Posted16 August 2022, 06:58
In LuxembourgThe pollens collected on the roof of the hospital screened
LUXEMBOURG – Almost every day for more than 30 years, a laboratory assistant has climbed onto the roof of the Luxembourg Hospital Center in Strassen to collect the traces of pollen floating in the air of the capital.
Almost every day for more than 30 years, a laboratory assistant has climbed onto the roof of the Luxembourg Hospital Center in Strassen to collect the traces of pollen floating in the air of the capital. This will change soon because since this year, a machine makes automatic readings. “She is in the running-in phase and will take over from this classic monitor,” explains Dr. François Hentges, former station manager who will remain there, 18 m above the ground.
“It consists of a weather vane, a pump that sucks in air then projects it onto a slowly unwinding drum. The pollen sticks to it on an adhesive tape. It remains to count them under the microscope. Thus the pollen.lu site can provide a precise day-to-day vision of the types and quantities of pollen present “within 20 km around”. And the immuno-allergology department of the Luxembourg Hospital Center has just compiled these three decades of data.
“Tree pollen has increased a lot”
“We normally spot around 30 pollens here. It starts in January and goes until August. First with tree pollen, then grasses,” adds Dr. Hentges. And what do the pollens reveal? In particular, they show the effects of global warming. “Tree pollens have increased a lot and are starting much earlier. Mainly because of the higher average temperature”, emphasizes Pierre Hentges, who took part in the study. “Weather conditions contribute to flowering and pollination. And the pollution releases Co2 which the plants feed on,” says Dr Hannachi, the current station manager.
Concentrations vary from year to year but trends are emerging. And we see that the first hazel or birch pollens arrive more than a month earlier than in the 90s. Their peak is also earlier and the quantities have sometimes more than doubled. Conversely, grass pollen tends to decline overall. Even if this year grass allergies are, according to experts, rather important.
The types of pollen detected have changed little over the past 30 years
At the same time, “we have noticed that there are more people allergic to tree pollen than 30 years ago. It used to be hay fever now it’s about the same frequency as tree pollen, notes Dr. Hentges. On the one hand the quantity of pollen increases and the seasons become longer”.
The types of pollen detected have changed little over the past 30 years, even if specialists expect to see the arrival in greater quantities of pollen from Ambrosia, a plant native to America and then introduced into Europe. It currently tends to go up France and causes strong allergies around the month of September.
And if they start earlier, allergies are not necessarily more severe. “Treatments have improved a lot,” notes Dr. Hentges.