Name a region that has experienced notable acid deposition due to long-range transport of sulfur and nitrogen pollutants, and explain the mechanism.

• A. Western United States; local emissions only.
• B. Eastern North America and parts of Europe; pollutants emitted far away are transported by atmospheric currents and deposited downwind, causing acidification.
• C. Southern Africa; acid deposition only from natural sources.
• D. Australia; due to rainfall.

Answer: (B)

Acid deposition from long-range transport occurs when sulfur oxides and nitrogen oxides released from burning fossil fuels react in the atmosphere to form sulfuric and nitric acids. These acids exist as rain, snow, or dry acidic particles and can be carried by atmospheric currents for long distances before being deposited downwind. In Eastern North America and parts of Europe, industrial regions emitted large amounts of SO2 and NOx, and the prevailing winds carried these pollutants across long distances, leading to acidification of soils and lakes far from the original sources. This downwind deposition explains why these regions have experienced notable acid deposition despite not emitting all of the pollutants locally.