(CNN)Allergies aren't just a sneezy seasonal annoyance.
Hay fever has major health and economic consequences. It exacerbates asthma and weakens defenses against respiratory viruses, resulting in more emergency room visits and disrupted schooling and work.
Climate change has already made pollen seasons in the United States and Canada worse, a new study of almost three decades' worth of data has revealed. The pollen seasons are getting longer and more intense.
The amount of time people in North America are exposed to pollen as well as the amount of pollen had "increased significantly" in recent decades, according to the authors.
The researchers looked at different pollen metrics between 1990 and 2018 from 60 monitoring stations across North America. Pollen seasons were starting up to 20 days earlier and lasting for up to eight days longer, the scientists found.