AUGUSTA – Maine violated federal ozone standards only once during the summer, the state’s best showing in more than 20 years of record-keeping.

Martha Webster, the state’s air quality forecaster, said July 30 was the only day when violations occurred, when ozone-monitoring stations in Kennebunkport and Kittery exceeded federal standards. Last year, the state exceeded the standards on five days, she said.

In 2002, Maine violated the federal standard on 14 days. Violations occurred on 10 days in 2001.