“Allergies are on the rise”: pollen concentrations will rise in 2023

“The pollen seasons follow one another, but are not alike,” but one thing is certain: “allergies are on the rise.” “As a result” of climate change, pollination rates are being disrupted, with records for certain pollen concentrations recorded last year, notes a new report on monitoring pollen in ambient air in France in 2023 by the National Network for Aerobiological Surveillance (RNSA). ), the Association of Sentinel Pollinariums of France and the Atmo Federation of France. “The constant rhythm of pollination has been disrupted by human activity,” they insist.

Due to the highly likely impact of climate change, some pollen seasons are also starting earlier and others ending later, experts note, a year after a previous report that already noted more severe allergies than before in 2022. An alarming discovery that 30% of adults and 20% of children over 9 years of age suffer from pollen allergies. “Climate change may affect pollen production, particularly by extending the pollen season, changing spatial distribution and air pollution, and thus affecting pollen and hay fever,” allergic reactions in the respiratory system and eyes, the report summarizes.

Ragweed pollen increased by “more than 10%”

“The future of pollination is unclear,” but several worrying trends were noted last year, explain monitoring experts. While climate change is leading to a “continuous increase in the concentration of carbon dioxide in the atmosphere”, the pollination phenomenon is changing, and in general, high temperatures, which are becoming more frequent, provide terrain favorable for the spread of pollen.

As such, some pollen concentrations in the air reached record levels last year, including ragweed, for example, “with pollen concentrations increasing on average more than 10% compared to 2022,” even if the trend remains “highly variable” from one area to another. another. This invasive plant, native to North America, is migrating due to climate change and is now spreading across the country. Rising temperatures also encourage pollen-producing trees such as cypress, ash, alder and hornbeam to bloom, experts said in a press release.

Climate change is also affecting the duration of pollination sequences. “Some pollen seasons are arriving earlier than at the beginning of the century,” the report notes, noting more broadly that “the 2023 pollen season got off to a strong start, creating significant discomfort for allergy sufferers,” following “unusually warm temperatures at the end of the century.” December and early January. “Such an early season has occurred several times in the past, but due to climate change it is becoming more common,” he insists.

At the same time, other seasons are “extended by summers with unprecedented temperatures like September 2023,” which was the hottest ever recorded in mainland France and the world, the press release highlights. For example, the ragweed bloom period has been extended, resulting in symptoms “particularly severe in the first week of September, with record concentrations of ragweed pollen at several sites.”

Write down the “clinical index”

“And then sometimes the unexpected happens, as in the Paris region, where a severe episode of storm asthma occurred on June 10 and 11, 2023,” an episode that led to the proliferation of small particles of highly allergenic pollen, the report notes. The virulence of symptoms was such that emergency department admissions peaked.

Only rainy weeks provide a lull, reducing the pollen concentration, “like the birch last year.” But still unable to slow down the upward trend. The “Clinical Index,” a measure that measures both the severity of allergic symptoms and the number of people affected, will reach its highest level in 2023, “after continuous growth over the past two decades.”

The figures could rise again in 2024 as the start of the year has already been marked by peaks in pollen emissions, which have triggered red alerts on mainland France several times since February, marked by very early spring weather.

Over the past decades, several studies have already revealed an increase in allergic respiratory pathologies. “The prevalence of respiratory allergies has tripled in 30 years,” for example, the National Food Safety Authority (ANSES) noted in a January 2022 note. Population.

Regarding the role of climate change, research has also shown that pollution, by transforming some grains, may also increase their irritant power, increasing their ability to penetrate deep into respiratory tracts that are themselves already weakened by the same pollution. government website Notre Environment.