Why your hay fever symptoms are getting worse

Spring brings warm weather — and peak allergy season — which means more intense hay fever symptoms for many people.

Climate change is contributing to rapidly rising spring temperatures, more frequent extreme heat events and heavier rainfall, according to Climate Central.

Those shifts, driven by human-caused greenhouse gas emissions, are leading to longer growing seasons and more volatile weather patterns. Climate Central is a nonprofit climate reporting organization.

How climate change affects hay fever

Climate change is worsening hay fever symptoms in several ways, according to the Centers for Disease Control and Prevention and other health experts:

• Longer pollen seasons: Warming temperatures cause plants to flower earlier in spring and persist later into fall, extending pollen seasons by weeks in many regions.
• More potent pollen: Higher carbon dioxide levels and warmer conditions cause plants to produce more pollen — and pollen that is often more allergenic.
• Increased exposure: As pollen exposure increases, so do allergy symptoms, diagnoses and health care use.
• Worsening air pollution: Climate change contributes to higher levels of air pollution, including ozone, particulate matter and wildfire smoke, which can amplify allergic responses.
• More severe symptoms: Heat-driven ozone formation and wildfire smoke are increasingly linked to more severe allergic rhinitis and asthma symptoms.
• Expanding plant ranges: Climate shifts allow allergen-producing plants to thrive in regions that were previously too cold.

More than one in four U.S. adults have seasonal allergies, and many are experiencing more severe symptoms — including sneezing, congestion and itchy eyes — as climate change alters pollen patterns.

Hay fever, also known as allergic rhinitis, occurs when the immune system reacts to allergens such as pollen, according to the CDC.

Human allergic responses to pollen — including hay fever, allergic rhinitis and pollinosis — represent a serious environmental health issue, according to research from Harvard University. Pollen exposure also contributes to asthma flare-ups, and the prevalence of both hay fever and asthma has risen significantly in recent decades.

The CDC advises allergy sufferers to check daily pollen forecasts, limit outdoor activity on high-pollen days and monitor climate-related health changes to help manage symptoms.

This reporting content is supported by a partnership with Journalism Funding Partners.

Erica Van Buren is the climate change reporter for The Augusta Chronicle, part of the USA TODAY Network. Connect with her at EVanBuren@usatodayco.com or on X: @EricaVanBuren32.