Clean Air Act

A Clean Air Act is one of a number of pieces of legislation relating to the reduction of smog and air pollution in general. The use by governments to enforce clean air standards has contributed to an improvement in human health and longer life spans. Critics argue it has also sapped corporate profits and contributed to outsourcing, while defenders counter that improved environmental air quality has generated more jobs than it has eliminated.

Additionally, air quality legislation has led to widespread use of atmospheric dispersion models, including point source models, roadway air dispersion models and aircraft air pollution models in order to analyze air quality impacts of proposed major actions.

Canada
There have been two acts proposed by the Canadian federal government with the name "Clean Air Act". The first, passed in 1970, sought to regulate the release of four specific air pollutants: asbestos, lead, mercury, and vinyl chloride. It has since been replaced by the Canadian Environmental Protection Act in the year 2000.

Former Canadian Environment Minister Rona Ambrose introduced the second Clean Air Act in mid-October 2006, containing mostly measures to fight smog pollution and greenhouse emissions. . On October 19, 2006, Ambrose revealed details of the plan which would include reducing the greenhouse emissions levels of 2003 by about 45 to 65% for the year 2050. There are plans for regulations on vehicle fuel consumption for 2011 and targets for ozone and smog levels for 2025. The effectiveness of this act has been challenged by the opposition parties, with Jack Layton of the New Democratic Party stating that the act does little to prevent climate change and that more must be done. After threatening to make this into an election issue the Conservative Party agreed to rework the act with the opposition parties.

United Kingdom
In response to the Great Smog of 1952, the British Parliament introduced the Clean Air Act 1956. This act legislated for zones where smokeless fuels had to be burnt and relocated power stations to rural areas. The Clean Air Act 1968 introduced the use of tall chimneys to disperse air pollution for industries burning coal, liquid or gaseous fuels.

United States
The United States federal government has enacted a series of clean air acts, beginning with the Air Pollution Control Act of 1955, and followed by the Clean Air Act of 1963, the Air Quality Act of 1967, the Clean Air Act Extension of 1970, and Clean Air Act Amendments in 1977 and 1990. Numerous state and local governments have enacted similar legislation, either implementing federal programs or filling in locally important gaps in federal programs.

The Clean Air Act Amendments of 1990 proposed emissions trading, added provisions for addressing acid rain, ozone depletion and toxic air pollution, and established a national permits program. The amendments once approved also established new auto gasoline reformulation requirements, set Reid Vapor Pressure (RVP) standards to control evaporative emissions from gasoline and mandated that the new gasoline formulations be sold from May-September in many states.