Call it a breath of fresh air
Pandemic has cut traffic, emission levels, could boost city’s songbird population
A dramatic drop in traffic since the pandemic began mid-march has led to cleaner air, potentially better mating conditions for some birds, and may have changed behaviours in animals who ventured into urban spaces while streets were calm.
Data provided by the City of Edmonton shows about a 30-per-cent drop in traffic volumes in March, and in April it was down by nearly 50 per cent. Volumes were down in May by about 30 per cent, but by June it was only about 15 per cent less than usual.
But even with some traffic starting to return to normal levels, scientists with Environment and Climate Change Canada say there has been roughly a 40-per-cent decline in nitrogen dioxide emissions in the Edmonton area since mid-march.
“One of the main emitters are probably (motor) vehicles and aircraft ... that’s probably where a lot of the drop is coming from because there’s less commuter traffic and aircraft,” scientist Debora Griffin said.
Environment Canada uses Tropomi satellites from the European Space Agency to monitor substances such as nitrogen dioxide, a gas that contributes to smog, and can have adverse impacts on human health.
Scientist Chris Mclinden says nitrogen dioxide is one of the best indicators of local sources of pollution.
“As unfortunate as it is, it is an interesting natural experiment where we’ve had this very rapid change in emissions,” he said.
Even so, he says it’s unlikely there will be long-term effects from a temporary reduction in traffic, but the decline will provide a baseline to be able to better understand and evaluate traffic and aircraft emissions.
“These are the emissions we see under business-as-usual conditions ... and it can help people understand, give them another point of reference to help them formulate their own opinions.”
Data captured by the Alberta Capital Airshed, which has multiple air monitoring stations in the region, shows a different picture.
Nitrogen dioxide averages from March to May were down about 55 per cent from last year, but compared to 2016 levels, it was only about five per cent less.
For sulphur dioxide, there was about a 60-per-cent drop — which was 50 per cent lower than 2016 levels. There was also about a five per cent drop in ozone averages in this time period.
SONGBIRD POPULATIONS COULD RISE
Walk through the river valley this summer and the chirps of the western tanager, or the “dee-deedee” of the black-capped chickadee may be a little louder and a little clearer — if they’re not choked out by a passing train or truck.
University of Alberta researcher Collen St. Clair, who studies wildlife interactions with humans, said the reduction in traffic volume could make it easier for some songbirds to attract a mate.
“Some of the species that are declining in urban areas are particularly sensitive to traffic noise,” she said, pointing to an earlier paper she co-wrote.
“It would follow then, that this big reduction in traffic noise that we had this year might mean there are more birds in urban areas.”
Male songbirds use specialized vocalizations to attract mates, and females prefer songs at different frequencies.
In the paper, the authors suggested black-capped chickadees changed the frequency of their songs when traffic was noisy.
MORE ANIMALS, OR MORE OBSERVERS?
Matt Besko, director of wildlife for Alberta Environment and Parks, said there has been an increase in reports of animal sightings, especially for animals that are sensitive to human behaviour on the fringe areas near natural areas, including bears and deer
“Certain species of wildlife, and wildlife in general, were able to venture closer in the boundary here, closer into town, and it was easier for them to do that because they didn’t have that human disturbance,” he said.
However, the increase in sightings doesn’t mean there are more animals — it’s a behavioural response, not a population change.
Besko added it also can be hard to tell if all the reports of more animal activity is because more animals are venturing out, or if more people are watching them.
“People are venturing out more and more, and there’s a lot of people walking ... so they’re able to see wildlife more, they ’re able to really observe their natural environment and they’re able to enjoy the wildlife that is here,” he said.
Ebird, a database that allows users to submit photos of birds for research, has seen a boost in new users flocking to sign up on its app. The website saw more than a 30-per-cent increase in submissions in April and May globally. Submissions were up 50 per cent over a five-year average in May.