An Air-Raising Experience at the Orpheum Theatre
This episode was nominated for best “Moment of Factual Clarity” in the 2025 International Women’s Podcast Awards in the UK.
Episode Two
Buildings need to breathe too! A field trip to the Orpheum Theatre in Vancouver to learn more about their ventilation system, built after the 1918 flu pandemic.
Ladies and Gentlethems, the show you’ve all been waiting for, the show that will keep you glued to your seat! A show all about preventing diseases and pathogens and, sometimes, things that go bump in the night…
Join Daniella on a journey through the belly of an old vaudeville venue, the Orpheum Theatre, in Vancouver, Canada, to learn a bit about how it keeps pathogens in the air at bay. We've known that fresh air is good for us for a very long time but it doesn't always translate to the air we breathe indoors.
We also meet a savvy Twitter/X user who measured the carbon dioxide levels in the theatre and revealed that the Orpheum had excellent ventilation. How does a building so old get such good numbers? And what could it mean for disease control in other places?
This episode was featured in Salon: “Tuberculosis is on the rise again. We can fight it if we try.”
(Transcript below images)
Mushroom-shaped air vent under a theatre seat
Ceiling mural inside the theatre
More images from the tour here
EPISODE CREDITS
Public Health is Dead is created, hosted, produced, written and edited by Daniella Barreto.
Fact checking support from Anika S.
Additional content editing by Lauren M.
Public Health is Dead runs on listener support! If you liked this episode or learned something from it, please share it with a friend. And if you’d like to contribute to ongoing production of Public Health is Dead, please support the show!
-
Ladies and Gentlethems
The show you’ve all been waiting for
The show that will keep you glued to your seat
A show all about preventing diseases and pathogens and, sometimes, things that go bump in the night.
A show about… public health!
Grab your ticket and prepare for the most fascinating story about building ventilation you will probably ever hear…
Welcome to Public Health is Dead! Hello! I’m Daniella, welcome to the show. I’m a longtime public health advocate with a background in epidemiology and health science.This show, Public Health is Dead, is your anti-establishment field guide to surviving in the era of pandemics. Public health is failing us and you deserve to know.
The general guidance from our leaders about the ongoing COVID pandemic often sounds like: wash your hands, get vaccinated, and hope for the best.
And it’s not going very well.Because washing our hands doesn’t protect us from breathing in pathogens that make us sick.
Many people aren’t aware that air ventilation, filtration and masking are also recommended. But they’re easy to miss. A good public health response would tell us loudly how and why these are key pieces to battling COVID, the flu, and other airborne transmissible diseases. Instead, such important information can feel like an afterthought.
If washing your hands over and over again isn’t really stopping you from getting sick, or if you think there’s a problem in disease control and you want more information, hopefully this show can help. We have a collective problem that requires collective action. Including… in our building design!
And I’ve got a building I want to show you. It’s called the Orpheum Theatre.
You’re going to hear a lot about this century-old glitzy, glamorous theatre, its very cool ventilation system and what we can learn from it to improve public health right now.
For this episode, I took a field trip so you’ll hear some stuff I recorded on my phone with a bit of background noise.
I also took some pictures along the tour - there’s a link in the show notes to see them.So come with me to the corner of Granville and Smithe streets in so-called Vancouver, Canada.
Look up at the giant Orpheum sign in lights,
Put your respirator on because we’re going inside. And meet the rest of us in the lobby; the tour’s about to start!
TOUR GUIDE: Now that we are here, I am going to take everybody in to the theater.
So if everyone wants to follow me, we are going to go inside.
(Doors open, Wurlitzer playing)
(Alright. We ….just want to go ahead and go, we'll go right into the middle, the first two. Just go right into the middle, yeah.)DANIELLA:
The Orpheum Theatre is a mainstay for any music-loving Vancouverite. It’s got the last Wurlitzer organ in Canada that’s still in its original location - you just heard it playing. You might also recognize the Orpheum’s interior and ceiling mural from just about any sci-fi show filmed in Vancouver. It’s a gold and red building on Granville and Smithe, designed by the same architect as the Pantages Theatre in LA. He did about 200 others throughout North America.
This one, and many other similar ones, are particularly interesting to people concerned about clean air and mitigating disease transmission because they have a fascinating public health feature.The Orpheum is a success of the past helping us today with its ventilation system
It had some pretty cool tricks up its sleeve. It wasn’t just vaudeville shows.
To get audiences in, the theatre tried some wild marketing tactics back in the day - they had an acrobat in a gorilla suit climb the Orpheum sign to promote King Kong - the owner had a cow he’d send walking down Granville St with a sign around its neck that said “There’s A Great Show Playing at The Orpheum – and That’s No Bull!”It might not be bull, exactly, but the thing about the Orpheum - is it’s all an elaborate set!
There’s a false dome ceiling suspended entirely by wires, the front entrance is really, really narrow but it’s lined with mirrors to make it look bigger and fuller when there are people in it.
It was all designed to give the illusion of a grand opulent venue … on a budget.
I was doom scrolling Twitter a couple of years ago and saw a Tweet that inspired this whole episode.
It was from a user called Sphagnum Moss in 2022.
They said: I had a chance to go to this Vancouver symphony orchestra at the Orpheum Theatre built after the Spanish Flu to be pandemic proof and WOW. This ventilating system is FULLY OPERATIONAL. …1/nSidenote: the 1918 flu was initially called the Spanish flu because Spain was one of the few European countries that actually reported on it. Others didn’t want to affect morale in WWI so media blacked out news about the pandemic. Interestingly, Spain thought it had come from France so they called it the French Flu. But, now it’s often just referred to as the 1918 flu.
Their comment about the ventilating system just kept rattling around in my brain, so, after deciding to make this podcast, I signed up for a tour by the BC Hall of Fame… FYI you might hear some of the other tour participants talking next to me.
TOUR GUIDE: You just want to check underneath your seats, there's little mushroom caps. Everybody see those? Yes. So, those are actually still in use today. And that's what I find really interesting, is how every single part of the Orpheum kind of works.
DANIELLA:
What are these mushroom caps?
They’re a kind of rusty red-brown colour roughly the size and shape of an upside-down cereal bowl, sitting on top of a pipe opening. Think “magical toadstool” without the spots on it.
What’s the mushroom’s job?TOUR GUIDE: So it's the air circulation. So like I was saying, the theater, you know, it's like a large furnace. So it kind of like, will shoot air out into it. Yeah. And it's still, they still use them to this day.
DANIELLA: It does push air out. I felt it! The guide didn’t go into too much detail, but nosing around and keeping an eye out for telltale signs of the ventilation system operating in the belly of the beast became my silent mission. I’m sure other guests were confused about why I was taking pictures of weird boxes and one of them did ask me. I told them maybe more than they wanted to know while we were waiting in groups to go and see the catwalk. Remember that false ceiling I mentioned? As well as being part of the feigned opulence, it’s also a big part of making sure the air is cleaned. Someone else in the group asked why it looked like they could see through some of the gaps in the ceiling…
TOUR GUIDE: Yes.WOMAN: (Woman’s voice kind of muffled) You can see the sky. Is there like a skylight up there or is there just like a door that goes [muffled] you know?
TOUR GUIDE: We are actually going to go up there and you’re gonna, I’m gonna show you all that. It’s really, when you go up there, it’s…it’s so interesting to -sounds of excitement-
DANIELLA: The group was really excited to see the catwalk.
I actually reached out to that Twitter user I mentioned before, who goes by the handle Sphagnum Moss.
I asked about their experience with low CO2 in the space because I was amazed that a building as old as the Orpheum had such good ventilation.
Their responses here are read by an actor because they wanted to remain anonymous.
SM: I was delighted that people were curious about how historic architecture can solve modern problems.I mean, this displacement ventilation was so common back then and its purpose was to create well-ventilated performance space. And it was so soon after a deadly influenza pandemic that nobody in their right mind would consider going into a crowded indoor space and not risk death. And the cool thing about architecture is that it lasts a hundred years!
As we approach the 5th anniversary of the COVID pandemic, the buzz about the quality of the air we breathe has only grown… maybe thanks to how scarily normal wildfires have become.
Leaders will reluctantly admit, if they do at all, that the virus that causes COVID is airborne.That means it floats in the air… kind of like dust in a sunbeam.
Have you ever been in a dark room with the sun streaming in from a window? And you can see little specks of dust floating in the air? And you can’t really see them when the sun’s not hitting them?
Viruses trapped in aerosols in the air are much much much much much smaller than a speck of dust, you can’t even see them with the naked eye, so you can imagine they might be suspended in the air pretty easily too.
These aerosols can stay suspended for a long time over long distances (yes, longer than 6 feet) so even if you enter an “empty” room, it might not be as empty as you think.Ventilation is one of the things public health bodies could increase as a way to reduce transmission and help protect people from getting sick.
They do often recommend opening windows for ventilation even if they sometimes stop short of explaining why. (And that’s a subject for a whole other episode.)
Ventilation is key to interrupting disease transmission, in combination with other measures, of course.
That’s why I’m in my respirator and on a tour in the Orpheum: maybe we can learn some things to help us out of this mess.
The Orpheum was opened in 1927, not that long after the 1918 flu pandemic began. It has better ventilation than many buildings today. It looks like people were considering the airborne nature of disease transmission even back then and making building modifications to account for it.
They also probably wanted to clear smoke from the audience since smoking was allowed in buildings at the time.Essentially, ventilation is a process that moves outdoor air into a building or a room and distributes that air within the building or room.
Those little mushroom caps we learned about earlier are under every seat.
They’re connected to an air cleaning system in the basement that pushes air from the outside inside to be cleaned.As we walk around, I see many furnace filters. Boxes and boxes of them - if anyone’s built a DIY air filter or Corsi-Rosenthal box, they were the same type of filters.
In the original thread that inspired my Orpheum ventilation interest, the author was sitting on the lower level.
Their CO2 monitor read 518ppm. CO2 monitors are small, palm-sized or smaller devices that read the level of CO2 in ppm or parts per million.SM: I was aware of the ventilating system and wanted to test it out using my CO2 monitor. I discovered that the levels were excellent at the Orchestra level, so the entire 1st floor.
DANIELLA: Carbon dioxide, CO2, the gas we exhale, can be measured as an estimation of how much exhaled air exists in a space. The higher the CO2, the more likely it is you’re breathing in air that somebody else has breathed out.This is important if you’re trying to minimize being exposed to respiratory aerosols, including pathogens, that other people exhale.
So measuring CO2 can be used as an indirect indicator for how likely it is that you’ll be exposed to exhaled respiratory aerosols, including SARS-COV-2, the virus that causes COVID.
We call measures like this proxy measures. They’re sort of like a stand-in for what you’re really trying to measure.
What would be really helpful, but also kind of hard, is to measure exactly how much exhaled SARS-CoV-2 is in the space.
We don’t quite have the tech for that yet. But since we know that aerosols are generated when we exhale, and pathogens can hitch a ride in those aerosols and be suspended in the air, measuring the amount of exhaled air gives us something else that can help us make an educated assessment of the space.While knowing CO2 levels is helpful in and of itself, because it’s not great for us to breathe in high levels of CO2, it’s also a helpful proxy for how risky it might be for covid transmission since we know covid is exhaled through aerosols generated by breathing, speaking, coughing, sneezing, laughing, shouting, and singing. All the things that require breathing OUT. And you can imagine, at events like concerts where fans are belting out their favourite hits at the top of their lungs… they might be sharing more things at the top of their lungs.
If you’re outside, you’d expect to see a CO2 reading in the 400/500s.
If you’re inside a stuffy building with no windows open and a lot of people breathing, singing and yelling, you’d expect a reading of maybe 1-2 thousand.
So for the Orpheum to have a reading in the 500s, that’s pretty damn good.
I took my mini CO2 monitor with me on the tour and I got a reading of 550 on the upper level but there were only about 15 people in the space.
I went to a different venue for a small concert once and measured the air there - it got to over 2500 ppm! So if you’re looking for a comparison about how good the Orpheum is!Anyway, a couple of other Twitter users shared their experience with CO2 in the Orpheum - in their descriptions, they sat in the balcony and said that the higher up seats closer to the ceiling did NOT actually have great ventilation and their CO2 measurements were much higher at around 1000 ppm.
So what’s going on here?
Now I’m not an HVAC expert (would you believe there are actually whole podcasts about that!) but looking into how the ventilation system works a little more, it makes perfect sense why the balcony seats might have higher CO2 measurements than the floor level seats…Here’s how it works
The Orpheum operates by displacing stale used air by pumping in fresh, cooler air from below.We know hot air rises, so as it warms up from being breathed and existing among warm bodies it slowly rises higher and higher to that porous ceiling!
That’s why we could see gaps in it.
Up above the false ceiling are giant exhaust fans pumping air out of the building.
This mechanism avoids air mixing. The temperature difference between the cool fresh air coming in and the warm exhaled air being pumped out is really important for this to work.There’s less mixing of fresh air and used air because the more used it is, the warmer it gets, the higher it rises, and it’s constantly being pumped out at the top.
Pretty ingenious!
So, this might explain why if you’re sitting higher in the balcony seats you’d see a higher CO2 reading compared to if you were sitting at the lower floor level because there’s more accumulated used air that’s on its way out.
I got a bit in the weeds in HVAC information but it seems like there’s a limit to how effective this is because the more volume of air you’re trying to move out in really big spaces, you need more force to pump it out um and it can get harder to avoid mixing. But I will leave that to the experts to figure out.
SM: So anyone wanting to attend the Orpheum should consider booking the 1st floor seats to really take advantage of the benefits of the ventilating system
Many theatres from that time period use this kind of ventilation: there’s one in Wisconsin, there’s another Orpheum in New Orleans that looks like it even had an ice pit the air had to travel through first to make sure that the air was cooler than the air above.
I’m sure this depends on various speed and temperature settings but the Orpheum Theatre in Vancouver is filled with completely new air every 3 minutes, which is pretty good!Everything we’ve heard about CO2 measurements is exciting as a way to stop making each other sick, but it’s important to reiterate that CO2 monitors are only measuring how much carbon dioxide is in the space. That’s pretty much exactly what it tells you. If there’s less carbon dioxide, it means there’s likely less exhaled air in the space and it’s less likely you’ll get sick if there are people who are sick also sharing the air.
We can’t directly assume a low reading means low risk in all situations in that space.While increased ventilation makes sharing air a lot safer, it’s not something we can completely rely on and ignore all other protections because close proximity or “near field transmission” is different from further proximity or “far field” transmission. Ventilation works best to tackle far field transmission. It really helps to ensure there’s a constant supply of clean air diluting the breathed air to lower infection risk in the space.
But when it comes to near-field transmission, if someone who has COVID or other illnesses who maybe doesn’t even have symptoms at the time is directly speaking or breathing into your face really close to you, of course the concentration of respiratory aerosols is higher in the space they’re immediately breathing into. The room ventilation can’t specifically focus on that particular interaction and it can’t displace the air fast enough to get inbetween that person breathing out and you breathing in. This is why wearing respirators can still be really important to block aerosolized pathogens from immediately entering or exiting our bodies, and do it quickly.
Another note: A higher CO2 rating doesn't automatically mean it’s high risk for pathogens if there is excellent filtration. Filtration is a way to ensure breathed or used or dirty air gets cleaned by trapping pathogens and allergens and smoke, things like that, in a filter. We’re not going to spend much time talking about filtration in this episode because that could be a whole other episode all to itself.
Um I asked our Twitter friend, Sphagnum Moss, if they use their monitor to monitor CO2 in other places:
SM: I use my [aranet4] monitor in many places and have discovered that you can't predict the CO2 levels at all based on visual cues like high ceilings, you must measure.
Of course, CO2 is not the only data to estimate ventilation. Low levels don't necessarily tell you much if the space is not occupied. But if a busy crowded space has low levels, then you can say the ventilation is likely good.
DANIELLA: We need more information than just a CO2 measurement to help us understand transmission risk. Got it.Sphagnum Moss is also a teacher! I asked them if they see any benefits to better ventilation and filtration in their classroom.
SM: I've loaned my aranet4 to many teachers who wanted to know the CO2 levels. They are always intrigued and the nice thing about it is that they often make changes to improve ventilation.
SM: Ever since I've opened my windows and turned on filters, I’ve noticed that students have a better mood. Uh, they're more focused and they’re more engaged in active learning, moving around my class during a lab.I try to get them moving because my classroom can get so cold by November, my my students are in winter coats spooling DNA from a strawberry, or creating hydrogen gas… looking at specimens under a microscope.
I give them warm breaks in the hall and I display the CO2 levels, telling them that if our class is <700ppm we are making an inclusive space for medically vulnerable people and those who live with them.
I tell them that if our CO2 levels rise too high, we have a choice. We either mask up together or open windows higher. They understand this concept of inclusion and they're willing to support an inclusive class.
DANIELLA: And that’s a crucial point. Safer shared air is an accessibility issue.
Increasing ventilation is one of the key tools we have available to implement. We don’t get to choose which air molecules we breathe in when we’re sharing space with other people. Disabled people and people with chronic conditions or who are immunocompromised shouldn’t have to do their own public health. That’s the point of public health. Plus, it benefits everyone to have cleaner air.Disability justice advocates have made this point often: being disabled is an oppressed group that we can fall into at any time, if we are currently abled. Things can change in an instant.
And, unless you die, you’re pretty much guaranteed to become disabled through age, injury or sickness.
SM: High CO2 levels can also lead to cognitive decline, so I incentivize them to care about CO2 and act if it's too high.
DANIELLA: So, if we’re worried about kids doing better at school, it’s something to seriously consider. If the CO2 is high, we can start getting sleepy and not being able to think clearly. In addition to the impacts of getting repeatedly sick and also missing school.
At the Orpheum, when I asked if there was any way they’d show me the ventilation system at the end of the tour, they looked at me a little oddly and said no.
But I’d been getting odd looks all day from being the only person in a mask there…
But if going to the theatre is something you’re going to do in Vancouver, the seats on the lower level at the Orpheum seem to offer decent ventilation and the likelihood you’ll get sick is probably lower since fresh air is being pushed in from your “seat mushroom” and used air is being pushed up and out.So to recap - or re:mushroom-cap - - air ventilation gives a fresh supply of clean unbreathed air.
What could public health learn from the Orpheum and its ventilation system today?
All things considered, while the arts are very important, there are lots of other places that could urgently benefit from better indoor air quality too.
Hospitals, schools and daycares could be places to focus our ventilation and filtration efforts now that we understand a lot more about airborne transmission in public health.
Or at least we should understand. It’s undeniable at this point.
And new buildings could take a few hints from the Orpheum.Daycares could paint mushrooms to look like toadstools, I don’t know.
The laws of physics are the laws of physics. If we know what we’re trying to avoid is aerosol or airborne transmission, then we need to design ways to intervene that actually address that.Wiping down tables and washing our hands is great but that’s not going to stop pathogens that travel in the air.
That’s like slathering sunscreen on ourselves to protect ourselves from the rain… like, yes, sunscreen is important but that’s not the right intervention for the problem.Public health leaders telling us to wash our hands against airborne pathogens is pretty ridiculous.
Good news - we already know how to interrupt aerosol transmission! Aerosol scientists, physicists and engineers are some of the most well versed and expert voices on how to minimize airborne transmission. We should be listening to them about how to make our air cleaner and our shared indoor spaces safer. Lucky for us, frustrating for them, they’ve tried to tell us about it for decades.
The American Society of Heating, Refrigerating and Air-conditioning Engineers, aka ASHRAE, have a set of updated indoor air cleaning standards to help reduce the risk of airborne disease transmission indoors. These standards are commonly referred to as ASHRAE 241.
The ASHRAE organization may have had an earlier opportunity to ensure health thresholds for indoor air vs. the odour threshold for indoor smoke. But like many places, the tobacco industry got right in there to reduce this threat to their bottom line.
Today, the ASHRAE standards could be a really helpful guide to cleaning the air to mitigate disease transmission. They could be adopted everywhere and mandated for new buildings. ASHRAE 241 outlines best practices about how to clean indoor air to minimize the health threats of things like wildfire smoke, aerosolized viruses and bacteria, and other particulate matter that is damaging to our lungs and overall health.
In fact, one of my guests on this show, Dr. Al-Aly, was actually looking into the association between air pollution and diabetes before he was studying Long COVID. Breathing in dirty air can be deadly for a variety of reasons. And that doesn’t land on everyone evenly.
Environmental racism places some people in harm's way more often - it falls along various lines of marginalization, including class and race, so Black communities, Indigenous communities, and communities of colour often bear the brunt of it. Toxic disposal is often placed near poor communities.In Canada, many toxic environmental disasters have impacted Indigenous Peoples most harshly and the long tail of increased cancer incidence and other chronic illnesses are well-documented. Look up what happened at Grassy Narrows with untreated mercury being dumped into the rivers and Mount Polley with mining refuse contaminating water and food supplies. Many Indigenous communities across Canada are still denied access to clean water, which is a widely recognized public health failure.
So clean water, clean air, how could anyone reasonably argue with these things?
Early in the pandemic, we kept hearing from our leaders that schools were the safest place for kids and that they were only minimally impacted by COVID. But there were studies as early as 2020 suggesting that children were getting blood vessel damage from COVID. And Long COVID is affecting children. Some estimates say 10-20% of kids (so, between 1 in 10 and 1 in 5) have long-lasting impacts from a COVID infection. And many kids and teachers keep getting sick in school, even if it’s not COVID. Is the plan to just let this go on indefinitely?
We need to intervene and ventilation could be one of the ways to help protect kids from harms from COVID and repeat infections.
Ventilation and filtration can help schools actually become safer for kids.Despite those unfounded claims that COVID doesn’t affect kids that much, it does. It could increase attendance by reducing the number of kids who get sick, and make the workplace safer for teachers and staff. They’re some of the hardest hit groups with Long COVID. It could help make hospitals safer and allow patients to get help safely, not put them at risk for another COVID infection. It would help healthcare providers who are also hit hard with Long COVID impacts. In the UK, one study suggests up to 1 in 3 healthcare workers have long-lasting COVID impacts. Nobody should have to risk their health by being exposed to preventable hazards in the workplace or at school.
SM: You look at the high levels and it can be discouraging as your complaints of high CO2 get minimized by staff. But your efforts will not go unnoticed by your child, who is growing up with a parent who cares about clean air. You are raising a child for whom ventilation, filtration & clean air is an expectation. And this is good news & eventually society will catch up as we teach the next generation how to love clean air. One child at a time. That's my goal as a teacher. If only one child learns this lesson by example then I'm happy and perhaps one day, a child will become an architect & they will build a well ventilated place that'll last 100 years…
The Orpheum Theater is coming up on its centennial.
If we have to share indoor air, we can choose a better way.
Weighing the cost of building upgrades and standards against the health of everyone now and future generations is a pretty clear answer. That’s the bottom line of public health. Expenses now hugely cut down on expenses in the future.
Bringing in engineers and physicists and people outside the medical profession with expertise in aerosol transmission is likely one of the key missing pieces to making it out of this pandemic horror show.
If we can understand that clean water is a necessity to avoid waterborne illnesses, like cholera, why not clean air for airborne pathogens, too?
There are all types of things lurking right under our noses.Oh, and if poor ventilation wasn’t scary enough…
TOUR GUIDE: One thing I also want to mention as well, the theater is haunted. Some say that there is a men's room attendant in the men's washroom, but I mean, who knows? We'll just keep an eye peeled…
DANIELLA: I wonder if the ventilation system affects how he moves around too.That’s all for this episode, folks. Public Health is Dead but we’re not dead yet.
Until next time! I’m Daniella. If you know a friend who might like this show, please text the link to them.
The show is created, hosted, written, produced, and edited by me, Daniella Barreto.Thanks to Anika S for fact checking support, Lauren M for content editing support, and Loida M and Maria W for their early feedback.
Thanks to the BC Hall of Fame tour guides for letting me record a little - go take their tour if you’re interested! There are a lot of other cool things to learn about the Orpheum and you can take a peek at the little mushroom under your seat too.