Wood smoke and road dust are getting the blame for poor air quality in Smithers.
The environment ministry and Northern Health have issued an Air Quality Advisory for the community due to the pollution.
Officials say a high pressure system and calm winds have allowed a high concentration of fine particulates to develop in the airshed.
Residents are advised to avoid strenuous outdoor activities.
Particulate exposure is a particular concern for infants, the elderly, and those with chronic health conditions like diabetes and heart disease.
The air quality is expected to remain poor until a change in the weather occurs.