Who sets the National Ambient Air Quality Standards (NAAQS)?

• A. World Health Organization
• B. State Health Departments
• C. Environmental Protection Agency
• D. Local Municipalities

Answer: (C)

The main concept: National Ambient Air Quality Standards are established by a federal agency, not by international bodies or local entities. The Environmental Protection Agency sets the NAAQS under the Clean Air Act, determining the national threshold levels for pollutants such as ozone, particulate matter, and other common air contaminants. These standards provide uniform health-based limits across the country, guiding states in designing their own air programs and control requirements. The World Health Organization offers international guidance, but it does not regulate or set U.S. ambient air standards. State health departments and local municipalities are responsible for implementing and enforcing the standards within their jurisdictions, often through state implementation plans and permits, but they do not set the national thresholds themselves.