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EPA Announces Significant Improvement in Air Quality for Central New Hampshire, Sulfur Dioxide Attainment

All areas of New England now in attainment for sulfur dioxide, should spur economic growth

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David Deegan (
(617) 918-1017

CONCORD, N.H. – The U.S. Environmental Protection Agency (EPA) has announced the Central New Hampshire area is now meeting air quality standards for sulfur dioxide (SO2). EPA has re-designated the Central New Hampshire area to "attainment" for the SO2 standard. With this re-designation, all areas in New England are now in attainment of the SO2 standard.

"Today's announcement is tremendous news for the people of Central New Hampshire and means cleaner air, improved health outcomes, and greater economic opportunity," said EPA Administrator Andrew Wheeler. "EPA is working closely with the states to help areas like Central New Hampshire reach air quality attainment, reduce regulatory burdens, and breathe new life into their local economies."

"The Central New Hampshire area has made significant strides towards improved air quality in the last several years," said EPA Regional Administrator Dennis Deziel. "We are pleased to be able to re-designate this area to attainment and not only celebrate an improved environment, but also reduce regulatory requirements and maintain good air quality."

"New Hampshire welcomes this re-designation action by EPA, which formally recognizes the result of many years of effort and collaboration between the former and current owners of Merrimack Station, the NH General Court, the NH Public Utilities Commission, and NH DES," said New Hampshire Department of Environmental Services (NH DES) Commissioner Robert Scott. "The resulting reductions in SO2 emissions benefit citizens of New Hampshire by reducing environmental and public health risks due to SO2 exposure while at the same time benefiting the New Hampshire economy by eliminating the potential for additional restrictions on economic development that could have been imposed under Clean Air Act as a result of the area's former nonattainment status."

Over the past decade, air quality in Central New Hampshire has significantly improved. Ten years ago, although meeting the previous federal standards for SO2 in place at the time, the area had some of the highest air concentrations of SO2 in the country. Today the area is attaining the current, more health protective standard by a wide margin. This improvement is due to both new technology installed at Merrimack Station, a power plant located in Bow, N.H., and new SO2 emission limits for Merrimack Station issued in a permit by NH DES.

In June 2018, EPA approved these emission limits as part of NH DES's plan to improve air quality and reach attainment for federal air quality standards regarding SO2 emissions in the Central New Hampshire area. The combination of the state's efforts has resulted in this area meeting the goal of attainment. Because Central New Hampshire now meets the SO2 air quality standard that is protective of public health, the state and industry in the area are now subject to fewer regulatory requirements. Because of the improved air quality in the area, investment and development in the local economy can now occur at a lower cost without the nonattainment area requirements.

Merrimack Station installed and has operated a highly efficient SO2 emissions control system since 2012. These upgrades have reduced SO2 emissions from Merrimack Station by 98 percent resulting in a dramatic improvement of ambient air quality in the area.

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