CONCORD, N.H. — The new Hampshire Department of Environmental Services said it expects air pollution concentrations to reach unhealthy levels for sensitive individuals in Cheshire, Hillsborough and Rockingham counties on Saturday, Jan. 1.DES officials said they were extending the Air Quality Action Day issued for Friday 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 a combined result of pollution transported from surrounding areas and cold, stagnant air and temperature inversions, which limit air movement.Much of this pollution is emitted from heating devices, especially residential wood burning stoves and boilers, and gets trapped and concentrated near the ground.Communities located in valleys or other low-lying areas where temperature inversions are common are more strongly affected. Conditions are expected to improve on Sunday with higher wind speeds, resulting in better mixing and cleaner air.the severity of the health effects increases as fine particle concentrations increase.Symptoms of particle pollution exposure for people with heart disease may include chest pain, palpitations, shortness of breath, and fatigue. 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.in addition to harmful health effects, fine particle pollution may create hazy conditions that reduce visibility.