A group of Canadian researchers says the amount of powdery pollen released by plants during their reproduction process has gone up across Canada in recent years and is exacerbating allergies from hay fever to hives.
Daniel Coates, director of Aerobiology Research Laboratories, which monitors pollen, said monitoring by his lab suggests pollen levels across Canada have doubled.
Climate change is partly to blame, he said.
"It's getting worse because pollen loves warm weather," he said. "When you have longer periods of warm weather, science and data have proven that you're going to see more pollen in the air as well."
Unpredictable weather could also be why allergies are more intense in 2026.
This year, spring across the country has been cooler, Coates said. That means pollen from trees that usually burst earlier in the season — cedars and maples, for example — are releasing pollen around the same time as those that release later, including birch, oak and poplar trees.
"Poplar this year was really high in Edmonton, for example, and now they're overlapping with what we more typically see around this time of year, which is like birch," he said.
"We're seeing a sort of a later start — but more intense start — to the season."
Kevin Sproule, an Edmonton-based arborist, said seasonal allergies have been particularly intense in Alberta, which has in recent weeks experienced dramatic weather shifts from blowing snow and ice to blooming trees and sunshine.
"My wife and my kids have been experiencing more allergy symptoms this year than they have in the past and I believe that's because of that intense explosion of pollen," said Sproule, who works for tree pruning company Davey Tree.
Dawn Jurgens, also with Aerobiology Research Laboratories, said pollen allergies in cities across the world have gone up over the years, and botanical sexism is partly to blame.
She said municipalities have historically preferred to plant male trees rather than female trees to reduce the amount of fruiting debris the females might produce after the release of pollen.
"It does make allergies a little bit worse because you get more pollen release when there's more male trees," she said.
Pollen allergies, she said, are also intense in cities because of the "heat-island effect," in which tightly packed buildings and paved surfaces in urban areas trap heat more than rural areas.
"So the temperature in the cities is much higher than it is in less urban areas," she said.
Jurgens said allergy sufferers can't do much to prevent intense allergic reactions to pollen other than changing their outdoor activities.
Amy Kish, senior laboratory technician with Aerobiology, said she's been itchy and has had a runny nose.
The Ontario resident said when the weather is nice, she usually keeps the windows closed.
"I can't have the windows open, and I get annoyed if my husband hangs the laundry out on certain days," she said.
"It's not fun feeling sick when your allergies are bad all the time."
This report by The Canadian Press was first published May 18, 2026.
