Environmental issues automobile exhaust

Automobiles are the primary source of air pollution in many parts of the world. The Clean Air Act was enacted in 1968 to address the issue of smog and other forms of pollution caused by automobile exhaust. This act has been amended to set new, more restrictive emission-control standards for automobiles driven in the United States. Table 2 lists the standards for pollutants in exhaust set in 1996 by the U.S. Environmental Protection Agency. 

There are several environmental issues facing automobiles today cleaner exhaust, reduced carbon dioxide (C02) emissions, and reduced use of fossil fuels to ensure future energy security. The Prius is just one of many eco cars to meet these challenges. 

Tlie removal of NO from exliaust gases is an urgent issue, and environmental regulations are becoming more stringent tlian ever. The selective catalytic reduction (SCR) of NOx vvdth ammonia is the technique, which was extensively applied in stationary NOx sources from tlie 1970s, while the successful development of a three-way catalyst made it possible to reduce NOx in gasoline automobile exhaust. 

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