The North Dakota Department of Health issued an warning Friday urging residents to limit times outdoors while smoky conditions remain in the area.
The warning is especially important to people with respiratory problems such as chronic obstructive pulmonary disease, asthma or allergies.
The smoke is being blown into the area from forest fires in northwestern Montana and Alberta, Canada. The smoke will likely remain in the area through Saturday although forecasted rain showers Saturday night could clear the skies.
The current warning is the third issued in the past three weeks by the Health Department regarding smoking conditions.