ReportMarch 8, 2023

Seasonal allergies: pollen and mold

Millions of Americans suffer from seasonal allergies each year, and climate change is making it worse.

About one-quarter of adults (26%) and 19% of children in the U.S. suffer from seasonal allergies, according to the Centers for Disease Control and Prevention. Seasonal allergies, such as “hay fever,” are allergic reactions caused by airborne plant pollen and mold spores.

A growing body of research shows that warming temperatures, shifting seasonal patterns, and more carbon dioxide in the atmosphere—all linked to climate change and greenhouse gas emissions—are affecting the length and intensity of allergy season in the U.S.

Allergies are more than just inconvenient—they are expensive to manage and can have significant health implications, such as triggering or worsening asthma. But there are ways to mitigate the impact of allergies in a changing climate.

This research brief provides background information and summarizes Climate Central’s relevant analyses on weather and climate trends that affect allergy season locally. These resources can help explain and report on the growing health risks of outdoor aeroallergens and their connection to climate change.

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