Question

The Clean Air Act (CAA) is the comprehensive federal law that regulates air emissions from stationary and mobile sources. Among other things, this law authorizes EPA to establish National Ambient Air Quality Standards (NAAQS) to protect public health and public welfare and to regulate emissions of hazardous air pollutants.

–“Summary of the Clean Air Act,”
Environmental Protection Agency

One purpose of the Clean Air Act is to

ensure clean air by regulating the emissions of pollutants.
set standards that make it easy for businesses to emit clean air.
guarantee that the air is free of hazardous pollutants.
force polluting countries to clean the air of hazardous emissions.

Answer 1

ensure clean air by regulating the emissions of pollutants.

Explanation: The CAA authorizes EPA to set and enforce standards (like the NAAQS) to protect public health and welfare by regulating pollutant emissions.