COVID-19 economic slowdown has cut air pollution in Canadian cities

COVID-19 economic slowdown has cut air pollution in Canadian cities

OTTAWA — Most major Canadian cities saw drastic improvements in air quality over the last two months as COVID-19 kept people at home instead of on the roads.

Experts say cleaner air, even just for a few weeks, can reduce illnesses like asthma attacks and heart attacks, which have been shown to spike when air pollution is at its worst, and which are also linked with higher risk of serious illness and death from COVID-19.

Chris McLinden and Debora Griffin, both scientists in the air-quality research division at Environment and Climate Change Canada, spend their days using satellite sensors to measure air quality and the presence of pollutants like ozone, carbon monoxide and nitrogen dioxide.

Since the middle of March, when most provinces began shuttering businesses and public spaces and asking people to stay home, their maps have shown significant drops in levels of nitrogen dioxide, one of the main gases produced when fossil fuels are burned to power and heat vehicles and buildings.

“It’s what we call an unexpected, natural experiment,” McLinden said. “It’s not really something you can duplicate in a lab.”

McLinden said nitrogen dioxide is one of the best measures for a day-to-day comparison because it tends to dissipate much faster than carbon monoxide, so its presence is a better indicator of changes in a short period of time.

In cities like Toronto and Montreal, the nitrogen dioxide levels fell more than 30 per cent, which McLinden said is mainly because there were fewer cars on the roads, and factories either closed or cut production. In Edmonton and Calgary, the drop was closer to 40 per cent, he said. In Atlantic Canada, where the levels are typically very low to begin with, the maps can’t pick up the data well enough to describe any reduction.

McLinden said the maps they are using don’t measure the levels of fine particulate matter, which is one of the biggest concerns for human health, but he said science suggests those would also be falling, though probably not quite as much as nitrogen dioxide.

In April, international air quality technology company IQAir found significant drops in 10 world cities of fine particles, known as PM2.5 (meaning particulate matter less than 2.5 microns across, a small fraction of the width of a hair). The study showed PM2.5 down 60 per cent in Delhi, compared to the same three-week period in 2019, and drops of 54 per cent in Seoul, 31 per cent in Los Angeles and 25 per cent in New York City.

Miriam Diamond, a professor of earth sciences at the University of Toronto, said even a temporary drop in air pollution can have a positive impact on human health. Nitrogen dioxide and PM2.5 can inflame air passages and trigger asthma attacks, heart attacks and strokes.

Health Canada estimated last year that more than 14,000 Canadians die each year because of exposure to air pollution.

“A couple of months (of reduction) will do us well because we’re avoiding air-pollution-related deaths and illness, especially at a time when we are really concerned about the respiratory system,” Diamond said.

“Hopefully it is also having a benefit of reducing the severity of symptoms should you get COVID-19 because your lungs are in better shape.”

Dr. Sandy Buchman, president of the Canadian Medical Association, said he suspects studies will show the drop in air pollution during the slowdown will coincide with fewer admissions to hospital for heart attacks and asthma. That in turn, he hopes, will drive policies to cut air pollution permanently.

“I think we have to see the data but it could speak volumes to the Canadian public, politicians and public health experts,” said Buchman.

McLinden also said the data he and Griffin are collecting right now will improve modelling for where air pollution is coming from and how best it can be improved over the long term.

This report by The Canadian Press was first published May 21, 2020.

Mia Rabson, The Canadian Press

Coronavirus

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Alberta children whose only symptom of COVID-19 is a runny nose or a sore throat will no longer require mandatory isolation, starting Monday.
477 new COVID-19 cases confirmed in Alberta on Thursday

Changes being made to the COVID-19 symptom list for school-age children

Three young Sylvan Lake residents are asking for lights to be added to the walking trail system to make them safer and less scary at night. Photo by @workinonmyfitness72
Young Sylvan Lake residents ask for lights to be added to walking trails

Three young Sylvan Lake residents appeared before Council recently to present their ask

Agriculture Minister Devin Dreeshen (Alberta government photo)
Town of Sylvan Lake recieves funding to help with COVID-19 related revenue losses

Minister Devin Dreeshen says the funding will help the Town pay staff and provide services

There were 410 COVID-19 cases recorded in Alberta Wednesday. (File photo by The Associated Press)
Alberta records 410 new COVID-19 cases Wednesday

Central zone dropped to 160 active cases

Shaun Isaac, owner of Woodchucker Firewood in Trochu, is awaiting a new shipment during a firewood shortage in the province. All of the wood he has left is being saved for long-time customers who need it to heat their homes. (Contributed photo).
Firewood shortage in central Alberta caused by rising demand, gaps in supply

‘I’ve said “No” to more people than ever’: firewood seller

Pilots Ilona Carter and Jim Gray of iRecover Treatment Centres, in front of his company’s aircraft, based at Ponoka’s airport. (Perry Wilson/Submitted)
95-year-old Ilona Carter flies again

Takes to the skies over Ponoka

Children’s backpacks and shoes are seen at a daycare in Langley, B.C., on Tuesday May 29, 2018. Alberta Children’s Services Minister Rebecca Schulz says the province plans to bring in a new way of licensing and monitoring child-care facilities. THE CANADIAN PRESS/Darryl Dyck
Alberta proposes legislation to change rules on child-care spaces

Record-keeping, traditionally done on paper, would be allowed digitally

Prime Minister Justin Trudeau shakes hands with US Vice-President Joe Biden on Parliament Hill in Ottawa on Friday, December 9, 2016. THE CANADIAN PRESS/ Patrick Doyle
A Biden presidency could mean good news for Canadian environment policy: observers

Experts and observers say even a U.S. outside the Paris agreement may ultimately end up in the same place

People take a photo together during the opening night of Christmas Lights Across Canada, in Ottawa, on Wednesday, Dec. 4, 2019. The likelihood that most Canadians will enjoy a holly jolly Christmas season of gatherings, caroling and travel is unlikely, say public health experts who encourage those who revel in holiday traditions to accept more sacrifices ahead. THE CANADIAN PRESS/Justin Tang
Ho, ho, no: Experts advise preparing for a scaled-back COVID holiday season

Many of the holiday season’s highlights have already been scrapped or are unlikely to take place

Sen. Kim Pate is shown in Toronto in an October 15, 2013, file photo. The parliamentary budget office says a proposed law that would give judges discretion on whether to apply a lesser sentence for murder could save the federal government $8.3 million per year. THE CANADIAN PRESS/Colin Perkel
Judicial discretion for mandatory minimum sentences for murder would save $8.3M: PBO

The result would be fewer people in long-term custody at federal correctional institutions, experts say

Husky Energy logo is shown at the company’s annual meeting in Calgary on May 5, 2017. THE CANADIAN PRESS/Jeff McIntosh
Husky pipeline spills 900,000 litres of produced water in northwestern Alberta

The energy regulator says environmental contractors are at the site

A raccoon paid a visit to a Toronto Tim Hortons on Oct. 22, 2020. (shecallsmedrew/Twitter)
Who are you calling a trash panda? Raccoon takes a shift at Toronto Tim Hortons

Tim Hortons said animal control was called as soon they saw the surprise visitor

Most Read