How to measure air quality

Air Quality Sensors

Created Tuesday, May 4, 2021

Discover how sensors are used in air filtration. Sensors are a key part to monitoring air quality. This month we find out more about their advantages and disadvantages and a potential future where they could automate the consistency of air quality. This week our guest speakers are Sotirios Papathanasiou an expert in air pollution and Anders Sundvik the VP of Camfils R&D team worldwide.

The Transcript

Sotirios Papathanasiou  0:00  

A user from Twitter told me you know, a way that I can connect my particular monitor sensor with an edge drive that I can place outside my house and the neighbours can see that the pollution is high. So in this case, I have to help them set up a system to do just that. And it's very effective.

Dusty Rhodes  0:26  


Hello there, and welcome to Let's talk clean air where we find out more about how clean air can affect the quality process for you and the workplace. My name is Dusty Rhodes and joining us today is Sirius Papathanasiouan air pollution expert with substantial experience in the field of environmental issues, and advocating clean air initiatives. He's written three books on air pollution and curate a popular blog on the topic. He's joined by Anders Sandvik, who has an impressive 20 years working with Camfil, the global leader in air filters and Clean Air Products. Anders is the VP of the research and development lab in Sweden. Sotirios . If I could start off with you, I'd love to know more about your blog, which is all about clean air initiatives. Can you tell me more about it?

Sotirios Papathanasiou  1:15  


Yeah, my blog is a side project of mine, which I try to educate. First of all, it is called Sivir. And through it, I try to make people understand that we cannot see air pollution in most in most cases. So we have to invest in technology in order to be able to measure and see what's going on with the air. And I use my blog as a tool in order to make my voice available all around them.

Dusty Rhodes  1:44  


And it keeps it very up to date as well unlike books. Because once a book is published, it's kind of very much a fixed thing. But you have written three books, what one of the books been about?

SotiriosPapathanasiou  1:54  


Yeah, exactly. The books contain the same material as my blog. It's a more formal way to communicate and share my knowledge with the rest of the people, especially in some places that they are not aware of my blog, or maybe our kids, because I have written some books for kids can also benefit


Dusty Rhodes  2:15  


So tell me about what is it that makes you passionate about air quality, what kind of got you interested in this field,


SotiriosPapathanasiou  2:22  


not nothing specific. To be honest, I have been asked a lot about it. I don't have any health issues. As a practice person, I think that we have to be ready and prepared to address everything before they get worse. So in my early adulthood, air pollution is a problem that is not regulated very often or when there are some regulations from the government. They are not applied or they are not following. So I tried to make people aware of the issues.

Dusty Rhodes  2:57  


And what do you find is the one kind of common issue that people just don't understand that they're gonna go, Oh, I never realised that.

SotiriosPapathanasiou  3:04  

Yeah, you know, in most cases, people think that Air and Air pollution or smoke is something that it disappears, it's not there, or if you burn something right now, it may create some smoking, you will see it, but after a few minutes, it will disappear. But this is not the case, it may stay there for a longer time, to particular matter, tiny particles, which we humans are unable to see. or other pollutants, gases, etc. can affect our health.


Dusty Rhodes  3:39  

Okay, and this, let me just let you come in there. What do you want to add to that?


Anders Sundvik  3:43  

Exactly like you Satori, assess, it's our pollution is very abstract to most people, we can feel at Camfilwe typically compare the health aspects of clean air and air quality, we compare that to the focus that you put on food and water, drinking water, which is much more abstract, because those are things that you can touch and feel in another way than you can on air. So people tend to think a lot more on those things than they think about the air quality that we breathe. But you actually consume a lot more air than you consume both water and food. So I think it's very important to make people aware of the importance of what we breathe, and exactly Sotirios says is nothing that goes away. Air is something that you need to take in constantly to survive. So you cannot just stop. You can choose not to drink a glass of water if you don't want to, or don't eat certain food, and you can wait for a couple of hours or even a couple of days, if necessary. The air is something that you need to take in all the time. So it's a very, very important to us. And breathing is unavoidable. So it's very important to see what we can do


Dusty Rhodes  4:50  

Sotirios . Maybe you can explain this to me because as we were saying, air you can't see it so you don't think about it. If you can't see it. How do you measure it? Can you tell me about the various different measurements that are usually carried out?


SotiriosPapathanasiou  5:03  

Yeah, it depends. If you want to measure some gases, or if you want to measure particle mother tiny particles, sometimes we call them aerosols, you need some instruments or some sensors that are able to scatter light on them and measure the presence. But again, you need some special instruments with lasers, etcin order for them to measure, then you get a value a number, which we have classified into safe or unhealthy or moderate, or severe, depending where you are around.


Dusty Rhodes  5:41  

And is it just one evaluation that you have? Because I would imagine that air like water is made up of different components?So do you are you able to measure each of them individually?


SotiriosPapathanasiou  5:50  

Yeah, of course, in the air we breathe, there are a lot of elements oxygen, co2, nitrogen, etc. But we do not pay attention in the quantities of oxygen, for example. But we pay more attention, for example, in the concentrations of particular matter, or in the concentrations of co2, carbon dioxide, which are the most common indoor indicators of poor air quality.


Dusty Rhodes  6:17  

I hear co2 monitor has been mentioned a lot these days, what they used to measure in the overall scheme of things and measuring air quality.


SotiriosPapathanasiou  6:26  


Well, they help us understand if we ventilate enough indoor environments, because without a we expel a lot of co2 and it buildupsreally quickly indoors, when you don't ventilate, manually, by opening a window or through automated systems like HVAC,

Dusty Rhodes  6:47  

they're very important for that. There's also of course with it with COVID, and everything going around this particle floating through the air, and you've got all kinds of organic things when people sneeze, are you able to measure them separately as well,


SotiriosPapathanasiou  6:56  

we cannot measure if the origin of that particular matter comes from a human. But yeah, we can measure that there is substantial concentration of particulate matter indoors, we may need to address or filter the air, which is the best way to do it, and then bring fresh air from outside as well.


Dusty Rhodes  7:16  

There is so much that we do know about air and to be able to measure it. What are the limitations to understanding air quality


SotiriosPapathanasiou  7:24  

for everyday people will in better education. And we need to educate people from a young age, what is air pollution, and what is the air we breatheit'scomposition, or the human activities, prionogenic activities that may produce pollution, and we may need to avoid in order to address all of this all the impact it has.


Dusty Rhodes  7:48  

Then also, naturally, when you are taking a measurement or doing any kind of a test in something, you're almost doing it in perfect circumstances, you know what I mean? Like I can imagine going into an office building, if you were going to measure the air quality in there, you may do it in the evening when there's nobody around. Whereas would you have a different measurement if the building was full during the day? Are there any limitations there?


SotiriosPapathanasiou  8:12  

Yeah, exactly. You're not going to take a sample and you leave you need to leave the device inside an office, for example, or a school and measure the air quality constantly throughout the day. And through a long time because seasons also affect the indoor air quality as well. Right now, for example, I'm conducting a study here in Spain, where I have placed some monitors inside some classrooms. And you can see, depending the temperature outside the conditions indoors, change drastically.


Dusty Rhodes  8:50  

And now that you're doing these studies this year, it would be different from say, March of last year when COVID was just rolling out. Have you adapted for the virus?


SotiriosPapathanasiou  9:00  

No, because I used to measure the same things as before, you know, co2 or carbon dioxide and particulate matter, which are basic indoor indicators. Excellent. So


Dusty Rhodes  9:13  


Excellent sothe technology that you're working with isa proven technology and it's not just something that has mysteriously appeared in the last six months. Anders, can I ask you just about air quality sensors what kind of air quality sensors Do you work with in the lab?

Anders Sundvik  9:28  

in the laboratory, like Sotirios  says we use a very advanced equipment, it's typically we're using different what we call a particle counter, and they as Sotirios saidit's laser particle counters, we could be more laser towards the particles in there. And then we measure the reflections by the reflections. We can count the particles and we can also size them how big they are. But this equipment has until recently been very expensive and it has not been possible to really put into the field, then on very rare occasions, and you can see that also when cities are measuring our quality in a typical large city will not measure their quantity on a very many spots in the city, because it's just frankly been too, too expensive. What is interesting in the development right now is that those particle sensors are becoming much cheaper, they're not going to be as sophisticated as the laboratory equipment that we have, but when not with the same accuracy, but with decent accuracy, too, instead of costing 10s of 1000s of viewers per sensor, they're now costing maybe 10 euros per sensor is a factor of 1000 in between in cost reduction, which makes this technology available to course using a completely different matter in the future. And the same goes issuppose as then we have all those gas pollutions. Carbon dioxide is one of them, of course, but also NOx and Sox, sulphur dioxide and nitrogen dioxide and different volatile organic compounds. All those are also interesting to measure from a health perspective. And also there the technology is going forward. And it depends a little bit between which gas you're measuring. And I'd say co2 is one of the easier gases to measure. And that's also why we have more sensors available for them, and that you can see more data on this. So technology is going forward. stuff that we had in the laboratory only, maybe a few years ago can now be put in the hands of the public. So when


Dusty Rhodes  11:37  

So when you talk about all of those different gases and everything that you measure, is there a hierarchy of importance? So like co2 is easy to measure, and we know that it's there. But where does it rate? If you like an order of importance?


Anders Sundvik  11:51  

Yeahit's hard to say how you would rate it co2 is important because it affects the human very rapidly. When the co2 level goes up in a conference room, every one of us recognise the drops in us that you feel, yes, the co2 level effectors immediately, as some other gases doesn't affect us in the same way immediately, but they have more long term health effects. Ozone, for example, is very oxidative, for example, so it's not very good for you to breathe over a long time. Do you see is that typically solvents, for example, and we all know that that's not so good to breed over time either. So I say those five that I mentioned co2, ozone, nitrogen oxides, sulphur oxides, and, and solvents, or our chemical verleden, volatile organic compounds, those are like the five most important ones. And then it's just a matter of which ones can you measure. And, and that big cocktail, also, all those different gases, and all the particles, it'svery difficult for the general person yes to take in all that make some sense out of it. I think you asked Sotirios , you know, how can we what is needed? You know, I think those are quality indexes that are out there. To simplify this to the general public.That'sthat's what we need. And then for the general public to understand what it means and what importance it has to them. That's what we will need going forward.


Dusty Rhodes  13:27  

Let me ask a Sotirios . Is there in your experience, what range of particles are the most important to measure?


SotiriosPapathanasiou  13:32  

Yeah, I completely agree with Andreas but also it depends the setting. For example, if you want to measure air quality in an office, you weren't going to pay is it located near a busy street? is it located near a port or near an industrial site? In this case, yeah, it makes more sense to measure sulphur compounds or nitrogen compounds. But if you are in a place like residential place, where there may not be so much traffic or industrial sites around etcthen there is no need to invest in in so many sensors because sensors come with a cost and not everybody can afford them


Dusty Rhodes  14:22  

Anders this is probably be more your area because in the lab you would be looking at the kind of thresholds that could be observed Are you able to give me an example of a threshold that you would find in an office building in in a city and subsidies you might look for that might be more suburban,


Anders Sundvik  14:39  

I think if you if you look at the more suburban area, then you will find typically larger particles in the air you would see dust from the farms and from the fields. pollens coming from the from the crops and from the trees. those particles are relatively large. I used to say that the human being is also relatively well prepared to if you're not allergic. If you're healthy individual, then the human body is quite well prepared for those types of particles because they are being around for, for the development and the evolution of the human being. But then there are other when you come to a larger city, for example, then we suddenly are faced by completely other types of particles, you see a lot of combustion particles, from diesel cars, for example, for power plants and power generation. And those particles do two very effective engines today and combustion processes in those, our plants are very fine particles, they are in the micrometre range, so a millionth of a metre. And you don't see that type of particles in the same quantities in the suburban areas. And I would assume without being an expert, or in scientist in any way that the human being is much less prepared for those particles, because we haven't had the time to actually adopt to them evolutionary. And also, it's proven that those particles penetrate much deeper into your, into your body. And it's also proven that very small fractions of those particles can be captured by your bloodstream through your lungs equally as a gases can be captured with your lungs and get out in your bloodstream. So, of course, the more you move into orbit urban area, you need to look for those fine particles, we typically call them, PM, one particles that are smaller than one micrometre. And then you need to start looking at all those guests that we talked about that you will not see so much in the suburban areas. We've been talking a lot about NOx, for example, with the with the scandal of diesel gate, for example, you have ozone generation, due to combustion in the cities, for example, all those areas which will not have to worry so much about in the suburban area.


Dusty Rhodes  17:09  

Okay. And you mentioned pm one there, I've heard pm monitors beingmentioned as well, this is another type of monitor for measuring air quality.


Anders Sundvik  17:18  

It is typically when you read the newspaper, and you talk about air pollution, outdoor air pollution, you talk about P10, and pm 2.5. And those are measurements, mass mesh measurements of particles of those certain particle ranges. Why have we talked so much about pm 10pm 2.5. In the past, my assumption is that those particles has been possible to measure. And that's why we have also developed standards and limit values, or those particle ranges. When you look at pm 1 which is much smaller particles, which more frames the particles generated from the combustion engine. There, we don't have any limit values today, or much less of those limit values, they can be locally but on a global scale, we still don't see a limit value. So key one, and we see very seldom that those particles are still being measured. And why is that? Because those are those particles difficult to measure.And the equipment to measure those particles in an accurate way. Is, is very, very expensive and difficult to handle.


Dusty Rhodes  18:29  

Let me ask Sotirios, in your experience because of the equipment is expensive. And you know, you can't have hundreds as a measuring everything. How can we ensure that that monitors are utilised to their full potential?


SotiriosPapathanasiou  18:43  

You mean by the users? Yes, yeah. And in this case, sometimes the companies that build their quality monitors, they try to lay the information as easy as possible. And this is what I do as well, I try to educate people in order to use the technology and the sensors as much as possible through various articles that I write, for example, I remember a user from Twitter told me, you know, a way that I can connect my particular matter sensor with a lead strike that I can place outside my house and the neighbours can see when they burn wood to wood burning stoves that the pollution is high in my neighbour. So in this case, so I have to help them set up a system to do just that. And it's very effective.


Dusty Rhodes  19:39  

And that is really just taking kind of the technology of the monitor and the amazing and intricate things that it does and brings it down to the most simplest thing in the world is red danger. That's brilliant. And is in the lab. Do you strive to make things that simple or do you feel that there's a case for A lot of detail with the monitors.


Anders Sundvik  20:03  

in the laboratory, we need a lot of detail. Of course, when we develop our filters for the end user, for the end user, we strive for simplicity. And we are also trying to go towards that type of scale, red, yellow or green. But I think the future is even demands more than that, I think I, I go back to my analogy with food and water. Let's take water as an example. For example, when you pour water out of your tap, you don't want to have a measurement device telling you whether the water is clean or not. or high, how clean it is, when you're drinking, do you just want to, you need to expect that that water is clean when you when you pour it to the tap, I think that's the systems that we need to go towards some sort of control loop and equipment measuring the air quality for you. If it gets too bad, it will bring it back to a decent quality again, without you even having to do anything at all about it, you will just have to expect that the ad that you have in your room is good enough. I think that's where people want to go. People don't want to bother about what they're drinking or eating. They want to know that that it's already quality controlled when they put it in their mouth. And it's same with air, I think that's where we need to go.


Dusty Rhodes  21:26  

So it was coming in them with monitors and measuring air in a particular area are the monitors able to tell us then if the filters in my system are working and doing their job, as you say,


Anders Sundvik  21:39  

I think the monitors that are coming out. Now, we have one monetary within Camfilthat we have commercially available, we call it our image, that's a particle sensor that we connect to an air cleaner. And if the air gets worse in the room, the air cleaner will rev up clean air and maintain a certain predetermined air quality predetermined by the user. So is that technology available? Yes, it is because we have we're already selling it. The problem as I see is that many users either in an office building, you have a central air handling unit, providing the air into the building. So you need to have connectivity to that air handling unit to control it. The problem is also that the air handling unit needs to take care of a lot of other things, then yes, the air quality, it also needs to take care of thetemperature and the humidity and the co2 levels. So those are the primary tasks of the of the air handling unit. So then I see Okay, so how do we take care of all the rest of the problem, which is particle matters and other things. Maybe in the future, this needs to be two separate systems. One being the base, this base unit being the air handling unit providing a base level of clean air to the building. But then maybe we need also to complement that with recirculating air cleaners throughout the building to ensure that we in every individual spot of the building have the decider quality level, I think that's kind of the technology may go how fast we don't know,

Dusty Rhodes  23:28  


well you're working in the r&d Lab. So how hard Are you working?

Anders Sundvik  23:34  


We're working hard. And I think it's a, it's a matter of the cost of the sensors, the not only the cost, it's also the accuracy of them, and how well they sustain their accuracy measurement over time also so that we can warrant the measurement also.

Dusty Rhodes  23:54  


And they need to be efficient as well, don't they, of course,

Anders Sundvik  23:57  



Dusty Rhodes  23:58  


Let me wrap up then without asking a Sotirios that is kind of under his vision of the future and the direction we're going, where do you see ourselves in maybe 10 years time,

SotiriosPapathanasiou  24:09  


I'm going to the fashion. So I think from here to 10 years, things will be much better. There will be more regulations, and people who will understand better, and hopefully, it's a knowledge that I try to share with them. It will bring some benefits for all of us a future.

Dusty Rhodes  24:31  


Do you think that we will have a system like you spoke of earlier, would you you've just got a simple red flag to describe the quality of the air around you might we have TV monitors or something like that giving you a percentage score for air quality in a room or a building?

SotiriosPapathanasiou  24:46  


I think yes. And I see a lot of interest from the real estate deal that they do investigate right now. And many people ask, what's the air quality in this area? should I invest my money Buying a house they are all of these things make quality and evolution more visible.

Dusty Rhodes  25:12  


Sotirios and Anders. Thank you both very much for joining us on our podcast today. If you'd like to find out more about what we've been chatting a bit today just follow the links in the show notes, including Sotiriosblog, which you can find at sea The Once you find that in the description of this podcast on your phone, or whichever device you're listening to us on the show notes include links contact details, anything else you might need to get more information. Our podcast today was produced by camfil, a world leader in the development and production of air filters and clean air solutions. You'll find out more of them at we have a brand new podcast for you every month of course to get it automatically just click the subscribe or follow button on the player that you listen to us on right now. Next time for myself too thrilled. Thank you so much for listening