By Mary Ward
Hay fever sufferers should be on alert over the coming weeks with the return of sunny days after Sydney’s wettest year on record creating perfect conditions for high loads of pollen.
Monitoring systems at Campbelltown, Camperdown, Hornsby and Westmead show pollen levels have risen across the city over the past week.
The expected break from the rain is expected to cause problems for hay fever sufferers. Credit: Flavio Brancaleone
Connie Katelaris, a professor in Western Sydney University’s immunology and allergy unit, said consistent rain through spring and summer helped curb the effects of La Nina on the city’s pollen count last year, but forecast clearer weather could create problems for hay fever sufferers.
“Generally in La Nina years you have higher pollen loads, because the vegetation grows beautifully and grasses are thriving, but that’s modified if it rains heavily every day during spring because that washes the pollen out,” Katelaris said.
“If it is going to be dry now for the next three or four weeks, it will be bad because the grass will be blooming.”
Sydney’s grass pollen season begins in late October and continues to early December, with a possible milder peak in January and February, depending on rainfall.
“For the past month, it’s been tree pollen that has been the problem. So people who have allergies to particular types of trees have been impacted,” Katelaris explained, adding it was mostly introduced species that produced high levels of allergenic pollen in spring.
“But now we are coming in to grass pollen season, which certainly accounts for the majority of people with seasonal allergies.”
Last week, the Australian Medical Association issued a warning for asthma sufferers in the NSW, with November and December typically the months when “thunderstorm asthma”, a condition triggered by spring and summer storms when pollen levels are high, can strike.
In 2016, a thunderstorm asthma event led to the deaths of 10 people in Victoria.
Alfredo Huete, professor of ecosystem dynamics, health and resilience at UTS, said grass pollen was more of a problem for people living and working in Sydney’s west than the city’s east and north.
“They’re right next to that strip of pastures and agriculture,” Huete said, adding the area around the construction of the new Western Sydney Airport was particularly bad.
However, grass pollen can be a problem anywhere with large amounts of overgrown grass.
“Right now, you can see grasses are flowering everywhere,” Huete said. “On highway medians or next to roads: it’s hard to avoid it.”
While this year’s La Nina event has led to a higher spring pollen count, Huete said climate change was also disrupting the usual pollen calendar in Australia.
Sub-tropical grass types – which produce pollen in autumn – are increasingly found in NSW, creating a year-round headache for hay fever sufferers.
In Brisbane, a city dominated by sub-tropical grass types, Queensland University of Technology researchers found pollen counts between 2016 and 2020 were triple those recorded between 1994 and 1999.
“For us, that means bad news in autumn,” Huete said. “But it probably doesn’t impact what we are seeing in spring.”
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