The Clean Air Act is

• A. A local ordinance on noise control.
• B. A major U.S. law that regulates air pollutants and sets air quality standards.
• C. A treaty among several countries to reduce pollution.
• D. A program to monitor water quality.

Answer: (B)

This question tests your understanding of what the Clean Air Act is. The Clean Air Act is a major U.S. federal law designed to protect air quality by regulating emissions of pollutants that harm human health and the environment. It sets national air quality standards for pollutants known to be harmful (such as particulate matter, sulfur dioxide, nitrogen oxides, ozone, carbon monoxide, and lead) and directs states to develop plans to meet these standards. The act gives the federal Environmental Protection Agency authority to regulate emissions from vehicles and industry, push for technology-based controls, and enforce compliance. It is a national law, not a local ordinance about noise, not a treaty between countries, and not a program focused on water quality.