That means people should avoid strenuous activities outdoors, especially children and the elderly, or if you experience coughing or throat irritation.
Dave Grundy, president of the Workers Safety and Compensation Commission, sent his employees home yesterday when the air quality index reached seven out of 10 — already a high risk.
He says he's never had this many calls about health problems.
“We had lots of employees who had trouble breathing, sore throats, nasal congestion, and headaches, so as an employer I have to make sure our employees are safe.”
The air quality index is forecast to dip to eight Tuesday evening and stay there most of Wednesday.
The territory's health department says prolonged exposure to smoke in the air can cause health issues. For a healthy person, those effects are not likely to be long term.
Environment Canada has issued smoke warnings in all of the communities around Great Slave Lake, including Dettah, Hay River, Enterprise, Fort Providence, Kakisa, Fort Resolution, Fort Smith, Gameti, Wekweeti, Whati, Behchoko and Lutselk'e.