12 departments remain on red alert due to ragweed pollen

This wild plant grows especially on roadsides. Despite the end of summer, its pollens remain very irritating for sensitive people.

Usually, the end of summer means an overall drop in allergy risk across France. But 12 departments in central and eastern France, in an area stretching from Nièvre to Gard, remain on red alert, according to the National Aerobiological Surveillance Network, due to ragweed pollen.

Ragweed, the most widespread in France, is recognizable by its reddish stem, covered in hairs, and its very jagged leaves. Native to North America, this invasive plant first appeared in fields in the Rhône-Alpes region in the 19th century, before spreading across a large part of France.

The problem with ragweed is that its pollen is highly allergenic; just five grains of pollen per cubic meter are enough to trigger symptoms in a sensitive person.

In these allergic people, these pollens almost always cause sneezing, itchy nose and eyes, and in half of the cases, also a dry cough or asthma that may require treatment. According to Anses, the National Agency for Food, Environmental and Occupational Health and Safety, between 1 and 3.5 million French people are affected by this allergy. Its management (medication and consultations) costs health insurance between 60 and 180 million euros each year.

An observatory of strategies to combat ragweed was created in 2011. The difficulty is that a single ragweed plant can produce up to 5,000 seeds, seeds that can then persist in the soil for 50 years. Beyond the allergy issue, ragweed also poses problems in agriculture, due to its highly invasive nature in fields. The reflex should therefore be to destroy them before flowering if they grow on your land. And if you identify them on the side of the road, report their presence on the signalement ambroisie.fr platform.