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COVID-19, Pollution & Worsening Allergy Seasons: How Much More Can We Take?

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Dr. Adler: Hi everyone and welcome to today's live event, COVID-19, pollution, and worsening allergy season - how much more can we take? Before we get started, just a few housekeeping items: this webinar will be recorded and sent to you after the event. Go ahead and find the Q&A button. Feel free to send in your questions as they come to you throughout the chat. We'll have time for Q&A in order to answer as many questions as possible at the end of the webinar. If we do not answer your question someone will follow up with you directly.

So for those of you joining us for the first time, BreezoMeter provides the world's most accurate environmental insights for more than 90 countries worldwide and down to a five-meter great resolution. So let's get started. I'll introduce myself: my name is Gabriela Adler, I'm BreezoMeter’s chief scientist. I'm an atmospheric scientist by training and before joining BreezoMeter I worked at the national oceanic and atmospheric administration as a researcher. 

I'm really really excited to be hosting Dr.Daniel Katz today who is a postdoc at Dell Medical School, the University of Texas at Austin. He's an ecologist and an aerobiologist and creates process-based models of airborne pollen to inform plant management in cities and basically a pollen modeling expert, and we have this great opportunity to ask him a bunch of questions about pollen. So hi, Dan, welcome.

Dr. Katz: Hey thanks, for having me on. A pleasure to be here.

Dr. Adler: Okay so, before we jump into the questions that we have prepared, we have some attendees who are more from the business arena rather than scientific, so I was wondering if you could explain in more layman's terms the work that you do and tell us a little bit about yourself.

Dr. Katz: The work that I do is to create predictions of airborne pollen concentrations at any particular time and place. The way I approach that is through understanding the ecological and biological processes that result in pollen being in the air, things like where plants are, how much pollen they're producing, and when they release it. So that's what I do in a nutshell.

Dr. Adler: Sounds super interesting actually. So let's start with the basics before we jump into the questions about pollen. What is pollen and why is pollen a problem for the health of so many people?

Why Pollen Impacts Health 

Dr. Katz: Yeah, so pollen is an important part of plant reproduction. it's the male gamete, but in layman's terms, you might think of it as the plant equivalent to sperm. So a lot of plants release pollen into the wind and that just gets blown around. From the plant’s perspective, this is great because it allows the pollen to go from the male flower to the female flower and fertilize it so the plant can produce seeds. From the human perspective, this can be a bad thing because when we breathe pollen in for some people it can trigger allergic reactions. So if you've ever heard of hay fever or allergic rhinitis, that is an allergic reaction that can be caused by pollen.

Dr. Adler: Yeah so I think a lot of people when they think about pollen, they think about beautiful flowers, but what we're actually talking about is not the flowers that have been pollinated by bees but rather by the wind.

Dr. Katz: Exactly right, and so pollen is produced by all of these plants whether they are pollinated by insects or birds or the wind. Now the ones that are pollinated by insects and birds and other animals, those tend to be really showy, those have those bright colors to attract their pollinators, they're what you think of when you think of a flower. But those are not the things which are causing people's allergies, because their pollen is just on those insects. It's the plants that just release that pollen into the wind that is the one that has allergic importance because these plants can produce literally billions of pollen grains in a single year, and that's just floating through the air and that's how people become exposed to it.

Dr. Adler: So basically the less beautiful flowers are more important to us that's what you're saying.

Dr: Katz: Exactly so when you look around you look at a field and there's a bunch of flowers in it that you notice then you don't have anything to worry about. It's when they are small green nondescript things hanging down from the plant that's when you might actually have some concern.

Dr. Adler: Okay. So a lot of people know that pollen exists and they're affected by pollen but they're less aware of the different types and species of pollen. So can you tell us a little bit about that?

Dr. Katz: Yeah I’d be happy to. There are so many different kinds of plants out there and the way that aerobiologists and the people who study pollen usually divide this up is into trees, grasses, and weeds. So trees tend to release pollen in the springtime at least in more temperate northern climates. Then grasses usually release pollen in the summer, and weeds usually release pollen in the summer and fall. But the thing is, different plants live in different places and so what happens in one part of the world is going to be different from what happens in another part of the world because the plants in each spot are adapted to local climate conditions.

Pollen Seasons Change According to Location

Dr. Adler: So you're saying that, for example, grass in, I don't know, in a place in the US will not have the same season as in Europe in a different place right?

Dr. Katz: Yeah it could be. So for example the species that I’m working on in my current postdoc down in texas it's a tree, but it's just getting ready to release pollen over the next month or so in December and January, versus some of its close relatives and say the eastern united states release pollen in the springtime. So there are differences between plants. I think that ultimately if we're going to create models of airborne pollen concentrations we need to understand what the plants in each of these places are doing.

Dr. Adler: Right. And are there any, I mean, can you talk a little bit about the subspecies of pollen, so for example, you mentioned trees and grass and maybe weed but are there different seasons to different trees for a specific location for example?

Dr. Katz: Yeah yeah totally. This really varies on a species-by-species basis. So the juniper trees that I’m studying here release pollen at different times according to which species it is. But there are those general trends. In temperate climates, the trees tend to release pollen a lot east earlier in the year and grasses often release pollen in the middle of the summer.

Dr. Adler: I think this is really interesting because I think often people, when they suffer from allergic reactions, in the spring they think, okay that's pollen. But if it's going to be later during the year or even in the fall they would not think that it's related to pollen, right? And what you're saying is that it could be.

Dr. Katz: Yeah entirely. For seasonal allergies, which are often caused by pollen, it can happen whenever there's pollen in the air, and there can be pollen in the air a good chunk of the year depending on where you are. A general rule of thumb is that if it's very cold out and plants are dormant then there won't be much pollen in the air. Although there are occurrences of long-distance transport of pollen and so there are times when you can have allergic reactions even when the plants around you aren't releasing pollen. Another layer of complexity.

How Far Can Pollen Travel?

Dr. Adler: Yeah definitely. Do you want to tell us a little bit about that, like how far would you know pollen is traveling? Should I be worried about a plant that is, I don't know, 10 kilometers away?

Dr. Katz: Well that certainly can happen. People have recorded pollen in the middle of the ocean. Pollen has the potential to disperse thousands of kilometers. That being said the vast majority of pollen that's in the air is from plants that are very close by. And so in general the plants which are within maybe a kilometer of you are the plants that are going to be causing most of your symptoms. There are exceptions but overall those exceptions are rare.

Traditional Pollen Monitoring Challenges

Dr. Adler: Okay so let's move into how we actually measure or model pollen. So in your experience what are the challenges and limitations in both pollen measurements and modeling and what is the current situation with that?

Dr. Katz: There are a few devices that have traditionally been used to monitor pollen. These devices are called Burkard samplers, and then there are Rotorod samplers, and these are devices that have been used to monitor pollen for the last 70 years, give or take a bit. The problem is that these devices require somebody to take this sample and then look at it under a microscope to manually identify what types of pollen are in the air. This is very labor-intensive and it takes a lot of expertise to identify that pollen. So over the last several decades, most pollen monitoring has been done by experts in pollen monitoring networks. 

In the United States, there's the national allergy bureau network which has about 80 stations. In the European aeroallergen network, there are substantially more stations than that, but even so, there's usually only one station in a metro area, and in many parts of the world there are far fewer stations than that. So for me what I see as the grand challenge is moving from the system of monitoring networks to using that data as well as other information about plants in order to create models of airborne pollen that take into account all of the relevant ecological and biological and atmospheric processes. 

Because I don't think these monitoring networks are ever going to achieve the density that we would need to tell an average person on the street how much pollen they're exposed to in their day-to-day life. In that way, I think we're kind of paralleling some of the trajectories that the air pollution world has taken to go from a fixed monitoring network with fairly sparse and expensive monitors down to models which do a good job of predicting how much of the air pollutant or in this case the pollen is in the air.

Dr. Adler: Right. So let me try to kind of summarize. What you're saying is that measurements are important but they're not enough at least in the current situation that they're very sparse and they're basically also based on the expertise of different people. Do they have a lag in time? In air pollution you don't need to look under the microscope it's more real-time and so in pollen, you're saying that you need someone to look at it so I’m guessing it's less real-time right? That you have more lag?

Dr. Katz: Yeah. So if you're looking at a media source that is reporting pollen concentrations from a station I’ve got bad news for you: those measurements are actually from the previous 24 hours because they had to have the device collecting pollen and then they take that sample and they analyze it. 

So yeah, it's an integrated sample over the previous 24 hours in the best case for when you're dealing with actual pollen measurements. So there is a lag there. There are a few developments in the field. Some people, including at the company Pollen Sense, are developing more real-time and automated pollen monitoring devices. So there is some possibility to move to a more real-time system but we are not there yet.

Dr. Adler: And what you're saying is that pollen can change from one location to the next and having one station in the entire region is just not enough.

Dr. Katz: Exactly. In some of my research, what I’ve seen is that pollen concentrations can vary by, literally, orders of magnitude when you're just going from one kilometer to another in a city. And that makes sense right? Because what plants there are in a neighborhood varies dramatically and since most pollen in the air is from the plants that are very close by it makes sense that what we measure on one rooftop in a metro area is not going to be representative of the entire city. 

Then given that most cities don't even have their own pollen monitoring station, it means that, yeah, what we get from that one empirical measurement source, it's very important, but it's not necessarily doing a good job of telling you what's in the air around you at that moment and it's doing an even worse job of telling you what is going to be in the air over the next 24 hours as you plan your day. If this was a weather forecast you'd be trying to decide whether you take your umbrella with you and we're just telling you what it was like yesterday.

Different Pollen Sensitivities

Dr. Adler: I like this comparison. Really nice. So let's jump into how it affects people’s sensitivity, so maybe you can tell us a little bit more about the sensitivity of different types of pollen? Are there trees, let's say, that are the bad guys in the forest that affect more people? Maybe crossover genetics between different types of pollen?

Dr. Katz: Yeah. Let me break that down into a few different parts. First of all, yeah there are some types of plants that release far more pollen than others. So for example, for trees, there are a few especially bad offenders and things like male white Mulberry trees are especially bad. They just produce such large quantities of pollen compared to other types of trees. 

There are also certain plants that produce pollen that is more allergenic on a pollen grain by pollen grain basis. So there are some worst offenders. The good news about that though is that it means that by understanding the science we can potentially go after those worst offenders and do something to reduce pollen loads in cities.

To answer some of your other questions about cross-reactivity: in general, pollen from species that are closely related it's likely that if somebody is sensitized to one type of pollen then they'll likely be sensitized to pollen from very closely related plants. But there's also all of these unexpected cross-reactivities because it turns out that some of the proteins that are in particular pollen grains are actually very similar on a molecular level to proteins that are in only very distantly related things. And so we sometimes see cross-reactivity between certain types of pollen and certain types of food. 

For example, there's a connection between allergies to birch pollen and apples, just as one example. It gets complicated and very interesting very quickly.

How Individuals Can Minimize Pollen’s Impact

Dr. Adler: Okay. What do you think people can do to manage their allergic symptoms, what actions can they take or how can we defend ourselves?

Dr. Katz: That's a great question. Right now people have a few options. They can buy over-the-counter medication, antihistamines. These work great for many people, but it doesn't always control somebody's symptoms completely, so it's very useful but it's not a magic bullet for everybody. Some people can go to an allergist and get immunotherapy, which changes how a person's immune system reacts to pollen.

The Need For Personalized Pollen Forecasts

So these are what has traditionally been done. People go to allergists, they get immunotherapy or they get allergy medication. What has not traditionally been done is thinking about how to reduce a person's exposure, and I think there's a lot of exciting possibilities there about how we can do a better job of that. 

Fundamentally, I think that if we had better estimates of how much pollen was in the air and if we could figure out what kind of personalized forecast people could use that information to make decisions that reduce their own exposure. So for example, if there's a pollen hot spot right around you on a particular day, maybe on that day you should stay inside and close your windows things like that.

But it can also be useful for managing medication because a lot of these allergy medications, they take a little bit of time to kick in like a day or so. And so giving somebody a warning ahead of time can help them to take their medication in a timely fashion so that's already activated by the time they're exposed. I think more information is more power, and this is something that frankly in my opinion we as a field have not done very well so far. Because when somebody looks at pollen concentrations on the news, what they usually see is just a total pollen concentration and most people don't even know what particular species they're allergic to. 

So I envision a future where somebody can pull out their smartphone and look at model pollen concentrations that are specific to their individual allergy profile for right around them. Anyhow, I think there's a lot of possibility for using that type of information to manage our allergies better by reducing exposure and managing our medications effectively. I hope that is an effective answer to your question.

Dr. Adler: Definitely. I think we see it in the same way. I think that information is the key to taking action basically and there is a lot to do so thank you for that. 

The Connection Between Worse Pollen Reactions and Air Pollution

I have another question that kind of relates to other factors, for example, air pollution. So is there a connection between pollen and air pollution? Is the allergy getting worse if there is pollution around, so other factors around pollen not only pollen by itself?

Dr. Katz: Yeah that's a great question and this is an area of very active research. There's still being an awful lot published on this topic and sometimes the consensus shifts a little bit. The current state of things is that, yes, there is a connection between air pollution and pollen. It seems that certain air pollutants can do things like bursting a pollen grain. For example, ozone can rupture a pollen grain, and when a pollen grain is ruptured it can release its contents which are much more allergenic and they're much smaller so they can penetrate deeper into airways. 

There's also a lot of other connections too. There have been several studies that have looked at how pollen from plants that are grown in high pollutant conditions like nitrous oxide, elevated NO2, for example, and a few other things, how that changes the allergenicity of pollen. There's a lot of evidence that it can. In some cases it increases the allergenicity of pollen in a few cases it decreases it. So that's still a connection that is developing. 

There are also all sorts of other connections too but I think at a certain point that's an area of academic research which I’m excited about but I don't know if getting into the weeds there is quite what this audience wants. But if you'd like I’d be happy to chat in too much detail about it.

Dr. Adler: I mean it's great. I think what I take from this is one should look at not only let's say pollen levels but also other factors around and see how this affects a specific allergenic reaction. 

COVID-19 vs Pollen Allergy Symptomsigital Solution Framework

Now the last part because we're kind of out of time, unfortunately, I have many other questions. We cannot ignore what happened this year and we hear a lot of symptoms confusion going around where symptoms that are connected to allergenic pollen are being confused with similar symptoms with Covid-19. So what's your take on that?

Dr. Katz: Oh yeah thank you for asking. This is a question I get now and then. Let me break it down for you if you. So you're having some symptoms and you're trying to figure out if it's seasonal allergies or Covid-19. There's a couple of things to look for. If you have a fever and a dry cough, well, those aren't really symptoms of allergies. So if you have things like that then you might want to lean towards getting tested. That being said, I’m not a physician but, in general, fevers, dry coughs, that tends to be for symptoms of Covid-19. Itchiness, or even just if you have had similar symptoms at that same season and previous years that also means it's more likely to be allergies.


Dr. Adler: Okay. I see that we're kind of out of time but I want to take one or two questions from the audience, so feel free to stick around. If you can't we'll send this recording to you afterwards so you can hear it. Please continue sending questions because we will get back to you later. We're happy to get as many questions as possible. So let's take the first question: We got a question about thunderstorm asthma, so can you tell us a little bit more about that? A question from Australia.

Dr. Katz: Yeah, well it makes sense that it's a question from Australia because they have had big problems with thunderstorm asthma. So thunderstorm asthma is this phenomenon where there's a thunderstorm that happens when there's a lot of pollen in the air, and it's thought that the pollen kind of gets sucked up into these thunderstorms and then the pollen bursts and there are all of these fine pollen particles in the air which then are inhaled. 

For people with seasonal allergies, this can just be a nuisance, but for people with asthma or chronic obstructive pulmonary disorder, this can be a big deal. There was actually this really big thunderstorm asthma event and, I think it was Melbourne 2016, where they had 3 000 people go to the emergency department because of thunderstorm asthma. So it's a really big deal because it can create these kinds of mass events. There's been a lot of work done on this topic in Australia especially, looking at how all of this happens. I hope that that addresses the question more or less.

Dr. Adler: For me for sure, and I’m sure for the audience as well. So one more question we got: regarding climate change, how does it affect pollen season, and is it harder to predict the pollen season because of climate change? 

Dr. Katz: The short answer is yes. Climate change does affect both pollen production and the timing of pollen release. There have been some excellent studies that have shown that pollen season for certain things like ragweed, which is one of those worst offending plants, that season is just getting longer. And this makes sense because plants respond very tightly to temperature changes. So as temperature changes it makes sense that the timing of flowering is shifting, often becoming earlier but not always. 

Actually, that's one of the things that makes it a little bit harder. As climate changes and becomes a little bit more erratic it's a little bit harder to predict exactly when something is going to happen. But luckily, even though some of these general seasons are being disrupted a little bit and either shifted forward or backward or extended, on the plus side at least now we have a lot more data and we can begin to create models of these pollen seasons which is quite useful. Remind me what the second part of that question was?

Dr. Adler: How it is affected and if it's more difficult to predict, and I think you kind of answered that. 

Dr. Katz: Okay cool.

Dr. Adler: Okay. I think we'll finish here, although we have many more questions and I’m really happy to continue talking to you, it was really interesting. So thank you so much. And thank you all for joining us. Again, this will be recorded and sent to you afterwards. If you have more questions please feel free to send them to us. See you on our next live event, and thank you.

Dr. Katz: Thank you so much for having me on. It's been a pleasure to chat about this. If anybody has other questions, also feel free to google me and shoot me an email too. I'm always happy to chat with folks. Thanks again, Gabbi for having me on.

Dr. Adler: Thank you.