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New England Experienced More Smog Days During Recent Summer

Release Date: 09/26/2005
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Contact: David Deegan (, EPA Office of Public Affairs, (617) 918-1017

For Immediate Release: September 26, 2005; Release # dd050917

(Boston) – As the 2005 summer ozone season comes to an end, EPA today confirmed that New Englanders experienced a modest increase in the number of poor air quality days this year, compared to 2004 and 2003. Based on preliminary data collected between May and September, there were 26 days when ozone monitors in New England recorded concentrations above levels considered healthy. By contrast, in 2004 and 2003 there were a total of 13 and 17 unhealthy ozone days, respectively.

The number of unhealthy ozone days in each state this summer were as follows: 20 days in Connecticut (compared to 6 in 2004); 20 days in Massachusetts (8 in 2004); 8 days in Rhode Island (4 in 2004); 4 days in Maine (one in 2004); 3 days in New Hampshire (4 in 2004); and no days in Vermont (one in 2004).

The increase in the number of days with unhealthy air this year was directly related to the increase in the number of hot days this year. Sunlight and high temperatures speed the formation of ground-level ozone smog, and many areas of New England had more days exceeding 90 degrees this summer than during the past two summers. Ground-level ozone, the main ingredient of smog, is unhealthy when average concentrations exceed 0.08 parts per million over an 8-hour period.

Although warm temperatures this summer led to an increase in unhealthy days, over the long-term, New England has experienced a decreasing number of ozone days, and peak ozone concentrations have decreased significantly over the last 30 years. In 1983, New England had 90 unhealthy days, compared with 26 this summer. Overall, ozone concentrations in New England have decreased by more than 20 percent since 1980.

“When we look back to the air quality conditions a generation ago, we can feel proud of the advances we’ve made in reducing pollution,” said Robert W. Varney, regional administrator of EPA’s New England regional office. “A summer like this one, however, reminds us that our efforts to use cleaner cars and fuels and our commitment to reducing power plant emissions and conserving energy in our own daily lives must continue.”

Ground-level ozone (smog) is formed when volatile organic compounds and oxides of nitrogen chemically react in the presence of sunlight. Cars, trucks and buses give off the majority of the pollution that makes smog. Fossil fuel burning at electric power plants, which run at high capacities on hot days, gives off significant 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.

Exposure to elevated ozone levels can cause serious breathing problems, and aggravate asthma and other pre-existing lung diseases. It can also make people who are vulnerable more susceptible to respiratory infection.

EPA has taken a number of steps to further reduce air pollution. Since 2004, new cars, sport utility vehicles, pickup trucks, and minivans are meeting stringent new emission standards. The requirements are being phased in between 2004 and 2009 resulting in vehicles that are 77 to 95 percent cleaner than older models. The program also requires a 90 percent reduction in the sulfur content of gasoline, which is helping reduce emissions from all vehicles new and old. Beginning in 2007, EPA’s standards for new diesel trucks and buses will reduce NOx and particulate matter emissions by 90 percent. In addition, EPA is requiring a 97 percent reduction in the sulfur content of highway diesel fuel starting in September 2006.

The record demand for electricity this summer is also a factor contributing to air pollution. High electricity demand worsens air quality by forcing power plants in the region to run at or near peak capacity, thus increasing air emissions from those plants. On July 19, 2005, electricity use reached 26,749 megawatts, exceeding the previous all-time record of 25,348 megawatts set in August 2002. Subsequently, on July 27, 2005, the new record was broken when electricity use reached 26,922 megawatts. On this day, unhealthy levels of ozone were recorded in Connecticut and Massachusetts.

EPA is working to address the air pollution challenges resulting from this increase in energy demand. This March, EPA finalized the Clean Air Interstate Rule (CAIR) to help reduce the transport of air pollution from power plants across state boundaries. When fully implemented, CAIR will reduce power plant NOx emissions by over 60 percent and sulfur dioxide by over 70 percent.

Also, additional improvements in air quality are expected as states implement plans to meet the 8-hour ozone standard. Last year, EPA formally designated areas that are not complying with the 8-hour ozone standard. All of Connecticut, Massachusetts, and Rhode Island, as well as parts of New Hampshire and Maine, are out of compliance. States with these nonattainment areas must submit plans by mid 2007 that will outline how they will meet the standard by the end of 2009. A map showing the 8-hour ozone nonattainment areas in New England is at

Although the 2005 ozone season has ended, 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 or fax, whenever necessary, to notify program participants when high concentrations of ground-level ozone or fine particles are recorded, or are predicted to occur, in their area.

Historical charts of unhealthy air days from 1983 through 2005 are available for each 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:

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