It's quite obvious that Montana's air quality is currently terrible. Dozens of counties with high particulate levels are now under an Air Quality Alert until further notice. 

According to the Montana Department of Environmental Quality:

AIR QUALITY ALERT FOR:

Beaverhead, Big Horn, Blaine, Broadwater, Carbon, Carter, Cascade, Chouteau, Custer, Daniels, Dawson, Deer Lodge, Fallon, Fergus, Flathead, Gallatin, Garfield, Glacier, Golden Valley, Granite, Hill, Jefferson, Judith Basin, Lake, Lewis and Clark, Liberty, Lincoln, Madison, McCone, Meagher, Mineral, Missoula, Musselshell, Park, Petroleum, Phillips, Pondera, Powder River, Powell, Prairie, Ravalli, Richland, Roosevelt, Rosebud, Sanders, Sheridan, Silver Bow, Stillwater, Sweet Grass, Teton, Toole, Treasure, Valley, Wheatland, Wibaux, and Yellowstone counties

  • In effect until conditions improve.
  • The air quality alert is due to smoke from wildfires in northwest Montana, Idaho, Washington, and British Columbia causing widespread unhealthy air quality.
  • Particulate levels are ranging between Unhealthy for Sensitive Groups and Very Unhealthy across Montana.
  • When air quality is Very Unhealthy... State and local health officials recommend that people with respiratory or heart disease,the elderly, and children should avoid any outdoor activity; everyone else should avoid prolonged exertion.
  • For hourly air quality levels visit todaysair.mt.gov
Air Quality Alert - KMMS