EPA Proposes to Strengthen Smog Standard

January 11, 2010

The United States Environmental Protection Agency has proposed the strictest health standards to date for smog. Smog, also known as ground-level ozone, is linked to a number of serious health problems, ranging from aggravation of asthma to increased risk of premature death in people with heart or lung disease. Ozone can even harm healthy people who work and play outdoors. The agency is proposing to replace the standards set by the previous administration, which many believe were not protective enough of human health. This action would put more than 300 counties across the U.S. out of compliance with air quality standards

Ground-level ozone is formed by the mixing of nitrogen oxides, volatile organic compounds, carbon monoxide and methane in sunlight. Emissions from vehicle traffic are considered a major contributor to smog. Experts believe that a reduction in tailpipe emissions through the use of natural gas, propane, and electricity could substantially reduce this ground-level ozone.

According to EPA administrator Lisa Jackson, "EPA is stepping up to protect Americans from one of the most persistent and widespread pollutants we face.  Smog in the air we breathe poses a very serious health threat, especially to children and individuals suffering from asthma and lung disease. It dirties our air, clouds our cities, and drives up our health care costs across the country."

The agency is proposing to set the "primary" standard, which protects public health, at a level between 0.060 and 0.070 parts per million (ppm) measured over eight hours. The existing standard is 0.075 ppm. Children are at the greatest risk from ozone, because their lungs are still developing, they are most likely to be active outdoors, and they are more likely than adults to have asthma.

EPA is also proposing to set a separate "secondary" standard to protect the environment, especially plants and trees. This seasonal standard is designed to protect plants and trees from damage occurring from repeated ozone exposure, which can reduce tree growth, damage leaves, and increase susceptibility to disease.