Ragweed pollen alert in central France

Asthma sufferers and people with lung problems are being warned of ‘high to very high’ levels of ragweed pollen in the air in Auvergne-Rhône-Alpes and Centre-Val-de-Loire which can cause severe allergic reaction.

The red alert from the National Aerial Surveillance Network (RNSA) comes a little earlier than most years and it warned people with breathing problems that the days until the weekend would be difficult and they should go out only in the mornings when the air was cooler and before the flowers had opened.

Even in small amounts, ambrosie has very strong allergenic potential and can cause allergic rhinitis, severe irritations, eczema and asthma.

Ragweed is flowering two weeks ahead of normal after there was a first spike at the beginning of this month – triggered by the rain and high temperatures.

Geographically speaking, the risk of allergy is classed by the RNSA as ‘high to very high’ from Lyon to Montélimar, then ‘average’ down to Nîmes and Avignon. There is also ‘average’ risk for an area between Angoulême and Périgueux, as seen in the map below.

Just five grains per cubic metre of air can trigger severe symptoms in those deemed sensitive enough to succumb (estimated at 13% of the region’s population).

Ragweed, which is native to the US, first appeared in France at the end of the 19th century. Today, this tenacious plant is spreading around Europe and according to a RNSA study, allergies could intensify – by 2050, its pollen could be four times more concentrated.

Mapping of the plant’s spread across France, requested by the Ministry of Health, has shown that the areas bordering the Auvergne-Rhône-Alpes region are also affected, as well as parts of Nouvelle-Aquitaine, Burgundy-Franche-Comté, Centre-Loire Valley, Occitanie, Provence-Alpes-Côte-d’Azur and Pays de la Loire.

This spread is caused mainly by human activity triggering seed dispersal.

To stem the spread, local authorities advise tearing up the plant in June to avoid its flowering in August and delaying spreading of the pollens until the beginning of autumn.

People who spot it on cleared land, building sites, wasteland or along roads are asked to report it to the local authorities using this website.