Department of
Environmental Quality

Air pollution in the Pinehurst area is predominately a winter season problem characterized by periods of high concentrations of fine particulate matter primarily from residential wood heating, open burning, and slash burning. The buildup of fine particulates is primarily a function of wintertime temperature inversions which trap air in the rural Pinehurst Valley area.

Background

Pinehurst and surrounding neighborhoods (Kingston and Enaville) are located in a valley near the western end of the Silver Valley, a historic mining area along the south fork of the Coeur d’Alene River in northern Idaho. The Silver Valley is about 22 miles long and varies in width from only one-tenth of a mile to slightly more than three-fourths of a mile. Elevation in the western end of the valley is 2,200 feet rising to 3,300 feet at the eastern end. The city of Pinehurst connects with the Silver Valley through a narrow gap.

The climate in northern Idaho is often influenced by Pacific storms, which are moist and relatively mild. Two to three times each winter arctic air brings bitter cold weather conditions. When this cold, stable air is added into the region by arctic outbreaks or cold Pacific storms, cold air becomes pooled in the narrow mountain valleys of the region. Cold air masses can further stabilize when high pressure aloft overtakes the region. Under these conditions, a prolonged strong inversion layer (or layers) near the ground limits vertical mixing, trapping locally produced pollutants close to the valley floor.

Particulate pollutant concentrations may build from day to day when inversion conditions do not break up in the afternoon. During such episodes, emissions in the area increase because more wood heating, a major source of particulate pollution in the area, is required due to the cold temperatures. The low sun angle at this latitude, the short length of the day during winter months, light and variable winds, and strong likelihood of snow cover to reflect solar radiation all limit daytime heating and aggravate the situation. As a result, the inversion builds and may not break for several days. Under this kind of stagnation condition, pollutant concentrations may build quickly in the Pinehurst area. When surrounding area emissions are high, even short-lived overnight inversions can affect air quality sufficiently to produce high concentrations of PM2.5 air pollution (fine particulate matter with an aerodynamic size of 2.5 microns or less) in this area.

Impacts of Air Pollution

Air pollution can have significant impacts on public health. Studies indicate that when people are not at work they typically spend 60-70 percent of their time at home. If they heat their home with wood, they are potentially exposed to fine particle pollution. In addition to the smoke that can be released inside the home, studies show that an estimated 70 percent of smoke from chimneys can actually reenter the home and neighborhood dwellings.

Numerous scientific studies have linked particle pollution exposure to a variety of health problems, including increased respiratory symptoms, such as irritation of the airways, coughing, or difficulty breathing; decreased lung function; aggravated asthma; development of chronic bronchitis; irregular heartbeat; nonfatal heart attacks; and premature death in people with heart or lung disease. People with heart or lung diseases, children and older adults are the most likely to be affected by particle pollution exposure. However, even healthy people may experience temporary symptoms from exposure to elevated levels of particle pollution. 

In addition to potential health impacts, areas with higher than permissible limits of certain pollutants may be designated nonattainment by the U.S. Environmental Protection Agency. When an area is designated nonattainment, it means the federal standard has been violated, which can have adverse impacts on public health, deter growth, limit job opportunities, and restrict highway funding. As a a result of recent changes to the federal health-based standard for PM2.5, it is anticipated that the Pinehurst area will be designated nonattainment for fine particulate matter. Nonattainment designation requires implementation of control measure to ensure that pollutant levels are reduced below the maximum permissible limit to protect public health.

Efforts to Control Air Pollution

DEQ has undertaken a number of efforts to help reduce smoke from open burning and wood stoves in the Pinehurst area.

• Public Outreach to Open Burners: DEQ encourages residents to avoid open burning unless no alternative is available. If scheduled house-to-house garbage service is available, open burning of rubbish is prohibited, although leaves, garden waste, and yard trimmings may still be burned. Better yet, consider mulching garden and yard waste or disposing of it with other solid waste. Learn more about open burning regulations and alternatives in Idaho.
  
• Public Outreach to Wood Stove Burners: Those who choose to heat their homes with wood stoves are encouraged to burn only clean and dry wood, wood pellets, or manufactured logs, to burn smaller, hotter fires, and to allow enough room for air to circulate. In addition, wood stove burners are urged to regularly inspect, maintain, and clean their stoves, fireplaces, and chimneys. Learn more about better wood stove burning techniques.
• Wood Stove Changeout Program: Several wood stove changeout programs have been conducted in Pinehurst over the years. The programs provide financial incentives for homeowners to replace old, air-polluting wood stoves with new EPA-certified stoves, inserts, or natural gas or propane units. A wood stove changeout program is currently underway for wood stove owners in Pinehurst, Kingston, and Enaville. Learn more about the 2011-12 wood stove changeout program.
• Prescribed Fires and Slash Burning: DEQ has partnered with the Idaho Department of Lands to reduce smoke impacts from prescribed fires and time harvesting slash burning.