Our Buildings, Our Health

As we continue to uncover the human health impacts associated with buildings – a space in which we spend 87% of our lives – it is important that we find new and innovative methods of construction to improve overall health and quality of life for occupants.

On this episode of Buildings and Beyond, Robb sits down with SWA’s Managing Director of Sustainable Housing Services, Maureen Mahle, to shed light on the primary health issues found in buildings and discuss the various approaches, resources, and certifications designed to improve occupant health and well-being. 

Episode Guest: Maureen Mahle

Maureen MahleMaureen Mahle is an engineer and specialist in high performance homes. Her background in sustainable design and construction includes piloting several LEED programs for the U.S. Green Building Council and certifying over 13,000 green homes in 10 states. Maureen is an advocate for connecting health to high performance homes, and is both a Fitwel Ambassador and a WELL AP. Under her leadership, SWA is a 6-time recipient of the Indoor airPLUS Leader Award.

Episode Information and Resources

Green Building Certifications:

We Want to Hear From You!

Send your feedback and questions to


About Buildings and Beyond

Buildings and Beyond is a production of Steven Winter Associates. We provide energy, green building, and accessibility consulting services to improve the built environment. For more information, visit


Robb Aldrich | Kelly Westby

Production Team

Heather Breslin | Alex Mirabile | Dylan Martello

Next up on Buildings and Beyond…

Eric Wallace Headshot


Solar PV- The Revolution Continues 
Guest: Eric Wallace



Episode Transcript

Kelly:                                  00:06                   welcome to buildings and beyond

Rob:                                   00:09                   the podcast that explores how we can create a more sustainable built environment

Kelly:                                  00:13                   by focusing on efficiency, accessibility, and health.

Rob:                                   00:18                   I’m Robb Aldrich

Kelly:                                  00:19                   and I’m Kelly Westby.

Rob:                                   00:21                   This week I’m talking with Maureen Mahle, who’s the managing director of sustainable housing services here at Steven Winter associates or SWA as you’ll probably hear us call it. She’s been here for at least 12 years, has been involved in green building programs since leed for homes came out and many programs since then. I believe I read, she has certified over 12,000 homes or housing units since she started here. This episode we’re focusing on health and green buildings, which is a big topic, an important topic, a topic around which there’s a lot of different advice, a lot of different programs, advising not necessarily the same things. it can be overwhelming to many. It is overwhelming to me at times, but you have to start somewhere. So that’s, that’s what we’re going to talk about. Here’s my interview.

Rob:                                   01:17                   We’re here to talk about buildings and health or green buildings and health, which is a huge topic. So we’re going to scratch the surface and do an overview. And of course, health is a huge part of green buildings. It’s one of the tenants. But there’s a lot of confusion. There’s a lot of misunderstanding. There’s a lot of, there are a lot of different programs that say a lot of different things. And I know you’ve given it quite a bit of thought. it’s a huge topic. But having you give us a primmer or an overview of some of the issues and what some of the programs are good for and not so good for, that would be great.

Maureen:                         01:58                   Absolutely. So I guess I’ll start by saying I have absolutely no training and topics surrounding health whatsoever. I’m not a doctor. I have no medical background whatsoever. My mother was a nurse. That’s as close as I get. but in my role working on buildings and advising people who work on buildings, I actually have a lot of influence over human health as do all of us in this industry. So that’s kind of the base turn that got me interested in. This is starting from the place of: we’re not health experts and yet we have a big impact on health. Therefore, we have a duty to figure out some basic things and more importantly to start taking action. Even if we don’t have everything figured out. If we wait until we know the absolutes, we’re never going to get anything done. And we could potentially do more damage in the near term and in the longterm.

Rob:                                   02:56                   Gotcha. So code built buildings, what do codes do for us? Do codes give us any kind of basic level of health protection?

Maureen:                         03:08                   codes get into ventilation, which is important, mostly focused only on new construction. There are very few codes that retroactively address ventilation and buildings and ventilation is what we’re doing to basically remove pollutants. Ventilation levels set by code are intended to be sort of minimally safe. And there is a difference as we’re starting to find out between minimally safe and optimally healthy. Right? So there is actually a pretty big gap there. I can throw it out right now- one of the pieces of research around this is the cog effects study. And we’ll link that in the show notes for this. But you know, long story short and summarizing, you know, very, very briefly, it’s sort of like if you double your ventilation, you might be twice as smart roughly. So that’s the kind of thing we’re talking about is the difference between surviving, which is what code is aimed at, and living your life to the fullest and sort of like being in peak operating condition as humans, we want our buildings to be in peak operating condition.

Rob:                                   04:21                   So not only just do no harm but actually make environments better, right? Can we make ourselves healthier? So this is much more a topic were thinking about now, recently, you know, certainly more than 10 years ago and certainly more than 30 years ago. But you know, buildings are different, buildings are getting tighter. Is that one of the main reasons why it’s a growing concern or people getting more paranoid?

Maureen:                         04:50                   I think it’s a mix of factors. I think buildings are getting tighter. I think we’ve got more products from more places around the world than ever before. We’ve got more plastics, we’ve got more composites, we’ve got all kinds of stuff, some of which is touted to be healthy. But it may be evaluated for certain criteria or it may be touted as being green in one aspect, like because it contains post consumer recycled content, but it may not actually be healthy. Right? So we’ve got more products, we’ve got tighter buildings. We have people with more sensitivities and maybe more health conditions that they’re managing because we’ve had declining air quality, even outdoor air quality in places like the asthma corridor in the Bronx. We now have people that have environmental inflicted asthma and so then they’re going to be more sensitive to what’s inside their homes and their workplaces as well.

Maureen:                         05:43                   Right. So it kind of all trickles down. So its that kind of combination things. I think also, we are paying more attention to health and buildings because we have more information. I think it’s incomplete. I think it’s a little bit scattered. But in general we’re starting to see bits and pieces of information come through that. Some of the things we were promoting as being really great or maybe not so great and that’s not really new, right? I mean, we’ve been down this path with asbestos and formaldehyde and lots of things. But now we start to get more information and as we do, you know, we’ve got a responsibility to follow through and utilize that information. I mean, one of the resources that I think is really pretty cool now, is if you ever see these warnings from California proposition 65 on products, you see it on Amazon, right. And be like, oh, this has got that warning. And that’s a requirement to disclose if you’re containing chemicals known to cause cancer, birth defects or other reproductive harm in the state of California

Rob:                                   06:51                   Right. It’s always baffled me when I go and buy something- I recently I bought something on Amazon, I forget what it was- And it had that label on it. This product is known to cause cancer in the state of California.

Maureen:                         07:01                   Yeah. But nowhere else. Anyways. Different standards. So we can use other, you know, metrics that maybe some of the more progressive entities have adopted and sort of extrapolate those back to ourselves, and say, okay, maybe I don’t have to know it as a building science person and not a medically trained person. Maybe I don’t have to know everything. Maybe I can adopt these other proxies to help me figure out my way through this whole health in buildings question.

Rob:                                   07:31                   Gotcha. But as you said, we know more and more, like we know now asbestos is bad, and it should be avoided. We know radon is bad. But I guess that list is kind of is kind of growing.

Maureen:                         07:43                   Well, it is growing in some ways. In some ways I don’t Think that the basic list has changes. The Center for Disease Control and EPA and everyone has kind of agreed on these top risk factors, as human health is affected in buildings. And it’s tobacco smoke, right? Which, again, something not regulated by code per se. Maybe regulated by covenant or something other than a code or municipalities. Biological contaminants. So that’s most often things like mold. And again, code not necessarily addressing it. Combustion byproducts, which may be addressed by code.

Rob:                                   08:25                   To a certain degree, yeah. If you have combustion equipment in a building, there are certainly requirements how you need to vent it safely.

Maureen:                         08:33                   Human health is also affected by household products and practices and that’s really tough to control. But that’s where those consumer warnings, like the proposition 65 kind of come in like, hey, maybe air fresheners aren’t the best idea in the world. Right. That’s an example, but there’s lots of, you know, flame retardants in your couch and stuff like that. That are known carcinogens, basically.

Rob:                                   08:56                   Known- really accepted pretty much across the board? I mean, not just in California or is it a range?

Maureen:                         09:03                   I’m sure there’s a lot of ambiguity in there. I think that, I, for one, am willing to trust some of the folks that have done the research, like the healthy buildings resources at the center for healthy buildings, places like that. I don’t know. I mean, yes, we could investigate every single one ourselves, but as practitioners, I don’t think we have the time, the funding, the bandwidth to do that. So yeah, we’re kind of accepting some of these proxies, especially the ones that are cited in multiple sources by multiple sources and multiple locations. So we’re kind of starting at the high level there. And toxic materials I think is going to continue to probably change the most in the near future as those things are defined a little bit differently. We’ve really had this approach in this country where all materials are innocent until proven guilty unlike, you know, drugs or food or other things, which from my limited understanding of those industries are sort of guilty until proven innocent.

Maureen:                         10:06                   It’s absolutely the opposite in building materials. It’s like slander if we say that, you know, vinyl is bad for us until it’s been proven in multiple lawsuits. Another big one on this top 10 toxic things from CDC is radon. And you mentioned that briefly, it’s a huge problem in the northeast as well as other parts of the country. And this is one where it’s really tricky because the EPA recommended levels for Pico Curies per liter are not what’s recommended by the health entities. So this is a place where for all intensive purposes, code is in conflict with what health people are recommending. They’re recommending two or lower. The World Health Organization has figured out that if you dropped the number from four to two, you would cut the instances of lung cancer caused by radon in half.

Rob:                                   11:03                   Now with radon in this, I don’t want to go down a rabbit hole, but it’s tricky to monitor radon down at levels that low. I understand. I thought one of the reasons it got stuck at four is because we can’t really measure more accurately below that with affordable tools. When everybody wants to buy a house, you get the little packet. Those aren’t maybe as accurate, but maybe that’s, maybe, that’s a red herring

Maureen:                         11:27                   I think there are questions around the accuracy. The radon professional I hired at my house told me, for example, in my conditions where we’ve got humidity in the basement, which is one of the places I wanted to test, because it’s outside the condition envelope- He told us to use the, scintillation liquid tests instead of the activated carbon tests. So there’s some things you can do with those home tests, but yeah. And, and it changes over time. It changes seasonally, so you kind of have to stay active a little bit and keep participating in your own personal radon monitoring if you want to maintain safe levels.

Rob:                                   12:11                   Yeah. And that’s something I think we talked about. Well, we’ll talk about that when we want to talk about what do we do? And there’s proven things that are bad for us, right? There are some proven practices that are good for us. We have to go beyond code. You have to embrace some programs. And I know you’ve gone through several programs in respects to health and indoor air quality, and they’re not all the same.

Maureen:                         12:42                   They’re not all the same. I mean the one that’s probably at the top of the list in terms of people’s familiarity, if they’d been watching this conversation develop over the last five years is WELL Building Standard. It’s something that is aggressive, thorough, addresses all aspects of health as has been determined by the international well building institute. So everything from the food that’s offered in buildings, to the ventilation, and the other things that we’ve been talking about, and the materials for sure- they get into water quality, which very few other green building rating systems do. And one of the things that they always sort of tout, one of the statistics, actually comes from the Center for Disease Control. It talks about what the various social determinants of health are for an individual. And they are citing this group of studies that talks about the fact that your genetics actually only makes up about 5% of your health outcomes, which is not what we would instinctively think, right?

Maureen:                         14:02                   You’d ask people what’s gonna determine your health and they think, “oh, it’s got to be like, you know, 60% genetics and 40% lifestyle choices.” Nope, it’s not. The Center for Disease Control is saying that genes or your biology are less than 5%. Your lifestyle is around 20%. The medical care you receive is about 15%, and your physical and social environment, which is where you live- discrimination, income, your gender, all that stuff- is at least 55%. So the catchphrase is like, it’s not your genetic code, it’s your zip code.

Rob:                                   14:41                   Do those one more time real quickly

Maureen:                         14:46                   Sure so genetics and biology is less than 5% of your health outcomes. Lifestyles responsible for about 20%, the medical care you get is about 15%, and then your physical and social environment is 55%. Buildings lie there. I mean, how big a portion of that is, you know, I can’t say, but it’s probably bigger than your genetics. Right? So, I mean, that’s the kind of thing that really spurred me to start looking at this and figuring out what we can do, because pretending that we’re not having an effect on people’s health in the building science industry, in the architectural or engineering or buildings development industries, is false. We don’t know where to start, so we do nothing. And that is where I think that these rating systems and so on are valuable.

Maureen:                         15:47                   And I’m not necessarily saying do the whole rating system, but I’m saying if you don’t have the time to research all of these aspects to the zillions degree yourself, refer to these as tools, compare them to each other, pick out the parts that seem to apply the best to your project or your circumstance or what you can control in a project, and then do something. Right. So that’s kind of what I advocate for. So if you think water quality in your building might be worth exploring, WELL Building Standard is the only one that seems to have much of a reference at all for water quality. So use theirs. I don’t know if it’s the best. I don’t know if it’s the ultimate, but it exists. It’s clearly written down and you can test for it. So it’s practicable I guess. So that’s why I would recommend that, but it’s not the only one for sure. Fit Well is an interesting one that’s getting a lot of traction. It’s a lighter touch than WELL, totally different organizations, but similar in that it attempts to address these various health factors. It was originally designed for commercial office buildings, but now they’re branching out into residential versions and things like that. it’s designed to be more of an entry level. Like if WELL is let’s say the platinum standard, fit well is sort of the, “I don’t know what to do, where do I start?” Start here.

Maureen:                         17:26                   So that’s, that’s a program to consider. And then I think it’s important to recognize that things that have been around for quite a while, including the LEED family of rating systems, including enterprise green communities, those have all kinds of health elements baked into them. Some as prerequisites, some as optional points. So if you actually look at those top 10 CDC risk factors of buildings and how they affect human health, and you map it against something like the Leed rating systems, they do something for every single one of those aspects, but it might be optional. It might be a prerequisite. So just because you’re getting one of those certifications doesn’t mean that you’ve necessarily built an optimally healthy building because you can skirt certain ones of them and you can do other things well, but then drop some major pieces of the puzzle. However, if you wanted to, you could use the guidance that’s in those rating systems to build a pretty healthy building.

Rob:                                   18:28                   And Energy Star has one too, right?

Maureen:                         18:32                   They do, indoor air plus. It was designed to be an accompaniment, and that’s very interesting because these pieces are all a little bit different. These rating systems are a little bit different. Indoor air plus was written for builders to read and implement themselves. It’s residential, but it’s also very prescriptive. It’s like, “do this, do that, avoid this, put in that” which is kind of a nice place to start actually. What it doesn’t touch on, which is actually what WELL and Fit Well are super heavy on, is any of that sort of end-user choice about things like how are you actually going to operate your systems? What kind of furniture are you going to put in there? What kind of chemicals are going to be in that furniture? You know, those sorts of things. So the responsibility under that type of a program under indoor air plus really stops at the day that you turn over the keys.

Rob:                                   19:28                   Yeah. And that’s a great point with that, as far as you know, it’s not just the specs you use to build the home. We talked about radon briefly because this is installing a passive radon vent is pretty typical in new construction. And then the idea, as you said, you know, you can test after construction and if you have a problem you can add a fan and make it active and really mitigate radon. How many people follow up and do the testing to actually check for radon and see if they need to add a fan or do a more rigorous solution.

Maureen:                         19:56                   I mean, that’s one of the challenging things about health and buildings, is that it spans all the way through. And if you drop the ball anywhere between design and 15 years of occupancy, you can undermine what you set out to do. But that isn’t to say that we should put it all on the occupants, and sometimes that’s the trend, right? I mean, one of the topics I like to talk about, that’s a great example where design really matters, is the active design concepts about how buildings are designed in the first place to allow people to, and entice people to, move physically and engage in and have opportunities for exercise and have inviting stairwells. I tried to take the stairs out of a parking garage the other day and we kept getting stuck. We literally wound up back in the same place four times because we kept hitting dead ends right. And we were following the exit signs and we couldn’t get out. So that’s a design choice. That’s not the end user. End User was trying to do their part to walk up the stairs. And it’s not just about stairs, there’s a lot of pieces to that. I’m simplifying, but you know, that’s an example of why it kind of all starts in the beginning. But you gotta you gotta follow it all the way through.

Rob:                                   21:13                   Excellent. Excellent. Huge topic. Any other big pieces? I’m sure we’re going to want to dive into more of this in future episodes.

Maureen:                         21:23                   I want to just encourage people not to be stymied by the fact that it is a huge topic. Pick something, pick one thing that peaks your interest and do it on your next project

Rob:                                   21:34                   and manageable, it’s practical and manageable and you can do it. Yeah. Nice. So if we talk about this again in five years, what do you think we’ll be talking about? What will have changed?

Maureen:                         21:45                   Oh Man. I think, you know what? I think we’re going to see a lot of change around that material sector and I am imagining that things will start to cause cancer outside of the state of California.

Rob:                                   21:56                   It’s also true on the sensor side of thing. We’re getting many more low cost, more affordable sensors so people have the capability to actually evaluate conditions a lot more.

Maureen:                         22:06                   That’s a great point. Yep. people will be taking more ownership of evaluating the health of their environments and then they’ll hold other entities including manufacturers and designers accountable

Rob:                                   22:19                   and consumers can actually assess their indoor air quality. And make changes. Awesome. Thank you very much, Maureen.

Maureen:                         22:31                   Thanks for having me on.

Speaker 4:                        22:37                   Thank you for listening to buildings and beyond. For more information about the topics discussed today, visit and check out the episode show notes. Buildings and Beyond is brought to you by Steven Winter Associates. We provide energy, green building and accessibility consulting services to improve the built environment. Our professionals have led the way since 1972 and the development of best practices to achieve high performance buildings. The production team for today’s episode includes Dylan Martello, Alex Mirabile, and myself. Heather Breslin, thank you for listening and we’ll see you next week.