Maine and the rest of New England experienced fewer high-ozone days during the summer that just ended than last year, according to figures released today by the U.S. Environmental Protection Agency.

Based on preliminary data collected from April through Sept. 21, there were 28 days when ozone monitors in New England recorded concentrations above the health standard. There were 53 unhealthy ozone days in 2007, according to the EPA.

Maine had a total of three high-ozone day this year, compared to 14 in 2007, it said.

Exposure to elevated ozone levels can cause breathing problems and aggravate asthma and other pre-existing lung diseases.

The EPA attributed the decrease to fewer hot summer days and a long-term decline in pollution emissions. Ozone is a component of smog and is created when pollution from motor vehicles exhausts and industry react on hot, sunny days.

Earlier this year, the EPA lowered the level of the ozone air quality health standard to 0.075 parts per million on an 8-hour average basis. For comparison purposes, all statistics on the number of unhealthy days are presented in relation to the new standard.