The Current

Seasonal allergies have been amped up by climate change, say experts

Studies have found allergy season is getting longer and more intense, and experts are blaming climate change.

Allergy expert Cecilia Sierra-Heredia says allergy season now lasts longer and hits harder

Pollen from orchard grass often causes allergy sufferers grief. Seasonal allergies may affect sufferers for longer, because of increased pollen days that experts say are due to global warming. (Dale Molnar/CBC)

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If you feel like allergy season is getting longer and more intense, you're not wrong — experts say that's the case, and climate change is the culprit.

"There are more days in the season, so for people who think that their allergies have been going on forever, yes, they're right. And we have more pollen grains in the air," Cecilia Sierra-Heredia told Matt Galloway on The Current.

Sierra-Heredia is a lecturer in the Faculty of Health Sciences at Simon Fraser University, and she studies the link between seasonal allergies and climate change.

A study found that, across the United States and Canada, pollen season is starting about 20 days earlier and pollen loads are about 21 per cent higher since 1990 — and that's partly because of global warming.

"With an increase in temperatures and an increase in carbon dioxide in the atmosphere, the plants respond by having longer flowering seasons. And then, of course, that means more pollen in the air," said Sierra-Heredia, who was not involved in the study. 

Fighting allergies

Anne Ellis has seen the effects of a longer allergy season firsthand. Ellis is a professor of medicine and chair of the Division of Allergy and Immunology at Queen's University, and also suffers from seasonal allergies.

"We have such a long winter, we tend to forget how bad our seasonal allergies were until we're back in the thick of them again," said Ellis. 

But Ellis says that while allergy season is getting worse, the medicine and therapies for it are improving. 

There are good options for seasonal allergy sufferers to treat their symptoms, and many anti-histamines no longer have side affects like drowsiness. (PhotoMediaGroup / Shutterstock)

"We have lots of new, very effective prescription medications that we didn't have five years ago. We have new and better immunotherapies, so ways which we can change a patient's immune system," said Ellis. 

Ellis explains that previous interventions may have required going to get a shot at a doctor's office, but now the same effect can be achieved by taking medication. 

"It is important to make sure you're purchasing the non-sedating newer antihistamines that say 'non-drowsy' on them, because some of those older antihistamines that are known to cause sedation also just aren't that effective and may not work as well for you," said Ellis. 

The root of the problem

Sierra-Heredia said towns and cities across Canada are trying to find ways to reduce the affect of seasonal allergies.

One of the options is planting more female trees. That's because female trees don't produce pollen, though tend to be perceived as messier because they grow fruits and seeds.

And in British Columbia, Sierra-Heredia said there has been a lot of planning by the provincial government and municipalities around decreasing the carbon footprint and increasing the sustainability of new buildings. She said that planting more native tree species would help as well. 

"Hopefully we'll see this more in the future because we know for sure that climate change will continue to worsen the allergy seasons," said Sierra-Heredia.

"We have to use this as an incentive to contribute to any potential initiatives in our communities, and individually, that mitigate climate change, that could help us to stop worsening these potential allergy issues."


Written by Philip Drost. Produced by Lindsay Rempel.

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