Sulfur oxides are gases released during the eruption of volcanoes as well as when fossil fuels (coal and oil) are burned. Large amounts are released when industries and power plants burn fossil fuels.The diagram shows two sulfur oxides:
- sulfur dioxide
- sulfur trioxide
Lightning causes nitrogen and oxygen in the air to combine forming nitrogen oxides. But, the main source of nitrogen oxides in the air comes from the exhaust of vehicles.
Nitrogen oxides and sulfur oxides in air react with rain to form ACID RAIN.
Acid Rain Formation
Nitrogen oxides and sulfur oxides in air react with WATER (RAIN) to form acids.
- sulfur dioxide + water —–> sulfurous acid
- sulfur trioxide + water—–> sulfuric acid
- nitric oxide + water—–> nitrous acid
- nitrogen dioxide + water—–> nitric acid
For information about the effects of acid rain, see ACID RAIN:EFFECTS
For more information about the nitrogen cycle, see