If you have a pre-existing breathing medical condition such as asthma or COPD, the Montana DEQ is encouraging you to stay indoors if possible Tuesday because of wildfire smoke.

A heavy layer of wildfire smoke is hanging over Billings for the second day in a row. The DEQ is listing Billings air quality as unhealthy for sensitive groups. If you can, stay indoors and use a HEPA filter if possible.

There are numerous big wildfires burning in Idaho and California according to InciWeb.