You're not crazy. Allergy season is getting worse. | The Excerpt
On a special episode (first released on April 10, 2025) of The Excerpt podcast: It’s allergy season and that means sneezing, coughing and itchy eyes for many. If you’ve wondered if your allergies are getting worse, you’re not alone. New research shows that pollen season is getting longer and more intense. But why? Lew Ziska, associate professor at Columbia University and a co-author of a new study on pollen, joins The Excerpt to share the science behind an intensifying allergy season.
Let us know what you think of this episode by sending an email to podcasts@usatoday.com.
Hit play on the player below to hear the podcast and follow along with the transcript beneath it. This transcript was automatically generated, and then edited for clarity in its current form. There may be some differences between the audio and the text.
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Dana Taylor:
Hello and welcome to The Excerpt. I'm Dana Taylor. Today is Thursday, March 10th, 2025, and this is a special episode of The Excerpt.
Spring is here and that means that we're sneezing, itchy eyes and noses and congestion that define allergy season. If you're one of those who suffer from seasonal allergies, you might've noticed that it seems to be getting worse with each year. Even if you didn't suffer regularly from pollen allergies in the past, you might've noticed that you are now. Turns out pollen allergens are getting worse. The question is why? To help us understand all the forces at play and what we can do to minimize our suffering is Lew Ziska, associate professor at the Mailman School of Public Health at Columbia University. Thanks for joining me, Lew.
Lew Ziska:
I'm happy to be here.
Dana Taylor:
You recently co-authored a study that looks now climate change is impacting allergy season here in North America. Tell me what you found.
Lew Ziska:
We've been looking at the role of changing winters. The winters are becoming more mild and that they're starting later, and spring is starting earlier and falls are being delayed. That increase in the frost-free season is allowing greater exposure of plant-based pollen to people who are allergic to that pollen. So with that change in seasonality, in addition to changes in carbon dioxide and other things that make plants grow more, we're seeing an increase in the overall amount of pollen, but also the time in which you are exposed to that pollen. So we think those are two of the underlying reasons why the pollen season is becoming more severe.
Dana Taylor:
It makes sense that with longer periods of warmth, plants have longer flowering seasons, but climate change also affects the range of where plants can grow. How are plants able to move into new environments?
Lew Ziska:
That's a very good point, and yes, they are. One of the things that we use as sort of a model for this is we looked at an urban environment. Urban environments are often called heat sinks because they're warmer than the surrounding area. And so we began by planting ragweed, which is a pollen source that everyone is familiar with, but we planted ragweed in a rural area, in a farm, and then we put the same ragweed in the same soil along this transect from the farm to downtown Baltimore. And what we found doing so was that the warmer temperatures in Baltimore, the longer growing season in Baltimore, the increased carbon dioxide in Baltimore allowed for an average ragweed plant to produce 10 times more pollen in that environment than it did out in the rural environment.
So it's something that we think is having a direct effect in regards to the amount of pollen that you're being exposed to, but that rural to urban transect is sort of a harbinger, if you will, of things to come with respect to climate overall. In addition, we also looked at, for the Northern Hemisphere, different pollen sets that we obtained from really dedicated allergists and botanists throughout the world, and seeing that in recent, the last 20 years or so, that what we were seeing at the city level is also occurring globally, at least for the Northern Hemisphere.
Dana Taylor:
One factor in how bad allergies are is the concentration of allergens. How has the concentration of pollen in the air changed over the years?
Lew Ziska:
We're seeing increasing changes with regard to the three stages of plant-based pollen. In the spring, it's primarily trees. In the summer, it drops off, but it's still there in terms of grasses and weeds. And then in the fall, it picks back up again with respect to ragweed, which is the primary pollen producer at that time. And what we're seeing is the concentrations are increasing, particularly in the springs and again in the falls in regard to the amount of pollen. And also we're seeing that if you have storms that occur at that time, particularly lightning storms, what it can do is it can break the pollen apart. So it's not just one bit of pollen, but it's lots of little bits of pollen that in turn can inflame your lungs and make it even worse. So those are the things that we've observed so far.
Dana Taylor:
I wanted to ask, how do longer and more intense pollen seasons impact public health, particularly respiratory health?
Lew Ziska:
Well, they obviously have an effect in regard to undermining respiratory health, making it much more difficult. I know for myself, one of the things I always carry with me and I have since I was a teenager is my inhaler, my rescue inhaler. In part, I guess I chose the wrong profession, but this is something that can really be an effect in regard to how it feels. When you have somebody standing on your chest and it's hard to breathe, it's not very pleasant. And so we want to have this be recognized as an impact with regard to your respiratory health, but also recognize that there are ways and means in which to deal with it.
Dana Taylor:
What groups of people are most affected by the changes in pollen season?
Lew Ziska:
Particularly young individuals and elderly are the most effected.
Dana Taylor:
What are some potential solutions or actions that can be taken to mitigate the impact of climate change on pollen seasons?
Lew Ziska:
One of the things that we can do, at least at the local level, is to begin to do a better estimate of when the pollen is coming about so we're prepared. But one of the ways to prepare is to make sure that you can close your windows, make sure the pollen isn't coming in, having HEPA filters within your home to process the air. And for myself, one of the things I do, particularly during high pollen season, is to wash my clothes more frequently, because often when I'm outside, I get a lot of pollen on my clothes, and then I start breathing it in. So I try to wash my clothes a little more frequently.
Dana Taylor:
And how can individuals with allergies or respiratory conditions manage their symptoms during longer pollen seasons?
Lew Ziska:
When you look at the symptomology and the effects of that, one of the things, of course, is to work with your doctor in terms of the medication that you need to take, whether or not you need to wear a mask to prevent large inhalation of pollen. There are a number of things that pharmacology and modern science and medicine can do to help in that regard.
Dana Taylor:
Lew, what's next for your research here?
Lew Ziska:
Well, yeah, they've cut all funding, so it's hard to know what the next steps are going to be. One of the things we'd like to try and do is to look at the secondary effects of breathing in pollen, particularly in regard to the immune system. One of the things that pollen can do is to stimulate your epithelial cells in terms of your respiratory pathway, and by doing so, it may actually increase your susceptibility for airborne viruses. There was some work that we were doing looking at how things like COVID and other airborne viruses could be impacted by pollen and the effects that pollen has on your immune system. That's something we think is important. We'd like to know more about it. That would probably be the next thing on my list of research topics.
Dana Taylor:
Thank you so much for being on The Excerpt and for sharing your important research, Lew.
Lew Ziska:
Thank you very much. We hope that this is something that we can do for folks who suffer like myself from allergies and asthma.
Dana Taylor:
Thanks for our senior producers, Shannon Rae Green and Kaely Monahan for their production assistance. Our executive producer is Laura Beatty. Let us know what you think of this episode by sending a note to Podcasts@USAToday.com. Thanks for listening. I'm Dana Taylor. Taylor Wilson will back tomorrow morning with another episode of The Excerpt.