Seeley Lake - Small Town, Big Challenge

Seeley Lake is a small, mountain valley community located north of Missoula in Missoula County, Montana. As is common in rural, forested areas, many residents rely on woodstoves to heat their homes. Unfortunately, the Seeley Lake valley is prone to frequent temperature inversions that have the potential to trap smoke from those stoves near the ground where it poses a threat to human health. The combination of strong nightly inversions and heavy woodstove use has resulted in a small community with a big air quality problem.

The First Look at Seeley Lake's Air Quality

The Missoula City-County Health Department (MCCHD) and Montana Department of Environmental Quality (DEQ) first started measuring fine particulate concentrations in Seeley Lake in 2005. The original monitor was next to the fire hall and took measurements once every three days. That initial study showed several days with 24-hour PM2.5 concentrations exceeding the NAAQS, so in mid-November 2009 the MCCHD and DEQ installed a new continuous PM2.5 monitor in Seeley Lake. This permanent PM2.5 monitor sits just outside the elementary school's athletic field. The school is centrally located in a residential area where many of the homes are heated with wood-burning appliances, and is therefore an ideal site for measuring particulates in the area.

The Initial Results:

  • In the 2009-2010 winter, 40 days had daily PM2.5 averages greater than the 24-hour NAAQS of 35 μg/m3.
  • In the 2010-2011 winter (November-March), 50 days with PM2.5 concentrations greater than 35 μg/m3 were measured.
  • In the 2011-2012 winter, 51 days with PM2.5 concentrations greater than 35 μg/m3 were measured.

In addition, these days with concentrations exceeding the national PM2.5 24-hour standard of 35 μg/m3 are, in general, significantly greater than the standard (they range from 36-69 μg/m3 and the average for the past two years is 46 and 48 μg/m3).  If Seeley Lake's winter air quality doesn't dramatically improve, nonattainment status is inevitable.

Woodstoves are the primary source of winter air pollution in western Montana, so, on April 7, 2010, the MCCHD conducted a visual woodstove/fireplace/pellet stove chimney survey in the residential neighborhood just south of the elementary school. In approximately a 16 square block area or a half square mile, the survey found 50 residences with chimneys and five residences with a second chimney for a total of up to 55 woodstove/fireplace/pellet stove chimneys in the survey area.

Why It Matters

During the 2010-2011 winter (November-February), Seeley Lake exceeded the National Ambient Air Quality Standard (NAAQS) for the 24-hour PM2.5 concentration 51 times. In general, an area can accrue six days in a calendar year over the NAAQS before becoming a nonattainment area for PM2.5. The NAAQS were established to protect human health, with a particular emphasis on a community's most vulnerable members: children, the elderly, and the chronically ill. Particulate matter poses a serious threat to human health. PM2.5 is so small it can bypass your natural defenses and burrow deep into the lungs and sometimes can pass right into the bloodstream. The particulate and the chemicals that piggy back their way into lungs and bloodstreams can compromise respiratory systems and are known to cause reduced lung function, increased hospital visits, pneumonia complications, asthma attacks and premature death. In addition, the challenge PM2.5 puts on your system can aggravate your body, bringing on increased risk of strokes and heart attacks.

In any community, children are among the most vulnerable. In Seeley Lake the highest levels of PM2.5 are concentrated at the Seeley Lake Elementary School.

Taking a Closer Look

In the fall of 2010, MCCHD, in conjunction with the DEQ, set up six additional PM2.5 monitors around the community, with locations in neighborhoods as well as outlying areas to the north, south and east of Seeley Lake. The goal of this study was to determine how PM2.5 is distributed around the community. After five months of data collection, the results were clear: the highest concentrations of PM2.5 were confined to low-lying, densely-populated neighborhoods, and the worst pollution was centralized near the Seeley Lake elementary school. In fact, the outlying monitors (which were located at the airport, the visitor center and the USFS Ranger Station), did not show a single day exceeding the standard due to woodstove use. Click here for a presentation outlining the results of the Seeley Lake Saturation Study. Click here for the Seeley Lake PM2.5 Saturation Study Report.


Avoiding Nonattainment Status

Reducing air pollution in Seeley Lake will have many benefits for the general health and well-being of the community. It will also help the area avoid a nonattainment designation. If Seeley Lake becomes a nonattainment area for PM2.5, Missoula County will be required by the Clean Air Act to implement enforceable regulations, similar to the woodstove regulations already in place in Missoula, to the move the area back into attainment. A nonattainment designation would also impact industry's ability to move into the area. 

Measuring Success

Even during a stubborn inversion during January of 2013, Seeley Lake's air quality was better than might be expected. Initial monitoring results suggest that the Changeout program is making a positive impact. Continuing educational efforts about efficient and responsible burning will help ensure the success of the Seeley Lake Changeout program. Ongoing monitoring throughout the winter months during the next couple years will help further clarify the program's results