Air Pollution Warning Expanded into Merrimack County

The New Hampshire Department of Environmental Services (DES) is expecting air pollution concentrations to reach unhealthy levels for sensitive individuals in populated valley areas in Cheshire, Hillsborough, Merrimack, and Sullivan counties the night of Jan. 8, into the afternoon of Jan. 9. 

This advisory expands the area of concern from the southwestern corner of the state, including Keene, to valley communities further north and east, including those along the Merrimack River Valley between Manchester and Franklin.

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

DES forecasts concentrations of fine particle pollution to be unhealthy for sensitive individuals in the above-mentioned region. The expected unhealthy particle pollution levels are 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 events 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 fireplaces, stoves and boilers.  Communities located in valleys or other low-lying areas where temperature inversions are common are more strongly affected. Conditions are expected to improve by Wednesday afternoon as wind speeds increase, resulting in better mixing and cleaner air.

The severity of the health effects increases as fine particle concentrations increase. People with asthma and other existing lung diseases may not be able to breathe as deeply or vigorously as normal and may experience symptoms such as coughing and shortness of breath. Symptoms of particle pollution exposure for people with heart disease may include chest pain, palpitations, shortness of breath, and fatigue. In addition to harmful health effects, fine particle pollution may create hazy conditions that reduce visibility.

For further information, contact DES at 603-271-1370. 

For air quality forecasts and current air pollution levels in New Hampshire, call 1-800-935-SMOG or visit the DES website at airquality.nh.gov.