Idaho Wildfires Charted in Missoula, MT

Missoula, a city in the western part of Montana, felt the effects of wildfires burning in the Idaho/Montana region during August 2000. Prior to the fires, the city of 69,000 inhabitants had last exceeded the US National Ambient Air Quality Standard for particulate matter in 1989. Normally, the city experiences the highest levels of ambient particulate matter and carbon monoxide pollution during the winter months due to local topography and inversions. But the summer of 2000 proved to be different.

The photo below shows wild fires burning in Idaho and surrounding states with the resulting plumes stretching into Montana.

Prevailing winds carrying particulate matter pollution from forest fires in Idaho on August 3 contributed to an hourly particulate matter reading of over 500 micrograms per cubic meter. The hourly mass concentration values measured during August 2000 by a TEOM Series 1400a Ambient Particulate Monitor located in the city are shown below.

The areas directly affected by wild fires in Idaho changed during the month of August 2000, as did the tracks taken by the resulting smoke plumes. The maps below show smoke-affected areas of Idaho and western Montana on 2 and 22 August 2000.

A description of the challenges faced by the Missoula Health Department during this wildfire episode is detailed in an article entitled "Wildfire Smoke: A Local Health Department Meets the Challenge," published in the Fall/Winter 2001 edition of Northwest Public Health. The maps and graphs above are reprinted with permission of the authors, Shannon Therriault and Benjamin Schmidt.

- May 02 -

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