The simple act of filling up a car with gasoline on a hot summer day can add to ozone levels with emissions that escape at the pump while refueling, which is why Heying recommends that people fill up at night on hot days. Cars, gasoline and diesel fuel and even lawn mowers are all getting cleaner, she added. Heying said mowing your lawn late in the day in summer or on cooler days will also help keep ozone levels low.

School districts in Utah have been tweaking buses to run cleaner while some schools have or will be implementing no-idling rules while buses pick up and drop off students. State DEQ officials also point out that Gov. Jon Huntsman Jr. has made it one of his top priorities to improve air quality while at the same time some state office buildings now have more energy-efficient policies.

"All of these things are happening," she said. "We should see a reduction in pollution from these things."

Whether certain counties in Utah will come into compliance by 2010 based on efforts already under way to reduce ozone is "crystal-balling it," Heying said. She added there is no cost estimate yet on how the new standard may impact industrial contributors to ozone.

The EPA estimates it will collectively cost states between $7.6 billion and $8.5 billion to implement plans that will get counties in compliance with the new standard. The savings, however, in health-care costs as a result of cleaner air could be as high as $19 billion, the EPA estimates. The EPA based changing the ozone standard on over 1,700 peer-reviewed scientific studies, five public hearings and about 90,000 written comments.

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E-mail: sspeckman@desnews.com