Which pollutant is a major contributor to acid deposition?

Which pollutant is a major contributor to acid deposition?

• A. Nitrogen oxides
• B. Ozone
• C. Sulfur oxides
• D. Particulates

Answer: (C)

Acid deposition is driven by pollutants that form acids in the atmosphere and then fall to Earth as rain or dust. Sulfur oxides released from burning sulfur-containing fuels (like coal) are the primary culprits. In the atmosphere, SO2 is oxidized to SO3 and then quickly reacts with water to produce sulfuric acid (H2SO4), which comes down as acid rain or as sulfate particles. Because this pathway is a major and widespread source of strong acids in wet and dry deposition, sulfur oxides are the leading contributor. Nitrogen oxides also form nitric acid and contribute to acid deposition, but sulfur oxides typically have the larger impact in many regions. Ozone is a pollutant linked to smog and does not directly create acid rain, and particulates are a mix of substances that can carry acids but are not the primary precursors themselves.

Acid deposition is driven by pollutants that form acids in the atmosphere and then fall to Earth as rain or dust. Sulfur oxides released from burning sulfur-containing fuels (like coal) are the primary culprits. In the atmosphere, SO2 is oxidized to SO3 and then quickly reacts with water to produce sulfuric acid (H2SO4), which comes down as acid rain or as sulfate particles. Because this pathway is a major and widespread source of strong acids in wet and dry deposition, sulfur oxides are the leading contributor.

Nitrogen oxides also form nitric acid and contribute to acid deposition, but sulfur oxides typically have the larger impact in many regions. Ozone is a pollutant linked to smog and does not directly create acid rain, and particulates are a mix of substances that can carry acids but are not the primary precursors themselves.