Air pollutants come from both natural and human-made sources.
- Natural Sources: Volcanic eruptions release sulfur dioxide (SO₂) and particulate matter, which contribute to acid rain and respiratory issues. Forest fires produce carbon monoxide (CO), carbon dioxide (CO₂), and fine particulate matter that cause air pollution. Dust storms, plant pollen, and decaying organic matter also release pollutants into the air.
- Human-Made Sources: The burning of fossil fuels (coal, oil, and gas) in industries and power plants releases large amounts of SO₂, nitrogen oxides (NOₓ), and CO₂. Automobiles emit carbon monoxide, hydrocarbons, and nitrogen oxides, contributing to smog and respiratory diseases. Industrial processes, such as chemical manufacturing and mining, release toxic pollutants into the air. Agricultural activities, including pesticide and fertilizer use, release ammonia and volatile organic compounds, affecting air quality.