Wildfire smoke from Prairies prompts air quality statement for London area Thursday

Smoke from wildfires in the Prairies has drifted into southwestern Ontario, triggering a special air quality statement for the London area on Thursday.

The smoke is causing or is expected to cause poor air quality and reduced visibility throughout the day, said Environment Canada. Air quality can fluctuate significantly from hour to hour and vary over short distances, depending on the movement of the smoke.

The federal weather agency said conditions should begin to improve from north to south as the day progresses.

Residents are being urged to take precautions, especially those considered more vulnerable, including older adults, infants, people who are pregnant, those with chronic illnesses, and anyone who works outdoors.

Symptoms of smoke exposure can include irritation of the eyes, nose and throat, headaches, coughing and even chest pain or wheezing in more serious cases.

"If you think you're having a medical emergency, don't wait, seek immediate help," the statement reads.

LISTEN | Why wildfire smoke is so hard on our health:

People are advised to limit time outside, especially during strenuous activities. If you must be outdoors, Environment Canada recommends wearing a well-fitting N95 or equivalent respirator mask to reduce exposure to fine particulate matter.

Indoors, officials say keeping windows and doors closed can help, and using a certified portable air cleaner or a clean filter in your ventilation system is also recommended.