Rising pollen levels pose deadly risk for older adults

As climate change intensifies pollen seasons across the country, new research from the University of Michigan reveals a connection between pollen exposure and death rates among older adults with breathing problems.

The study, published in BMC Public Health, shows that high pollen days aren’t just an inconvenience for allergy sufferers—they could pose serious health risks for vulnerable populations. With pollen seasons growing longer and more intense, understanding these risks has become increasingly urgent for public health officials and health care providers.

The study found that high levels of certain pollen, particularly from deciduous trees and ragweed, were linked to increased risk of death from breathing problems. The effects could last up to two weeks after exposure.

The findings suggest that exposure to certain types of pollen can increase the risk of death from breathing-related problems, particularly for people with chronic conditions. This is especially concerning given expectations that climate change will exacerbate the severity of pollen seasons in coming years.

“As pollen levels continue to rise and seasons get longer, more people may face serious health risks, especially older adults with existing breathing problems,” said Peter Larson, Ph.D., first author of the study and a research investigator in the Department of Epidemiology at the School of Public Health.

To study the connection between pollen and serious health risks, researchers from U-M’s School of Public Health, Institute for Social Research and College of Engineering analyzed death records in Michigan from 2006 to 2017, focusing on deaths related to breathing problems.

They looked at four types of pollen: deciduous tree pollen from trees that lose their leaves, evergreen tree pollen, grass pollen and ragweed pollen.

Using advanced computer models, they estimated daily pollen levels across Michigan and studied how exposure to high pollen levels affected death rates over different time periods, from same-day effects to up to two weeks later.

While not everyone is equally sensitive to pollen, the findings highlight the importance of tracking pollen levels and taking precautions during high pollen days, especially for older adults with breathing problems, the researchers say. And, they add, with predicted climate change, preparing for the risks will be increasingly important for public health.

Additional authors: Allison Steiner, U-M College of Engineering; Marie O’Neill and Carina Gronlund, U-M School of Public Health; Alan Baptist, U-M School of Public Health and Henry Ford Health.

Study: Chronic and infectious respiratory mortality and short-term exposures to four types of pollen taxa in older adults in Michigan, 2006-2017 (DOI: 10.1186/s12889-025-21386-3)