Many counties across Montana are reporting hazardous air quality today. If you're sensitive to smoke, the best bet is to stay indoors with your windows closed.
Yellowstone National Park, along with most counties in western Wyoming are still dealing with unhealthy air quality. The air quality index for YNP has been hovering around 100 which is "unhealthy for sensitive groups".
A couple of air quality monitoring stations around Billings had readings in the "unhealthy" range on Monday (7/26), and with a high concentration of pollutants expected to continue from western wildfires, being outdoors will make it hazardous for some groups this week.