SHERIDAN —Though Wyoming has so far been spared from the major wildfires raging in other parts of the region, the state, and Sheridan, are feeling their effects.

Much of the state has been covered in a haze of smoke for the past few weeks and Sheridan, and other areas of the state along the Montana border, appear to be experiencing the most smoke.

Over the weekend, the Wyoming Department of Environmental Quality’s Sheridan mobile monitoring station was showing elevated levels of particulate matter 2.5, which DEQ spokesman Keith Guille said is associated with wildfire smoke.

PM 2.5 is a fine particulate matter that contains extremely small particles that can cloud visibility and cause irritation of the eyes, nose and throat, as well as respiratory problems.

Guille noted the levels of particulate matter were higher in Sheridan last week, but there are a number of factors that could explain that variation.

“It depends on the winds, and humidity, which can cause (the smoke) to get trapped here and those type of things will affect whether you have more smoke one day; it can change,” Guille said.

Monday morning, the air quality index, which the Environmental Protection Agency uses to measure the concentration of pollutants in the air, was a 75; an AQI of 50 or under generally represents good air quality while any AQI under 100 is considered satisfactory, based on national standards for public health. Sheridan’s 75 means adults in good health are unlikely to be affected by the air quality beyond minor irritations, similar to those caused by seasonal allergies.

By contrast, areas in Idaho, where some of the wildfires are located, have reached AQIs as high as 145, which according to EPA standards are unhealthy for sensitive populations. AQIs over 150 are considered unhealthy to the general population. 

Wyoming Department of Health spokeswoman Kim Deti said the smoke can cause respiratory health issues, especially among vulnerable populations such as the elderly, children and people with existing respiratory conditions, but urged everyone to use common sense when it is hazy.

“If you can see the smoke in your area and you can smell it, sometimes you can even taste it, it’s something to be aware of and to be careful of,” Deti said. “Really no one should be out running a marathon when it’s visibly smoky.”

Deti added that normally when her department deals with smoke concerns they are related to a local fire, which provides the department with a better sense of what to expect and how long the smoke is likely to persist. Because the smoke affecting Sheridan, and much of Wyoming, is coming from fires in neighboring states, it’s difficult to know how long the smoke will continue to be an issue.

Considering that, Deti suggested people keep an eye on the local air quality and use caution when smoke levels are elevated.

The DEQ has monitoring stations throughout the state, including in Sheridan, that update in real-time at

The Environmental Protection Agency also offers air-quality monitoring throughout the country at