A growing number of pollinariums in France are providing accurate indications of pollen activity in the areas around them.
One in five children and 30% of adults suffer from pollen allergies, according to a Health Ministry estimate.
The worst period is spring but problems can persist from January to October.
Pollinariums are, simply, gardens where the trees, bushes and grasses which can cause pollen allergies are planted.
They are inspected daily and as soon as they show signs of pollen, information is sent out online to people signed up to receive alerts. The service is free and has been mostly funded by local health authorities.
The first pollinarium was set up at Nantes in 2003. There are now 16, mostly in the northwest but four are in Nouvelle Aquitaine. The most recent has been set up in the grounds of Lanmary hospital at Antonne-et-Trigonant, Dordogne.
The plants have been placed in a situation which encour-ages them to be the first to produce pollen in the area, so the pollinarium can warn in advance when a particular plant is likely to cause allergies.
Charlotte Delpeux from Air Pays de la Loire, the organisation responsible for the quality of air in the region where the first pollinarium was set up, said they are a surprisingly sophisticated way of helping both sufferers and doctors.
She said: “They help give more specific information.
“A doctor can tell you that you are allergic to grasses in general but with this system, because you know which species of grass is producing pollen at a given moment, you will know which grass causes you particular problems.
“It can help doctors decide what medication to give.
“If allergic reactions start with the first signs of pollen and continue for a long period, they will perhaps prescribe a desensitisation programme, while if there is only a reaction at the end of the period, short-term medication is likely to be chosen.”
It also means sufferers can start medication as soon as they know the pollen affecting them has started, making treatment as effective as possible. Pollinariums are accurate in a 50km radius and some 20 species of plants are chosen from those growing in that area.
About 14,000 people have signed up to the services, and the Association des Pollinariums Sentinelles de France encourages more to join the scheme for free via the website alertepollens.org.
It is advisable to see an allergy doctor who can analyse how the results affect you and give you treatment accordingly.
The second system of pollen alerts, used more widely up to now, is managed by the Réseau National de Surveillance Aérobiologique (RNSA).
A machine is placed on a roof which imitates the way someone breathes by sucking in air.
At its “mouth” is a sticky band which captures the pollen as it travels sometimes hundreds of kilometres.
The bands from 75 captors throughout the country are analysed every week to discover which pollens are present (and in what quantity), with the information used to draw a pollen “map”. Sufferers can look up the Carte de Vigilance des Pollens online at pollens.fr and you can sign up to receive emails by putting in the name of your department and the plant you are allergic to.
The trees which give the most allergic reactions to their pollen in France are hazel, alder, birch, cypress, ash and olive.
Ragweed is a serious problem in some areas and there are several different species of grass. Airborne spores from different types of fungi can also cause allergies.
They are caught on the captors but they are more difficult, and take longer, to analyse.
The main fungi are alternaria, often found in homes, basidiospore, parasite fungi found in woods and meadows, and cladosporium, found on decaying plant matter and in damp buildings.
In a study of pollen counts last year, the RNSA found that birch pollen levels had broken records for three years running due to warmer than usual temperatures. It warns that it shows global warming is likely to lead to increased pollen levels in the years to come.