UW Medicine: Climate change causing longer allergy seasons

A growing body of research indicates climate change is making allergies worse, with local experts saying allergy seasons are starting earlier and pollen counts are continuing to increase.

Allergy season arrives early across the Pacific Northwest

“We see that allergen season is starting earlier, pollination counts are getting higher earlier and lasting longer,” University of Washington Medicine’s Dr. Jenny Sun said. “There’s not only a longer allergy season but also more overlap between, say, grass pollen season and tree pollen season.”

Sun said climate change is a big factor. “So all those things combined together can make allergies a little more difficult to bear.”

With longer days, more sunshine, and warmer weather, grasses and weeds will then replace tree pollen and offer their own pollen later this spring, heading into summer.

Studies have shown that since the 1950s, summer is now three weeks longer worldwide, with the fall, winter, and spring seasons all shorter in length.

Research published in the Proceedings of the National Academy of Sciences (PNAS) shows the effects of climate change are lengthening allergy seasons by increasing pollen concentrations.

In addition, wildfire smoke can irritate the eyes and respiratory systems of people with allergies.

“We do know that smoke pollution, in general, can cause increased irritation, especially in the nasal lining and the linings of the eyes, things along that line,” Sun said. “So especially for someone who’s prone to these symptoms or has these symptoms at a baseline, having exposure to irritants certainly isn’t helpful, and if anything, can make symptoms worse.”

Even though many suffer allergies during spring and summer, western Washington has a significant advantage when it comes to seasonal allergies – rain. Rain washes away pollen in the air, offering great relief to allergy sufferers. But when it comes to where to live to reduce allergy sources, this region is number one in the country. The 2023 Asthma and Allergy Foundation report reviewed data from 100 cities across the United States, and the Seattle area is ranked at the top of all those cities.

In fact, all but one of the top 10 cities in the nation is in the western third of the country. The worst city in the report was Scranton, Pa., and joined many other cities from the Central Plains states and Texas eastward to the Northeast.

When North Sound weather does get warmer and drier, pollen counts rise. The Northwest Asthma and Allergy Center posts daily pollen counts, including the most common offending pollen contributors. The next rainy or even windy day will reduce pollen in the air and offer allergy relief.

So what can you do to prevent these worsening allergens?

Dr. Sun has some ideas for allergy sufferers to minimize how much pollen they are exposed to that could be triggering their allergies.

“We focus on things like not bringing pollens into the home. So, taking off shoes when you’re entering the home and not opening windows for long periods of time, especially during peak allergy season, are all things that will help not bring pollen into the house,” Sun said. “And also, pollen loves to stick to the hair. So, if you’ve been outside for a long period of time, I always advise patients to wash their hair or wear a hair cap before going to be at night.”