Program: Lab Notes: Why your hay fever will get worse with climate change

Belinda Smith: It's September and spring is here. For much of the country, the wattles are blooming, magpies are swooping and the days are getting a little bit longer. But for millions of Australians, the warmer months also bring… Hay fever. Red, itchy, watery eyes, runny nose, lots of sneezing and maybe a bit of wheezing. And I'm sorry to say, but our hay fever future under climate change does not look good. Hi, I'm hay fever sufferer Belinda Smith and you're listening to Lab Notes on ABC Radio National, where every week we dissect the science behind new discoveries and current events. To explain why global warming will continue to wreak havoc on my nose and throat is Kira Hughes, who studied airborne allergens like the ones that cause hay fever for her PhD.

Kira Hughes: So do you get hay fever? I do, unfortunately. I actually got an allergy test recently, one of the skin prick tests, and they tested me for pollen and nuts. And I was actually more allergic to the pollen than nuts, which I currently have an EpiPen for. Wow! Yeah, my arm actually swelled up so much from the pollen that I couldn't move it for two days.

Belinda Smith: Wow. OK, so you not only do you study it, but you suffer it as well. I do,

Kira Hughes: unfortunately. Which, you know, lets me put a lot of my disdain for allergy into my work.

Belinda Smith: So, you know, I get hay fever as well. We're an N of two. How many people do get hay fever?

Kira Hughes: It's actually very common in Australia. So recent studies have put it at around one in four Australians that suffer from it. You know, you've got a high chance of having hay fever if you're in Australia, unfortunately. And

Belinda Smith: in terms of what we can expect for hay fever down the track, like, will that one in four remain steady?

Kira Hughes: It will not, unfortunately. So if you look at the Australian Bureau of Statistics, they do a lot of testing on how many people report allergy and hay fever symptoms over the years. And the most recent one back in 2022 was, you know, about 25% one in four Australians. And about 15 years ago, about 2008, it was about 15% of Australians. That's quite a big jump. It is a big jump. We don't see that with asthma. Asthma is usually pretty steady. It's currently around 11%, which is one in nine Australians. But the increase in hay fever is pretty alarming because it means more people are getting sensitised to pollen in the air and experiencing more frequent and potentially more severe symptoms.

Belinda Smith: One thing that climate change will do is it will affect what grows, where and how it grows. So what can we expect with a future under climate change when it comes to hay fever?

Kira Hughes: I have only bad news, unfortunately. So there's already been a lot of studies looking at the last couple of years when it comes to hay fever rates, when it comes to pollen production, when it comes to pollen seasons. And all of them are pretty bad outcomes. In the US, for example, and they found that the pollen season has been increasing by days or even weeks at a time. So it's starting earlier and ending later, which means the plants are going to be producing more pollen more often because of changes in weather. It's also becoming a lot warmer, potentially a little bit drier when we get into the warmer seasons, too, which is when plants like to produce their pollen. And they've even found that increases in pollution could also be making the pollen more allergenic. So remember like how I mentioned before that grass pollen has those tiny particles inside of it? They're basically just proteins inside of the pollen itself. And they found that if you introduce or expose pollen or even other allergens like fungal spores to, let's say, increase carbon dioxide levels, they should produce more of those proteins.

Belinda Smith: Oh, great. OK, so not only are they growing more pollen, but what's inside, there's more of those proteins inside each pollen grain or granule.

Kira Hughes: Yes. Great. Good. Which, you know, is very unfortunate, especially as a very severe hay fever sufferer. It's not a very good outcome. And even additionally as well, as we're going to likely talk about thunderstorm asthma soon, there's been reports of more extreme weather events happening due to climate change, which could potentially result in more thunderstorms.

Belinda Smith: And, you know, you were saying that grass is the main culprit here when it comes to hay fever, but mould spores can also trigger hay fever. I imagine in terms of extreme weather floods and things that might mean more fungi as well,

Kira Hughes: perhaps? Yeah, yeah, definitely, potentially. So, like, there's a lot of different types of fungi out there, but a lot of them tend to like very wet, damp conditions. And mostly when you think about mould, you mostly think about, like, you know, the one that might be growing in your home behind the walls, under the carpet.

Belinda Smith: The pink one that grows in my shower.

Kira Hughes: Exactly. Same in my sink. My landlord didn't hear that. But an interesting thing is that they've looked at the diversity of mould inside the home and almost all the time that mould comes from outside. So, those spores are somehow finding their way inside the home and that could be through, you know, like windows. If you leave the fireplace open through the chimney, it could be coming through the door. So, all this mould is coming inside the house and then releasing these spores. Because there's a lot of fungi that exist outside. A lot of common ones when it comes to hay fever, there's a species called Altenaria and it's a plant blight. So, it grows on crops. It's a bit of an agricultural pest and it accounts for up to 13% of fungi allergy worldwide.

Belinda Smith: Wow. OK. It feels like you did warn me that this is all going to be bad news. But it just seems like everywhere we turn, it's like, ah, more bad news. And in terms of where grasses will grow under climate change, you hear about, you know, plants shifting their range because maybe they can grow further south or further north or whatever. Like, are we going to expect to see that happening as well?

Kira Hughes: Potentially. So, they love when it's wet because that means that they get to grow more. And we've had a lot of wet winters recently. And what we've seen when we have a particularly wet winter, we get more grass. And that means when we get into spring, we tend to get more pollen. Either it becomes more frequently, so earlier in the season, or even our peaks are higher than usual as well. Which we're going to potentially see that increase. An increase, especially crops like ryegrass, is also an agricultural crop. We have a lot of it up north in Victoria. We have, you know, some in New South Wales as well. And, you know, grass is also just a very common plant. It's everywhere. It is everywhere. And unfortunately, because of that cross reactivity between so many of these species, you're not really going to be safe, unfortunately. The risk of cross reactivity, I think, is in the high 90s

Belinda Smith: for some of these. Oh, my goodness. Right. Yeah. Okay. Well, look, we live in Melbourne, which has the dubious honour of being the thunderstorm asthma capital of the world, along with a few other capitals of the world. So, just, you know, what is thunderstorm asthma?

Kira Hughes: The basic definition is it's a particular event where there's a high amount of pollen or other allergens during a thunderstorm. And what happens is the thunderstorm will suck up all of those allergens in the air. And then while it's inside of it, breaks it up into those tiny pieces I discussed before. And then the downdraft of the storm will push that out at ground level, exposing it to very vulnerable hay fever sufferers like we have here in Melbourne. And because it's usually pushing out a tonne of these highly concentrated, highly allergenic particles, it can cause people to have sudden and severe asthma attacks, even within 15 minutes of breathing it in. And if we look back at events in the past, like what we saw in Melbourne in 2016, we saw thousands of people hospitalised in a single night from this event. And unfortunately, 10 people passed away from it because we just weren't prepared for how severe or catastrophic of an event this was.

Belinda Smith: And so many of those people had never had asthma before. If

Kira Hughes: you look back at the data from all the people that were hospitalised, the people that had asthma only made up maybe like a third of people that were hospitalised. Or potentially, like those were the only people that had a history of asthma. They, you know, maybe could have been undiagnosed at the time. But almost 100% of people that were hospitalised either had hay fever or were sensitive to grass pollen.

Belinda Smith: What can the average hay fever sufferer do to prepare for that kind of thing?

Kira Hughes: There's a couple of different ways that you can prepare yourself for a future event. That could be talking to your GP, setting up an asthma action plan if you don't have one in place. Only about a third of asthma sufferers actually have an asthma action plan in place. Making sure you have access to asthma medication if you do suffer from it. And also just making sure that you know how to use it properly. Do you want to guess what percentage of asthma sufferers actually know how to use their medication properly? Oh, it's going to

Belinda Smith: be horrifically low, isn't it? I don't know, maybe 12%? Six.

Kira Hughes: No! Yeah, the Asthma Council estimates that 94% of people do not know how to use their asthma medication properly.

Belinda Smith: Whoa, okay. Yes,

Kira Hughes: which is alarmingly high. That could be maybe people haven't used it in a while, that maybe they were taught as a kid and, you know, haven't used it properly. So always good to check with your GP and pharmacist that you're actually using your puffer properly. Make sure you're taking your medication at the correct time as well because there's a lot of different forms of asthma medication out there. And if you're a hay fever sufferer, make sure you have medication that works for you. That could be antihistamines, nasal sprays. In terms

Belinda Smith: of research, how seriously are scientists taking hay fever?

Kira Hughes: Yeah, it's a big issue and especially with thunderstorm asthma now being, you know, at the front face of public health since the 2016 event, we're putting a lot more energy and a lot more focus into understanding why these events occur and also better ways to actually monitor them as well. So across Victoria, we have set up a pollen monitoring system. We've got eight stations across the state and there's a couple as well set up in different states across Australia. There's ones in WA, in Canberra, New South Wales, for example. So you should be able to find one, hopefully online. It will usually be the Sydney, like, you know, Sydney pollen or Melbourne pollen. And when spring rolls around or when your pollen season is happening, it will estimate how much pollen will be in the air for the next 24 hours. But it will also tell you the thunderstorm asthma risk as well in your area. And that can be particularly important because that could potentially give you a lifeline to tell you, hey, maybe you don't need to spend so much time outside today. Take your medication just to be safe or carry it on you. Even if you do need to go outside, I always recommend people wear face masks as well because it can help reduce the allergens that you breathe in. And a lot of my research has been looking at the machines that we currently use for these monitoring systems and figuring out better ways that we can improve on them.

Belinda Smith: That was aerobiologist Kira Hughes. And thank you for listening to Lab Notes on ABC Radio National, where every week we dissect the science behind new discoveries and current events. I'm Belinda Smith. This episode was produced on the lands of the Wurundjeri and Menang Noongar people. Fiona Pepper's the producer and it was mixed by Angie Grant. We'll catch you next week.