Aggressive pollen Why more people than ever are suffering from hay fever

Longer flowering periods, more aggressive pollen and a weaker immune response are causing more people to suffer from hay fever than ever before. The causes are climate change, air pollution and good hygiene.

One in five people in Switzerland suffers from hay fever. A hundred years ago it was less than 1 percent. How is it that so many more people are allergic to pollen? Researchers are on the trail of the phenomenon. Three causes are crystallizing.

1. climate change leads to more pollen in the air

It is getting warmer earlier than it was a few decades ago. If the winter is as mild as the last one, certain plants, such as hazel, begin to flower as early as January. By the time the last grasses have released their final pollen, it is August to September. This results in a pollen season of six months or more for people who are sensitive to both.

The pollen flies longer and there is also more pollen flying. Both are shown by studies quoted by SRF._CO2 acts like fertilizer on the plants, which now produce more seeds.

The diversity of pollen has also increased because new plant species have immigrated to Switzerland and are now spreading their genetic material here. According to the Tages-Anzeiger, new farming methods have also contributed to the expansion of the pollen spectrum.

2. exhaust fumes make pollen more aggressive

Birch pollen makes life particularly difficult for many people. And they suffer most in cities. Based on this observation, a team from the University of Augsburg conducted experiments with birch trees. The results are as astonishing as they are unpleasant for allergy sufferers.

Birch trees that are exposed to exhaust fumes produce more aggressive pollen. This is shown not only by trees near busy roads, but also by identical birch trees grown in the laboratory, half of which received pollutants and the other half clean air. Test subjects reacted more strongly to the exhaust pollen from the laboratory than to those grown in clean air.

As a result, various experts are calling for plants with less allergy potential to be planted in cities.

3. excessive hygiene can make you more susceptible

The demands on personal hygiene have increased. Children in particular come into contact with far fewer pathogens than their parents and grandparents did as children; not only because of increased hygiene, but also because they live with fewer siblings.

Their immune system is therefore less well prepared for allergenic substances. The German Robert Koch Institute describes the hygiene hypothesis as the best explanation for the increase in hay fever and asthma over the last 50 years, even though the link has not been definitively proven. Nevertheless, it has been shown that children who attend daycare centers are less susceptible to both respiratory diseases.