The Ministry of Environment and Climate Change Strategy issued one last Monday (March 8) and it stuck around all of last week and into the weekend.
Air Quality Meteorologist Gavin King says the main reason for taking down is the snow that fell on Sunday.
“The snow pulls the dust out of the atmosphere and it’s kind of trapped all that material down by the ground again, and it’s holding that traction material and other dust at the surface, which means it’s not in the air and conditions have improved. However, we are still looking at dry, sunny days for the next couple of days so it wouldn’t surprise me to see that snow disappear and that dust come back.”
The provincial air quality objective for PM 10, particles of dust 10 micrometers or smaller in diameter, is 50 micrograms per cubic metre over a 24-hour rolling period.
Quesnel was well above that all of last week and peaked at 192 on March 9 at 2 pm.
The reading as of this (March 15) morning was at 46.6
Williams Lake is at just 13 micrograms per cubic metre.
The Lake City did top 50 once last week, but King says he didn’t feel an advisory was necessary.
“An advisory is issued when the meteorologist who is looking after the area at the time feels that that number is going to remain above the objective for a significant period of time. Generally, we consider a full 24-hour cycle, that’s adjustable based on professional judgement and on conditions at the time. For Williams Lake last week, I was looking at those numbers, and I didn’t feel confident that that value was going to stay above 50 for a long enough period that that advisory would have been appropriate.”
Up to date numbers are available on the BC Air Quality website.