Maine officials said Thursday they had hoped the federal government would hand down more stringent regulations to deal with air pollution, especially the dirty air blowing into Maine from downwind states.

The new rules announced earlier this week by the U.S. Environmental Protection Agency mean that several Maine counties likely will have to do more to reduce smog levels on hot summer days.

Nonetheless, state officials and health groups say the EPA did not go far enough when it set new standards for ground-level ozone. That’s because Maine’s air quality is largely dependent on how much pollution drifts into the state from urban areas to the south.

Maine is in what Tom Downs, chief meteorologist with the state Department of Environmental Protection, calls the “ozone transport region,” meaning it is on the receiving end of pollution generated in the megalopolis from Washington, D.C., to Boston. Coal-fired power plants and industry in the Ohio Valley and Midwest also contribute to the state’s pollution problems.

“The cleaner [states downwind] are, the cleaner things are going to be here,” said DEP deputy commissioner Deborah Garrett. “If the folks downwind of us [switch] to tougher standards, then that is going to benefit us.”

The EPA measures an area’s compliance with ozone standards by averaging air quality measurements over eight-hour blocks of time taken during the past three years. On Wednesday, the agency announced that the allowable level of ozone would drop from 80 parts per billion to 75 parts per billion.

While a crucial part of the Earth’s upper atmosphere, ozone can cause serious breathing and heart problems – especially among the very young, elderly and infirm – when it is located on the ground. Ground-level ozone, or smog, is formed when vehicle exhaust and smokestack emissions containing nitrogen oxide and volatile organic compounds combine with sunlight and oxygen.

Hancock County very likely will fall out of compliance with EPA’s ground-level ozone regulations under the revised standards announced Wednesday. But Hancock County probably won’t be alone on the noncompliance list, according to Downs.

Downs said that, based on figures from the past two years, all of mid-coast and southern coastal Maine could end up with air measurements considered too dirty for public health if this summer produces some hot and hazy days.

Downs said Hancock County’s ozone levels are often higher than other areas of the state because the measurements are taken at two elevated locations in Acadia National Park, including on top of Cadillac Mountain.

Winds carry pollution from other states into Maine and on hot summer days the ozone camps out on top of Cadillac, Downs said.

“When [factors] all line up perfectly, we can get some high numbers up there,” he said.

The 75 parts per billion threshold adopted by EPA administrators is actually considerably less stringent than what the agency’s scientists had recommended. EPA’s Clean Air Scientific Advisory Committee had wanted the cap set at somewhere between 60 and 70 parts per billion.

Health organizations, including the American Lung Association of New England, as well as Maine environmental officials, also had advocated lowering the standard to 70 parts per billion or less.

“Higher ozone leads to decreased worker productivity, increased hospital visits and health problems for the most sensitive groups including asthmatics, children and the elderly,” David Littell, commissioner of the Maine DEP, said in a statement. “EPA should follow the advice of its own Clean Air Scientific Advisory Committee under the Clean Air Act, which charges EPA with protecting the public’s health from the effects of air pollution.”

DEP officials acknowledged Thursday that lowering the standard to 60 to 70 parts per billion would mean more Maine counties likely would fall out of compliance with the EPA standard. That, in turn, would force the state and counties to undertake additional air pollution prevention measures.

Exactly what those measures would be is unclear at the moment and state officials would have years to bring the state into compliance.