Which pollutants are primarily responsible for acid deposition transported long distances?

• A. Ozone and PM.
• B. Carbon monoxide and lead.
• C. Sulfur and nitrogen pollutants.
• D. Methane and nitrous oxide.

Answer: (C)

Acid deposition that travels long distances is driven by sulfur and nitrogen compounds released from burning fossil fuels. When sulfur dioxide and nitrogen oxides enter the atmosphere, they react with water and other chemicals to form sulfuric acid and nitric acid. These acids can ride on cloud droplets and precipitate as rain, snow, or fog, and the pollutants can be carried by winds for hundreds to thousands of miles before deposition. That long-range transport is what makes distant ecosystems vulnerable to acid rain. Other listed pollutants are linked to smog, health effects, or greenhouse warming, but they’re not the primary carriers of acids that are deposited far from their sources.