COVID-19 lockdowns helped clear our air. How can we keep it?

In the early days of COVID-19, as Toronto’s streets emptied and toilet paper practically vanished from store shelves, many residents noticed something else unexpected: unusually lovely air.

The sky looked bluer, the breeze somehow smelled fresher. With Toronto’s usual chorus of traffic suddenly gone, birdsong became the city’s new soundtrack.

This wasn’t a figment of our imaginations — COVID-19 shutdowns brought a noticeable drop in traffic on Toronto’s roads and a decline in air pollution, researchers have found. And if we wanted to, we could keep this newly clean air for good through policy changes to increase use of electric vehicles and lower-emission transport trucks, say experts at the non-profits Ontario Public Health Association (OPHA) and Environmental Defence.

“Other jurisdictions are doing it. They’re fine, they’re thriving economically,” said Sarah Buchanan, clean economy program manager at Environmental Defence.

“The sky is not going to fall if we get electric vehicles on the road. In fact, the sky will get cleaner.”

A pandemic, of course, is not a good or sustainable way to lower air pollution. The entire population of a city cannot stay home forever. And the cost of coronavirus has been horrific: as of Tuesday, 2,768 people in Ontario had died from COVID-19, an unimaginable tragedy.

In a broader sense, decreasing air pollution would be good for public health, said Helen Doyle, the environmental health workgroup chair at OPHA. It’s linked to higher rates of asthma, allergies, heart disease and lung conditions. Early studies are showing that people who are exposed to more air pollution tend to be at higher risk from COVID-19.

In the Greater Toronto and Hamilton Area, air pollution leads to 3,000 premature deaths a year, a June report from the University of Toronto’s Transportation and Air Quality Research Group, the OPHA, and Environmental Defence found.

Cleaning our air would help marginalized communities the most — the health impacts of air pollution disproportionately affect people who are racialized, lower-income or vulnerable, who often live closer to sources of pollution. People of colour and other marginalized communities are also more vulnerable to COVID-19.

These factors are all connected to each other, and decreasing pollution in a way that can be maintained long term could make communities more resilient to future pandemics, said Robin Edger, executive director and CEO of the non-profit Canadian Association of Physicians for the Environment, or CAPE.

“The health benefits are respiratory at a time when a respiratory illness is holding us all hostage,” Edger said.

“When you look at the COVID map of Toronto, it looks a lot like the poverty map of Toronto,” he added.

How did the shutdowns change our air?

Because the COVID-19 shutdowns happened relatively recently, scientists are still working through air pollution data to understand what happened and why.

Debora Griffin and Chris McLinden, scientists with Environment and Climate Change Canada, used satellites to study levels of nitrogen dioxide — an air pollutant that comes from traffic and other fossil fuel combustion — in cities across Canada, including Toronto.

Their findings showed that from mid-March, when COVID-19 shutdowns began, to mid-May, nitrogen dioxide went down by about 40 per cent in Toronto. In other cities across Canada, it went down a similar amount, in the 30 to 40 per cent range. (Those figures account for meteorology, the researchers said.)

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It’s not clear yet exactly what caused the drop, Griffin said: “It’s hard to tell exactly where the reductions are coming from, just purely from the satellite data.”

But it’s important because nitrogen dioxide is a major pollutant. It contributes to smog, McLinden said, and can have a cumulative impact on soil and water. It can also contribute to acid rain.

Other research from the University of Toronto’s Southern Ontario Centre for Atmospheric Aerosol Research (SOCAAR) has made similar findings.

Focused only on Toronto, researchers found levels of nitrogen oxides — a group of compounds that includes nitrogen dioxide — decreased by nearly half in the weeks following the shutdowns. So did ultra-fine particles, another traffic-related pollutant. (Those figures haven’t been corrected for seasonal and weather changes, which can have a significant impact on what blows into Toronto and how long it sticks around.)

“The change is real,” said SOCAAR director Greg Evans.

Graphs for both pollutants sharply dropped off the week of the shutdowns, and appeared to rebound slightly as Ontario began reopening.

The SOCAAR team is also still working to figure out whether pollutants dropped because of reduced traffic or other sources of pollution like industrial facilities, and how the province’s reopening might have played into it. But the researchers also observed a significant drop in traffic near their downtown Toronto air monitoring station, Evans said.

These are just two pollutants of many, and assessing the climate impacts of such a decrease in air pollution would require another round of research. But this kind of research could be a game-changer for public health, Doyle said. Aside from premature deaths, air pollution also causes more hospital visits, and the cost of the added health care adds up for society.

“I don’t think there’s enough attention being paid to this,” she said.

A drop of this size, if maintained, could save many lives, she added.

“There are health (benefits), there are social benefits in terms of cost savings, and there are climate benefits,” she said. “From a public health perspective, we’re interested in all three.”

How could we keep our air this clean?

There are several ways to keep Toronto’s air this clean forever, green advocates say.

Getting cleaner vehicles on the road is one path, the report from the University of Toronto’s Transportation and Air Quality Research Group, the OPHA, and Environmental Defence found.

Switching the oldest and more polluting transport trucks out for newer diesel-burning ones could prevent 275 premature deaths in the Greater Toronto and Hamilton Area annually, Buchanan said. Electrifying trucks could eventually have an even greater impact, although the technology is emerging and “not quite there.”

“Trucks proportionally are quite dirty and deadly,” she added. “Taking those off the road would save a lot of lives.”

Electrifying public transit could save more, she said. And policies that push consumers towards buying electric cars could also go a long way.

Governments could do that without giving out incentives for electric vehicles: they can mandate automakers to ensure a rising percentage of their sales are for electric cars, something that’s already in place in Quebec and British Columbia. But Buchanan said incentives are a good idea as well.

“It’s unfortunate that many governments only see electric vehicles as a tool to fight climate change,” Buchanan said. “I would argue they’re an even bigger tool to fight premature deaths from pollution.”

Investing in cycling and pedestrian infrastructure would help too, she added.

A recent report from CAPE outlined other ways we could get there, focusing on how reductions in air pollution from meeting Canada’s climate goals would save lives.

Governments could reduce emissions from the power grid by investing in renewables, and long distance energy lines that could carry clean hydro power farther, Edger said. They could also introduce regulations to ensure buildings emit less carbon, and subsidize retrofits on existing buildings.

Much of the technology we need to do this already exists, Edger said.

“We need political breakthroughs, we don’t need a technological impact,” he said.

The chances of that happening, at least in the short term, are unclear.

The federal government has committed to net-zero emissions by 2050, and hinted that green measures will be part of its COVID-19 economic recovery plan.

But Ontario’s current climate plan doesn’t include anything of the sort, though Environment Minister Jeff Yurek has said it’s an evolving document. Neither did the province’s recently passed economic recovery bill. The Ford government has also cut green energy programs.

The sooner a green push begins, the better the results will be, Buchanan said.

“I think there are a lot of lobbyists that are claiming it's going to be very difficult, when, in fact, it’s much more difficult to face the escalating health and climate toll of continuing to use fossil fuel powered vehicles,” she said.

“Start moving on this, get things shifting faster. We’re really going to pay for it if we don’t do that.”