The average person in the US spends roughly 90% of their life indoors, according to Harvard researchers Joseph Allen and John Macomber, authors of Healthy Buildings: How Indoor Spaces Can Make You Sick―or Keep You Well. It’s a statistic that took on new weight over the past few years of Covid, as we collectively reconsidered the mental and physical health implications of our built environment—and one that feels especially salient right now, as more employees are returning to office buildings and employers are rethinking what those buildings look like.
To better understand what workplaces can do to make their physical spaces more conducive to worker health, we reached out to Allen, an associate professor of exposure-assessment science at the Harvard School of Public Health. Here is a transcript of our conversation, lightly edited for clarity:
What is a healthy building?
It's thinking about places that we spend all of our time in—offices, homes, schools—and how they can be designed and operated in such a way that they are optimized for human health and performance. For the past 40 years, we've done the opposite. We've designed our buildings without a health-first mindset, and that's the reason we've been in what's known as the sick building era for the past 40 years. We’re in buildings that underperform. You walk into them and you don't feel alert, it's not comfortable, you can't think straight. You get a headache and sometimes worse. That's largely because public health hasn't had a seat at that table when we think about the design standards around buildings. And so the idea of the healthy building is, let's flip that script. Let's move from the sick building area into the era where buildings are designed for people.
I'll often start a presentation by asking people to calculate their indoor age. So take your age, multiply it by 0.9. And when you start to think of it that way—I’ve spent years of my life breathing the air inside these buildings—you wonder, is it healthy? I usually follow that with asking people to think about what they know about healthy living. And everyone answers the same things: exercise, eat well, don’t smoke cigarettes. How many people then turn to these places where we spend all of our time as next on that list? Not many. It’s been ignored in our conceptual model of what it takes to lead a healthy life.
To what extent does mental health play a role in the healthiness of a building, and how?
Something like air quality, which definitely influences physical health, is also going to influence mental health. It's going to influence cognitive function, performance. You could think about the role of nature, how we've designed buildings largely to wall ourselves off from nature, and the new push towards biophilic design and bringing nature back in, which has clear mental-health benefits. We all know being connected to nature is good for us, but it has been backed by quantitative research that it’s linked to better creative performance, better stress recovery.
A lot of times we think of health in these different domains: I’m thinking about Covid and that's infectious disease, or I'm thinking about productivity, or I'm thinking about mental health and wellbeing. It's all related. Health is not just the absence and disease. It's about thriving, flourishing. My interest is demonstrating that the building plays a central role in all of that, because we spend so much time in these places and we haven't leveraged all the great science that's out there in terms of how to do better with our buildings.
You mentioned that we've been in the sick building era. How far do we have to go before we're out of it?
We're clearly in that era, but the difference is that now there's been an awakening. When Covid hit, we had a virus that spread nearly entirely indoors in under-ventilated spaces. It forced this population-level awareness of, ‘Wow, the indoor space is really having an influence on my health.’ So the solutions we've been talking about, better ventilation, better filtration, might be the first time some people start to look at their buildings and think, ‘Well, where do I stand on this? Am I hitting these enhanced targets?’
I'm optimistic because of that awareness. We've been talking about this for a long time now. It's in the public consciousness. For the first time ever, the White House held a summit on indoor air quality. I was there and I couldn't believe it, because our field has been so ignored for so long, and now you have the biggest bully pulpit in the country saying this is important. So I think there are some fundamental shifts that have happened that mean we're ending that sick building era, that give me confidence that we are entering the healthy buildings era. The scientific and medical literature is being rewritten around airborne transmission. There was a lot of debate about how influenza was transmitted. For a year and a half, there was debate about how the Covid virus was transmitted. But that debate is over. In the top medical journals— the Lancet, JAMA, the New England Journal Medicine—there have been shifts. You have the top people in government talking about this.
We'll never have another pandemic response that doesn't include buildings right away, the failure we had with this pandemic. Public awareness has changed. People are talking about this. They have CO2 monitors out. I often share that my neighbor talks to me about MERV 13 filters. This was not a topic of conversation prior to the pandemic. And I see organizations from nonprofits and schools to the biggest multinationals changing their approach to their buildings. That keeps me optimistic that this won't be forgotten once we're through with Covid, whenever that is.
What should workplaces be doing and thinking about at this point regarding Covid, especially as a lot of organizations are rethinking their office designs?
First and foremost, you have to recognize how this virus and other respiratory viruses spread. They're spread through the air. Respiratory air cells travel beyond six feet. That means the building matters. So if you start from that, how it’s spread, then the rest flows naturally. If you want to prevent the buildup of respiratory particles, you have to pull it out of the building with good ventilation or clean it out of the air with filtration. So organizations should be thinking about beyond the current minimums, because the current minimums of ventilation filtration are not designed for health.
The standard for ventilation right now is called the standard for acceptable indoor air quality. The problem with the name ‘acceptable’ is, it's a minimum. The typical filter that's used is designed to protect equipment, not people. We need filters that are designed to protect people. We need ventilation standards that are designed for the health of people, and that hasn't been the case. This isn't hard, it's not expensive. It's not the case that only shiny new buildings can do this work. Any building can be a healthy building. So I'd focus right there, because the strategies are going to be good for influenza, coronavirus, whatever hits us next, RSV. It's going to be good for managing outdoor air pollution. It's good for filtration against pollen and other allergens, protection against wildfire smoke. So you shouldn't think of these strategies as Covid strategies. They're just general public-health strategies that keep your employees healthy, keep them from getting sick, and also help them perform their best in your space.
What are the other important considerations in this space for business leaders right now?
There are some important things that businesses should be aware of. I wrote an article in Harvard Business Review two weeks ago talking about this. When Covid hit, we had this big pendulum swing towards ventilation, filtration. We have a climate crisis that's happening at the same time, and there's this impression that our healthy buildings movement and green buildings movement are at odds. ‘I want better ventilation, better filtration, and that comes with an energy penalty. How am I going to meet my energy efficiency goals?’ But I show in that article how it's this false dichotomy, and there are ways to have both a healthy and green building. So I think business owners should be recognizing that the healthy building movement is here to stay, and it’s going to have to merge with our green building efforts.
Early in the pandemic, I, others, ASHRAE—the standard sitting body for ventilation—told people, bring in more outdoor air, use better filtration. Several of us then gave targets. You can't tell people to bring in more outdoor air without saying how much. But ASHRAE had not put out targets. The Covid commission I chaired for the Lancet, we put out a report this fall with specific numbers on ventilation. ASHRAE followed up with that and said, by May of this year or April of this year, they're going to have specific targets. So why is this important for business leaders to pay attention to? Whereas before you might have been able to say, ‘Yes, I improved my ventilation,’ when these targets get published, someone may ask you, ‘Yes, but are you hitting this specific target?’ Someone's going to say, ‘Well, are you hitting four to six air changes per hour?’ It's a different question. It'll be a different level of accountability. And I think business leaders should be aware and not get caught off guard.
In your book, you wrote about the building as a human-resources tool. What does that mean in practice?
I'll say it this way. When I got my appointment at Harvard, one of the things I negotiated on was my office. I know the place where I work is going to influence my health. I have a great office. I'm looking out over a tree line. I selected this. I interviewed my building.
People interview their office for all sorts of things: Where am I going to work? Does it look good? Is it interesting? Is it a cubicle? These healthy buildings become a strategy for recruitment and retention. And then when you have the people there, you're ensuring their performance is optimized. We talk about this in the book, where we look at Glassdoor and people are talking about the building. ‘It’s too hot in here. I can't concentrate. The air quality's bad. This feels like being on a virus-infected cruise ship.’ Great talent you're trying to recruit is going to see that. But if your building's performing, then you would see the positive attributes. And I think what the pandemic has done has made it that healthy buildings are table stakes. Now, who's going into a building that's not healthy? The expectations have changed. A couple years ago I was working with the facilities team at a big company and they called me and said, ‘Hey, for the first time, HR called me because they're about to hire somebody, and they asked about the building and the healthy building strategies.’ This was before the pandemic. So you do have people asking about it, and if you don't have an answer, you're going to get caught.
What does it mean for employees to ‘interview’ their building?
During the interview, people are interested in the values of the organization: ‘What do you do on sustainability? What are you doing for climate? What are you doing for equity, diversity, inclusion?’ You could ask, ‘What do you do on healthy building strategies? Have you enhanced ventilation?’ And without having to be technical, you'll learn a lot just from that answer. If they stare at you blankly, there's your answer. A good organization's going to say, ‘Yeah, we have a great diversity, equity, and inclusion plan. We are committed to green buildings and energy efficiency. Here's what we do on climate. We've enhanced all the ventilation. We have great filtration. We have green cleaning products. We're really integrated in this healthy buildings, green buildings space.’ You don't need to know anything more than that to know that the organization has prioritized your health in the right way. You don't have to ask, ‘Are you hitting 30 cfm per person?’ or ‘What grade filter do you have?’ Just ask the question and see the answer you get back.
To your point about recruitment and retention, it feels like ‘We have really good air quality’ doesn’t carry the same weight as ‘We have these great benefits, we have this great culture.’ What are the best practices there for actually providing that information in a way that makes a difference?
It's a real challenge, but you have to communicate it because good air quality is invisible, right? They'll walk in and they'll see your foosball table, they'll see paintings on the wall, but you have to communicate to them that this is a building that's performing with their health in mind. I do think it's a differentiator. Maybe it's my bias in the field of public health, but if I walk into a company and I know they're taking air quality seriously, that tells me a lot of other things about the organization. They're on top of the latest science, they’re prioritizing their employee health. And also, it's just good business. You perform better when you're in a place you want to be, that feels good, where the air quality is good.
And there's been a proliferation of these lower-cost, real-time air-quality sensors. So we're all familiar with that concept in one way or another, like the thermostat on the wallet for temperature. There are now similar devices that will give you carbon-dioxide concentrations, which indicate ventilation performance. You'll have information on particles, outdoor air pollution that penetrates inside. So there's a movement right now to deploy these kinds of sensors because it makes the invisible visible, and then communicate that.
We've done this at Harvard. Early on in the pandemic, my team deployed an air-quality monitoring network around the school. We shared the data with faculty, students, staff, and we communicated that we're on top of our buildings and we're also monitoring this. And if something changes, we're going to fix it. So I think that's where the field is going in terms of communicating air quality.
What do employees have a right to expect from their employers in terms of building healthiness? And on the other side, what do employers have an obligation to provide?
Clean indoor air is a human right. We have things like national ambient air quality standards for outdoor air, but very nothing similar for indoor air. But employees should expect an environment where they don't get sick first and foremost, but it goes beyond that. A place where you flourish, where you can perform your best. You feel good being in this space. And it's not just that absence of disease we should be chasing, it’s the positive attributes. That's where the expectation should be. I don't know why we've accepted this sick building era for so long. I've been doing these forensic investigations for a long time. I've seen a lot of sick buildings. But there was never a building we couldn't turn into a healthy building with just a little bit of attention. I think it largely escaped the public's notice because you assume, ‘Well, of course this is healthy, we designed buildings to code.’ And code is good, but code is a bare minimum. And so it's really quite frustrating. But it's also why I'm hopeful that we're going to leave that era behind us, because the public is just way too aware of the problem at this point. We just accepted that a lot of our buildings were underperforming, our schools were underperforming.
Let's say I'm an employer who rents my office space. What’s within my power to make my workplace healthier, and what do I need to lean on the landlord for?
The landlords and the tenants have to work together on this. You could think about having that conversation: What kind of air is being delivered to the space? What kind of filtration? What's being delivered into the space I've leased or rented? But then there are things you can do in your space too. You can make better decisions in terms of the materials you select. So using things with low VOCs or lower loads of other classes of toxic chemicals. You can also modify that indoor space even if the base building can't be modified. You can use portable air cleaners, which are great for capturing particles out of the air. You can use portable humidifiers to change the quality of the air. You can do improvements around lighting and biophilic design.
So there are things that you can do in the tenant space, even if the base building is not doing that. But the best strategy is one where they're both aligned and it's in everyone's interest. It's in the landlord's interest to provide a good building. Which building is the future tenant going to go to? An unhealthy building or healthy building? Clearly they're going to go to the healthier space.
Are there any principles from healthy building design that remote workers can incorporate into their home work space?
The principles are the same, but the change that has happened with work from home means that we think about our space differently, in the sense that you might have a room where you want to relax and sleep and you have a room where you need to be hyper-productive. It might be the same room for some people, or it might be one doorway away. But we can modify the indoor environment to be optimal for both conditions. When I'm in my office, I want to be productive. I want great lighting, I want good airflow. I want good ergonomics. Think about your whole setup. And when I leave that room, I want the lighting to be a little different. You're trying to create a space that's a bit more relaxed or a place that you sleep better. But the fundamentals are still the same in terms of, you want clean air, you want good ventilation rates, humidity. You can choose better products, manage dust levels in the space, capture allergens and things like that. So it's different being home or in the office, but a lot of the fundamentals of the healthy buildings movement apply to both, depending on what you're trying to optimize.
Can you talk about your work on the CogFX study and what your research has shown about the link between air quality and productivity?
We did a series of studies we call the CogFX effects study that looks at how indoor air quality influences cognitive function, the influence of air quality on decision-making and performance, things like strategic thinking. How do you respond during our crisis? How do you search out and utilize information? What we find is that controlling for all other factors—Did you just have coffee? What's your baseline cognitive function?—the air quality matters as well. And the results are really striking, because when we model this out in terms of the economic impacts, we estimate that the cost to achieve these healthier building ventilation standards is in the order of tens of dollars per person per year. And the benefits are in the order of six to $7,000 per person per year.
So when you take the CogFX study, which we've done in a lab, we've done in buildings across the US, and we've done replicated in buildings around the world with the same results, you see that indoor air quality becomes a worker productivity issue. Think about the business case for healthy buildings. On an individual level, breathing better air is better for cognitive function and performance, and in our book, we roll that up into what that means for business. What we find is if you make these improvements, it leads to reductions in absenteeism, better cognitive function, and leads to 10% gains to the bottom line. You could roll that up even further. Our colleagues down the road at MIT did a study showing that healthy buildings commanded higher rents per square foot. You could take that to another level. There have been studies looking at the macroeconomic benefits: over 20 billion in benefits to the US economy with improvements to indoor air quality. So whether you look at an individual level, a business level, an investor, owner level, a societal level, there's a business case to be made.
I'm a public-health professor, so I'm interested in people's health as the ultimate goal, but it's also just good business. And if we can motivate organizations to make this decision for the health of their employees, for the health of their business, then it's a win-win.