m54.    How has legislation affected air pollution?

The Clean Air Act of 1990 required coal burning power plants to cut their 1999 annual SO₂ emissions in half and their NO_x emissions by ¹/₃ by 2000. A utility that emits less SO₂ than its limit receives pollution credits.  They can then avoid reduction in SO₂ in some of their other facilities. Car makers were to reduce hydrocarbon emissions by 35% and nitrogen oxide emissions by 60% for all 1994 new cars. Gasoline producers were to sell cleaner burning fuel in the 9 dirtiest cities (including Houston) by 1995. Since 1970, the US has reduced pollution from 5 of the 6 major outdoor pollutants. Most of the pollution laws are based on clean-up rather than prevention.

g19.    Where do you find air pollution?

e20.    What are environmental hazards and risks?