Indoor Air Quality and Energy Efficiency: Part 2
Indoor air quality (IAQ) stands at the intersection of the public health and energy fields. Since the early 2000s, CEE has conducted several field research studies measuring secondhand smoke (SHS) in multifamily buildings and hospitality venues. Part 1 of this interview laid out the connections between IAQ and energy efficiency. In Part 2, I asked Director of Research Martha Hewett and Director of Indoor Air Quality Dave Bohac how the SHS projects overlap with their building science research.
Anna: When I think about CEE’s research areas, SHS stands out as different. I’m curious how you first got interested in the topic.
The Association for Nonsmokers - Minnesota (ANSR) was hearing complaints from renters about secondhand smoke coming from other apartments and trying to help them deal with the problem. ANSR wanted measurements to quantify the extent of SHS transfer between apartment units. CEE was already interested in the dynamics of airflow in multifamily buildings, which is an issue from both energy and general IAQ perspectives. There are a lot of linkages between the IAQ and energy aspects of multifamily building performance. For example, in the winter vertical air movement in multifamily buildings (“stack effect”) causes first floor units to have more infiltration and be cold, while top floor units may be overheated. It also moves contaminants from lower apartments to upper apartments.
Our first project looking at SHS in multifamily buildings wasn’t so much an exposure assessment, but trying to better understand how air moves from unit to unit, how much air is transferred, and what could be done to reduce air transfer through air sealing and ventilation improvements. The air sealing part ties in nicely with our experience in single family houses. And we had completed ventilation improvement projects in multifamily buildings through the Metropolitan Airport Commission (MAC)’s aircraft noise mitigation program.
SHS is carried along with the bulk air transfer between units. And that air movement was certainly something we had experience evaluating. As Martha says, it ties in nicely with some of our work on multifamily energy issues.
Working with ANSR, we proposed our study of SHS transfer in multifamily buildings to the Minnesota Partnership for Action Against Tobacco (now ClearWay Minnesota). We were really the only organization in Minnesota proposing projects to measure secondhand smoke in the air. Other people were taking urine samples and looking at metabolites of nicotine, but that’s a really different thing. We had the equipment and experience and capabilities to answer a lot of questions that were of interest for tobacco control policy in the state.
Smoking bans in bars and restaurants were a very hot topic, and tobacco control and public health interests were trying to pass smoke-free legislation in Minnesota. After our first multifamily project, ClearWay Minnesota funded us to conduct exposure measurements in bars and restaurants. It was a little bit of an expansion of our capabilities but still tied in nicely.
Ours was one of the few studies of SHS in hospitality venues that actually selected a probability sample of businesses and considered the different types of restaurants: full service, limited service, and bars. We took measurements at different times of the day and on different days of the week to characterize the variation in concentrations. We recorded the details to really see how people’s exposure varies by when they go out, and to which type of venue. We also compared SHS levels in the smoking and nonsmoking sections of restaurants, which showed that the typical practice of designating separate areas of the same space as nonsmoking provides very little protection from SHS.
We worked with Lara Gundel and Mike Apte at Lawrence Berkeley National Lab to measure gas phase tracers of secondhand smoke as well as SHS particles. Ruiling Liu, a graduate student of Kathie Hammond’s at UC Berkeley, worked with Kathie and Mike to conduct a formal health risk assessment using our data, projecting the number of lung cancer and heart disease deaths due to smoking in hospitality venues in Minnesota.
When Minnesota passed its smoke-free legislation in the middle of our research, we were able to go back and do monitoring in almost all of the same venues with the ban in place. Those before and after measurements showed a median reduction in particle concentration greater than 95% at all three venue types.
Anna: So I’m hearing that the SHS projects drew from your experience with both building science and indoor air quality. To flip that around, what implications does your work with secondhand smoke have for improving the efficiency of buildings?
Our first multifamily SHS project included air leakage tests of individual units that looked at not only the leakage between units, but also the leakage to the outside. Our results were probably some of the most extensive data on individual units ever generated in the U.S. This info has both energy and IAQ implications: How leaky are the units? How much heat is being lost due to infiltration/exfiltration? Are the apartments leaky enough that it’s cost-effective to tighten them, and can you can do that without raising indoor air quality concerns? In Minnesota, the code requirements for building tight envelopes and including mechanical ventilation have lagged in MF buildings compared to the requirements for single family houses. How can you upgrade ventilation systems in ways that both improve IAQ and use energy efficiently?
And there are other issues with multifamily secondhand smoke that relate to building performance. In cold climates like ours, mid or high-rise building have problems with stack effect, as I mentioned earlier. You know how sometimes it’s hard to open the door to a downtown office building in the winter?
It’s because of a huge suction – or negative pressure – at the bottom of the building. That suction causes air to go into the building at the bottom, rising up because it’s warm inside, and going out the top. If each floor was completely compartmentalized from the floors below and above it, you wouldn’t have that problem. Some of the things that we learned in our multifamily building study relate to compartmentalization and stack effect, how to control it, and how much you realistically can control it.
Anna: Wow, a lot of that experience does carry over nicely. Can you see any difference in how the results from your SHS research are being used in the public health field as opposed to in the energy field?
Our building testing and the related surveys of renters and landlords were some of the earliest work in this area. On the public health side, ANSR really took that research and ran with it. Their efforts have helped to move that whole field along. Here in Minnesota they have established and maintained effective working relationships with key multi-housing organizations. They’ve developed materials that speak landlords’ language, address their business concerns, and provide tools and guidance that make it easy for them to adopt smoke-free policies. They’ve developed a website - Live Smoke Free - to promote the growing number of smoke-free apartment complexes statewide. They’ve worked with apartment-finder magazines to develop icons to “tag” smoke-free properties in their advertising.
Nationally, they’ve been a key player, too. Most recently, they’ve had funding in 2012 to provide technical assistance on smoke-free multi-housing nationwide. Through that, they’ve trained people in New York, Rhode Island, Florida, Iowa, South Dakota, Arizona, New Mexico, Wyoming, and Montana on how to set up smoke-free multi-housing programs. There work has helped to change how the issue of SHS in multi-housing is perceived.Ten years ago, landlords were concerned that making a building smoke-free would be discriminatory. Today, the U.S. Department of Housing and Urban Development, which enforces federal fair housing laws, explicitly states that landlords can make apartment buildings smoke-free and actively encourages public housing authorities to do so.
On the bar and restaurant stuff, Dave, I think you testified at some hearings?
Yes, at Hennepin County when they were considering repealing their smoke-free legislation.
Through some work that Dave did with the Minnesota Institute of Public Health, we provided some of the technical information used by advocacy groups to get smoke-free legislation for bars and restaurants statewide. So in the public health sphere, I think our research has been used quite a bit. Maybe you want to talk more about how it’s been used in the building science community, Dave?
There are probably two main things that came out of our first project on multifamily secondhand smoke. One is that our monitoring showed conclusively that nicotine was being transferred from a smoker’s unit to a nonsmoker’s unit. There might have been some people out there that understood there was air transfer between apartments, but a lot of people look at an apartment’s walls, floors and ceilings and think, “how could air transfer from here to someplace else? There’s really no obvious openings.” For those that were skeptical, we showed documented evidence that, yes, this is happening.
The other thing we were able to show is that you can seal leaks and improve the ventilation system to help reduce the transfer of SHS, but you can’t ever really eliminate the transfer from unit to unit. As the U.S. Surgeon General has stated, no level or concentration of SHS can be considered safe. Any kind of transfer presents a health risk, and it’s going to be an issue even if you do this sealing.
Those are two real key pieces. In the energy field, if you reduce air transfer by say 50%, that’s a good thing, you can live with that. And if some of your ventilation is coming from places you don’t really want, it’s okay from an energy perspective. But from a health perspective it’s still a concern.
A lot of people think of SHS as an issue from the perspective of lung and other cancers, but it is even more of a public health concern due to its effect on cardiovascular disease. Work that Repace did suggests that SHS causes about ten times as many deaths from cardiovascular disease as from lung cancer. There have been about a dozen observational studies that have shown really substantial decreases in heart attack rates after smoking bans have been passed in different cities. SHS is a major public health concern.
Anna: Anything else you want to say about SHS?
We also have a little bit of unpublished data looking at how long the nicotine levels in the air persist after a bar and restaurant smoking ban goes through. This third-hand smoke topic is starting to get a lot more interest. Nicotine sorbs to the surface while people are smoking and then a long, long time afterwards it out-gases. That’s a big part of the reason why after a smoker moves out of an apartment unit, there’s still a smoke smell coming from carpeting and all the walls.
Anna: It’s third-hand smoke?
It’s third-hand smoke, it’s the stuff that’s out-gassing. Another issue is that other people have documented the fact that more bars and restaurants put in outdoor patios when states or countries pass a smoke-free policy. So in another ClearWay-funded project we did monitoring on bar and restaurant patios to determine the extent of SHS exposure. We found that for short periods of time, if you’re near enough to a smoker and depending on wind conditions, you can be exposed to SHS at the same concentration as if you were inside a smoky restaurant or bar. The exposures just tend to occur only when people are smoking around you, whereas indoors, SHS lingers. It takes awhile for it to get diluted and ventilated away.
Anna: Thanks for taking the time to explain all this.
Related journal articles:
D.L. Bohac, M.J. Hewett, K.I. Kapphahn, J. Novacheck, D.T. Grimsrud, M.G. Apte, M.G., and L.A. Gundel. 2012. Secondhand Smoke Exposure in the Nonsmoking Section - How Much Protection? Nicotine & Tobacco Research.
M.J. Hewett, W.H. Ortland, B.E. Brock, C.J. Heim. 2012. Secondhand smoke and smokefree policies in owner-occupied multi-unit housing. American Journal of Preventive Medicine 43(5)(S3) S187-S196.
D.L. Bohac, M.J. Hewett, K.I. Kapphahn, D. T. Grimsrud 2012. Ventilation rate investigations in Minnesota bars and restaurants. ASHRAE Transactions 118(1).
D.L. Bohac, M.J. Hewett, S.K. Hammond, and D.T. Grimsrud 2011. Secondhand smoke transfer and reductions by air sealing and ventilation in multiunit buildings: PFT and nicotine verification. Indoor Air 21(1) 36-44.
M.J. Hewett, M.J., Bohac, D.L., Kapphahn, K.I., Grimsrud, D.T., Apte, M.G., and Gundel, L.A. 2011. Secondhand Smoke Concentrations in Repeated Visits to a Probability Sample of Bars and Restaurants. Proceedings of the 12th International Conference on Indoor Air Quality and Climate – Indoor Air 2011, Austin, TX. International Society of Indoor Air Quality and Climate.
R. Lui, Bohac, D.L., Gundel, L.A., Hewett, M.J., Apte, M.G., and Hammond, S.K. 2011. An Assessment of Risk from Exposure to Secondhand Smoke in Minnesota Bars and Restaurants. Proceedings of the 12th International Conference on Indoor Air Quality and Climate – Indoor Air 2011, Austin, TX. International Society of Indoor Air Quality and Climate.
D.L. Bohac, M. J. Hewett, K.I. Kapphahn, D.T. Grimsrud, M.G. Apte, L.A. Gundel 2010. Change in indoor particle levels after a smoking ban in Minnesota bars and restaurants. American Journal of Preventive Medicine 39(6S1) S3-S9.
D.L. Bohac, M.J. Hewett, J. Fitzgerald, and D.T. Grimsrud, 2008. Measured Change in Multifamily Unit Air Leakage and Airflow Due to Air Sealing and Ventilation Treatments. Proceedings of the Buildings X Thermal Performance Conference, Clearwater, Florida.
M. J. Hewett, S. D. Sandell, J. Anderson, Ph.D., M. Niebuhr 2007. Secondhand smoke in apartment buildings: renter and owner or manager perspectives. Nicotine & Tobacco Research 9(S1): S39-S47.