FOCUS – The pollen season begins in spring and lasts until autumn. For about thirty years, however, this period synonymous with allergies for about 20% of children and 30% of French adults, has tended to lengthen and concern more and more people.
Coughs, sneezes, irritations, asthma… We are in the middle of pollen season. These small grains ensuring the reproduction of flowering plants are responsible for many allergies – about 20% of children and 30% of French adults are affected. Over time, more and more people are sensitive to their presence in the air. The number of allergy sufferers has moreover tripled since the 1970s. A multifactorial increase.
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According to Sophie Silcret-Grieu, allergist and member of the board of directors of the association Asthme et Allergies, the hygienist theory, which advocates the existence of a link between exposure to microbes during early childhood and the reactions allergic, is the most recognized track. “Our way of life is becoming more and more sanitized. Care is taken not to expose the child to microbial components, which increases the risk of developing an allergy. An immune system that doesn’t have to do its job against something really dangerous starts reacting against something that isn’t.“, she explains. Allergy, in this case, is therefore the excessive immune response of the body when it comes into contact with certain harmless elements, such as pollen.
- Global warming
Global warming is also contributing to this increase in cases. It contributes to the pollen seasons starting earlier, lasting longer and being more violent. “If we compare the temperature curve and that of the amount of pollen present in the air, we see that over the last thirty years they have increased at the same time.“, analyzes Samuel Monier, communication manager National Aerobiological Surveillance Network (RNSA). There is also the appearance of allergies to pollens in regions in which they were not present until then. “Due to climatic changes, some plants are progressing. This is the case, for example, of ambrosia, which was present in the Rhone Valley and which is now growing further north.», continues Samuel Monier. This phenomenon is also observable with cypresses or birches, plants with very allergenic pollen which are gaining new territories.When I started my career I treated a birch allergy a day. Today we are at 10“says Sophie Silcret-Grieu.
The explosion in the concentration of carbon dioxide in the air has a significant impact on pollens. “CO2 is a gas that plants absorb and which contributes to their growth. As a result, more pollen is produced”, explains Samuel Monier. In addition, the air pollution induced by the increase in the presence of CO2 acts directly on human health. “This aggravates the phenomenon because the pollution weakens the respiratory tract so we observe a facilitating effect for the pollens.“says Sophie Silcret-Grieu. The chemical particles present in the air also act on the pollen grains:They weaken or even crack the shell around the pollen grain, which will therefore release a greater quantity of allergenic substances.“, describes Samuel Monnier.
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Preventive actions exist to limit allergic reactions to pollens. Ventilating your home, wearing sunglasses to protect your eyes and not drying your laundry outside to prevent pollen from sticking there are all simple solutions that can limit contact with allergens. For more advanced cases, taking antihistamines or following a desensitization treatment can be solutions.
However, according to experts, if the effects of global warming were not limited in the years to come, half of the French population should be affected by allergies by 2050.