What did the EPA put limits on because of the clean air act?

The Environmental Protection Agency (EPA) established limits on several harmful pollutants under the Clean Air Act, including sulfur dioxide, nitrogen oxides, particulate matter, carbon monoxide, ozone, and lead. These regulations aim to improve air quality and protect public health by reducing emissions from various sources such as vehicles, industrial facilities, and power plants. The act also mandates the establishment of National Ambient Air Quality Standards (NAAQS) to ensure that air quality remains safe for all Americans.