Smoke from forest fires in northeastern Ontario and Quebec is expected to create high levels of air pollution in southwestern Ontario over the next couple of days.
Environment Canada issued a special air quality statement Tuesday morning for areas including London-Middlesex, Sarnia-Lambton, Chatham-Kent, Windsor-Essex, Huron-Perth, as well as Elgin and Oxford counties.
Smoke plumes from forest fires will move into southwestern Ontario Tuesday afternoon or evening, but they are not expected to stick around very long.
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," read Environment Canada's advisory.
The air quality for different areas of Ontario can be monitored throughout the day using the Air Quality Health Index.
Residents are encouraged to reduce their exposure to wildfire smoke as it can be harmful to one's health, even at low concentrations.
However, those with lung disease (such as asthma) or heart disease, older adults, children, pregnant people, and people who work outdoors are at a higher risk of experiencing health effects.
"If you must spend time outdoors, a well-fitted respirator type mask (such as a NIOSH certified N95 or equivalent respirator) that does not allow air to pass through small openings between the mask and face, can help reduce your exposure to the fine particles in smoke," read the advisory. "These fine particles generally pose the greatest risk to health. However, respirators do not reduce exposure to the gases in wildfire smoke. It is important to listen to your body and reduce or stop activities if you are experiencing symptoms.
Areas of southwestern Ontario have been affected by smoke plumes over the past month as Canada deals with an unprecedented wildfire season.