How do SO2 and NOx emissions from power plants affect the environment and human health?

• A. They improve air quality by neutralizing acid rain.
• B. They have no effect on human health.
• C. They only affect aquatic ecosystems and not human health.
• D. They contribute to acid rain, smog, respiratory problems, and formation of fine particulates; harm ecosystems and human health.

Answer: (D)

SO2 and NOx emissions from power plants affect air quality and health because they react in the atmosphere to form sulfuric and nitric acids, which fall as acid rain and also contribute to fine particle pollution and ground-level ozone. Acid rain lowers the pH of soils and water, harming forests, crops, and aquatic ecosystems by changing nutrient availability and metal solubility. At the same time, the resulting fine particles and ozone irritate the human respiratory system, increasing asthma, bronchitis, heart and lung problems, and the need for medical care. This combination of ecosystem damage and health risks explains why the best answer describes acid rain, smog, respiratory problems, and harm to ecosystems and human health. The other options ignore or misstate these impacts.