Climate Change and Health Seminar Series: “The climate and health benefits from intensive building energy efficiency improvements”

Transcript

• 00:00<v Host>Welcome to the first seminar of our seminar series</v>
• 00:04in Climate, Air, and Health.
• 00:06We have some online audiences joining us today,
• 00:09and before we get started, just wanted to let you know that
• 00:12this seminar is recorded, and later on,
• 00:15the recording will be posted on our center's website.
• 00:19On the monitor today,
• 00:20I have chosen assistant professor
• 00:22at Yale School of Public Health,
• 00:24and also the director of research
• 00:25at Yale School of Public Health.
• 00:27So, it's my great pleasure today
• 00:30to introduce our very first speaker, Dr. Drew Gentner.
• 00:35Dr. Gentner is the associate professor in the department
• 00:39of chemical and environmental engineering.
• 00:42Also, the department of the School of the Environment.
• 00:44He got his master and the PhD from UC Berkeley,
• 00:48and also he has been at the Department of Chemical
• 00:52and Environmental Engineering since 2014,
• 00:56where his research group focuses on
• 00:58air quality, pollution, emissions, and chemistry.
• 01:03His application in books and [Indistinct].
• 01:07And today we are very fortunate to have both Dr Gentner,
• 01:12and also Professor Gillingham joining us online.
• 01:15Today the main topic will be focusing on their recent paper,
• 01:21the Climate and Health Benefits
• 01:23from Intensive Building Energy Efficiency.
• 01:27So without further ado, please.
• 01:29<v Dr. Gentner>Thank you so much.</v>
• 01:31And my one request of the virtual audience
• 01:34is let me know if you can't hear me clearly.
• 01:37I will try to speak loudly and through a mask,
• 01:40but just chime in if you're having trouble
• 01:43and I'll stay closer to my computer.
• 01:46Alright so, you have both and Ken and I here today,
• 01:52and I wish he could have been here in person,
• 01:54but I get to present this paper that we worked on along with
• 01:59Professor Jordan Peccia in Environmental Engineering,
• 02:02a PhD student of mine, Colby Buehler,
• 02:04and former postdoc of Ken's
• 02:07from the School of the Environment.
• 02:08So, this was a cool project
• 02:11that we were really excited about because
• 02:12it was a true interdisciplinary science
• 02:15where I was excited to work with Ken
• 02:18to do some energy modeling, and then bring that
• 02:20into looking at outdoor and indoor air quality
• 02:24across the building envelope.
• 02:26And so, this brought in some expertise
• 02:28from Professor Peccia and I to look at air pollution,
• 02:32and then extend it to the health effects.
• 02:34This fell under the purview of, our,
• 02:40hopefully I can click here.
• 02:42Alright, of our search center,
• 02:45which I, Michelle Bell has been the director
• 02:49of up at the School of the Environment,
• 02:51and we're in our last year at the center now.
• 02:55But the overall objectives of this were to look at energy
• 02:57transitions and look at the the wide range
• 02:59of sources related to energy production use,
• 03:03in the context of other sources
• 03:04that attract urban air quality and health.
• 03:08And then, we paid key attention to both
• 03:10transitions and key modifiable factors.
• 03:12So which things can we change,
• 03:13either through policy or personal choices,
• 03:15so that we can make smarter decisions
• 03:17related to transportation, land use,
• 03:20our power generation, and distribution networks.
• 03:23So, this had a number of different
• 03:25projects involved with it.
• 03:28Ken's project was number one and mine was number two.
• 03:32We were doing this in collaboration with Johns Hopkins,
• 03:35and we had a couple other projects.
• 03:37And so these things,
• 03:38we're focused on distinctly different areas of air quality
• 03:45where I was focused more on source characterization
• 03:48and measurements in project two and Ken was doing
• 03:50a lot of modeling on energy and emissions.
• 03:52So this project represented, and this paper,
• 03:56one of a couple things that we were doing has inter-center
• 03:59collaboration within a much larger center structure.
• 04:04<v ->And you can check it out online</v>
• 04:05and see a lot of the other great work
• 04:07coming out of Michelle Bell's group
• 04:09and others at Yale, Johns Hopkins,
• 04:11and our partner institutions.
• 04:14Which span some co-PIs at Johns Hopkins, and other PI's,
• 04:20and Dan Esty, at the School of the Environment.
• 04:26So, onto this paper. So, now it's like dive in and focus.
• 04:30This started, I can actually remember the workshop
• 04:33that Ken and I were at when we were talking
• 04:36about this research question.
• 04:38Thinking about how the climate and health
• 04:41benefits intersect when we look at
• 04:44building energy efficiency measures.
• 04:46'Cause Ken's group was thinking about
• 04:49building energy efficiency scenarios,
• 04:51how we reduce energy use in the building sector to reduce
• 04:56C02 emissions and affect change for climate mitigation.
• 05:01And I started asking, well Ken,
• 05:04what about the indoor air quality on that?
• 05:06You know, we're gonna drop emissions of pollution
• 05:09outdoors from reduced energy production,
• 05:11but what happens with the
• 05:13building energy efficiency measures?
• 05:14And so, thus this project and this paper was born.
• 05:21As a brief overview of where we're going with this today,
• 05:24we start with the fact that buildings
• 05:26account for 40% of energy usage,
• 05:29a lot of our energy command nationally.
• 05:33So, it makes it a really prime target for
• 05:36climate change mitigation and producing
• 05:40both energy use and associated emissions.
• 05:44These are emissions of not only climate pollutants,
• 05:46but also air pollutants, slight particulate
• 05:49matter sulfur dioxide, carbon dioxide, nitrogen oxide.
• 05:54So, with these scenarios that I'll show you in a moment,
• 05:58we looked at reductions in energy related emissions
• 06:01that would be occurring outdoors from power generation,
• 06:05and then translated that to its
• 06:07effects on indoor air quality.
• 06:09And, I'll talk about that feedback loop in a moment.
• 06:13But, the approach here is to use the Yale-NEMS model,
• 06:19which Ken runs up at school of the environment,
• 06:23to look at energy efficiency scenarios
• 06:25across the entire US housing stock.
• 06:27So we're not just studying one building,
• 06:30we model all the homes of the US and their changes
• 06:33over time with a lot of simulations
• 06:36and a couple models that were interconnected.
• 06:40Then we evaluated the outdoor
• 06:41indoor air quality implications.
• 06:43So how do the changes in emissions
• 06:46affect exposure and human health,
• 06:50both for outdoor and indoor exposure pathways,
• 06:52and look at the bad effects
• 06:53on human health, all of these together.
• 06:57So, I'll walk through this in a bit more detail,
• 07:01but we start from something where
• 07:03we take a reference scenario,
• 07:06an intermediate energy efficiency
• 07:07scenario just for buildings.
• 07:09An optimistic energy efficiency scenario for buildings
• 07:12and look at the changes in energy consumption
• 07:15and then test the carbon pricing scenario
• 07:18for those to see how that affects it.
• 07:21And we'll walk through this before,
• 07:23but if you fast forward all the way,
• 07:24you can see how we will then be able
• 07:27to look at projections in particular manner,
• 07:30emissions from that reduced energy use.
• 07:34So, the scenarios, without going into them in great detail,
• 07:39although there's a lot of information in the paper
• 07:41and tech would be happy to answer questions,
• 07:44looks at changes in both appliances and equipment
• 07:46and in the building shell.
• 07:48So we have all of this stuff indoors
• 07:50for heating, cooling, cooking, lighting,
• 07:53and other things like refrigeration
• 07:58and those have a certain amount of energy use with them,
• 08:00and that's been a target of a lot
• 08:01of governmental programs through efficiency.
• 08:03You know, you can go and buy energy star things,
• 08:06you see them when you go to the store,
• 08:09and so, there are targets related to the energy efficiency.
• 08:12And then in the building shell is where we start to look
• 08:16at the interconnections at indoor air quality.
• 08:19'Cause the indoor environment is really complex.
• 08:22The air that gets to us here,
• 08:23or the air in your home navigates a lot of places.
• 08:27Either through a forced air system or just naturally,
• 08:30you have some penetration coming through the walls,
• 08:33and some infiltration of air,
• 08:35and the pollutants coming in,
• 08:37and some ventilation of the air going out.
• 08:38You may do that on purpose, opening you know, a door,
• 08:42turning on a fan, or that might just be happening naturally,
• 08:46and depending on the age of your home
• 08:48and how well it's sealed,
• 08:49that could be happening at quite a high rate.
• 08:52So, we look at the changes in the building shell
• 08:56across a range of environments,
• 08:57and we're gonna talk more about residences today,
• 09:00'cause that's where we do spend most
• 09:02of our time and a lot of our time,
• 09:05a lot of our PM2.5 emissions indoors
• 09:09occur in our residences.
• 09:11So we'll look at that, and we'll look these scenarios
• 09:13where we have existing homes and we look at changes
• 09:15in efficiency that happen at slower incremental rates.
• 09:18And then new homes that are built
• 09:21to the newest specifications which follow these
• 09:25ambitious but demonstrated improvements.
• 09:29So Ken's model, which is the national energy modeling
• 09:34system model that is the scale installation of this,
• 09:38and the launch model developed by the US EIA,
• 09:44covers a whole lot of things in the supply side,
• 09:46convergence side, and demand side,
• 09:48electricity, and integrates it together.
• 09:50So, where we're gonna focus on today for this paper
• 09:54is looking at the changes in the residential demand
• 09:56and commercial demand that are derived
• 09:59from these changes in energy efficiency.
• 10:02So if we change the design of a building,
• 10:04we are changing the energy in the air there,
• 10:07and that has feedbacks to reduce demand,
• 10:11to increase production and thus we have changes.
• 10:15So, there are a lot of things that are in this model,
• 10:18and if you are a big fan of supplemental
• 10:21information sections and papers,
• 10:23I encourage you to check out the,
• 10:26somewhere around 55 pages that exist in the paper
• 10:31with hopefully, every question that you might have
• 10:36about the energy modeling system and then hence,
• 10:39other work using this model.
• 10:42And so, if we look at the scenarios,
• 10:44you have the reference case at the top here in red
• 10:49that we play around the carbon pricing initiative on there.
• 10:54Now we look at the intermediate energy efficiency,
• 10:56just for buildings here and see that that drops
• 10:58consumption down somewhat than a more optimistic
• 11:01one with without carbon pricing.
• 11:04The direct effects on carbon dioxide emissions are shown
• 11:07over here where you can actually see a pretty sizable effect
• 11:11on overall carbon dioxide emissions
• 11:13just from building energy efficiency improvements.
• 11:16So, this really points back to that fact that
• 11:1940% of our energy use occurs in maintaining
• 11:25our buildings and in our buildings.
• 11:26So, any change that we make here,
• 11:30a policy level has a pretty sizable effect
• 11:33on energy demand and related climate pollute emissions.
• 11:39This also has a sizable effect on air pollutant emissions
• 11:44like criteria pollutants for particular matter, NOx.
• 11:48SO2, VOCs, a sub effect on ammonia and carbon dioxide,
• 11:54excuse me, carbon monoxide,
• 11:57though today we're gonna focus mostly on PM2.5,
• 12:01since that is driving factor of premature mortality,
• 12:06and what's the key pollutant of interest for this paper.
• 12:12So here we've defined what the changes are
• 12:15for each of these scenarios over this time rise
• 12:19and extending to 2050 for the energy related
• 12:23emissions that are occurring outdoors.
• 12:24So if you wanna visualize it,
• 12:26what's coming out of the smokestack for PM2.5 emissions.
• 12:32So that's gonna vary a little bit across the country
• 12:34where we generate that power, how we generate it.
• 12:36And so we'll talk about that at the end
• 12:39of the presentation today.
• 12:43So, we spend close to 90% of our time indoors, so,
• 12:51so we're thinking about exposure to pollutants.
• 12:54We really need to be considering that
• 12:55indoor environment and how it modulates our exposure
• 12:59to pollution coming in from outdoors,
• 13:02but also how it affects,
• 13:06how the design of that indoor environment
• 13:07affects our exposure to pollutants that are generated.
• 13:13Now, I wish I had Jordan Peccia here with me today,
• 13:15so he could answer all of your COVID-related questions,
• 13:19relating to ventilation and filtration,
• 13:22because that is not my area of expertise.
• 13:24But you can take this admissions term here,
• 13:28and think really about whatever pollutant or microbe
• 13:32or anything that you want, for your own work,
• 13:36and think about how that's affected by the design
• 13:39of your home or the space that you're currently in.
• 13:44This is a box model.
• 13:46It is actually simplified considerably,
• 13:49to just a singular box representing a space indoors.
• 13:53But yes, there's still one equation. For that, I apologize.
• 13:57You can ignore the equation if you like,
• 13:59I can try to cover it up and we can
• 14:01focus on the terms that are used here.
• 14:04So, I'm going to point out a few things
• 14:06on how the model connects,
• 14:07just to try to show how this all comes together.
• 14:10So first thing, we have recirculation with a filter.
• 14:16Now you're predominantly talking about HVAC system.
• 14:19So, forced mechanical air filtration system
• 14:22that you would have in an indoor building.
• 14:24You have them here, your apartment,
• 14:26perhaps up the east rock,
• 14:28that was built 80, 90 years ago may not have that,
• 14:33or some newer builds don't have of course, HVAC system,
• 14:38but that is where you would have some
• 14:40active particle filtration that's occurring.
• 14:43Now in the the era of thinking about filtering for
• 14:49you know, viruses and other microbes doors,
• 14:52whether it be COVID or otherwise.
• 14:54We've started to put in some affordable air filters,
• 14:56so you could also think about that,
• 14:58but we're predominantly looking at this
• 15:00in terms of the HVAC system.
• 15:02So, on the other side here you have air coming in.
• 15:08So, infiltration is that, what I was talking
• 15:10about was coming through the cracks.
• 15:12You have bad windows, ceiling, it's an old building.
• 15:15You know, there's some areas where air just gets in.
• 15:19If it's a newer, newer, newer building,
• 15:21those seals tend to be better and better,
• 15:23and you have fewer spots for
• 15:25air to infiltrate from outdoors.
• 15:28But then you have this,
• 15:29and you have a penetration factor in there
• 15:30for how much particles
• 15:31get through those little cracks.
• 15:33So they can get stuck on the way.
• 15:35It's kinda like a filter like our mask.
• 15:38And you have natural ventilation,
• 15:41so you open the window because
• 15:43it's hot out or if you burnt toast,
• 15:46and that's gonna provide some natural (indistinct).
• 15:51Indoors, you know, the main thing is
• 15:53you have emissions for cooking,
• 15:56you burn a toast or just you know, regular,
• 15:59you were frying up some eggplant for dinner,
• 16:01and that generated some PM2.5.
• 16:06Number of appliances while you're cooking,
• 16:08actually have a pretty sizable PM sources,
• 16:11but that depends a lot on cooking style,
• 16:13and I forget you're affected by some
• 16:17of the filtration over your stove.
• 16:20We also worked into the model,
• 16:21the two loss terms of the deposition of the six.
• 16:24So, particles go to surfaces and also
• 16:26they could be meddling outside.
• 16:30But we're thinking today about,
• 16:32what is the changes that happen to these terms,
• 16:37and how it affects the concentrations indoors.
• 16:40But built within this is thinking about the housing stock.
• 16:45So Colby Buehler,
• 16:46a PhD student in environmental engineering,
• 16:49did a literature view of the US housing stock
• 16:51working with Peg Long from School of the Environment
• 16:55to determine the filtration flow rates for
• 16:59homes' HVAC, and the fraction of homes with HVAC systems
• 17:02and also the quality of filters in there.
• 17:05If I was, if we were all talking
• 17:07about this a couple years ago,
• 17:08you would probably not be very familiar with the quality of
• 17:11filters that exists up in these systems.
• 17:14But there's this whole rating system
• 17:17for 2, 4, 6, 8, 10, 12, 14
• 17:20and it goes up to 16, then we get the half a grades,
• 17:23and that has a major effect on the efficiency
• 17:26of those filters and the filtration of particles,
• 17:30doors or air barns, microbes or dusts or anything else.
• 17:36And then the infiltration and natural ventilation rates
• 17:41are also affected by house, home aid.
• 17:45So you think about infiltration,
• 17:46a home with more cracks, more gaps,
• 17:49has more infiltration through those penetration points.
• 17:57Then, the residential energy demand consumption survey
• 18:00was used to determine appliance usage across all homes.
• 18:04So, we could look at the distribution in homes.
• 18:08Obviously, it comes down to how many people live in a home,
• 18:11but some of us are cooking all the time.
• 18:13We cook at home every single night,
• 18:15we use the toaster while we're using the stove,
• 18:17while we're using the oven.
• 18:19And some people, you know,
• 18:21will stop by and, you know,
• 18:25pick up something from the local
• 18:27falafel shop for dinner most nights.
• 18:33So, that's gonna have a huge effect on this admissions term,
• 18:36and it's going to propagate through this whole system,
• 18:38as you'll see later.
• 18:43So we then model over time,
• 18:46the changes in the US housing stock
• 18:49up through 2050 for this analysis.
• 18:52And changes in the building type,
• 18:56which includes the volume of home,
• 18:58sizes are going up,
• 19:00the amount of new homes that are built
• 19:03and the characteristics of those homes
• 19:06with respect to the installation of HVAC systems
• 19:11and filter types and all of that.
• 19:14So, and ultimately, the big effect that this
• 19:18has with the changes in the housing stock
• 19:21and energy creation or energy efficiency
• 19:24scenario is on this infiltration.
• 19:28So, how much ventilation occurs
• 19:30in your home without you actively doing that.
• 19:35You didn't turn on the HVAC system,
• 19:38you didn't necessarily open the window,
• 19:40but you have some pressure changes in home,
• 19:43and air is also very good
• 19:45at moving through cracks and things,
• 19:47and it will bring (indistinct) with it.
• 19:52If any of you just moved to New Haven,
• 19:53wait until a nice cold day,
• 19:57go stand near a window at an older building,
• 19:59and you'll certainly feel that
• 20:01cold air moving through some of those gaps.
• 20:04I know I had that experience when
• 20:07I first moved to New Haven.
• 20:13So, we also look at the changes,
• 20:14changes in the appliance type throughout the study.
• 20:22I'm gonna talk about something not,
• 20:23I won't refer to it as a Monte Carlo analysis
• 20:26over and over again but I want to make the point that
• 20:29to constrain the uncertainty in the study,
• 20:33Colby Buehler ran this a lot, a lot, a lot of times.
• 20:38Thousands upon thousands, across the entire
• 20:41US housing stock.
• 20:42So if you go through and you simulate
• 20:43a whole bunch of homes with this model,
• 20:46and you look at all the different conditions you can have,
• 20:49what is the net outcome of those?
• 20:51So again, we're not just talking about
• 20:52one home with one set of conditions,
• 20:53or a small perturbations that
• 20:56we will look at one or two things.
• 20:57But trying to put those all together so
• 20:59we can show sensitivity to these different features.
• 21:03So, the HVAC system and what it means for emissions,
• 21:05and how does infiltration change
• 21:07with energy efficiency measures, and the age of a home.
• 21:17So questions before we start moving out to results.
• 21:25If not, good work, you just got through like lecture five,
• 21:29or six of my class on box models so that's great.
• 21:36<v Speaker>We do have a student.</v>
• 21:38<v Dr. Gentner>Yes.</v>
• 21:39<v Student>Yeah, I'm just, how confident are</v>
• 21:43you in modeling how the housing stock group
• 21:45change also changes in appliance?
• 21:48Like out to 2050, or did you use different scenarios?
• 21:53<v Dr. Gentner>So, actually Ken,</v>
• 21:57I'll let you answer that one.
• 21:59It's phone a friend time already.
• 22:00The question was how confident are we in the changes
• 22:03of the housing stock and appliance shifting over time,
• 22:06and how are those scenarios, model there,
• 22:10are there multiple scenarios in the NEMS model?
• 22:13<v Dr. Gillingham>That's a a great question.</v>
• 22:14What we do is we use,
• 22:16so it's built into NEMS and NEMS explicitly
• 22:21is modeling housing stock changes
• 22:23based on trends in the past.
• 22:26We easily could do uncertainty analyses over those numbers.
• 22:32I think that kind of, main takeaway on that
• 22:35from my understanding is that those aren't gonna be
• 22:39the driving forces of our final results
• 22:42unless you are really dramatically
• 22:44changing the housing stock.
• 22:46And I know this from another paper, not this paper.
• 22:49You'd have to really dramatically change
• 22:51the kind of core housing stock itself.
• 22:54And the reason for this is that there's
• 22:56a lot of inertia in the housing stock.
• 22:58So, there may be changes in how well it's insulated
• 23:02and you know, broader retrofits in how they're done.
• 23:06But the basic stock itself is quite slow moving.
• 23:11That said, I think you should take anything out to 2050
• 23:14with a grain of salt, maybe a very large one,
• 23:18and so I'm not gonna hang my hat on the exact numbers on
• 23:22the nature of the housing stock,
• 23:24'cause it's the full nature
• 23:25of the housing stock that's being modeled.
• 23:26And I'm not gonna hang my hat on the
• 23:28full nature of the housing stock in 2050.
• 23:30But I'm pretty confident that the numbers are gonna be
• 23:32pretty close to right in 2030, 2035,
• 23:35in that range and maybe even now out to 2040,
• 23:38just because of how much inertia
• 23:39there is in housing stock.
• 23:40But only a small amount of turnover actually occurs.
• 23:46<v Student>Just on the second part though,</v>
• 23:48I'd have to be more concerned about appliance type.
• 23:52It seems like, you know,
• 23:54we have possible scenarios of
• 23:56complete electrification, right, by 2050.
• 23:59Versus not doing that and still having a substantial
• 24:03number of gas stoves for example,
• 24:06would have a large effect on your conclusions.
• 24:12<v Dr. Gentner>So, the question's on</v>
• 24:14the changes in appliance tech Ken,
• 24:15and I'll take a quick shot at it and let you add to it.
• 24:19But, so that does get discussed in the paper.
• 24:23We don't include specific perturbations but we talk about
• 24:27how stoves changing up,
• 24:30changing to full electrification could affect that.
• 24:34We get into some really interesting questions
• 24:36then about where the emissions coming from.
• 24:38Are they derived from the use of natural gas,
• 24:42or are they derived from the process itself?
• 24:45If I, like your toaster is generating PM,
• 24:48based on what you're doing with it,
• 24:50not so much based on how much power,
• 24:51obviously, if it's not a natural gas toaster.
• 24:54But if we're thinking about a stove,
• 24:57some fraction of that PM comes
• 24:59from the actual burn itself.
• 25:01But if it's a reasonable stove,
• 25:05the PM is probably coming more from the cooking itself.
• 25:09And that's a really interesting question,
• 25:11and one that there was a cool paper
• 25:16that came out of Stanford looking at the emission rates,
• 25:20although they were thinking more
• 25:20about methane in particular,
• 25:22which is where you have a huge impact on (indistinct).
• 25:28So, on the climate side is where I think
• 25:32we can see a large effect of
• 25:33short lived climate pollutants there.
• 25:37And we do build in a few scenarios
• 25:41in there to look at some of these changes
• 25:43and try to bound them.
• 25:46Ken, can you grade my response
• 25:48and add anything to help there?
• 25:50<v Dr. Gillingham>I liked your response.</v>
• 25:51I wanna add a few things.
• 25:52One thing is this paper is explicitly
• 25:54about improving the efficiency,
• 25:57given the existing forecasted technologies in NEMS.
• 26:03In our scenarios, it's not about fuel switching,
• 26:07and I think fuel switching is a really,
• 26:08really important question and we actually have work underway
• 26:12to explore that question, where we're looking at scenarios
• 26:16that actually would allow fuel switching.
• 26:18So, say switching from burning natural gas in your range,
• 26:22to an induction range, right? Electric induction range.
• 26:26So, that type of fuel switching, we hold constant in this.
• 26:31So we don't, any trends that are in
• 26:34the baseline in NEMS, we continue,
• 26:37and we don't focus on those,
• 26:38our scenarios are very much about improving the efficiency.
• 26:42I think in reality,
• 26:44you may end up seeing both
• 26:46happening somewhat at the same time.
• 26:48But it depends on the policy direction.
• 26:51You could see a world in which you do see a lot of fuel
• 26:53switching and not much efficiency or vice versa.
• 26:56And I think from a intellectual perspective
• 26:59it's really helpful to parse those out,
• 27:01and understand them separately.
• 27:03So that was sort of the,
• 27:05some of the thinking behind it,
• 27:07how it plays out in what we do here in this analysis.
• 27:12But it's a really great question
• 27:13and a really important point.
• 27:15I think it's becoming increasingly important as we move
• 27:18forward because of the IRA, you know, the recent act,
• 27:23and other efforts to lead to electrifying the home.
• 27:27There's been a real push in that direction, so I think,
• 27:31but this framework that we've set up is reasonably
• 27:34well suited with some modifications to understanding
• 27:37the implications of some of those questions, too.
• 27:42<v Dr. Gentner>Right, thank you for the questions.</v>
• 27:44Just so I don't have to skip slides at the end,
• 27:47I'm gonna move forward.
• 27:49Johan, to answer your question,
• 27:51the exact materials that are used to change
• 27:54the building efficiency in terms of insulation
• 27:56are not explicitly worked in here,
• 27:58but they are part of changes in building shell efficiency.
• 28:02So we look at, in the paper we discussed,
• 28:04how changes in installation versus
• 28:06changes in building ceiling
• 28:08could affect the ultimate outcome.
• 28:11Alright, so, participation time.
• 28:15How many people in the room have an
• 28:18HVAC system in their home or apartment?
• 28:23Alrighty, so we're talking,
• 28:25alright so that number came in at about 10%.
• 28:28I don't know, hands were really kind of low on there.
• 28:30So, now is where we have like,
• 28:32a choose your own adventure moment in the presentation.
• 28:35So for those who are in homes that do not have,
• 28:43it's gonna come back I promise. Alright.
• 28:48Recirculation with filtration,
• 28:50here are the overall results for
• 28:52the entire US housing stock,
• 28:55comparing the reference scenario
• 28:57here in the reddish orange color
• 29:00to the intermediate case in blue.
• 29:02And then green is the optimistic energy
• 29:04efficiency case for buildings.
• 29:06On the bottom here, you're looking at
• 29:08the indoor emissions percentile.
• 29:11So the far left,
• 29:14this is the person who picked up
• 29:16falafel for dinner every night then.
• 29:19Hopefully, they got different toppings but they
• 29:22did not do much cooking in their home,
• 29:24and breakfast they got on the way to campus.
• 29:27And on the far right here,
• 29:28this is the person who wanted deep fried cauliflower
• 29:31three times times that week, and is cooking a lot.
• 29:36Maybe it wasn't deep fried cauliflower,
• 29:38but you get the point.
• 29:39Here is where there's a lot more indoor emissions.
• 29:41So it's what you could imagine a home that is,
• 29:44has more PM generated from various appliances,
• 29:49but ends up being an an important one,
• 29:51And on the far left,
• 29:52this one you can think as a cleaner home
• 29:55just in terms of the indoor emissions.
• 29:56So, if you're all the way here on the left side,
• 30:00you're seeing actually a benefit
• 30:04compared to the reference case of building tighten.
• 30:09So reducing that infiltration actually yields you a benefit.
• 30:12And the reason is, any of the PM that is outside
• 30:16is not making it indoors because your home is sealed off.
• 30:21You have a very, you have a tighter box that you live in.
• 30:24So you are just living with your own emissions,
• 30:26and you don't have as much
• 30:27infiltration of particles from outside.
• 30:29If you move to this other side here,
• 30:32and you can see where it is worse than the,
• 30:37oh excuse me, this is with recirculation.
• 30:39I said before this is without,
• 30:40this for the 10% of you that have an HVAC system.
• 30:45Here on this side is showing
• 30:48if you're doing a lot of cooking indoors,
• 30:50you actually see a penalty from
• 30:52those energy efficiency measures.
• 30:54'Cause now you have bottled up your home,
• 30:57you have filled all the cracks,
• 30:58maybe not every last one of them but you haven't improved
• 31:04the ceiling through your home to the point that you
• 31:06spend a longer time with any of your emissions indoors.
• 31:12So, the bummer is that that toast
• 31:15that you burnt lingers longer,
• 31:18or any other combustion source that you have indoors.
• 31:21And so, thus you would have more exposure to that.
• 31:25Or it could be a continued source of something,
• 31:27if you had a bad pilot light or something
• 31:29else in your home then that continues, or persists along.
• 31:35So, when you're looking at this,
• 31:39the reference case models the building stock without
• 31:42any changes from the energy efficiency scenario.
• 31:45So what is the current inertia,
• 31:46and everything that we talked about.
• 31:48And then this represents the change,
• 31:51where the left shows some benefit,
• 31:53and the right where you get about
• 31:56the reference case line shows a detriment indoors.
• 32:00So, for those of you,
• 32:04the 90% in the room that don't have an HVAC system,
• 32:08or other recirculation with filtration,
• 32:12this is what it looks like.
• 32:13So, everything is the same here.
• 32:15The only difference is now we're looking at the 38 to 45%
• 32:19of homes depending on the scenario that have
• 32:25no filtration or HVAC system at the home.
• 32:28So, now you can see this effect is exacerbated.
• 32:30There's a smaller fraction of homes that see a benefit
• 32:34for their indoor pollution from
• 32:37these energy efficiency measures,
• 32:39and a larger fraction that get
• 32:40greater exposure to particulate matter,
• 32:44because they spend more time with those emissions.
• 32:47So this shows two things,
• 32:50the importance of the indoor emissions
• 32:54in determining your indoor exposure
• 32:57and target ventilation there.
• 32:59And the importance of recirculation
• 33:01with filtration, just for PM2.5. Yes?
• 33:05<v Student 2>This might be a silly question, but,</v>
• 33:06is there, is like the,
• 33:10it's hard for me to to believe,
• 33:11to understand how building efficiency,
• 33:15have that much impact over HVAC.
• 33:17Like I would think that homes have the circulation system
• 33:22would be filtering air more than like,
• 33:26having cracks in the wall,
• 33:27and like, not as great of efficiency
• 33:30would like, have an impact on this.
• 33:33Does that make sense?
• 33:34Like, just looking at the reference line there.
• 33:36So like, if there were no
• 33:37improved efficiency in the building,
• 33:39you would still be having this kind of like,
• 33:41being close to the one to one line
• 33:43if you had a lot of indoor air emissions.
• 33:46But then, you improved, like how is the HVAC not filtering?
• 33:54<v Dr. Gentner>Improving?</v>
• 33:55<v Student 2>Yeah, I guess, or I guess, yeah.</v>
• 33:56I just think of it as like constantly pulling air out,
• 33:59and like, pushing fresher air back in.
• 34:02So that was the, how is the increased
• 34:05efficiency of a building making that almost worse.
• 34:08Does that make sense?
• 34:10<v Dr. Gentner>It does, and it's actually</v>
• 34:11a great opportunity to make a clarifying point here,
• 34:17that in the current paradigm of building temperature,
• 34:24climate control, infiltration, this is a closed one.
• 34:28Your HVAC system takes air, conditions it,
• 34:31and puts it back into your home.
• 34:34So, it comes down to the efficiency of that filter,
• 34:37rather than if saying, we're gonna give you
• 34:39completely fresh air from outside,
• 34:41to get rid of all our air
• 34:43from the inside and put it outdoors.
• 34:45This is where we're starting.
• 34:47We'd be thinking about like, next generation things.
• 34:51Is there any opportunities to get fresh air while
• 34:55not paying the penalty for having to completely
• 34:57recondition, well I say recondition,
• 35:00I mean, change the temperature of all the air coming in.
• 35:03<v Student>Perfect, yeah.</v>
• 35:04<v Dr. Gentner>No problem, that's a good point to clarify,</v>
• 35:06so thank you for that.
• 35:07The only major everyday example for a lot of us,
• 35:13or exemption to that would be in some of our labs,
• 35:16we have a fume hood obviously,
• 35:17we'd dump all of that out the building,
• 35:20we don't recirculate that.
• 35:22And there were some changes in various buildings,
• 35:27like on campus I know where the percentage of fresh air
• 35:30versus recycled air has changed over the past couple years.
• 35:35So, alright, so,
• 35:43If we think about this effect,
• 35:45this is looking at the overall effect,
• 35:47the entire housing stock for these two cases,
• 35:52or two types of homes across old and existing.
• 35:57Then we have this result where we end up
• 36:00at steady state having higher overall concentrations.
• 36:03If you wanna visualize this more,
• 36:05as what's happening for any singular event,
• 36:08you can think about the response time to something.
• 36:11So if you just look at this as a singular case,
• 36:14let's say here,
• 36:15you, oh, stick with the burning toast scenario,
• 36:20you burnt toast or you were frying something,
• 36:23you generated really high concentrations
• 36:24and then you stopped.
• 36:26How long does that take to decay down?
• 36:29And specifically, we think about that as the folding time,
• 36:32so down to one over just 37%, to keep it going on.
• 36:40And, so we look at that in the different scenarios
• 36:43with and without filtration.
• 36:45One other point, actually I wanted to make
• 36:47about your quick filtration question
• 36:49is in a lot of homes,
• 36:52we're not recirculating air
• 36:55at a range of like, the entire house
• 36:56over 6 points or something.
• 37:01During COVID we increased some of
• 37:04those ventilation rates for public spaces.
• 37:06Marketing air exchange rate of 4 or 5,
• 37:09those are probably the goal ones.
• 37:11So air exchange per hour,
• 37:13but we're not changing everything.
• 37:17<v ->So, that's why there are differences</v>
• 37:19here with the filtration and recirculation
• 37:22for dropping it quicker,
• 37:24in the cases of having an HVAC system.
• 37:26And then you can see, you know,
• 37:29as we tighten up the building more and more
• 37:30in the optimistic energy efficiency case,
• 37:34you know, that time that you're spent with the burning
• 37:38of be it toast or whatever else,
• 37:41that happen indoors increases,
• 37:44and you can see the theory we're approaching.
• 37:48(indistinct)
• 37:53So, that helps to visualize what's happening,
• 37:55just in terms of the time.
• 37:57Hopefully, that's a useful comparison.
• 37:59<v ->So, but we know that the system</v>
• 38:03is sensitive to outdoor PM concentration.
• 38:07So, we did all this modeling,
• 38:09and then we did a couple case studies
• 38:12within it across all different outdoor PM concentrations,
• 38:16and looked at how the system responded to outdoor PM.
• 38:23Because if we go back to that box funnel,
• 38:25and I won't put it back on the screen again,
• 38:28but you know, remember we have
• 38:28the concentrations of PM outside,
• 38:31and that's trying to come in
• 38:32and then we have our indoor PM and that's going out.
• 38:34So we have this really complex game
• 38:37that's happening over the building.
• 38:39And so, if we keep our indoor emissions on the bottom.
• 38:43So, again, this is the home of the most indoor emissions
• 38:46and this is the home of the least,
• 38:48and we look at the outdoor
• 38:49concentrations on the Y axis here.
• 38:55So this is the ambient outdoor PM2.5 concentration.
• 39:00The national average is here,
• 39:02the annual standard is here,
• 39:03and then the 24 hour standard's up there.
• 39:07So, depending on where you live,
• 39:08and even time of year or if it's a pollution event,
• 39:11you're going to fall on different spots.
• 39:16This graph vertically and that ratio of what it is
• 39:20in the optimistic energy efficiency case,
• 39:22versus the reference case is shown here.
• 39:26Where red has just energy efficiency measure
• 39:30increasing the indoor concentrations,
• 39:34and blue shows it decreasing the indoor concentrations.
• 39:41And that's just because again,
• 39:43here you are preventing the PM from outdoors coming in.
• 39:49Imagine it's a wildfire scenario,
• 39:52and you know, you're living in the northwest
• 39:55and your home is really tightly sealed,
• 39:59so your concentrations are really high outdoors,
• 40:02and you're up in this space where your home
• 40:03is more well sealed so less stuff gets in.
• 40:07If you go all the way to the right of this
• 40:09and you're in cleaner conditions outdoors,
• 40:11but you have a lot of indoor sources,
• 40:14now that tighter building with with less infiltration
• 40:18actually increases your indoor content.
• 40:21So point says, interesting interplay between outdoor
• 40:25and indoor PM and how that interacts.
• 40:29So, if there's anything you take away from today,
• 40:33whether it be for particulate matter
• 40:34or other atmospheric public health considerations,
• 40:38I hope it's thinking a little bit about that
• 40:41interaction between outdoor and indoors.
• 40:43So, in summary for this slide,
• 40:49which it literally has a lot of different
• 40:52information on it and colors.
• 40:54The impacts of these energy efficiency measures
• 40:56on indoor air quality are partially dependent
• 40:59on outdoor air quality,
• 41:01in addition to the in-home emissions.
• 41:03So if you were to translate this to Delhi,
• 41:07or another city that has higher outdoor concentrations,
• 41:11have to help how you approach this.
• 41:15There are some studies that were done,
• 41:17just looking at a few homes back in Beijing.
• 41:22And, probably like a decade ago,
• 41:24(indistinct) at Berkeley looked at the changes
• 41:27in home infiltration and ceiling and how that actually
• 41:31affected imperfect air concentrations to outdoor ratios.
• 41:36So, it does have an impact in other locations,
• 41:39and it can be different than what we're showing here.
• 41:44Okay, so to wrap this up and look at it together.
• 41:50I said we wanted to look at the outdoor effects
• 41:52and the indoor effects.
• 41:53We spent a little bit more time on the indoor stuff today,
• 41:58but we get this huge gain
• 42:02from the reduction in outdoor PM2.5.
• 42:06This is really like the energy related PM2.5.
• 42:09So we've dropped the energy demand for buildings
• 42:13considerably with the cases here.
• 42:17So intermediate, optimistic, optimistic with carbon pricing.
• 42:21And so we have a few benefits
• 42:24in reduced premature mortality that's avoided in 2050.
• 42:30We just talked about the complexity of indoors.
• 42:34And so overall, we see a detriment indoors
• 42:42but this is not for every home,
• 42:45'cause there's many homes that see a
• 42:46health benefit from the energy efficiency improvements
• 42:50based on this modeling.
• 42:53And so it's those high emissions homes,
• 42:55high indoor emissions homes that
• 42:57drive the overall effect negative.
• 43:02So, those graphs that I showed you before
• 43:03that had the lines across them for HVAC and non-HVAC
• 43:08were showing that, you know,
• 43:09there's a fraction of homes that see a detriment
• 43:12and need to see a benefit from this as well.
• 43:16But overall, the indoor effect offsets
• 43:22this positive outdoor effect,
• 43:24but it's weighted towards a
• 43:25subset of homes and a subset of the population.
• 43:29We look at this on net for those three scenarios.
• 43:33Intermediate, optimistic, optimistic with carbon pricing.
• 43:36We see that we get a net benefit from energy efficiency
• 43:39for avoiding premature mortality for PM2.5.
• 43:44This is stacked on top of all of the benefits
• 43:46that we get from the reduced climate pollutants.
• 43:54So, we get a climate benefit in terms
• 43:56of reduced CO2 emissions,
• 43:59and we get a benefit in terms of improved public health.
• 44:05And that's driven by a large decrease
• 44:08in energy-related pollutant emissions,
• 44:10and to some degree,
• 44:13some of the homes that have poor indoor air quality.
• 44:17But we do see some of the negative effects
• 44:19on indoor air quality overall.
• 44:23That's what I said in summary.
• 44:27And then, we wanted to test how the effect
• 44:31of HVAC usage or or filtration system's effectiveness.
• 44:37So, if we look at the case where we actually upgraded
• 44:41all homes to have 100% good HVAC systems.
• 44:44So boost that investment up,
• 44:47actually increases the health benefits that occur.
• 44:52So, basically if we improve indoor air quality
• 44:55through improved filtration indoors at PM2.5,
• 45:01we can achieve a larger benefit there.
• 45:07This can be put up as a summary.
• 45:12Here, where reductions in outdoor emissions,
• 45:15yielding that benefit across the entire building stock.
• 45:21And, the observed changes indoor air quality,
• 45:25due to these energy efficiency improvements,
• 45:28really require us to think about
• 45:30improvements to our indoor PM2.5 emissions,
• 45:36the targeted ventilation of those emissions.
• 45:38So, better ventilation of cooking emissions,
• 45:41improving the PM2.5 filtration efficiency.
• 45:44So, upgrade your filters, get better efficiency
• 45:47for those of you who can.
• 45:49And then, careful consideration of these energy efficiency
• 45:53policies and how we look at ventilation in buildings.
• 46:01And this is yet another time
• 46:02where I wish I had Jordan Peccia
• 46:06on the line as well, to make a few comments on that.
• 46:09Because it is a really interesting, important topic
• 46:13for how design, building ventilation for quality of life,
• 46:18wellbeing and thinking about a range of pollutants.
• 46:21So we present this today in the paper,
• 46:24through the lens of PM2.5.
• 46:27And we include some discussions in the paper
• 46:28about different pollutants,
• 46:31I think for indoors, and we did it in various amounts,
• 46:35so that goes through the range of criteria pollutants.
• 46:38We can even start to think about radon
• 46:39in some areas of the country.
• 46:42We can start thinking about disease transmission.
• 46:47No worries, it has nothing to do with this paper,
• 46:49but it does come up against the space
• 46:53where we think a lot about
• 46:54building design, and filtration and ventilation.
• 46:59So, looking at these benefits across the country pay.
• 47:05The graduate student who was working,
• 47:06sorry, the postdoc who was working on this,
• 47:09modeled it spatially and across various geographic regions.
• 47:14And you can see for the intermediate
• 47:16energy efficiency pace, the optimistic one.
• 47:18And then when we employ carbon pricing
• 47:21and carbon pricing with the optimistic
• 47:23case where the benefits occur.
• 47:27And these differences come down in many ways
• 47:31to how power is, generator,
• 47:33how electricity is generated in
• 47:35various areas of the country.
• 47:37So where we see some of the largest
• 47:40benefits depending on the case.
• 47:43So, carbon pricing is gonna have a sudden different effect
• 47:46than on the optimistic case on it's own.
• 47:50It's going to change the
• 47:52underlying fuel that we're using for generator outlets.
• 47:56So, you know, we think about
• 47:58the midwest and the northeast here,
• 48:01the types of fuels that we're using for power plants.
• 48:05So, using that demand is going have a larger effect,
• 48:12where there's a higher amount of renewables.
• 48:15So, in summary, and then we'll open it up to questions
• 48:17with whatever time we have.
• 48:20The study used the NEMS model coupled
• 48:23with The Monte Carlo analysis.
• 48:25Indoor air quality box model across
• 48:27the entire US housing stock.
• 48:29We see a 6 to 11% reduction in carbon dioxide emissions.
• 48:34and a 18 to 25% reduction in
• 48:37outdoor energy-related emissions of PM2.5.
• 48:42So, this is not including other PM2.5 sources.
• 48:47These reductions are complimentary with carbon pricing.
• 48:49It takes the pressure off as we're
• 48:52trying to decarbonize electricity going forward.
• 48:55So these building event, energy efficiency measures
• 48:59provide a huge opportunity,
• 49:01but they require attention to indoor PM2.5 emissions,
• 49:06and improving PM2.5 filtration,
• 49:09and thinking about how we implement
• 49:11these ventilation-grouping policies
• 49:14that get at some of the nuances that
• 49:16you're talking about with
• 49:18fresh air exchange and energy recovery.
• 49:23And so, in all the majority of homes see improvement
• 49:28or little change to indoor air quality,
• 49:30with these energy efficiency improvements.
• 49:33A subset of homes have increased
• 49:34PM2.5 concentrations indoors,
• 49:38which there, overall are driving
• 49:40health effects going forward there.
• 49:44And we're seeing that benefit in total, outdoors.
• 49:47So with that, we are at 12:50,
• 49:51so I'm happy to take any questions that people have.
• 49:54I have Ken here to answer all the tough ones
• 49:56that I can't or don't wanna answer,
• 50:00and thank you so much for you time
• 50:01today and for the invitation.
• 50:07(indistinct)
• 50:09<v Host>So, I think we have two questions.</v>
• 50:12<v Dr. Gentner>Okay.</v>
• 50:13<v Host>I guess each student</v>
• 50:14already prepared some questions.
• 50:15So, and what would you want to ask?
• 50:18<v Student 3>Hey could you go back to</v>
• 50:19the health impact slide?
• 50:23Sorry, yeah, thank you.
• 50:27First, if there was a bar on there
• 50:30for no, like without the energy efficiency,
• 50:35like, whereabouts would it be?
• 50:41<v Dr. Gentner>So this is all comparisons</v>
• 50:43to the reference case.
• 50:45So to the current trajector.
• 50:48So, this is the changes that occur on top of
• 50:52whatever we expect to happen
• 50:55in the absence of these standards.
• 51:03<v Student 3>I guess I didn't consider, (indistinct)</v>
• 51:10<v Dr. Gentner>It does.</v>
• 51:18Though, it doesn't include a distribution
• 51:22of clients saying you know, across different subsets
• 51:25of the population who is spending more or less
• 51:30time at their residence.
• 51:33But it does scale for them.
• 51:37<v Student 4>I was wondering if there are plans</v>
• 51:41to put your study off to different groups,
• 51:43so looking at how (indistinct)
• 51:54You know, what are the,
• 51:55are there plans to study the specific (indistinct)?
• 52:02(indistinct)
• 52:21<v Dr. Gentner>Yeah, so-</v>
• 52:23<v Host>The online audience is gonna hear the students-</v>
• 52:26<v Dr. Gentner>Oh, okay.</v>
• 52:28Yeah the first question, prior to that
• 52:30was about the half of the slide that's up.
• 52:35What the zero line is,
• 52:36and that's the comparison to the reference case.
• 52:38The question was just posed is is how much does
• 52:43or do we have plans for another study
• 52:46or set of studies looking at gas phase pollutants?
• 52:49And so we include some commentary in the paper about some of
• 52:52the factors that need to be considered.
• 52:54And it does, it comes down to how much
• 52:57the emissions current indoors
• 52:58versus outdoors.
• 53:00The other for Nox,
• 53:03you already really got out one of
• 53:04the huge factors there, is there is no,
• 53:09there's not a readily available filter that we already have
• 53:11in all the homes that filter NOx with
• 53:14the kinda efficacy that we have with particle filters.
• 53:17So, that adds a really interesting thing that makes it
• 53:21so that HVAC system doesn't have as
• 53:23large effect on that gas phase pollutant.
• 53:27So, Ken and I have have some things
• 53:29that we're thinking about and working on,
• 53:31although NOx is not one of 'em at the moment.
• 53:35Unless Ken's gonna send me an email later today,
• 53:38telling me to start writing.
• 53:40But yes, there's a lot of interesting things here.
• 53:45Yeah, we're just kinda scratching the surface
• 53:48to thinking about how other pollutants
• 53:49behave in these changes.
• 53:52And Jordan Peccia spends a lot time thinking about moisture,
• 53:56and how that's going to affect
• 53:56microbial activity at home.
• 53:59So we think about holes, and other standpoints.
• 54:01That's an area of interest.
• 54:03I encourage you to try to catch up with
• 54:06Jordan, because he'd love it.
• 54:09That is a real important factor on developmental health.
• 54:16Great. <v Host>Thank you everybody.</v>
• 54:18And because we have across right of us, so we're happy,
• 54:21and thank you everyone for coming.
• 54:22Thank you again Ken and Drew.
• 54:24<v Dr. Gentner>Thank you Ken.</v>