What characterizes acid rain?

• A. It is precipitation that is drier than normal
• B. It contains pollutants like sulfur dioxide and nitrogen oxides
• C. It only occurs in winter
• D. It is harmless to the environment

Answer: (B)

Acid rain is characterized by its composition, which includes pollutants such as sulfur dioxide and nitrogen oxides. These compounds are released into the atmosphere primarily from burning fossil fuels, such as coal and oil, as well as from industrial processes and vehicle emissions. When these gases combine with water vapor in the atmosphere, they form sulfuric and nitric acids. Thus, the rain that forms can have a significantly lower pH than normal rain, making it acidic. This acidity can lead to environmental damage, affecting soil, water bodies, and forests by harming plant and aquatic life and degrading buildings and infrastructure.

The other choices do not accurately describe acid rain. For instance, it is not related to being drier than normal and does not only occur in winter; acid rain can happen at any time of the year when the conditions are right for precipitation. Moreover, it is certainly not harmless; its environmental impacts are a primary concern in discussions about pollution and ecological health.