KEENE, N.H. — Calm, cold nights are a cause for concern in Keene.

Because the city sits in a valley, it’s prone to a meteorological phenomenon called an air inversion, where a lid of warm air traps cold air and harmful pollution close to the ground.

Fireplaces and wood stoves can take the chill off inside, but the smoke they produce is a big part of the problem outside. And they’re the focus of a broad project to research the problem and teach the public how to burn wood in a way that maximizes heat and minimizes pollution.

“We can’t change the weather, but we can change the emissions,” said Sherry Godlewski, a program manager at the state Department of Environmental Services. The department collects data from 14 air monitoring stations around the state, including one in Keene.

After noticing a few years ago that particulate matter pollution levels in Keene exceeded federal clean air standards several times a year, it created a voucher program to help dozens of residents replace older woodstoves with more efficient models and enlisted local officials to collaborate on the research and outreach project.

The project’s partners include Keene State College, Cheshire Medical Center/Dartmouth Hitchcock-Keene, the Greater Monadnock Public Health Network, the city of Keene and the Southwest Regional Planning Commission.

The main message for residents is to burn the right wood, in the right stove, in the right way, said Godlewski. That means using only seasoned hardwood in a stove certified by the Environmental Protection Agency and maintaining a bright, hot fire rather than letting it smolder.

Statewide, 7.2 percent of people heat with wood, according to a census five-year estimate from 2008-12. That compares to about 15 percent in the Keene area.

The planning commission has taken the lead in the outreach piece of the project, giving numerous presentations in the community and arranging for the distribution of brochures and other materials.

Meanwhile, Keene State faculty and students are conducting research to identify where air pollution is concentrated and whether fluctuations in pollution levels are associated with the number of emergency room visits for respiratory illnesses.

The small particles in wood smoke can also cause heart problems, eye irritation, headaches and allergic reactions.

Starting in January, students will be using a mobile monitoring station to collect data from a variety of locations at 10-second intervals to give a more detailed picture of pollution levels, said Nora Traviss, a professor of environmental studies.

“We know Keene has air inversions, but what we don’t know is whether the pollution levels measured by the central monitoring station are representative of the entire city, or are there areas within the city with higher or lower levels?” she said.

Traviss suspects the latter, and in that case, the data could be used to target future outreach activities to specific neighborhoods, she said.