Contact Us


All News Releases By Date


New England Experienced Fewer Unhealthy Air Quality Days During Recent Summer

Release Date: 10/01/2009
Contact Information: Dave Deegan, 617-918-1027

(Boston, Mass. – Oct. 1, 2009) – EPA today confirmed that New Englanders experienced a decrease in the number of unhealthy ozone air quality days this year, compared to 2008. The decrease in the number of days with unhealthy air quality is related to the cool, wet summer experienced throughout the region.

Based on preliminary data collected between April and September, there were 11 days when ozone monitors in New England recorded concentrations above the ozone air quality health standard. By contrast, in 2008 there were a total of 28 unhealthy ozone days and in 2007, there were 53 unhealthy ozone days.

The number of unhealthy ozone days in each state this summer was as follows:

-6 days in Connecticut (compared to 22 in 2008);
-7 days in Massachusetts (18 in 2008);
-1 day in Rhode Island (6 in 2008);
-3 days in Maine (4 in 2008);
-2 days in New Hampshire (8 in 2008); and
-0 days in Vermont (3 in 2008).

Ground-level ozone is the main ingredient of smog. Last year, EPA made the ozone standard more stringent. Ozone levels are considered unhealthy when average concentrations exceed 0.075 parts per million over an 8-hour period. EPA is currently reconsidering the 2008 ozone standard. During this reconsideration, air quality notices to the public will continue to be based on the 2008 ozone standard.

Sunlight and high temperatures speed the formation of ground-level ozone. This year's decrease in the number of days with unhealthy air was directly related to the cold, rainy summer, especially in the critical June time frame. Over the long-term, New England has experienced a decreasing number of unhealthy ozone days. In 1983, New England had 113 unhealthy days, compared with 11 this summer, a 90% decrease.

Also a major factor in the long-term decline in unhealthy days is the substantial decrease in air pollution emissions from all sources. For example, since 2004, new cars, SUVs, pickup trucks, and mini-vans have stringent new emission standards resulting in vehicles that are 77 to 95 percent cleaner than older models.

Ground-level ozone (smog) is formed when volatile organic compounds and oxides of nitrogen chemically react in the presence of sunlight. Cars, trucks, motorcycles and buses give off the majority of the pollution that makes smog. Fossil fuels burning at electric power plants, which run at high capacities on hot days, emit substantial amounts of smog-making pollution. Gas stations, print shops, household products like paints and cleaners, as well as gasoline-powered lawn and garden equipment, also contribute to smog formation.

Although the 2009 ozone season is ending, pollution from small particles in the air is a year-round concern. The daily air quality index forecast will continue to be available at New Englanders can also sign up at this address to receive air quality alerts. These alerts are issued by e-mail, whenever necessary, to notify program participants when high concentrations of ground-level ozone or fine particles are predicted to occur, in their area.

Historical charts of unhealthy air days from 1983 through 2009 are available for each New England state on EPA New England’s web site at: A preliminary list of the unhealthy readings recorded this summer by date and monitor location, and corresponding air quality maps for each day, can be found at:

# # #