Hot weather, stagnant air raises air quality index in Greater Victoria

Hot weather, stagnant air raises air quality index in Greater Victoria
Hot weather, stagnant air, and regular pollutants are contributing to an increased air quality risk, according to Environment and Climate Change Canada.

Environment and Climate Change Canada is predicting that air quality in Greater Victoria will reach a moderate risk throughout the rest of the week.

Derek Lee, meteorologist with the agency says the air quality rating will raise to a level four due to a combination of factors.

“Generally when we have these hot days, we are under a ridge of high pressure, meaning the air mass is pretty stagnant,” Lee said. “So ozone levels, which are likely to contribute contributors to that high air quality or just a moderate level is generally due to emissions with cars.”

“So during the peak of the day, probably in the morning period and the late afternoon period, we get a lot of that traffic going on, that ozone level really kind of peaks and then, especially under our sunny days, that ozone really gets enhanced by that sunlight and turns into air pollutants in the atmosphere.”

READ MORE: Records fall as Vancouver Island swelters under late-July heat wave

The Air Quality Health Index rates the pollutants in the air on a scale from one to 10+, with one being the lowest risk.

With a level four rating, it is advised that at-risk populations reconsider outdoor strenuous activities if they are experiencing symptoms of coughing or throat irritation, and no need for the general population to reconsider outdoor activities unless the same symptoms present.

Lee says generally the breeze would clear through the pollutants from the air, but since the air is currently stagnant it is causing the air quality index to rise.

“The highest level we are anticipating would be a level four today,” Lee said. “Whenever say a sea breeze comes in, that can help alleviate some of the air quality temporarily. But it’s not saying that it’s going to be level four all day long, we just advise that the highest level of air quality is at four for the time period.”

Environment Canada’s air quality forecast only shows until Thursday evening, but Lee says due to the current predicted weather patterns it is likely the air quality index peak for Victoria/Saanich and the West Shore will remain at four for the rest of the week.

READ MORE: City of Victoria opens cooling centres amid heat warning

Other parts of the Island are predicted to remain at level two or three, which are moderate levels. Duncan is predicted to remain at a level three, Nanaimo will fluctuate between level two and three, and Comox and Courtenay are predicted to remain at level two.

Vancouver has been issued an air quality advisory that some areas are expected to reach a level five. Lee says similar factors are causing elevated air quality index levels, but the wildfire near Lytton is also a contributing factor.

“There’s a mixture of events happening there. So in the Lytton area, in the Fraser Canyon, there is a forest fire of note, the Nohomin Creek fire is generating local smoke in the Fraser Canyon area,” Lee said.

“And a little bit of that has kind of drifted over as far as the Metro Vancouver area, but it’s likely that it’s more on that northeast and southeast quadrants of Metro Vancouver and meaning more inland into that Langley and Coquitlam area.”

Laura BroughamLaura Brougham

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