(Montreal) Weed pollen increases the risk of respiratory problems in children, including asthma, according to a new study which reveals that tree cover protects children from developing asthma linked to this type of pollen .

Weed pollen brings the same kinds of symptoms as tree pollen such as coughing, itchy eyes and respiratory tract irritation.

The increase in the risk of developing asthma is not enormous, however, specifies the lead author of the study, Éric Lavigne, who is an adjunct professor at the School of Epidemiology and Public Health at the Faculty of medicine from the University of Ottawa. “But we think that if you are exposed at a very high level, it can have greater importance,” he says.

The link between asthma and pollen in general had already been reported in other studies, he said, but not with respect to weed pollen.

Lavigne’s research team used an Ontario asthma database by age group and analyzed data over an eight-year period to identify cases of asthma occurring in children. between birth and the age of six.

“When there are potentially higher pollen levels, we can be more vigilant, especially if we know that our child is going to be more vulnerable or susceptible to pollen symptoms,” he mentions. This also applies to other types of pollen such as grasses or trees.

Mr. Lavigne argued that cities and municipalities have programs to combat weeds, including brigades that properly pull and dispose of weeds.

He is hopeful that the results of his study, first published in the European Respiratory Journal, will encourage other cities to follow suit.

“We think there are several factors that may play into the equation to ensure that tree canopy is going to have a protective effect on the development of asthma,” said Lavigne, who is also a senior epidemiologist at Health Canada.

“The tree canopy is going to make sure that kids can be exposed to a place where maybe there’s a reduction in stress that’s going to happen, maybe they’re going to have more fun outside, their level of physical activity will be good, maybe that will help mitigate the impacts of the heat,” he explains.

Trees also provide benefits in terms of air pollution. “We know that when there are trees, it can in some way buffer exposure to air pollution, and we know that pollution has an effect on asthma,” says the researcher.

Mr. Lavigne believes the results of his study could have implications for the work of urban planners when it comes to thinking about park development. Other factors such as the type of tree must also be taken into account since certain tree pollens are more allergenic than others.