Pollutants considered to be harmful for the health of the public and environment have air quality standards set for them by the Clean Air Act of 1970 which was last amended in 1990. The Clean Air Act has set two types of national standards for air quality. The two types of standards set are Primary and Secondary.
Primary air quality standards were set to protect public health. The Primary standards include sensitive pollutants such as those that contribute to asthma and the pollutants dangerous to children and the elderly.
Secondary air quality standards are those set to the welfare of the public. The pollutants included in the Secondary standards include pollutants effecting animals, visibility, buildings, crops and vegetation.
The Clean Air Act needs the EPA to set the levels for Carbon Monoxide and five other harmful pollutants. The six harmful pollutants that the EPA Office of Air Quality Planning and Standards or the OAQPS has set standards for are Carbon Monoxide, Lead, Nitrogen Dioxide, Ozone, Particulate Matter and Sulfur Dioxide. These six pollutants are called criteria pollutants. The units used to measure these pollutants are parts per million (ppm) by volume, milligrams (mg/m3), and micrograms per cubic meter of air (g/m3).
These standards have been set because the Clean Air Act needs the EPA to set the standards. The Clean Air Act also tells the EPA to review and update these standards to make sure that they continue to protect the public and the environment as the updates are needed.
The EPA and industry use these requirements to inform the public of the quality of air in the United States of America. With this information the EPA and industry can also know if the steps they are taking to improve the standards are effective.
If the quality went down then both the EPA and the specific industry creating the decline will know that they must change the way they are attempting to improve air quality.
If the air quality has improved then the EPA and industry can investigate what improvement methods can be named as responsible for the specific improvements. After the responsible methods have been named the EPA can use these facts to update the standards, laws and regulations so that the improvements can be both continued and hopefully accelerated.
In review, the Clean Air Act has been used to set standards for the EPA to set and follow. These standards are regularly tested and updated. As the air quality standards are updated, we know the level of success our improvement methods are having on the air quality around us.