A special air quality statement that has been in place for a week due to the wildfires burning across Alberta was lifted Tuesday for the City of Edmonton.
It was still in place for the parts of the province north of Edmonton, as well as regions directly west and east, including Beaver County and Leduc County.
Environment Canada issued the air quality statement for the Edmonton area on May 16.
Since then, Edmonton has experienced an air quality health index ranging between levels seven (high risk) and 11 (very high risk).
The weather agency said: “Air quality and visibility due to wildfire smoke can fluctuate over short distances and can vary considerably from hour to hour.”
Wildfire smoke can be harmful to people’s health, even at low levels, and is particularly dangerous for older adults, children and pregnant people, and those with lung or heart disease.
However, rain in the north and west parts of the province is expected to help the wildfire — and smoke — situation.
Sara Hoffman, a meteorologist with Environment and Climate Change Canada, said Tuesday that some areas of northwest Alberta received between 30 and 50 mm of rain.
In the last 48 hours, areas just east of Grande Prairie saw about 70 mm of rain, “which is exactly where we’d like to see it.”
As of 11 a.m. on Tuesday, Edmonton’s air quality health index was listed as level three (low risk).
Canadians can access both an air quality health index forecast and an air quality health index on Environment Canada’s website.
“The air quality health index is a number and that is created by looking at three different air quality values that go into making that: NO2, which is from your car; ozone, which is produced by hot, sunny days creating ozone within the atmosphere; and then there’s PM2.5, which is a part of smoke,” Hoffman explained.
“There are four sensors in Edmonton and they’re averaged together to give a value for Edmonton.”
Special air quality statements are issued when either the air quality health index is at a seven or higher or if the PM2.5 value is 81 or higher.
“That’s our small particulates value that our sensors pick up,” Hoffman said. “If that’s recording 81 micrograms per cubic metre of smoke in the area, or higher, then we’ll issue a special air quality statement.
“Just for context, over the weekend, we had some PM2.5 values over 300 micrograms per cubic metre, so it definitely was warranted.”
In order for the alert to be cancelled, air quality has be lower than a level seven or the PM5.2 value has to be lower than 81 micrograms per metre cubed.
“If both those things are happening and we forecast it to stay improved, then we’ll end the special air quality statement,” Hoffman said.
Special air quality statements have been issued on and off in Edmonton-area communities such as Parkland County since the end of April, when the wildfires began to flare up.
“When it comes to smoke affecting air quality, we can kind of sense that ourselves,” Hoffman said. “If we see reduced visibility due to smoke or that really, really strong smoky campfire smell, we don’t need to look at stats to tell us the air quality is no longer safe.
“Those are kind of indications that the smoke is at a density or a concentration in the atmosphere that it’s no longer safe for us to be outside, especially not outside doing strenuous activities.”
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