[Ambrosia pollen under high surveillance].

Area of Science:

• Environmental science
• Allergology
• Meteorology

Background:

• The 2003 summer meteorology significantly impacted the ragweed (Ambrosia) pollen season.
• Allergenic risk from ragweed pollen is a growing concern in several French regions.

Purpose of the Study:

• To analyze the spatial and temporal distribution of ragweed pollen allergenic risk in 2003.
• To investigate the daily patterns of pollen peaks and long-term trends in allergic risk.

Main Methods:

• Analysis of meteorological data and pollen counts from various regions in France.
• Monitoring of daily ragweed pollen allergenic risk levels (risk >= 3).
• Long-term data analysis of ragweed pollen risk in Lyon since 1987.

Main Results:

• Rhône-Alpes experienced over 40 days of high allergenic risk (>= 3).
• Peripheral areas like Centre Auvergne, Saône-Savoie, and the Mediterranean region also reported significant days with high risk.
• The 2003 season had lower peak intensities but was prolonged until September 20, with diverse daily pollen peak timings across regions.
• Long-term data from Lyon showed a stagnation in high-risk days despite reduced pollen counts.

Conclusions:

• Meteorological factors heavily influence seasonal ragweed pollen distribution and associated allergic risk.
• Regional variations in daily pollen peaks highlight complex atmospheric transport dynamics.
• Long-term monitoring suggests a complex relationship between pollen concentration and the number of high-risk days for allergies.