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Missoula Measures - Air Quality



graph levels of PM 2.5, Missoula, 2000-2014 

Why this topic?

Missoula County’s valleys surrounded by mountains are prone to periods of inversions and poor air quality. The primary contributor to pollutants in the air is wood smoke from wood stoves, outdoor burning, and naturally occurring wildfires. Missoula County’s programs to monitor air quality and regulate burning have led to significant improvement in the outdoor air quality over the years, especially in the winter.

Air quality is monitored by measuring the concentration of particulate matter 2.5 microns in diameter (PM2.5). Particles of this small size can remain suspended in the air for long periods of time. They can lodge deep in the lungs and exacerbate chronic conditions such as asthma and heart diseases. PM2.5 concentrations greater than 21 ug/m3 are considered unhealthy for sensitive groups by the Montana Department of Environmental Quality.

Healthy children and adults may experience temporary minor irritation when levels are above the standard. However, individuals with respiratory or circulatory problems may have their conditions aggravated by even short-term exposure to elevated levels.


graph poor air quality days 2000-2014 



Wildfires pose a sporadic but significant air quality challenge in the summer and fall. Wildfire location, wind direction, and stagnant air due to weather conditions create bad wildfire days. In 2012, which was an especially bad year, Missoula experienced 11 days that were unhealthy for sensitive groups due to wildfires (compared to 9 in 2013 and 1 in 2014), 10 days that were unhealthy for everyone (3 in 2013 and 1 in 2014), and 4 very unhealthy days. (MCCHD Air Quality Program)


Related Websites

Current, local air quality issues: Missoula City-County Health Department, Environmental Health Division, Air Quality Program.

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