Longer allergy season due to climate change, experts say

With the warm weather came the start of a bad allergy season for Montreal.

Spring is in full swing and experts say Montreal is seeing a longer allergy season due to climate change.

David Wees, a faculty lecturer in the plant science department at McGill University, says that over the past 20 to 30 years, spring has been arriving earlier, resulting in pollen being released sooner and for longer periods.

“Things that normally would have flowered say mid-May are now flowering early May. Things that flowered normally early May are now flowering in April,” said Wees.

He says, as a result, there is potentially more pollen floating around in the air.

“That’s what’s triggering our allergic reactions.”

In Montreal, birch trees are among the biggest contributors.

“It’s most of the trees that are pollinated by wind. So, birch trees, but also poplars, alders, ash, oak, maple and so on,” said Wees.

One in five Canadians suffers from seasonal allergies.

Moshe Ben-Shoshan, an associate professor in the pediatrics department at McGill University, says another factor may be making symptoms worse: the pollen itself.

“Something genetically has changed also in the pollens to make them more allergenic […] so, even if the level is more or less the same or even a bit lower, it doesn’t mean that we will have less allergic symptoms,” said Ben-Shoshan.

He says people with seasonal allergies may need to start treatment months in advance.

Wees adds that while tree pollen is the source of spring allergies, grass pollen is the main trigger during the summer, and ragweed is the main culprit in the fall.

“The ragweed will keep on growing and blooming until there’s a killing frost.”