North American Pollen Season Lengthens 20 Days as Counts Rise 21% From Climate Change
Updated
Updated · The Gardner News · Jun 18
North American Pollen Season Lengthens 20 Days as Counts Rise 21% From Climate Change
1 articles · Updated · The Gardner News · Jun 18
Summary
A 2021 study found North America's pollen season grew 20 days longer from 1990 to 2018, while pollen counts climbed 21% over the same period.
Experts cited human-driven warming and higher carbon dioxide levels for extending growing seasons and boosting plant reproduction, which increases pollen output and worsens respiratory health risks.
Massachusetts allergists said 2026 may feel especially intense locally because a colder-than-normal May delayed tree pollen release, potentially concentrating exposure when it arrived.
Seasonal allergies already affect 1 in 4 U.S. adults and 1 in 5 children, with annual medical costs topping $3 billion; doctors recommend antihistamines, nasal steroids and limiting outdoor exposure on high-pollen days.