The N.H. Department of Environmental Services is expecting air pollution concentrations to reach unhealthy levels for sensitive individuals in populated valley areas in southwestern New Hampshire — especially in Keene — for tonight into the late morning hours Wednesday.

State officials are calling for an Air Quality Action Day for this time and are advising sensitive individuals in the area to take precautions to protect their health by limiting prolonged exertion. Sensitive individuals include children, older adults and anyone with heart or lung diseases, such as asthma, emphysema, and bronchitis. Even healthy individuals may experience mild health effects and should consider limiting strenuous or prolonged activities.

The department forecasts concentrations of fine particle pollution to be unhealthy as the result of locally emitted pollution stagnating under temperature inversion conditions. Temperature inversions occur during calm, cold nights when warm air above traps cold air below. Such inversions prevent pollution near the ground from mixing with cleaner air aloft and diluting. As a result, ground-level pollution concentrations can increase. Much of locally emitted pollution comes from heating devices, especially residential wood burning stoves and boilers.

via Air quality alert issued for the area – SentinelSource.com: Local News.