Air quality monitoring

Timothy J. Verville, a supervisor with the N.H. Department of Environmental Services' Air Resources Division, conducts a quarterly quality assurance audit at the Water Street air quality monitoring station in Keene in January 2018.

For the first time, Cheshire County’s air quality earned the highest marks in this year’s report from the American Lung Association.

But according to a local expert, the report doesn’t offer a full picture of area air pollution.

Released this morning, this year’s State of the Air report tracks and grades levels of particle pollution and ozone nationwide from 2017 to 2019.

At certain levels, both ozone and particle pollution can cause premature death and other serious health effects, such as asthma attacks and cardiovascular damage.

Ozone in the upper atmosphere helps filter out damaging ultraviolet radiation from the sun, but once it’s in the air we breathe, it can become harmful to our respiratory system. Harmful ozone occurs when sunlight interacts with certain chemicals, such as those caused by car and chemical emissions.

In both categories, Cheshire County received an “A” ranking — up one grade from the “B” it’s received for the past several years and the first “A” it’s gotten since the report was initially released 22 years ago.

“Cheshire County by all accounts did really well on this year’s report,” said Michael Seilback, the national assistant vice president for state public policy at the American Lung Association. “Certainly any time you could receive ‘A’s without any levels of elevated pollution is something to be really happy about.”

For ozone levels, an “A” means the county had zero days during the marked time period on which the ozone was elevated, according to the report.

Particle pollution, meanwhile, is measured in two ways: average annual levels and short-term spikes.

Historically, Cheshire County — especially Keene — has had problems with fine particle pollution due to a combination of factors: the city’s location in a geological bowl and people’s use of wood stoves in the winter. A meteorological event called inversion leads the fine particles emitted from those stoves to be trapped in the valley.

But this time, the county fared well. It had no short-term spikes — measured in 24-hour periods — in particle pollution, and the average annual level also did not show a heightened rate of pollutants.

But Nora Traviss, an environmental studies professor at Keene State College, said the report shows only a general view of the area’s pollutants.

“This is a great broad brush approach for the goal of the report, which is to identify highly polluted areas in the United States,” she said in an email. “But it is a big brush so it misses important details and context, which are very important to rural areas like Keene and other New England valley communities.”

Traviss — who is working with her students to predict local air inversions — added that the county being in compliance with the Environmental Protection Agency’s regulations for ozone and particle pollution doesn’t mean there aren’t still health risks.

The report shows Cheshire County has higher rates of asthma (10 percent) than Fairbanks, Alaska, (9 percent) and Fresno, Calif., (8 percent), which are considered the two cities with the highest levels of particle pollution in the United States, according to Traviss.

Additionally, the report doesn’t consider indoor air quality, which Traviss said is critical since people spend so much time inside. Poor indoor air quality in the winter, for example, could increase asthma rates.

“Sometimes its critical to get into the ‘weeds’ of these reports to point out the constraints of the conclusions,” she said.

Meanwhile, air quality measurements might not be representative of an entire county.

Seilback explained that each county is given one monitor, which is then placed in a community that’s reflective of the county. For Cheshire, that is on Water Street in Keene.

Traviss added that most rural areas have few, if any, regulatory monitors, so it’s difficult to know the entire region’s air quality.

“Generally, the monitor should reflect a broad perspective of the air quality for the county,” Seilback said, “but there are cases where a monitor is placed in one part of the county, and it’s so far away from a source that local residents would sometimes complain and say ... ‘We need a monitor here because they are saying it’s good in the county, but it’s not here.’ “

The four other New Hampshire counties for which the American Lung Association had particle-pollution data— Belknap, Hillsborough, Rockingham and Grafton — received an “A.” For ozone, Belknap, Merrimack and Coos kept their “A” rating, while Grafton kept its “C.” Hillsborough and Rockingham improved their ratings, receiving a “B” and “C”, respectively.

Seilback added that Cheshire’s rating bump is likely not due to one or two events, but rather a combination of local, state and federal efforts, as well as increased education, monitoring and awareness.

But despite this work and a good rating this year, Seilback said “we can’t become complacent.”

“We all have a way to contribute to keeping our air quality clean, whether that means making sure we are turning off our lights or not pumping up our air conditioner when we’re not home,” he said. “... Being cognizant of our contributions to air pollution is important.”

Olivia Belanger can be reached at 352-1234, extension 1439, or Follow her on Twitter @OBelangerKS.