Stay indoors: more ozone-laden smog expected

By Ty Tagami

The Atlanta Journal-Constitution

The string of bad ozone counts that started several days ago is expected to persist at least through Wednesday, when the Clean Air Campaign is predicting yet another "code orange" day for metro Atlanta.

The alert means ground-level ozone, a principal component of smog, is expected to concentrate at a level that is unhealthy for people with heart or lung disease, those with ozone sensitivity and all children.

But exposure to the pollutant isn't good for anyone.

"Exposure to ground-level ozone is almost like getting a sunburn on the inside of your lungs," said Brian Carr, a spokesman for the Clean Air Campaign. It makes breathing more difficult and exacerbates asthma and bronchitis, he said. And it is linked to other serious health risks -- including death from heart and lung disease.

In other words, stay indoors as much as possible. And limit strenuous outdoor exercise during the heat of the day. On the worst days, you might want to nix strenuous work outs altogether, since ozone particles can pollute buildings.

There are several causes of the bad air. Automobile tailpipes spew nitrogen oxides, a raw ingredient of ozone, and Carr noted that the re-opening of schools after summer break has put more vehicles on the road.

Another, perhaps surprising source, is trees and other vegetation. They exhale volatile organic compounds, another ingredient of ozone.

But the primary cause is the same thing that nearly everyone has been complaining about since spring: "The heat is really the key that cooks all this together," Carr said.

Ozone concentrations are difficult to predict more than a day in advance, but more of the same weather would set the stage for more bad ozone days, Carr said. A cold front, rain and even wind could clear the air, he said.

The bad air so far this year isn't as bad as what hit Atlanta in 2008. That year, the metro area endured 25 code orange days and four code reds, which are worse, for a total of 29 violations of federal environmental standards. (There have been no code purples, the worst possible, since 2002.)

Last year, there were 14 violations, all of them code orange. So far, this year, there have been 11 orange days and one red, for a total of 12. That number will rise to 13 assuming that actual measurements for Tuesday prove out the orange prediction. It will rise to 14, if Wednesday's forecast comes true.

Then, Atlanta will have matched last year's count, while still in the depths of the hot season.

The likelihood of exceeding last year's violations is compounded by a technical change. The EPA is scheduled to release new ozone standards Aug. 31 that Carr expects will be more strict at defining the health risks of ozone accumulation.