Explain how acid rain forms and its environmental impacts.

Explain how acid rain forms and its environmental impacts.

• A. Acid rain is formed by natural rain with no pollutants.
• B. SO2/NOx emissions transform into sulfuric and nitric acids; deposition lowers soils and water pH, harms forests and aquatic ecosystems, and corrodes infrastructure.
• C. It only affects urban surfaces and has no ecological effects.
• D. Acid rain is a myth and does not occur.

Answer: (B)

Acid rain forms when sulfur dioxide and nitrogen oxides released from burning fossil fuels react in the atmosphere with water, oxygen, and other oxidants to form sulfuric and nitric acids. These acids attach to cloud moisture and fall as precipitation or are deposited as gases and particles. When this acid deposition reaches soils and water bodies, it lowers their pH, which changes nutrient availability and increases the solubility of toxic metals like aluminum. That stresses trees and other vegetation, depletes essential nutrients from soils, and disrupts microbial and nutrient cycles. In aquatic ecosystems, lower pH can harm or kill sensitive species, alter food webs, and reduce biodiversity. Acid deposition also accelerates the decay of infrastructure and buildings by corroding metals and dissolving concrete or stone. Because these pollutants can travel long distances, regions far from emission sources can still experience these ecological and practical impacts.