The smoke blanketing southern British Columbia from wildfires in the United States is expected to remain in place through Sunday.
“We need a change in air mass,” said Environment Canada meteorologist Armel Castellan.
A weak offshore low-pressure system is expected to gradually move in overnight but Castellan said it is unlikely there will be any noticeable change in air quality until Monday — starting on southern Vancouver Island.
Metro Vancouver extended an air quality advisory due to fine particulate matter (PM2.5) for the Lower Mainland Sunday morning that has been in place since Tuesday.
Environment Canada air quality advisories covering more than two-thirds of the province also remained in effect.
“Really it’s affecting everybody, our air quality health index is at its maximum category for risk in terms of health, both the at-risk population and the general population,” said Castellan.
“So healthy adults should heed the health message which is really to postpone any strenuous activity outside and to reduce that exposure as much as possible.”
The Air Quality Health Index across southern B.C. Sunday was rated at 10+, meaning “very high risk.”
Castellan said concentration of fine particulate matter on the coast was topping 100 micrograms per cubic metre, while in Castlegar in southeastern B.C., it has approached 500 micrograms.
Air quality in Metro Vancouver on Saturday was ranked the worst in the world Sunday morning, according to one tracking website. Portland, Ore. and Seattle, Wa., took the No. 2 and No. 3 slots as massive wildfires continued to rage across the west coast of the U.S.
“What we’re seeing clearly in the western part of the United States is probably one of the best examples in the world of the effects of climate change,” said David Phillips, senior climatologist with Environment Canada.
Phillips said there has been a “dramatic difference in character” in the nature of wildfires in the last decade, which he tied to warming temperatures, and pointed to record-high heat reported in California this year as an example.
There has also been an increase in dry lightning in recent years, he said, noting that lightning events during thunderstorms are less frequently accompanied by heavy rain than in the past.
“What we do know, you warm up temperatures by one degree, you cause about 11 to 15 per cent more lightning strikes,” he said.
“We’ve seen parts of western Canada warmed up by two or three, three and a half degrees. You can do the math.”
You can find more information on how to protect yourself from wildfire smoke at the B.C. Centre for Disease Control.