Which compound is the main cause of acid rain?

The primary cause of acid rain is sulfur dioxide. When sulfur dioxide is released into the atmosphere, typically from burning fossil fuels, it reacts with water vapor and oxygen to form sulfuric acid. This process occurs when sulfur dioxide interacts with natural elements in the atmosphere, leading to precipitation that is more acidic than normal rainwater.

Acid rain can harm ecosystems, soil, and buildings by altering the pH of water bodies and damaging vegetation. The presence of sulfuric acid contributes to the acidity of rain, demonstrating why sulfur dioxide is a crucial component in the formation of acid rain.

Other compounds, though harmful in different ways, do not play the same role in acid rain formation. For example, nitrogen dioxide can lead to acid rain as well, but it primarily forms nitric acid, which tends to be less prevalent compared to the impact of sulfuric acid from sulfur dioxide. Carbon monoxide is principally associated with air pollution and health risks, while ozone is a significant air pollutant at ground level, yet not a direct contributor to acid rain. Understanding these distinctions highlights the distinct impact sulfur dioxide has on acid rain formation.