Wildfires are to blame for the smell of smoke and hazy weather in the Edmonton area Thursday, according to a special air quality statement issued by Environment Canada.
The Air Quality Health Index was at a moderate risk level of 4 for Edmonton as of 9 a.m. But by 10:21 a.m., Environment Canada predicted the risk level could reach 8 — considered high risk on the index.
When the air quality index goes above 7, Environment Canada suggests reducing or rescheduling strenuous outdoor activities, especially for children and seniors or those experiencing a cough or irritated throat.
Wildfire smoke is causing poor air quality and reducing visibility, the statement said.
It is also "a constantly-changing mixture of particles and gasses which includes many chemicals that can harm your health," it said.
The smoke is coming from several directions, but mainly from wildfires in B.C. and the United States, said Kevin McCullum, data manager and chief scientist of the Alberta Capital Airshed.
Winds coming from different directions form a T-shape and create eddy effects, he said.
As a result, there can be higher concentrations of smoke off the winds "because [it's] stuck there until the winds start to shift again," said McCullum.
Smoke affects those with and without lung conditions. Children and older adults are most at risk, said Nina Snyder, chief operations officer with the Alberta and Northwest Territories branch of the Lung Association, an organization that promotes lung health.
"For someone without lung problems, wood smoke can irritate their eyes, their lungs, their throat, sinuses. It is known to increase the risk of heart attacks. It can trigger headaches and allergies," Snyder told CBC News.
For those with COPD or asthma, smoke can cause their existing symptoms to greatly worsen. Someone with a chronic cough, for example, would cough worse, she said.
"It might be uncontrollable so that they can't catch their breath."
With the air quality as is, Snyder said it's best to stay inside unless absolutely necessary.
In Alberta, there are currently 14 out-of-control wildfires, 37 that are being held and 41 that are under control.
Alberta Transportation warns one wildfire near the highway north of Janvier, a hamlet in the Regional Municipality of Wood Buffalo, was causing poor visibility due to smoke Wednesday evening.
The weather agency expects the smoke to remain into Friday night.
The Edmonton area was also under a heat warning Thursday, with daytime high temperatures near 30 C.