The Air Quality Index is a metric used to reflect the local air quality across the country. Taken daily in over a thousand locations, the Environmental Protection Agency regulates 1987 air pollutants under the Clean Air Act. The metric range is broken down by value, air quality and color code. The major pollutants that are monitored are ozone, sulfur dioxide, carbon monoxide and particulates. Ozone is a form of oxygen but has a pungent odor and bluish color. Carbon monoxide is an odorless, colorless and very toxic gas that comes from common objects like vehicles. Particulates are bits and pieces of debris in the air that can be breathed into the lungs. Sulfur dioxide is a toxic gas and a major pollutant that results from the burning of fuels such as coal and oil. The Clean Air Act, established in 1963, is celebrating its 50th anniversary. It is a federal law that the Environmental Protection Agency regulates. There were major amendments applied to the Act in 1970, 1977 and 1990. With the Act as its guideline, the Environmental Protection Agency has set a series of standards for the major air pollutants. Infographic provided by www.Oransi.com.