Seasonal allergies seem worse this year. Experts explain why it may feel that way

It's that time of year again — seasonal allergies are back.

With allergy season arriving earlier than usual — starting around March — many seasonal allergy sufferers feel their symptoms have been worse than ever. While experts said this isn't necessarily the case, a changing climate and weather conditions are intensifying the effects on our immune systems. 

"It seems this time of year there's always a lot of complaints about allergies, and it really will depend on the year, the weather we're having," said Randy Howden, pharmacist and owner of Crowfoot Medicine Shoppe Pharmacy. 

Howden said there are no real measures for comparing how bad allergy season is each year, but certain years have more pollen and poplar tree fluff compared to others, amplifying allergy symptoms.

"It's really hard to say why it'll be harder year-to-year for some people," he said. "It really depends on what they're actually allergic to."  

Whereas tree pollen is more common in the spring, grass and weed pollens become an issue in the summer and autumn, according to IQAir, an air quality technology company.

According to Asthma Canada, one in five Canadians suffers from respiratory allergies each year. Researchers from John Hopkins University School of Medicine in Baltimore found that over 30 per cent of the world's population reports suffering from seasonal allergies.

Howden said changing weather conditions — such as the shifts between wet and dry periods Calgary has seen lately — can aggravate seasonal allergies as pollen and other irritants are stirred up.

"Depending on the weather cycle, we'll get a bunch of wet weather and then we'll get a few warm days, and it almost seems like all the pollen is released all at once," said Howden.

He noted rain usually reduces pollen while heat worsens it.

Globally, climate change and warmer global temperatures are also factors, said Cecilia Sierra-Heredia, an adjunct professor in the School of Population and Public Health at the University of British Columbia. 

"Climate change and allergies are linked through the increasing greenhouse gases that cause changes in the environment and cause changes in how plants respond and produce pollen grains," she said. 

Sierra-Heredia noted the pollen season starts earlier and ends later than it used to due to warmer global temperatures. The Climate Atlas of Canada refers to this period as the "frost-free" season, or the length of the growing season, where temperatures remain above freezing. 

The longer the frost-free season lasts, the more pollen can circulate in the air. Sierra-Heredia said this extended exposure can also prolong allergy symptoms.