The primary air pollutants that contribute to acid rain are sulfur dioxide (SO₂) and nitrogen oxides (NOₓ). These pollutants are released mainly from the burning of fossil fuels such as coal, oil, and natural gas in power plants, vehicles, and industrial facilities. Once emitted into the atmosphere, sulfur dioxide and nitrogen oxides react with water, oxygen, and other chemicals to form sulfuric acid and nitric acid, which then fall to the ground as acid rain in wet forms (rain, snow, fog) or dry forms (acidic particles and gases)
. Key sources include:
- Electric power generation (two-thirds of SO₂ and one-fourth of NOₓ emissions)
- Vehicle exhaust (cars, trucks, buses)
- Industrial processes and manufacturing
- To a lesser extent, natural sources such as volcanic eruptions and lightning also emit these gases, but human activities are the dominant contributors
In summary, sulfur dioxide and nitrogen oxides from fossil fuel combustion are the main pollutants responsible for acid rain formation.
