A blood orange sun rose over much of British Columbia on Monday, a warning of high levels of smoky particulate and elevated ground-level ozone in the air.
Environment Canada has issued air quality advisories for every region of B.C., except Haida Gwaii on the northern edge of Vancouver Island and a small corner of the province bordering Yukon and Alaska.
Meteorologist Matt MacDonald of Environment Canada said 20 straight days without rain combined with the past nine days of stagnant heat and sunlight have reacted with vehicle emissions and chemical solvents, which have produced elevated levels of ground-level ozone in Metro Vancouver and the Fraser Valley.
“It’s not good for humans,” said MacDonald.
He said tests show ozone levels were at moderate risk, adding that Monday and Tuesday would likely be the sunniest days of the week and see higher levels.
The warm, dry weather is due to a “semi-permanent California high,” said MacDonald, a ridge of high pressure that rotates clockwise from northern California to Alaska. It’s also why British Columbia has seen smoke from wildfires in the United States and across the Pacific Ocean.
An air quality advisory issued by Metro Vancouver said the smog is in addition to a layer of wildfire smoke from a bog that’s on fire in Richmond, blazes in the B.C. Interior, United States and as far away as Greece.
The weather office says most of the advisories outside of Metro Vancouver and the Fraser Valley are due to high concentrations of wood smoke and conditions could be revised on short notice, but those with heart or lung conditions, the elderly, infants and children were advised to limit exposure to the smoky air.
MacDonald said Environment Canada predicts colder and humid air that is trapped over the ocean will surge inland as the existing high-pressure ridge breaks down, which could cause temperatures to cool by as much as 10 degrees on Wednesday.
But that temperature drop doesn’t necessarily mean good news for other parts of the province fighting wildfires.
“Unfortunately for the southern Interior, it will be accompanied by a trough of low pressure on Wednesday or Thursday, and that will give rise to lightning,” said MacDonald.
Conditions, especially for regions of B.C. covered by ongoing heat warnings, are not expected to ease until at least mid-week, with clouds and possible showers in the forecast for late Thursday or early Friday.
As for the red sunrise, MacDonald said high levels of pollutants from forest fires create the colours when light from the sun refracts off the particulates in the air.
“In the winter when it gets really cold you see these crisp sunsets, and there’s no refracting happening because the sky and the atmosphere are so clear,” MacDonald said.