On-Demand Webinar

Healthy Indoor Living in the Time of COVID-19

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Ronit: Welcome to today's live event: Healthy Indoor Living in the Time of COVID-19, featuring leading wellness, real estate, and technology company and BreezoMeter partner Delos. Delos’ Darwin homes in Australia integrate BreezoMeter’s outdoor air qֶֶuality data into their dashboards that display indoor environmental conditions, highlighting the importance of understanding both indoor and outdoor air quality in tandem.

We wanted to thank you for joining us. We do not take it for granted that you've decided to spend this time with us and we hope the presentation will be of value to you. Before we get started, we wanted to go over a couple of housekeeping items. Today's session will be recorded and emailed to you afterwards. There will be a Q&A session at the end of the webinar, but feel free to send your questions at any time by using the Q&A panel that can be found when you click on the QA button at the bottom of your zoom screen. 

Today's hosts for the special live event are BreezoMeter’s chief scientist Dr. Gabriella Adler, who has an MSc and Ph.D. in atmospheric science and has worked as a research scientist at NOAA, National Oceanic and Atmospheric Administration, and is an expert in chemical and physical processes related to air pollution. Gabi believes it is her greatest duty as a scientist to bring science to the people. Her role at BreezoMeter is cross-departmental, to say the least, and includes consulting on all algorithmic queries, both internal and external facing, product development and roadmap from the scientific aspects, as well as furthering the environmental research in the name of the company.

And today we have the honor of being joined by Dr. Chuan He, senior director at Delos labs, Delos living LLC. Chuan is a researcher of indoor air quality, indoor environment monitoring, and building systems. He leads the framework development of algorithms for home automation systems that work to improve the indoor environment and the well-being of home residents. Before joining Delos, Chuan focused on evaluating the performance of air cleaning technologies under different conditions with the American Society of Heating Refrigerating and Air Conditioning Engineers. Thank you for joining us, Chuan. 

Disclaimer: This presentation is intended to educate and inform and nothing herein and in any resources provided by BreezoMeter or Delos should be considered as or used as a substitute for medical advice, diagnosis, or treatment. 

So, in order to grasp the importance of the air we breathe in this new normal, I think it would benefit our understanding of what we are dealing with in terms of the indoor solutions to come. If we address some of the facts regarding the virus, the virus spread, pollution indoors and out, and even the connection between the two. And with that, I will pass it off to our experts. Chuan, take it away.

COVID-19 Transmission Routes

Dr. Chuan: Exactly, Ronit. As the saying goes, in order to win we need to know the enemy. To be able to come up with efficient solutions we first need to understand how COVID-19 is transmitted from one person to another. Based on what we currently know, the virus can spread from person to person through small droplets from the nose or mouth once the infected individual coughs, sneezes, exhales, or just talks. People can be exposed to COVID-19 if they breathe in those droplets during close contact with a person with COVID-19. This route is labeled as number one in the figure.

These droplets can also land on objects and surfaces. So another way that we can get exposed to COVID-19 is by touching objects or surfaces, where COVID-19 droplets have landed and then touching our eyes, nose, or mouth. This is the second route. Despite me calling these droplets small they are actually quite big aerodynamically. About 5 to 10 micrometers in diameter. They usually don't travel far or stay in the air for long, but before we take a big breath while we are 6 feet away from one another, there is still one more transformation mechanism that is plausible and becomes more complicated. It is called airborne transformation, labeled number three in their figure. 

The droplet is generated by an infected person through talking or exhaling, quickly breakdown within milliseconds, and become fine particles that could hang in the air for up to about three hours according to the latest research. It may travel with airflow in the room farther than the large droplets and be inhaled by people who are in the room but not necessarily at the same time as the infected person. While direct transformation is thought to be the main way that the COVID-19 spreads we actually don't know yet which of the lots of the transmissions is the dominant one.

PM2.5 vs Coronavirus - How Big is Particulate Matter?

Ronit: Thank You, Chuan.

Dr. Adler: I think we should pause here for a minute and focus on this third mechanism that you mentioned. This mechanism is less known, I think, to the general public, and the implications of it are that wearing gloves and keeping the six feet or two meters from each other is just not enough, as the virus is actually present in these small droplets that are suspended for a long time in the room. Let's discuss for a minute what these small droplets are. These small droplets are technically called aerosols, which are defined as solid or liquid particles suspended in the air. In terms of air pollution, they're called particulate matter, which is taken as measures either up to two-and-a-half microns or up to ten microns. 

For a visual reference, you can see in the slide a human hair in comparison with particulate matter of both sizes. Imagine if I take the hair and divide it by a thousand, that would be more or less the size of a typical aerosol. And between you and I, Chuan, or rather, between me and the screen, because we're far away, we have about, I estimate five thousand aerosols floating right now.

The coronavirus is also a type of PM, around the size of 0.1 microns. You can see in the slide reference of the size compared to a blood cell or other particulate matter. On that topic, I want to refer the audience to professor Linsey Marr, an environmental engineering professor from Virginia Tech who is an expert on the airborne transmission of viruses and has a series of YouTube videos explaining this and other papers that she has written about this subject. 

What she says in short, as Chaun touched on, is that understanding the size of these respiratory droplets is important to understand the way that the virus is actually transmitted. Often people think that the person who sneezes or coughs presents the most danger, but actually, from speaking or even just breathing, small droplets are emitted which can linger in the air for a long amount of time and spread to distances there farther than 2 meters or 6 feet.

Evidence Suggesting Air Pollution as a Carrier of Coronavirus

If I want to complicate this even more, there are recent studies that suggest that particulate matter can act as a carrier for COVID-19, allowing the virus to float in the air longer and to be widespread to larger distances. For example, you can imagine that the virus is on top of a dust particle and that travels for very long distances. But again, we need to keep in mind that these are very preliminary results and require further study. 

Regarding the images you see on the slide, the image on the right is based on a variety of environmental factors that contributed to the pollution burden score derived by the California Office of Environmental Health Hazard Assessments in 2018. This is compared to the COVID-19 numbers released by the city of San Francisco last week. You can see the similarity. But of course, we need to take these similarities with a grain of salt, which is also a type of PM by the way, because the pollution burden score is derived from several factors. But not only because of that. It does further support the case of a potential connection between air pollution and COVID-19 spread.

So to summarize, we discussed two potential under investigation very dangerous mechanisms for the spread of the virus. One, which is directly related to indoor spread, is the danger of small droplets lingering in the air for a long amount of time, and the other is related to a spreading mechanism outdoors, which has the potential to affect the air that we let indoors through open windows, ventilation, etc.

Harmful Airborne Particles In Indoor Environments

Dr. Chaun: Thank You, Gabi. Thank you for the correlation between the Coronavirus and air pollution. In fact, Americans spend approximately 90% of their time indoors. This is based on research before the COVID-19 outbreak, so now I'm imagining we spend even more time indoors. This is important, Gabi, because most of the transmission will occur indoors these days, as that is where people are. We are following the stay-at-home guidance to limit exposure to those whom we interact with by staying within our individual family unit.

But that means longer exposure times to indoor air, which can be contaminated by many types of pollutants like particles, chemicals, pollen, as well as germs. This presents an opportunity to focus on the overall indoor air quality including pollutants as well as potential passengers that can lead to infections. For example, a longer time spent indoors especially with all family members leads to higher CO2 generation. Certain acts that should normally be done outside the room, such as workouts, exercising also generate lots of CO2. People also cook more when they are staying at home. That generates particulate matter, NOx, CO, or VOCs. 

Innovation increased the use of chemicals in our home for surface disinfection and increased personal exposure to those chemicals. And finally, the common indoor air pollutants source still exist such as off-gassing from furniture and floor, infiltration of outdoor pollutants mold, and fungi that can be easily found in wall decay.

Dr. Adler: Thank you, Chaun. Actually, it makes you think that the exposure or long-term exposure to these pollutants and linking back to the COVID-19, there is a really interesting study, first of its kind, by a group of scientists at Harvard that found a potential correlation between air pollution exposure and COVID-19 mortality in quite a dramatic way, as you can see in the slide. And it's not just indoor pollutants that we need to be concerned about, right? We are still going outside. The amount of time that we spend outside will begin to increase hopefully as the virus stagnates across countries. And even when we are indoors we are opening the windows, we ventilate with the air outdoors, and we need to take the outdoor pollutants into consideration as well.

The Different Types of Pollutants - Natural vs Manmade

There have been many articles about pollution in the time of COVID-19 and long-term exposure to air pollution and respiratory diseases. So I wanted to take a moment to explain the differences between the different types of pollutants, as Chuan explained the indoor pollutants, I’ll explain a little bit about outdoor pollutants.

So what is air pollution? Air pollution is basically any substance, it can be a gas or particulate matter or particles, that in high concentrations can be harmful to our health. We can divide pollution into natural or anthropogenic, meaning man-made. So examples of natural pollution can be mineral dust, dust storms, or pollen, fungi, bacteria, viruses. Examples of anthropogenic emissions can be for example NOx that comes from traffic or CO that comes from industry and soot. 

But there are pollutants that can come from both natural and anthropogenic, like particulate matter, that can be dust that is natural and it can be soot that is coming from vehicles for example or VOCs. VOCs, volatile organic compounds, can be very harmful and come from anthropogenic sources like benzene, and it can be a gas that smells like lemon for example. Limonene is a VOC that comes from lemon trees.

Pollen Season Adds to COVID-19 Threat

But there is another pollutant that is not always thought of as a pollutant and has a harmful effect on our half, and that is pollen.

As the coronavirus broke out exactly during the peak of pollen season in many locations, you can see the impact it has on the health system, as well as the impact it may have on the severity of sensitive populations. This also must be taken into account when making decisions about indoor or outdoor air we breathe.

Methods to Improve Air Quality

Dr. Chuan: Thanks, Gabi. Knowing there are many types of air pollution around us there are three approaches to improve our indoor air quality, including source control, ventilation, and air cleaning technologies.

Source control is about identifying the pollution source and then removing it from the environment. It is usually the most effective method but is also the most difficult one to apply in the real world, especially when the pollutants are coming from outside. Traffic emission, pollen from grass and trees, and combustion pollution, as Gabby described earlier.

Let's take a look at the other two approaches:

Ventilation basically means replacing indoor air with outdoor air through a mechanical fan system or through the windows or other openings of the building.

The third one, air cleaning technology, removes targeted pollutants from indoor air by using filtration or purification devices. 

Now let's take a look at some typical cases:

Natural Ventilation

The first one is natural ventilation, the most common one. In the US, many homes do not have a forced-air ventilation system, so the only way to improve indoor air quality is to open the windows. One simple approach is to open the windows as frequently as possible and use an exhaust fan in the kitchen or bathroom when the windows are open, otherwise, the ventilation rate may not be sufficient. 

So the idea is to borrow the power of fan systems to enhance natural ventilation. The important thing is to know when to open the windows and when to purify the air. Gabi, I think you can give us some insight into being aware of what's going on outside.

Traffic May Be Down Due to COVID-19 Lockdowns

Dr. Adler: Right. Thanks, Chuan. It's actually confusing, right? Especially in these times when we are seeing coverage all over the news about the decrease in pollution in countries under lockdown. And yes it's true that emissions from factories and also traffic have dropped dramatically, which does impact the air quality we breathe. As you can see in this video, you can see the before and after the lockdown in Italy, and you can see a dramatic difference in the air quality between the two times in the video. 

This makes you think that it's always a safe time to open the window during the lockdown because the air is so clean. But unfortunately, I will be bursting the bubble here, because as we touched upon earlier, there are different types of pollution and different sources that you need to be aware of.

But That Doesn’t Mean There’s No Pollution

One example of that is in this video, where you can see a major dust storm that occurred last week in Israel. Dust storms are actually a naturally occurring phenomenon, a natural pollutant. Whether there is a lockdown or not, air pollution from natural sources will continue to occur. The same goes for pollen. We see that the lockdown happens at the peak of the pollen, season pollen continues regardless of the lockdown.

There are also other examples that some pollutants surprisingly actually increased. For example, there is a new study that suggests that ozone increased in China when the NOx from traffic decreased. This is because of photochemical reactions. As you can understand air quality can change dramatically from one hour to the next, from one location to the next, even during the lockdown and you cannot be sure if the air quality is good or not. Hence you need a reliable source of data to provide you with that information.

A Multi-Layered Data Approach to Air Quality

So the most basic data source would be the monitoring stations operated by the local governments. However, there are two main problems with the monitoring stations. One is the location. It could be that the closest monitoring station to your house is actually very far, it could be even 100 kilometers away. But even if it's not so far the air quality changes from one place to another, and if I'm located next to a road but the monitoring station is across town at the park, the air that it actually measures is not the air that I’m exposed to. 

The other issue with monitoring stations is that they have a delayed time. It takes time till they process the data and deliver it to the public. Hence, it may be that the air quality report is two hours, even seven hours old, which is not relevant to what we see now.

So what we think at BreezoMeter is that you need a comprehensive understanding of air quality. And in order to achieve that you need to combine different layers of data, which includes dispersion models, models for dust, include models for fires, and pollen as well. We need also to take into account traffic, or emissions that come from traffic, and satellite data. Only by combining all these lanes together can you get a true understanding of real-time air quality and basically decide when is a good time or safe to open the window, right?

Mechanical Ventilation - All For One

Dr. Chuan: Thank you, Gabi. Thank you for the valuable background information before I dive into the other solutions. Some of us may live in a house or apartment where there is mechanical ventilation. In such cases, there are more options to increase the ventilation, such as turning on the AC unit to 100%, outdoor air mode, and turning off or turning down the return air. The windows can be open as well, especially when it is a large home or there are many occupants in the home. As Gaby has mentioned, it is important to know what air quality is even while we are talking about mechanical ventilation strategies. 

A more complex case is the mechanical ventilation system that is shared by multiple rooms. What we have learned with the SARS virus is that virus particles can travel through air vents. Researchers have already collected COVID-19 samples from return air ducts in hospitals. In some cases that we have seen, such as in cruise ships but also in some buildings, there may be a risk of virus particles being spread through a system that shares returned air. 

Dr. Adler: It's actually interesting. I saw recently on the news how they need to rebuild some sections in the hospitals for the COVID-19 patients just because the air system is the same as the whole hospital and they needed to separate it in order to not pass the virus as you mentioned.

Dr. Chuan: Very good point, which is why it is important, Gabi, that if you happen to live in a building with such a system you should contact the operating manager and ask them to turn off the circulated air in the building or confirm whether there is air cleaning equipment in place. There are several high-rise apartment buildings in New York, I know, using a shared return air system. There are more in some other major cities. If you are not sure about the system type in your home, opening a window as the main way of ventilation is a good way to go.

Air Cleaning - Filtration and Purification

Lastly, we have air cleaning technology, including filtration and purification. Filtration targets pollutants such as particulate matter that Gabi explained before. Purification addresses gaseous pollutants like volatile organic compounds, VOCs, carbon monoxide, and NOx. To reduce the risk of airborne transmission, air cleaning technology can be used to capture particles in the air that are potentially carrying the virus. And if you decide to go with an air purifier for a family, look for one that is equipped with a HEPA filter, as they can remove particles even smaller than 0.3 micrometers in diameter through a physical process called diffusion.

Air cleaning technology that offers antimicrobial features is also very helpful. Another important thing to note here is that the concentration of air pollution indoors is never evenly distributed. So when considering where to put a HEPA air purifier it is a good idea to place it in the room or area that you frequently occupy so that the air purifier makes sure where you spend most of your time is as clean as possible.

Darwin Home Wellness Automation by Delos

Earlier Ronit mentioned Delos Darwin homes in Australia that integrate BreezoMeter data. I just want to briefly introduce the overall product to help everyone understand it a little better. Darwin is a home wellness intelligence platform designed to passively enhance your house and well-being. To do so, it continuously monitors indoor air quality by sensing the levels of several pollutants, including particulate matter and VOCs. 

When the levels of those pollutants exceed a set threshold, Darvin engages HVAC systems to remediate the situation through its air cleaning system. In addition to AQ monitoring, it also monitors outdoor air quality, which comes from BreezoMeter, and it is integrated into the overall dashboard displaying indoor environment conditions. We wanted our homeowners to be equipped with this information as the air quality is important everywhere, both indoors and outdoors, as knowing what is the quality of outdoor air can impact the decision making such as whether and when to open windows to let outdoor air inside.

Ventilation or Purification?

All right, before we go to the conclusions, I have mentioned that there are many reasons why people are not opening windows enough, like sensitivity to pollen, poor outdoor air quality, or simply it is too cold or too hot or too noisy outside. Here I prepared some practical solutions to help:

  1. If you are sensitive to pollen, especially given that we are right in the pollen season, consider using real-time pollen data to avoid the peak time during the day.
  2. If you live in a big city or near to high traffic, look at your local air quality index or pollutant data.
  3. If you feel discomfort when the window is open perhaps it is too cold or noisy outside. Consider using an indoor air quality monitor and then look at the carbon dioxide level. When the CO2 level is between 400 to 800 ppm or even lower your room is very likely well-ventilated already so you do not need help. You don't have such a need to open the window during those times.


Ronit: Thank You, Chuan, and thank You, Gabi. So, we've come to the end of our live event today and we do have a few moments to answer a couple of questions. I have one that can go to Chuan quite clearly, and one that's more directed towards Gabi. So Chuan this one's for you: how does Delos think about healthier home environments more broadly?

Dr. Chuan: Ok, thank you for the question. I think it’s a good one. It's addressing not only air quality but something else. So we focus a lot on IAQ - indoor air quality. But actually, that concept belongs to a bigger one IEQ - indoor environment quality. 

There are several more features at a home we want you to take into consideration, like the water filtration, to remediate the important water quality issues from all water sources in your home: kitchen, bathroom. We also want to address the aspect that mimics a circadian lighting system that can mimic natural sunlight throughout the day to balance your sleep and wake cycle. 

And finally, it also includes comfort-focused technology in your bedroom, for example, such as dynamic temperature control or automated blackout shades to create a supportive and comfortable sleeping environment that minimizes the potential disturbance, and promotes restful sleep. 

Ronit: Thank You, Chuan. We have one more that we're gonna pass to Gabby and then we're gonna part for today. Gabby, you mentioned before very briefly the high-risk populations for COVID. Is there a connection between this high-risk population and those who are sensitive to pollution?

Dr. Adler: Right. Thank you for the questionץ I think it's a great question because we touched on the connection between long-term exposure to air pollution and the COVID-19. But actually, the relation is two parts: we can divide it into the relation between long-term exposure to air pollution and some diseases, for example, different respiratory diseases like asthma or COPD, or heart diseases. 

The second connection is between people that are sensitive, older than 65 or have diabetes or have heart issues, or have respiratory diseases, and the severity of COVID-19. These people are likely to have more severe symptoms and sometimes unfortunately that also leads to mortality. So the answer is that yes, I mean, many many of these groups are shared in terms of the same people that are sensitive to air pollution are also the same groups that are sensitive to COVID-19.

Ronit: Thanks, Gabi. So now it's time that we're gonna say goodbye. I want to say thank you to Chuan and to Delos for being a part of this interesting event that we really enjoyed. And thank you to Gabi for joining us today. And lastly, I want to say thank you to all of you for being here with us, and we hope to see you at our next live event. Have a good one.

Dr. Adler: Thank you, Ronit.

Dr. Chuan: Thank you.