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New Hampshire Department of Environmental Services

Media Center

DATE: November 19, 2012
CONTACT: Jim Martin, 603 271-3710

25 for 25: Ensuring That Particle Pollution is Nothing to Choke Over
By Thomas S. Burack, DES Commissioner

If you’ve ever been to a big city or hiked in the White Mountains you may have experienced “hazy” conditions that restricted your view. This haze is a result of particle pollution. Since man began to burn wood and other fuels, we have had particle pollution. Particle pollution also forms in the air when gasses condense into solid matter or when chemical reactions convert nitrogen- or sulfur-based pollutants into small particles. Since the formation of the Department of Environmental Services (DES) 25 years ago, progress has been made in protecting the public from the harmful effects of particle pollution and in preserving New Hampshire’s majestic views. In the last 25 years we have seen significant reductions in particle pollution due to increased efficiency and regulation of emissions from vehicles, power plants and industry. Despite these overall improvements, we continue to have unhealthy air quality days due to particle pollution.

Particulate pollution data has been collected in New Hampshire since 1967. Originally DES tracked all sizes of particles. As technology improved, scientists better understood the harmful effects particle pollution has on human health. The smaller the particle, the more deeply it can penetrate into our lungs. In 1997 the federal Environmental Protection Agency (EPA) recognized the need to monitor and control particle pollution that is 2.5 microns in diameter (PM2.5) due to health concerns. By comparison, the human hair is 70 microns in diameter, so these are very small particles. They can lodge deeply into the lungs and some of the smallest can cross into the blood stream and affect people with heart problems.

In 1999 DES began monitoring PM2.5 in six communities throughout the state using paper filters collected once in a 24-hour period. DES currently measures PM2.5 at eight air quality monitoring stations and has introduced advanced technology samplers at five of these stations. The new technology tracks PM2.5 concentrations each hour and provides real-time reporting to the state website ( These new sampling devices have provided DES with a tool that helps us better understand how local weather patterns can trap local PM2.5 emissions. During cold and calm winter nights, particle pollution can get trapped in valley areas, causing overnight build-ups that reach unhealthy levels.

One of DES’ latest and most exciting projects has been mobile monitoring, which involves measuring PM2.5 from a moving vehicle. Thanks to special one-time EPA project funding, DES now has sampling equipment that can be used to collect short-term PM2.5 samples during periods when PM2.5 is predicted to rise overnight. This work has greatly helped DES understand the PM2.5 exposure risks in communities that don’t have permanent air monitoring stations.

DES focuses on PM2.5 in wintertime when residential heating, including wood stoves, adds to the problem along with other local sources. However, elevated PM2.5 concentrations can occur anytime of year when winds blow the pollutants into the state from other areas. Such pollutants can originate in cities, industrial areas, and even from forest fires located hundreds to thousands of miles away.

New Hampshire has met the PM2.5 health standard since it was first set in 1997. There are periods when PM2.5 concentration levels are forecasted to reach unhealthy levels for sensitive groups, and DES issues air quality alerts when such events are expected. The PM2.5 health standard is also currently being reviewed by EPA to determine if it provides enough protection to human health or if it should be more protective.

Fortunately, recent emission reduction programs for cars, trucks, heating devices, power plants, and industry have helped reduce PM2.5 and other pollutants. These measures are also helping the state meet its responsibilities under the federal Regional Haze Rule of 1999 which has a long-term goal of returning 156 national parks and wilderness areas (two in New Hampshire) to natural visibility conditions.

As we move forward, DES will strive to deepen its understanding of the sources and problem areas for PM2.5 pollution and will seek corrective measures. DES will continue to work with federal and other state agencies to reduce air pollution transport. Locally we will continue to raise awareness and encourage residents and businesses to take actions to reduce particle pollution. With all of us working together, our residents and visitors can enjoy year-round healthy air to breathe and crystal clear views of New Hampshire’s scenic beauty.

Author’s Note: In recognition of the New Hampshire Department of Environmental Services’ 25th Anniversary, over the course of the year, I am highlighting 25 agency activities, programs, projects and accomplishments of the past 25 years. This article, the 21st in the series, discusses efforts to reduce particle pollution in New Hampshire. All of the editorials in the series are available at

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NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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