Urban lighting has a surprising effect on your allergies

Increased nighttime lighting is accompanied by a lengthening of the atmospheric pollen season in the northeastern United States, reveals an American study published in the journal PNAS NexusBy combining pollen readings from ground stations with nighttime infrared satellite images, researchers have shown that the pollen season can begin up to twenty days earlier in areas with high levels of artificial light and end several weeks later compared to areas with less exposure to artificial light. This effect is independently amplified by rising temperatures but is only slightly influenced by rainfall. Furthermore, the proportion of days with high pollen concentrations is significantly higher in the most illuminated areas.

Worsening of allergic rhinitis and asthma

This large-scale experiment highlights the crucial role of light in plant development cycles and flowering. The authors thus warn of the health consequences of excessive lighting: pollen concentrations in the air are directly correlated with the severity of... rhinitis and allergic asthma attacksThey also point out that the choice of plant species in cities, where population density is high, should take into account their sensitivity to photoperiod.

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In France, climate change is negating efforts on lighting

While this study was conducted in North America, the question also arises in Europe. But...In France, the nighttime lighting of municipalities has been steadily decreasing for two decades for both economic and ecological reasons. However, the amount of pollen in the air continues to increase every year.. “ In this case, climate change is responsible, with increasingly earlier pollen seasons, which also translates into a steady increase in the amount of pollen in the air over the past two decades.” "Gilles Oliver, a specialist at Atmo, the organization that took over last year from the former National Aerological Monitoring Network (RNSA) responsible for monitoring pollen and atmospheric mold spores, testifies.