Regulators: Tighten NC metro air quality rules

RALEIGH -- Although air quality has improved in much of North Carolina, regulators say unhealthy ozone levels may result in tighter federal regulations for metropolitan areas. The News & Observer of Raleigh reported Tuesday that regulators said millions of people inhale unhealthy levels of ozone, which is a primary ingredient of smog. State air quality officials plan to recommend that the U.S. Environmental Protection Agency adopt tougher rules in March for cities, the Great Smoky Mountains National Park and several other areas. Regulators are required to review the standards every five years. The current standard is 75 parts per billion in a sample taken at ground level over an eight-hour period. (Copyright 2009 by The Associated Press. All Rights Reserved.)