The smell of a fresh pine tree is an essential part of Christmas for many Australian households.
But National Asthma Council Australia is warning that a Christmas tree could put people's health at risk.
Spokesperson Sheryl van Nunen said pine trees were like a "pollen trap", acting like a Trojan horse to carry large amounts of pollen indoors.
"Other weed, grass and tree pollen sort of sticks to the pine tree," Professor Van Nunen said.
"And as the tree dries out once it's cut down, it releases all this other pollen which then becomes airborne inside the house."
Christmas tree syndrome
The pollen can cause "Christmas tree syndrome", which affects people's respiratory system and causes wheezing, sneezing, a disrupted sleep, and possible severe asthma attacks.
Professor Van Nunen said the syndrome was first described in 1929, when several people's asthma worsened in a hospital after Christmas trees were erected in the ward.
It's estimated the syndrome affects about 6 per cent of people.
Professor van Nunen also said dust and mould that accumulated on artificial Christmas trees could cause similar problems.
"I mean, one feels like the Grinch saying this about Christmas trees — because I do love Christmas trees and decorating them — but we do have to be a bit careful," she said.
"People can get bad asthma from pollen, and rhinitis (hayfever) as well."
Asthma deters customers
Christmas tree farm manager Alex Costa says asthma is a concern for many customers of his business near Ballarat.
But for some, their love of a fresh pine tree at Christmas is too great to ignore.
"For example, I've had customers come out in the past and say they love the smell of Christmas trees, but their partner is asthmatic," he said.
"But some of them say they've agreed to get a tree anyway, their partner just can't go near it.
"I'm not sure how well it works."
Professor Van Nunen says there are more effective tricks to help minimise the problem.
For a live pine tree, she recommends hosing down the tree before bringing it into the house, to help wash off the allergens.
She says people should also give artificial trees a "good shake" outdoors and a wipe down before putting them up inside.
The same holds for dusty decorations that have spent 12 months in the closet.
"Do all of this before you start decorating, and then you can have a really pleasant time with your Christmas tree," Professor Van Nunen said.
