← What's That Rash?
What's That Rash?
What's so bad about fine particulate air pollution?
00:20:17
Long-time listeners would have heard Norman decrying fine particulate air pollution and its negative effects on health. But when it’s all around us – on our worksites, in our offices and on our motorways – how are you supposed to protect yourself? Norman and Tegan explain what fine particulate air pollution is, and what it does to the body once it’s breathed in. References: Estimates of global mortality burden associated with short-term exposure to fine particulate matter (PM2.5) The health effects of fine particulate air pollution Ambient (outdoor) air pollution - World Health Organization Particulate matter (PM10 and PM2.5) - Australian Department of Climate Change, Energy, the Environment and Water Air pollution is not ‘the new smoking’: comparing the disease burden of air pollution and smoking across the globe, 1990–2017 East Side Story: Historical Pollution and Persistent Neighborhood Sorting
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- [00:01]
A
Listen. That's the sound of the fully electric Audi Q6E Tron. The sound of captivating electric performance, dynamic drive and the quiet confidence of ultra smooth handling. The elevated interior reminds you this is more than an EV. This is electric performance redefined. The fully electric Audi Q6E Tron.
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B
ABC Listen. Podcasts, radio, news, music and more. So Norman, you do all that cycling now. Have you ever swallowed a bug on your. On your bike?
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C
I have actually, but only once. And it's not pleasant because you think, well, was that a wasp or a bee or just a blow fly?
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B
It's just a little bit of extra protein for your bike ride.
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C
Well, that's right. Don't tell everybody about it cause they'll all want one. But I have thought about what else I'm breathing in. Whether I'm actually benefiting the rest of society by scrubbing the air through my lungs.
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B
Indeed. Well, that really brings us to today's topic on what's that Rash?
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C
Where we answer the health questions that everybody's asking.
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B
This week. The everybody is Liam. Liam says, I love your show and listen regularly. And I recently had a moment to pause when the Lovely Tegan and Dr. Swan agree.
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C
He doesn't think I'm lovely.
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B
Well, I think that my title is lovely in the same way that Your.
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C
Title is Dr. Dr. Norman. I'm going off Liam very quickly here, but let's get, let's get going that.
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B
We agreed that pollution in the form of fine particulate matter is the same as smoking. Liam says, I cycle to work regularly but have often questioned if I'm actually doing myself more harm than good. Especially as the bike track I use is next to a motorway. Can you unpack the science and evidence for me on this topic, please? And Liam finishes by saying, P.S. if it's bad, feel free to underplay it.
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C
No, I'm liking Liam again. It's good.
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B
Very relatable by the sounds of it.
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C
My kind of guy. Head in the sand. It's good.
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B
Before we go any further, Norman, I need to call out the fact that you have said fine particulate air pollution almost as many times, I think, as you've said your favourite favorite diet ting, the Mediterranean diet. And so I thought it was only right that I had some sort of sound effect for fine particulate air pollution.
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C
Oh, what is it?
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B
Well, you suggested a whoopee cushion. Yeah, because I am classier than you and also because I couldn't find one in my children's bedroom, I have settled on a harmonica.
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C
How musical.
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B
I feel like it kind of conveys air and lots of different things happening. It's an auditory metaphor for a fine particular emotion.
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C
Good. Okay. Since it takes up about three minutes for you to play in the sign, I won't be saying it too often.
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B
It's a little less snappy than the bell, but look, just go with me.
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C
All right. But for the sake of today's. What's that? Rash. We might just do it once. Great.
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B
Now that we've got that out of the way, most important item of business. What about a bit of a definition? Because fine particulate air pollution, you probably can guess what it's about, but there are definitions around what is fine and what is just particulate.
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C
Yeah. So most air pollution is particulate. If you burn coal, there's dust in the air, smog and so on. I mean, it's all about particles. But in terms of the health impact, the really salient metric is what size are those particles? And we're talking about particles in this case in fine particulate air pollution, which are absolutely tiny. The ones that are thought to be really toxic are called PM2.5, so they're 2.5 micrometers or less.
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B
Oh, that's minuscule. Yeah.
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C
If you actually take a grain of sand, it's maybe 90 micrometers. If you take human hair, it's between 50 and 70 micrometers. So just imagine how much smaller that is than a human hair. If you take PM10, which is 10 micrometers, that's things like dust, pollen, molds and so on. And PM2.5 are the products of combustion, particularly from diesel organic compounds from bushfires and so on, and heavy metals. So the problem here in terms of health and well being is that these particles are small enough when you breathe them in, that they go through the lining of the lung into the blood.
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B
Oh, talk me through in a bit more detail what it is about these invisible particles going into our bloodstream that's so bad for us.
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C
Let's take the epidemiological evidence, the evidence in terms of health and well being in populations, there is solid evidence. When fine particle pollution goes up, say after a bushfire, or when you've got a particularly bad traffic day, there tends to be a spike in fine particulate air pollution, because a lot of it comes from internal combustion engines, particularly diesel. So when you look at the epidemiology internationally, there are millions of deaths each year attributed to fine particulate air pollution, and the causes tend to be stroke, coronary heart disease, perhaps infections counterintuitively, and respiratory disease. Particularly asthma attacks and what have you. And there are definite spikes in hospitalizations when there are short bursts of extreme fine particulate air pollution, such as after a bushfire. And when you look at countries with high fine particulate air pollution levels, much higher than Australia, Australia's not too bad in this area, the attributable deaths to air pollution become quite high.
- [05:56]
B
How does Australia compare to the rest of the world? Because I know that at least Tasmania loves to brag about how it has the cleanest air in the world. Where do we fit in terms of the burden of disease from fine particulate air pollution compared to other countries?
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C
We are amongst the countries that have the cleanest air in the world, but that hides some other, which is where air pollution occurs according to the time of day. So if you take the east coast of Australia, let's just take Sydney as an example, where you have on a hot day, the air rises off the land and you tend to get a prevailing northeasterly wind that tends to focus fine particulate air pollution in the southwestern suburbs of Sydney. So I was just looking at a map and today, which is not a high fine particulate air pollution day, by the way, we're pretty good at reporting it as well. Sure enough, the moderate levels of pollution are indeed in the southwest suburbs of Sydney and it's true of other cities as well. So the average might be low, but some areas can be much higher. And if you take Europe, there's this thing where the east end of towns and cities tends to be the areas where poor people live and health and well being levels are lower than in other parts of the city.
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B
This is so interesting to me because it seems like a function of industrialisation and the way that the prevailing winds blow, which is what you're sort of saying there. But you were talking about fine particulate air pollution as opposed to coal dust or smoke, which is probably what would have caused a lot of the pollution in early industrial times when those cities, you know, east ends would have been becoming the place where poor people ended up living.
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C
Yeah, and that would have been because it wasn't very pleasant, the air was dirty, not nice places to live and therefore the poor could afford housing in those areas. So it's a conflation of lots of different factors, but in today's world it's where you're often situated internationally in those areas next to motorways, next to roads, with high levels of truck traffic and therefore diesel fumes. And there have been studies of child development being more affected the closer a house is to to roads and roads which are particularly heavy in diesel engine traffic.
- [08:20]
B
So my question is then, the closer you are to a major highway noise pollution, smelliness, those houses are going to be more affordable. How do you unpick the health effects of the fine particulate air pollution, specifically from the other things that we know often goes along with poverty?
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C
It's hard. And international estimates of what's called the population attributable risk, which is the risk attached to fine particulate air pollution, are probably underestimates because you've got the dilutionary effect of all the other factors you're talking about. So this is something that's harder to study. It's much easier to study somebody who buys a packet of 20 cigarettes and buys another one the next day and is smoking 20 a day. You know what they're taking into their airways. And they're taking not just carcinogens, they're taking fine particulates into their airways. They're taking fine particulates into their airways when you vape. So that's much easier to measure than what you get from the ambient air surrounding where you live and where you.
- [09:19]
B
So that brings us to Liam's question, because I think it was a bit of a throwaway line in a podcast a month or two ago, but you sort of made the comment that fine particulate air pollution was as bad for you as smoking. How do we actually put the two head to head?
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C
When you look at what's called the burden of disease studies, so these are studies which look at how many years of life do you lose because of a particular risk factor, and how many years of healthy life, of disability free life, do you lose as a result of a particular risk factor? There's no question that when you look at that, smoking has a much higher burden of disease effect than fine particulate air pollution. And I probably was over egging it in terms of just as toxic as tobacco, in terms of world health, it's not. The question is what do these fine particulates do? And it depends what's in them. So in tobacco smoke, the fine particulates include carcinogens in terms of diesel fumes, general air pollution with fine particulates in them. What's thought to happen, and there's some experimental evidence to support it, is that these particles get into the bloodstream and two or three things happen. One is there's a physical effect of these particles in the blood and in the lungs. And secondly, there's an effect on the immune system which reacts to them and it generates Inflammation, which is essentially the first layer of the immune response. It's called the innate immune response, trying to get rid of these particles. When this innate immune response goes up, there's more absorption of cholesterol from the blood into the arteries and that gets oxidized and turned into atherosclerosis, the blood becomes more clotable and so on and so forth. And it could also relate to immune dysfunction, which would explain increase in infection. So there are biological explanations for why fine particulates might not be good for you at all.
- [11:19]
B
I mean, I think with smoking it is a behavior, whereas fine particulate air pollution, you've got no choice, you don't really have much choice at all. So what can you actually do about it?
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C
Well, you can wear an N95 mask pretty hard if you're cycling and you've got a. You've got a high need for oxygen. Yeah, you can try. So Liam's got a problem because he is cycling next to a busy motorway and that's where fine particulates could be high. Particularly if it's a motorway which carries a lot of trucks. In that situation, for the period that you're going to be cycling along there, you might want to wear a mask. If you're able to take a more suburban route through streets, on bicycle paths, which some cities do, they don't cycle you along motorways, they will take you away from motorways, then it's very likely that the fine particulate air pollution will be, in an acute sense, much less.
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B
And with an N95 mask, it has to be that kind of mask because of how small these particles are.
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C
Yes. And of course, that's the origin of these N95 masks is actually to block out these PM2.5 particles and they happen to actually block viruses as well. In addition to the N95 mask, you can use a HEPA filter, which is a fine particulate air filter that you can install at home or in the office. But it costs money and costs money to run and not everybody can afford it and you've still got to go outside at some point.
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B
I always think that HEPA is like a brand name, but it actually stands for high efficiency particulate air filter. HEPA filter.
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C
It just tripped off the tongue for four or five years on Corona test.
- [12:53]
B
That's right. And yet I still had to look up what it stood for just then.
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C
I think the main thing in terms of what you can do is that in most parts of Australia, we're very good at reporting the level of fine particulate air pollution in your area and if it's high and you've got asthma or you've got heart disease or you're at all frail, then you might choose not to go out on that day.
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B
There's certain groups of people who are more sensitive to fine particulate air pollution than others, including people over the age of 65, babies and kids and pregnant women. How do you protect these particularly vulnerable groups?
- [13:27]
C
Well, this is a population effect, this is passive inhalation of these fine particulates. You're not making a choice, even though when you're addicted to tobacco, the choice is less easy to abandon. It's actually about government, it's about regulation, it's about reducing air pollution, it's about reducing the prevalence of internal combustion engines, it's about making energy generation more efficient, it's about making industrial processes more efficient so that we reduce air pollution and we've not done too badly in Australia, however, there was a study a few years ago which showed over the period of that study, which I think was about five year time frame or so, even though we've got very low levels of fine particulates compared to other countries, the attributable deaths to air pollution still went up by about 40%.
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B
Coming back to Liam's question, which is really at its heart about balancing the risks and benefits of cycling, which we know is good for you, and fine particulate air pollution, which we know is bad for you, how does Liam work this equation, Norman? Because I know it's one that you've wrestled with yourself.
- [14:29]
C
Yeah. I'm lucky that on my cycle to work, I'm able to take a route which is well away from traffic, so it stops me getting knocked over and also means I'm breathing cleaner air. But from Liam's point of view, where he's got to go along a motorway, you probably just want to monitor what sort of day it is outside and what the level of pollution is before you jump on the bike.
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B
That traffic light system.
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C
Yes, effectively, when you look at one of these maps, it is a traffic light system where orange is moderate, red is severe.
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B
Well, Liam, thank you so much for the question. I hope that's cleared things up for you. Give us a little ring on your bicycle bell if you liked what we had to say and if you have a question that you'd like to ask us, all you have to do is email us. Thatrashbc.net au let's go to the mailbag. Yes, Dr. Rockley has messaged in, Norman, and I just Love that name. Dr. Rockley says, here's my personal N equals one success story with a good hypothesis attached.
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C
And just to remind new listeners to watch that rash. This is the thing we've had going for a while now, which is n equals 1 means it's a study of one person and their experience.
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B
And we definitely coined the term and no one else has ever used it before.
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C
Never before. Never before.
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B
Anyway, not Dr. Rockley. This is about cramps, because we talked about cramps the other day and everyone wanted to talk about it and had questions. Anyway, Dr. Rockley's got a solution. Saying, some years ago, someone told me to stop cramps using two spinal cord reflexes. If they get a cramp in your left calf, I pull up the toes of my left leg and at the same time point the toes of the opposite leg. So opposite muscle on the same leg and same muscle on the opposite leg. He does clarify. If you get these confusing instructions the wrong way around at 2am the cramp will get much worse immediately.
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C
So kind of immediate feedback. Right? Okay. So up on the side, you've got the cramp, down on the side where you don't have it. Okay.
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B
And actually it's not a man.
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C
I'm usually screaming in so much pain, I would never think about how to do that.
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B
And it's actually Not n equals 1 because Mary also emailed in with effectively the same advice. So next time you've got a calf cramp in the middle of the night, do this. Write down what happened and let me know. Another piece of cramp advice from Merva. In a casual conversation before a Golden yogi's senior yoga class about 18 months ago, Steve, who's a train driver, told us how to release a muscle cramp. Put your forefinger under your nose, press firmly but gently, and the cramp will disappear in moments. And Merva's acupuncturist says that she thought the position under the nose was an adrenaline release point.
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C
It's cheaper than magnesium. Go for it.
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B
So, Norman, when you're in bed, you have to release the toes of one foot, point the other, and pinch my.
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C
Nose with the forefinger and the other. Okay, Right.
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B
Two more.
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C
This is getting very complicated, but I'll try and remember. But okay, let's see what Bernadette has to say.
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B
So this is a good one. Bernadette says, some years ago, I was hiking in a very humid, hot climate and experienced severe cramps in my calves. Someone told me to try bananas as they're high in potassium, and that may be the problem.
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C
So what are you doing with the banana?
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B
Well, I think you're pressing it under your nose. I think you're eating it. A banana a day. The cramp stopped instantly. At the time, I wasn't aware that I was conducting my own n equals 1. Waiting for the invention of the podcast so I could share it with you. Bernadette says, interestingly, I don't really like bananas, but discovered that twisties. Twisties also have high potassium. Bernadette says, I'm sure they are a major component of the Mediterranean diet.
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C
Sure thing. Okay, so. So feet up, feet down, forefinger, and with your spare hand, you eat a banana. Okay, got it.
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B
No, a twisty.
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C
A twisty or twisties. Right. That's easier.
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B
Final piece of cramp hack advice. Jill says, I suffered severe cramps for many years not being satisfied with the effects of tonic water. Ah, we did talk about quinine last week, Norman.
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C
We did.
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B
I moved onto a daily dose of magnesium and immediately noticed an improvement after 12 months. I heard she says on the health report, Norman, that there was no evidence that it worked. So I stopped. The cramps returned at once.
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C
Oh, I'm Sorry, Jill.
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B
This N1 has been taking magnesium with success ever since.
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C
Well done, Jill. Well done, Jill.
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B
I do love the fact that she tried something. It worked for her. She heard it on the health report and stopped.
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C
I mean, there's a validity to N1, which is that we're all different and some people do have an effect which is hard to measure on a large scale.
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B
Exactly.
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C
Quinine is not something we recommend on. What's that? Rash. It's toxic. The approval has been removed. You can find that out by listening to last week's Watch that rash. But magnesium is pretty harmless as long as you're not taking excess B vitamins with it.
- [19:05]
B
Well, that is it for this week's WhatsApp rash. But if you ever want to send us your thoughts, Your N equals 1, your feedback or your questions, you can always email us. We are thatrashbc.netau and don't forget our.
- [19:17]
C
Sister podcast, the Health Report, which you can get from wherever you get your podcasts, including ABC Listen app.
- [19:23]
B
This sounds like you shouldn't take any advice you hear on that channel.
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C
Well, I think stopping magnesium is one thing, but stopping listening to watch that rash, that would be really bad for your health.
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B
Oh, bad for your health indeed. Absolutely.
- [19:33]
C
See you next week.
- [19:34]
B
See you then.