# EPA proposes tightening emissions standards

The EPA announced its decision on January 7, 2009 to investigate the need to tighten the ground-level ozone standard from 0.075 parts per million (ppm) to between 0.060 and 0.070 ppm.

Ground-level ozone, or smog, forms when emissions, such as nitrogen oxide (NOx), from industrial facilities, power plants and landfills react in the sun. If the standard is finalised, the EPA has calculated it could yield health benefits equal to between $13 billion and$100 billion in 2020 alone.

However,