By Sean Brady, Kamloops This Week
The poor air quality on Aug. 3, was possibly the worst in Kamloops history, reaching a 49 on the air quality health index. Typically, readings in Kamloops don’t go beyond a 7 on the scale.
Although the air has cleared somewhat since then, a smoky skies bulletin for the area remains, and Interior Health is warning people to pay attention to their symptoms and avoid strenuous outdoor activities. Things could also still return to yesterday’s unprecedented levels, if the conditions are just right.
“A whole bunch of things have to happen. You have to have the winds lined up exactly right and you have to have an increase in activity on the fire at the same time. It’s certainly possible that we’ll see them again,” said Ralph Adams, air quality meteorologist for Kamloops with the Ministry of Environment. “Really everything depends on the weather, because the weather affects both the transport of the smoke and the generation of the smoke through the fire behaviour.”
The city’s mark of 49 on the AQHI is extremely rare, but it wasn’t quite a record in B.C., with Williams Lake seeing similar figures just weeks ago.
“Williams Lake has all those fires burning right around them and it only happened there once in the last month, so it’s not something that is likely to happen very frequently,” Adams said.
The AQHI is based on three pollutants: ozone, nitrogen dioxide and PM2.5, which is the measurement of particulate matter smaller than 2.5 microns (or, very fine).
When the AQHI is driven up by smoke, it’s the PM2.5 that is driving the figure way up, according to Adams. Those paying attention to the AQHI may notice that the figure doesn’t update right away when smoke rolls in or gets blown out.
“It’s based on a three-hour running average, so that’s why it takes a little bit of time to drop after,” Adams said, noting that forest fire smoke is different than most other pollutants in that it comes in quickly and leaves quickly.
Adams also clarified that the AQHI is not simply a scale of 1 to 10.
“The formula has no limit. It just increases as the concentrations and mixing ratios of those three pollutants increase,” he said.
What’s important are the cutoff points, according to Adams. Anything above 10 is considered “very high risk.”
To really clear the smoke, Adams said that not only do the fires need to calm down or blow in another direction, but we also need wind or turbulent weather to clear existing smoke out of the valleys.
The smoke also continues to cause problems at the Kamloops airport, with visibility reaching just one kilometre yesterday, flights were cancelled or delayed. Airport management is recommending customers contact their carriers for the most up to date information.
Event organizers are feeling the pinch when it comes to the smoke. The Kamloops Dragon Boat Festival has cancelled due to smoky conditions.