Which is a primary cause of acid rain?

Which is a primary cause of acid rain?

• A. Nitrogen dioxide
• B. Ozone
• C. Methane
• D. Sulfur dioxide

Answer: (D)

Acid rain comes from pollutants in the air that react with water in clouds to form acids, mainly sulfuric and nitric acids. The most important driver is sulfur dioxide, which is released in large amounts when fossil fuels like coal are burned. In the atmosphere, sulfur dioxide is oxidized and transformed into sulfuric acid inside cloud droplets, and when this acidic content returns as rain, the pH drops. Nitrogen oxides also contribute by forming nitric acid, but sulfur dioxide generally has the larger influence on rainfall acidity, especially in regions with heavy coal use. Ozone and methane don’t directly form the acids responsible for acid rain, so they aren’t the primary culprits.

Acid rain comes from pollutants in the air that react with water in clouds to form acids, mainly sulfuric and nitric acids. The most important driver is sulfur dioxide, which is released in large amounts when fossil fuels like coal are burned. In the atmosphere, sulfur dioxide is oxidized and transformed into sulfuric acid inside cloud droplets, and when this acidic content returns as rain, the pH drops. Nitrogen oxides also contribute by forming nitric acid, but sulfur dioxide generally has the larger influence on rainfall acidity, especially in regions with heavy coal use. Ozone and methane don’t directly form the acids responsible for acid rain, so they aren’t the primary culprits.