Smoke from area fires impacting regional air quality

The Mission Valley has seen increased smoke in the air over the past week as fires throughout western Montana continue to grow and produce large smoke plumes.

Smoke from the Liberty Fire (southeast of Arlee), Sunrise Fire (southeast of Superior), and other fires around the area have poured smoke into the Mission Valley, reducing visibility and air quality.

According to the Montana Department of Environmental Quality’s (DEQ) Air Quality Bureau, the air in the Mission Valley has mostly fluctuated between moderate and being unhealthy for sensitive groups, with the air quality near Arlee being in the unhealthy category Sunday and Monday.

“The concentrations are going to be more in the mornings when the smoke particles have settled closer to the surface,” DEQ meteorologist Kristen Martin said. “The air will look hazier in the afternoons as the fires pick up during the heat of the day.”

According to information Martin posted on DEQ’s website Monday, “we should finally see a change to the seemingly endless pattern of hot weather beginning on Tuesday. The ridge of high pressure will rebuild along the west coast, keeping Montana on the eastern side and ushering in cooler air along northerly winds aloft. A cold front is expected to move through on Tuesday night into Wednesday across the region. Surface winds will be from the east to northeast. The cooler temperatures and change in wind direction will have mixed results on smoke impacts across Montana. I don’t think we will see a huge improvement in air quality overall, with air quality impacts ranging from moderate to unhealthy for sensitive groups likely to continue through mid-week. The ridge will slowly strengthen for the remainder of the week, spreading eastward towards Montana. Temperatures will slowly increase on Thursday and Friday and surface winds will decrease and slowly shift back to be from the northwest. Hazy skies and air quality impacts are expected to continue through the end of the week.”

The DEQ monitors air quality conditions across Montana with the use of 19 monitoring stations positioned across the state. Data from the stations is compiled and listed on the DEQ’s “Today’s Air” website at http://svc.mt.gov/deq/todaysair/.

The results from the monitoring stations are updated hourly and are categorized into one of six air quality levels:

- Data Unavailable: Air quality data for the current hour are unavailable.

- Good: No health impacts are expected when air quality is in this range.

- Moderate: Unusually sensitive people should consider limiting prolonged outdoor exertion.

- Unhealthy for Sensitive Groups: People with heart or lung disease, older adults, children, and people of lower SES should reduce prolonged or heavy exertion.

- Unhealthy: People with heart or lung disease, older adults, children, and people of lower SES should avoid prolonged or heavy exertion; everyone else should reduce prolonged or heavy exertion.

- Very Unhealthy: People with heart or lung disease, older adults, children, and people of lower SES should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy exertion.

- Hazardous: Everyone should avoid all physical activity outdoors; people with heart or lung disease, older adults, children, and people of lower SES should remain indoors and keep activity levels low.

According to Martin, low air quality affects children and the elderly most significantly (and those with respiratory conditions), and those groups should be aware of air quality when planning outside activities. The ‘Today’s Air” website says that visibility is an easy and effective way to judge air quality without taking measurements. The visibility guidelines for the different air quality levels are as follows:

- Good: 13.4+ miles

- Moderate: 13.3 - 8.8 miles

- Unhealthy for Sensitive Groups: 8.7 – 5.1 miles

- Unhealthy: 5.0 – 2.2 miles

- Very Unhealthy: 2.1 – 1.3 miles

- Hazardous: less than 1.3 miles