Tuesday was the second bad-air day in a row for metro Atlanta, with smog readings in Conyers and McDonough exceeding the federal limit.

Since smog season began May 1, the region has violated the federal standard on seven days.

Under the old standard used from 2005 through 2007, the air quality on only one of those days would have been considered hazardous for children, the elderly, and people with heart and lung diseases.

The old standard was 84 parts per billion of ground-level ozone, a major ingredient in smog, measured in eight-hour increments. The new standard, which was changed earlier this year to protect public health, is 75 parts per billion. Metro Atlanta's violations have ranged from 77 parts per billion to 90 parts per billion.

Forecasters also issued an orange alert for Wednesday. During orange alerts, public health officials advise children and people with heart or lung diseases to limit outdoor exercise in the afternoon and early evening when ozone levels peak.

To sign up for air quality alerts and get more information about smog and how you can help, go to: www.cleanaircampaign.com

For up-to-date air pollution measurements, go to: www.air.dnr.state.ga.us/amp/index.php