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Viruses & Designing For Health Outcomes In Buildings

This article will be updated as new research findings emerge. Details and nuance may change as we strive to keep up to date with the latest science available. If you have any information sources you think would benefit this writing, please drop us a line and let us know.

By Kristof Irwin, Diane Irwin, and M. Walker

Now, more than ever, there is a tremendous amount of attention on how interconnected we are to our immediate environmental conditions (and to each other) as the spread of the Novel Coronavirus has reached a pandemic level. As of writing this, the President has declared a State of Emergency in the United States in response to the situation. We can confidently say it’s a serious public health crisis.

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There are a great many resources out there about what you can do to prevent the virus’ spread in your daily lives, but rather than focusing on those here, we’ll point you in the right direction instead so we can focus on another perspective - the impact of building design/function on indoor air quality. The button below will take you to the Harvard Health Coronavirus Resource Center, which has loads of great practical information, FAQs, and other resources. If you have not already leveraged this resource, we highly recommend it.

In our own office, as have many other companies lately, we have instituted rigorous protocols for social distancing, hygiene, cancelling non-essential travel, and are encouraging virtual meeting for as many of our operational functions as possible. We’re even hosting our first ever virtual Building Science Philosophical Society meeting next week to keep everyone safe, but keep the monthly tradition going. We’re definitely still doing business designing great outcomes for projects, but we’re doing so as safely as possible.

More than anything, we want to give each of you a chance for calm. We will move forward together and continue to be a force for good and change in our world.

Designing For Health Outcomes In Buildings

We were inspired by the recent NYT Opinion piece, titled “Your Building Can Make You Sick Or Keep You Well” by Dr. Joseph G. Allen, director of the Healthy Buildings program at Harvard T.H. Chan School of Public Health, and wanted to take a few moments to clue you into the way Positive Energy thinks about buildings, their mechanical designs, and the impacts of our design/engineering decisions on indoor air quality. We are not claiming that any of the following suggestions will keep you or anyone from getting coronavirus, or any other pathogen for that matter. But we have a large body of epidemiological science - the study of public health and disease spread - to draw from in making good recommendations for healthier building outcomes. The information we’re presenting comes from relevant and peer reviewed epidemiological research and these data have long been guiding principles in our design practices. This is what the field of building science does well - taking what we know from multi disciplinary research bodies and creating applicable solutions for the real world to use in making better buildings.

Why this information, why now?

We are building science consultants. Our family, friends, colleagues and clients have been asking us about information that will help them reduce their exposures to pollutants, like viruses, in their homes, offices, and other indoor spaces. Our target audience is not other building scientists, but rather anyone who lives, works or spends time indoors. We’d like to communicate basic ideas about creating healthy indoor environments that people can remember and act on, rather than be comprehensive. Take these ideas and explain them to your mother, sister, brother, dog, etc. If they get it too, then we’ve all passed on some useful information and helped normalize these ideas.

We are the indoor generation. We spend most of our lives indoors. Just as fish spend their lives immersed in water, we spend our lives immersed in air. We spend our lives in fishbowls of our own making. This is particularly true for our homes and even more so for our bedrooms. We also spend our entire lives breathing!

“We breathe 12-16x/minute, 24/7/365 (30+ lbs per day)”

Unfortunately we typically don’t notice air because we can’t see it, but what you don’t notice does matter quite a lot. We know not to drink water from the rivers and streams in our cities, even if the water looks and smells fine. Air also has things in it that we can’t see or smell that are not healthy to take into our bodies, mainly by breathing.

What’s in our Fishbowl?

Many things are in our fishbowl and on the inside surfaces; some are living, some not. The particular indoor environments shape the impacts of these things in big ways.

Not living - Chemicals that come from what we do and what we bring inside our fishbowl

  • Cooking (e.g. bacon)

  • air “fresheners”

  • perfumes

  • scented cleaning products

  • that new sofa

  • rugs and carpets

  • etc.

Living – Creatures that also enjoy living inside, some we can see, most we can’t.

  • Can See

    • big dust mites

    • roaches

    • rodents

    • all the other hiding critters

  • Can’t see

    • viruses

    • bacteria

    • fungi

    • protozoa

    • archaea

    • etc.

Our Fishbowl Is A Microbiome

Let’s keep this simple. We all know Biology is the study living creatures. Microbiology is the study of living creatures that are too small to see with our eyes. Microscopic living creatures are called microbes. All living creatures live in certain habitats. The collection of living creatures in a certain habitat forms a biome. Microbes live in microbiomes.

Outside, we call this the outdoor microbiome, or “old friends” biome. Think fresh air, dogs, horses, goats, good old fashioned soil. It’s a healthy scenario generally speaking. Indoors, we call this the indoor microbiome. As you saw above, it’s where we spend a lot of time and it can be filled with some nasty stuff. Indoor and outdoor microbiomes have very different populations of microbes and our bodies generally do better with the outdoor microbiome. What’s really wild is that billions, even trillions of microbes live in and on our bodies. This is called the human microbiome. We need microbes to survive but they can cause us to get sick, or even die - the difference depends on the type of microbe and there are hundreds of thousands of types.

microbiome

So What About Viruses?

Viruses, bacteria and fungi can all make us unhealthy in the right conditions. Viruses can make us sick (or worse) when they reproduce inside our bodies. In order to stay healthy we avoid exposure to them so that we don’t breathe them in or let them in by touching them and then touching our eyes, nose, or mouth

Avoiding exposure doesn’t seem complicated, but the truth can prove otherwise - just look around at the negative health outcomes of any viral outbreak. We want to have less of them around us and we want to keep them out of the air and off of surfaces. This is made complicated by the fact that viruses can survive several days at normal indoor temperatures (65-75F) and relative humidity levels (40-60%). They can survive in the air or on surfaces for weeks longer if the air is either extra dry (30% RH or less) or humid (70% RH or more).

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But again, the core strategy is to keep viruses out of our air so they stay out of our sinuses, throats and lungs so we don’t get sick. Viruses move around when we sneeze or cough - they spray out (20’ or more) - then stay in the air, or land on surfaces and dust. They can move around when we do things that disturb dust like walking on carpet, vacuuming and sweeping. When we do these things and viruses are in the air on in our dust we will likely end up breathing viruses in because our bodies don’t filter our particles as small as most viruses.

As for the Novel Coronavirus specifically, let’s take a look back at Dr. Allen’s NYT piece we mentioned earlier:

Current guidelines are based on evidence that the virus is transmitted primarily through respiratory droplets — the large, sometimes visible droplets expelled when someone coughs or sneezes. Thus the recommendation to cover your coughs and sneezes, wash your hands, clean surfaces and maintain social distancing.

But when people cough or sneeze, they expel not only large droplets but also smaller airborne particles called droplet nuclei, which can stay aloft and be transported around buildings.

Previous investigations of two recent coronaviruses showed that airborne transmission was occurring. This is supported by evidence that the site of infection for one of those coronaviruses was the lower respiratory tract, which could only be caused by smaller particles that can be deeply inhaled.

This brings us back to buildings. If managed poorly, they can spread disease. But if we get it right, we can enlist our schools, offices and homes in this fight.


As of March 13th, a new report of findings by a research team at UCLA discovered that the Novel Coronavirus can live on certain surfaces, like stainless steel, for up to 72 hours in laboratory conditions. The same study found that the virus’ particles can remain viable floating in the air for several hours, which creates what’s called aerosolized transmission. What isn’t well understood yet in this research is exactly how many of those viral particles are necessary for an infectious dose, nor exactly how the virus will behave in non-laboratory conditions.

So what are some best practices we can employ in our buildings/designs to help keep indoor pollutants like viruses away?

Ventilation

Ventilation is crucial. Bringing in more filtered outdoor air in buildings heating/cooling systems (or opening windows in buildings that don’t) helps extract airborne contaminants from the building, making infection less likely. For years, we have been doing the opposite: sealing our windows shut and recirculating air. Just look at the residential code requirements for ventilation (or even scarier, look at the enforcement). The result are homes, schools, and office buildings that are chronically under ventilated. This not only gives a boost to disease transmission, including common scourges like the norovirus or the common flu, but can also significantly impair cognitive function.

If you don’t have mechanical ventilation in your home, make yourself a calendar reminder to open up the windows a few times per day/evening (whenever you’re home) for as long as you can. Obviously, depending on your climate this may prove difficult for thermal comfort or humidity introduction into your space, but still generally a good idea.

Back to the good Dr. Allen:

A study published just last year found that ensuring even minimum levels of outdoor air ventilation reduced influenza transmission as much as having 50 percent to 60 percent of the people in a building vaccinated.

Let that sink in.

Filtration

Keep viruses out of the air by using an appropriate type of filter. Especially for buildings without mechanical ventilation systems, or if you want to supplement your building’s system in high-risk areas, portable air purifiers can also be effective at controlling airborne particle concentrations. Most quality portable air purifiers use HEPA filters, which capture 99.97 percent of particles.

A HEPA filter lets air through but traps viruses (and other chemicals plus, bacteria, pollens and mold). Using a HEPA air filter connected to your central air/heat system can drastically decrease indoor air pollutants. This kind of air purification will reduce the viruses in the air, not just swoosh them around the room. However, remember that simply replacing a non-HEPA with a HEPA filter in existing equipment may worsen the problem. Make sure your system can accommodate the air flow needs of a HEPA filter. If your system can’t, you can explore a more decentralized approach through portable room air cleaners instead. Take a look at The Wirecutter’s recent review of portable room air cleaners for a pretty comprehensive list of consumer grade pieces of equipment you can buy online today.

Humidity & Temperature Control

Humans and viruses prefer different indoor temperatures and humidity to thrive. Use this to your advantage. Keep it dry. If you have a damp indoor environment due to the general climate, excessive cooking, washing, or bathing use a dehumidifier to control the indoor moisture. Keep it warm. Viruses thrive in cold environments. Setting your thermostats above 65 degrees will decrease the lifespan of most viruses.

And finally, we’d like to bring it back to Dr. Allen’s recommendations for operations:

Last, coronavirus may spread from contaminated surfaces — things like door handles and countertops, elevator buttons and cellphones. Frequently cleaning these high-touch surfaces can also help. For your home and low-risk environments, green cleaning products are fine. (Hospitals use E.P.A.-registered disinfectants.) Whether at home, school or the office, it is best to clean more often and more intensely when infected individuals are present.

Limiting the impact of this epidemic will require an all-in approach. With significant uncertainty remaining, we should be throwing everything we have at this highly infectious disease. That means unleashing the secret weapon in our arsenal — our buildings.

Remember that we’ll get through this. It’s an inflection point for us to realize how interconnected we are on the planet together. And remember, the same principles of design that create healthy buildings are almost always the same principals that create resilient, low carbon buildings.

Find your calm. Practice good personal, social, and building hygiene. Let’s use this new awareness to help us design better spaces to prevent future, potentially much worse outbreaks.


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