ATLANTA - Thursday's another bad air day for the metro Atlanta area. <br>
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The area is under a ``Code Orange'' alert, with the possibility the alert might be increased to a ``Code Red'' by later Thursday. <br>
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Temperatures are expected to reach into the 90s again. <br>
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It's the third straight day for Code Orange. <br>
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Ground-level ozone forms when sunlight combines with low winds and moderate humidity to react with pollutants emitted by power plants and idling vehicles. People with respiratory problems are advised to stay inside on days when the air quality is worse than an orange rating. <br>
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On smog-alert days, people are advised to limit their outdoor activities during the afternoon and evening hours. <br>
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In 2001, metro Atlanta's air quality reached only a code red three times. In 1999, the region had 21 code red days. In 2000, there were eleven.
