Persistent high temperatures and droughtlike conditions across the East and Midwest have created the worst air pollution in a decade in many metropolitan areas, say federal and state environmental officials.

Levels of ozone, caused by auto and industrial emissions combining with sunlight, have substantially exceeded the Environmental Protection Agency health standard in communities from Maine to Louisiana.Officials said that this summer has been particularly bad because there has been little air movement along with the record high temperatures.

Stifling heat is part of every summer season, but in many sections of the country there haven't been weather fronts moving in to clear out the pollution.

"It's been horrible," said S. William Becker, executive director of the State and Territorial Air Pollution Program Administrators."The pollution is being emitted in significant quantities," he said. "What we are finding in many areas is that they are exceeding the (EPA) limit over many hours or even days at a time."