Pollen et changement climatique

Pollen: Climate change, a factor increasing allergies

Climate change is an undeniable reality that significantly impacts our planet. Among its numerous adverse effects, we observe a notable increase in pollen allergies. These seasonal allergies, recurring as early as March, also known as hay fever, affect a growing number of people worldwide.

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Seasonal changes and pollen allergies
Public health consequences”
What can be done to limit the impact of pollen on health?

According to the French Agency for Food, Environmental and Occupational Health & Safety (ANSES), nearly one in three adults and 20% of children over the age of 9 suffer from seasonal rhinitis caused by pollen allergies.

Seasonal Changes and Pollen Allergies with Climate Change

Climate change manifests through fluctuations in weather patterns, notably resulting in higher temperatures, prolonged flowering periods, extended seasons, and increased air pollution.

These changes promote:

🌼 Earlier flowering and pollination: Higher temperatures associated with climate change induce an earlier spring onset. Consequently, many plants, trees, and grasses (such as cypress, ash, birch) start their flowering period earlier in the year. This early flowering exposes individuals to higher concentrations of pollen for an extended period.

📅 Prolonged pollen seasons: Pollen seasons, corresponding to periods when plants release pollen, also extend due to climate change. Warmer temperatures in autumn and an earlier spring onset prolong the period when pollen is present in the air.

💐 Variation in pollen types: Climate change alters pollen types. Under different climate conditions, some plants produce more pollen, which becomes more allergenic. This exposes people to new allergens. For example, ANSES noted that temperature increases the amount of allergens in birch and ragweed pollen grains.

☁️ Air pollution: Atmospheric pollutants (nitrogen dioxide, fine particles, volatile organic compounds, etc.) can worsen the situation by altering or damaging the surface of certain pollen grains. This can make pollen more reactive and potentially more irritating to the respiratory tract. Moreover, rising temperatures promote ground-level ozone formation, an atmospheric pollutant known to exacerbate allergic symptoms. The combination of increased pollen exposure and poor air quality worsens allergic reactions.

The Public Health Consequences

The increase in pollen allergies has significant consequences for public health.

Exposure to airborne pollen allergens or their inhalation can trigger allergic reactions of the nose (allergic rhinitis, commonly known as hay fever), eyes (allergic rhinoconjunctivitis), and bronchi (bronchial asthma). It is also a major cause of sleep disturbances, mental well-being impairment, decreased quality of life, loss of productivity or decreased academic performance in children, as well as associated healthcare costs.

The effects of climate change on pollen seasons, concentrations, and allergenicity are expected to lead to increased exposure of the European population to pollen and aeroallergens in the future, prolonging allergies affecting physical and mental well-being.

What can be done to limit the impact of pollen on health?

To mitigate the impact of climate change on pollen allergies, adaptation and prevention strategies are necessary. This includes the establishment of pollen monitoring systems, public education about allergic risks, and the development of policies aimed at reducing greenhouse gas emissions.

Limiting the planting of allergenic species in cities  

To reduce the risks of pollen-related allergies, it is recommended to create hypoallergenic green spaces in and around cities. This involves carefully selecting tree species, limiting the presence of potentially allergenic pollens such as those from grasses, cypresses, alders, and birches, often more prevalent in urban gardens. It is crucial to consider tree species adapted to urban environments when planning space and implementing climate change adaptation measures to avoid exacerbating allergy risks.

💡 Good to know: However, there are also international standards, such as those defined by the World Health Organization (WHO), which serve as a reference for assessing air quality on a global scale.

Implementation of air quality and pollen monitoring in cities

Pollen monitoring is of crucial importance due to its direct implications for human health, especially for individuals suffering from respiratory allergies. By identifying and tracking pollen levels in the air, health authorities can anticipate periods of risk and implement preventive warnings, enabling sensitive individuals to take appropriate measures to minimize their exposure. Furthermore, pollen monitoring provides essential data to understand long-term trends related to climate change, pollen seasons, and plant biodiversity, thus contributing to better allergy management and more effective public health strategies.

Raising awareness and educating citizens

According to an IFOP survey (2018), 50% of French people do not consider allergy as a disease. This phenomenon contributes to patients’ lack of knowledge about their symptoms, and pollen allergy is often underdiagnosed and left untreated or mistreated.

💡 Good to know: 30% of untreated respiratory allergies progress to asthma.

Thus, it is essential for health authorities to consider pollen allergies as a major public health issue and to raise awareness about the impact of allergies to help recognize, prevent, and manage symptoms.

How are pollen levels modeled at Meersens?

Meersens models pollen concentrations for the most allergenic species across more than 60 countries worldwide. Concentrations are assessed using satellite imagery, meteorological data, and pollen seasons in each country or region. Pollen seasons are determined through comprehensive literature research and updated annually to best adapt to climate change.

For France, concentrations of grasses, alder, olive, birch, ragweed, and mugwort pollen are estimated in real-time every hour and for the next 48 hours to best prevent the majority of allergies.

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Pollen: Climate change, a factor increasing allergies

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