sulfurous acid, while sulfur trioxide reacts with water to form sulfuric acid. Sulfuric acid is considered the primary cause of the acidity found in acid rain. These acidic compounds mix with cloud moisture, significantly lowering the pH of precipitation.12

When this acidic precipitation falls, it can damage forests, harm aquatic life in lakes, and corrode materials like limestone and metal. Because these pollutants can travel long distances in the atmosphere, they often affect regions far from their original industrial or natural sources.231