HARTFORD, Conn. — New England’s air quality improved this summer from 2010 because of fewer sweltering days, the Environmental Protection Agency said Thursday.
Between April and September, the six-state region had 16 days when ozone levels were considered unhealthy, according to preliminary data from the EPA. There were 29 during the same time frame in 2010.
This year’s air quality improvement is directly related to the decrease in the number of hot days, the EPA said. At Bradley Airport near Hartford, Conn., the temperature reached at least 90 degrees 15 days this year; there were 34 days with 90-degree temperatures in 2010.
But over the long term, stricter vehicle emission standards have resulted in cleaner air, EPA officials said. New England has had a steady decline in the number of smoggy days over the past three decades.
“We can all feel proud, and breathe easier, thanks to the progress we have made in reducing air pollution,” EPA regional administrator Curt Spalding said in a statement.
Connecticut this year had 14 unhealthy days, compared with 24 last year. Massachusetts had 10, down from 14. New Hampshire had six unhealthy days, the same as last year.
Rhode Island had had six unhealthy days, the same as 2010, and Maine had three, down from eight. Vermont — which had none last year — was the only state with an increase, logging one unhealthy day this year.
This year’s number of unhealthy days is the second-lowest since 1983, when New England had 113 unhealthy days. The lowest figure was in 2009, when ozone concentrations reached unhealthy levels on 11 days.
Cars, trucks and other vehicles emit most of the pollution that causes smog, but power plants that use fossil fuels can also give off substantial amounts, the EPA said. Gas stations, gasoline-powered lawn equipment, print shops and household products like paints and cleaners also contribute.