Fort Smith and the Salt River Reserve are experiencing environmental smoke exposure from wildfires in Alberta.
The amount of smoke is expected to change due to weather conditions.
Exposure to smoke is highest in people who are physically active outdoors and can quickly result in sore eyes, tears, cough and runny nose.
Those at risk of more severe health impacts include young children, the elderly, people with diabetes, lung or heart conditions, and (potentially) pregnant women.
Anyone experiencing serious symptoms such as wheezing, chest discomfort, or shortness of breath should go to their local health centre.
The advisory was Issued jointly by Environment Canada and the GNWT Departments of ENR and HSS.