If you’re thinking of mowing the lawn today, maybe you should reconsider. Today is another "orange" day for Hall County’s air quality, meaning the concentration of particulate matter that creates smog is higher than normal and not safe for sensitive people.

Even normal, healthy folks should limit their outdoor exertion on orange-alert days, said Brian Carr a, spokesman for the Atlanta-based Clean Air Campaign.

"Across the board, we encourage all adults to think twice before they go outside and exercise and get their heart rates up," Carr said.

Most at risk are children, the elderly and those who have respiratory diseases such as asthma.

If confirmed by ozone monitors maintained by the state Environmental Protection Division, it would be the 18th code orange day this year in the 20-county metro air pollution zone that includes Hall County.

The EPD does not have an ozone monitor in Hall County, but relies on computer models and wind pattern estimates to figure Hall into its air quality equations.

Gainesville has always been a part of what the federal government has designated as a region of Georgia susceptible to high ground-level ozone concentrations, though the National Weather Service only recently began posting the alerts on its Web site.

Carr acknowledged that when folks think about smog, they think about the big city. But he said the combination of car pollution (half of all smog-forming emissions come from tailpipes) and the number of coal-burning plants in the region means that "air quality issues pervade across the state, including North Georgia."

"Where there’s more density, you can see it, but the truth is, it’s everywhere," Carr said. "It may not be visible to the naked eye, but it is absolutely there."

Red alert days are far more uncommon. There have been two so far this year.

Last year there were 24 code orange days and five code red days. In 2006 there were 23 code orange days and seven code red days.

Georgia is in the midst of smog season, which lasts from May 1 to Sept. 1. The statewide burn ban coincides with smog season.

Carr said more orange days should be expected, with the federal government this year making air quality standards more stringent.

"The change has been dramatic," he said. "In June we had several days of code orange that would not have shown up last year as bad air quality days."

Carr said he’s glad folks in the Gainesville area are paying attention to the air quality alerts that have been part of life in the big city for years.

"We would love to see more people treat smog alerts much as they do the daily weather forecast," Carr said.