Sarnia and Grand Bend had the worst air quality in Ontario Tuesday.
At mid-afternoon the Air Quality Health Index (AQHI) was listed as "very high risk" in each community, according to the Ministry of Environment Conservation and Parks.
The high levels of air pollution are the result of smoke from forest fires in northeastern Ontario and Quebec.
As a result, Lambton Public Health (LPH), is encouraging residents to take the proper precautions to protect their health.
The organization said children, older adults, pregnant individuals, people with chronic health conditions, and people who work outdoors are at a higher risk of experiencing negative health impacts because of poor air quality.
At-risk individuals are being encouraged to avoid strenuous activities outdoors, monitor for medical symptoms such as irritated eyes, increased mucous, and difficulty breathing, and to contact their healthcare provider if severe symptoms develop or if they need guidance.
If possible, set your HVAC to recirculate air or use a portable HEPA air cleaner and keep windows closed if the temperature is not too hot.
LPH recommends residents stay up to date on the AQHI and change activities based on the AQHI table.
Hourly updates are available by clicking here.
Environment Canada's Special Air Quality Statement was still in effect as of late Tuesday, and is expected to continue into Wednesday.
The national weather agency said conditions are expected to improve for some areas on Thursday. Air quality and visibility due to wildfire smoke can fluctuate over short distances and can vary considerably from hour to hour.
Meanwhile, the high levels of air pollution have prompted Sarnia Fire and Rescue to implement a temporary ban on all open-air burning to limit further impacts to air quality.
They said the ban will be lifted once conditions improve.