The Environmental Protection Agency (EPA), USA, is suggesting that air quality standards for ground level ozone should be tightened up - standards have not been changed since 1997. Ozone is the main component of smog.

EPA Administrator Stephen L. Johnson, said "Advances in science are leading to cleaner skies and healthier lives. America's science is progressing and our air quality is improving. By strengthening the ozone standard, EPA is keeping our clean air momentum moving into the future."

The EPA would like to see ozone standards within the 0.070 to 0.075 parts per million (ppm) range.

According to the EPA, people with asthma or other lung diseases can be seriously affected by high levels of ozone. The agency added that children who spend a lot of time outdoors might also be affected.

Since 1980, ozone levels in the USA have fallen by 21%, says the EPA.

Ground level ozone is created through a reaction of nitrogen oxides and volatile organic compound emissions in the presence of sunlight - it is not emitted directly into the air. The major man-made ozone precursors come from motor vehicle exhaust, chemical solvents, electric utilities and industrial facilities.

A 'secondary' standard for ozone is also being proposed. This is aimed at improving protection for plants, tress and crops during the growing season. Scientific evidence indicates that even fairly low levels of ground-level ozone can harm vegetation.

The EPA will take public comment for 90 days following publication of the proposal in the Federal Register and will hold four public hearings. The hearings will be held in Los Angeles and Philadelphia on Aug. 30, and in Chicago and Houston on Sept. 5.

http://epa.gov/groundlevelozone

http://www.epa.gov

Written by: Christian Nordqvist
Editor: Medical News Today