Pandemic restrictions have improved Vancouver air quality, but can the clean air last?

In the past few weeks, as Vancouverites were encouraged to stay at home and only cautiously enjoy parks and outdoor spaces to avoid spreading the virus behind a catastrophic global pandemic, the city was treated to a spell of beautiful weather, with much clearer skies than normal.

The high-pressure system stripped the skies of clouds, leaving a rich blue dome over the region. On social media, people commented on the lack of condensation trails left by airplanes, and the clear views of distant mountains.

The weather wasn't especially seasonal in a place known for plentiful spring showers, but according to Douw Steyn, professor emeritus of atmospheric science at the University of British Columbia, the conditions were perfect to demonstrate what impact the COVID-19 pandemic has had on air quality.

"Under these conditions ... you'd expect to see poorer air quality," said Steyn. Light wind doesn't blow away pollution, there's no rain wash to it away, and the "lid" the high pressure system creates traps pollution lower down.

"And yet at the same time we have literally seen with our eyes improved air quality — the skies have been clearer; in the Fraser Valley, Mount Baker has been just stunning scene," he said. "This has been repeated all over much of the province and in fact all over much of the world."

Steyn said, for example, there have recently been rare Himalayan vistas in northern India, and clearer views of the Alps in northern Italy.

But he doesn't rely solely on anecdotes and a perception of cleaner air — Steyn is also doing the research.

He has looked at the nitrogen oxide and nitrogen dioxide levels — clear markers of emissions from vehicles — at two busy Vancouver sites: Clark Drive at 11th Avenue, which is a trucking thoroughfare, and Robson Square in downtown Vancouver, which is in the midst of plenty of personal vehicle traffic.

Based on data gathered by Metro Vancouver from March 21 to April 16 this year and last year, there are definitely improvements this year.

"When we do the analysis, we discover that 2020 is notably cleaner," said Steyn, adding that the weather in 2019 was typical for spring in Vancouver and punctuated by rain.

Steyn said in Metro Vancouver, air quality is primarily affected by vehicles on the road, and to a certain degree airplanes. The province relies largely on hydroelectric power generation, meaning coal burning and other dirtier power sources aren't a major issue.

He considers the restrictions put in place as part of the response to COVID-19 sort of a massive involuntary experiment, and the results can help inform how major challenges like climate change and unhealthy pollution can be addressed. 

"This experiment will be very powerful in helping understand how future reductions in emissions — not through some pandemic but through actions of the citizens — how those will result in improved air quality," said Steyn.

"It would be terribly sad if a new normal were like the old normal, because the old normal was not a particularly desirable one — for both air pollution and global warming," he said.

Douw Steyn on air quality

5 years ago

Duration 1:13

Douw Steyn, professor emeritus of atmospheric science at the University of British Columbia, discusses whether a return to normal after the pandemic mus include a return to normal emissions and poor air quality.

Steyn is not advocating for economic activity to cease, nor is he celebrating the pandemic and the toll it has taken on people's lives — he's eager to see a return to a healthy society.

"The real challenge is to come out of this determined not ever to let another pandemic get away from us," he said. "But at the same time, determined that when we return to to a healthy society — in full terms — that that health is reflected in both environment and society and economics, with all three of those things to be improved."

"And we hope that humans will rise to that challenge," said Steyn.

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