# Condo or apartment air flow



## james4beach (Nov 15, 2012)

I'm looking to rent a condo or apartment (in a building with many occupants) but am concerned about air circulation and COVID-19. The scientific picture is not clear. Some sources say that building HVAC systems are not a significant COVID-19 threat, but I don't want to take any chances. Officials have been very slow catching on that COVID-19 is airborne.

The dangerous situation I want to avoid is where air flows from someone else's unit into the hallway, then into mine. I've previously been in apartments where I can smell someone else's cooking or cigarette smoke. Clearly, that also means that if they are coughing up a storm, those particles are coming into my home.

One "test" I have thought of is to walk around the building's hallways at 6 pm, smelling for odours or cooking. If I get whiffs of odours in hallways, it means air is flowing the wrong way. Do you think this is a good test?

Any other ideas on how to avoid buildings that have a hazardous kind of air flow, or bad recirculated air? Should I be avoiding all central heating where vents blow directly into the unit?


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## james4beach (Nov 15, 2012)

And in case it helps, here are a few different things I've seen in buildings before. I just am not sure which are good, which are potentially dangerous.

*Hallway pressure*. Some buildings pressurize the corridors, keeping them at positive pressure, resulting in airflow _into_ each unit. As far as I can tell, this is good. If working properly, it prevents air from inside a unit from spreading to others. Cooking smells and coughs stay inside each unit.

*Central heating / forced air*. The air is centrally heated and then blown out of vents into each unit. But could these vents also connect the air flows between units, resulting in contamination?

*Radiators*. Old fashioned fluid circulating through radiators will heat each unit, without blowing air around.

*Other local heat*. Instead of radiators or central heating, I've also seen electrical heating inside individual units.


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## sags (May 15, 2010)

If I had to live in a high rise I would want windows that open or a balcony with a door.


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## Beaver101 (Nov 14, 2011)

^^ Not sure how you can avoid the "free air all around us" or in your situation breathe in your neighbour's air other than wearing a mask inside to hopefully filter out some of the the dirt, bugs, et al.


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## cainvest (May 1, 2013)

james4beach said:


> Some sources say that building HVAC systems are not a significant COVID-19 threat, but I don't want to take any chances.


Which sources say this?


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## Just a Guy (Mar 27, 2012)

If you’re afraid to breath air that was breathed by others, there is only one solution...stop breathing. All air has been contaminated in your view.

btw, most apartments are heated with hot water radiators.


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## Longtimeago (Aug 8, 2018)

Just a Guy said:


> If you’re afraid to breath air that was breathed by others, there is only one solution...stop breathing. All air has been contaminated in your view.
> 
> btw, most apartments are heated with hot water radiators.


I find the topic irrelevant. Covid19 is not known to be airborne, only droplet spread.

Your comment re apartments being mostly heated with hot water radiators is more interesting Just a Guy. That may be true in a given area or for apartments of a given age group but I don't think it can be said to be 'most' overall. Many places use electric baseboard heat for example in both apartments and houses. The downtown Toronto condo my brother used to live in had individual heat pumps. That building was put up in the 70s. I only expect to see hot water radiators in older buildings.

Our 2006 built condo in the Okanogan had a 'swamp cooler' roof mounted to cool hallways and common areas. Individual units had wall mounted air conditioners and electric baseboard heating. I don't think we can really say 'most' use one way or another unless we add a location and building age to the picture.


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## Just a Guy (Mar 27, 2012)

Hot water heating is the one form of heating that I’ve seen in every province. The same cannot be said for any other heating system that I’ve seen. Yes, there are other forms of heating, but hot water is the most common one I’ve seen. Even new builds are getting hot water heating still, it’s not some abandoned technolog...it’s very efficient. Heck, even my house is heated that way.


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## james4beach (Nov 15, 2012)

Beaver101 said:


> ^^ Not sure how you can avoid the "free air all around us" or in your situation breathe in your neighbour's air other than wearing a mask inside to hopefully filter out some of the the dirt, bugs, et al.


Well, there are differences in how buildings manage their air and I'm wondering if some types are better than others. The one I mentioned with pressurized hallways involves, as far as I can tell, fresh air coming from outside. There is typically a unit at either the top or bottom of the building which takes in fresh air, and pressurizes the corridors. It sounds to me like this results in excellent air quality in the units.

Compare that to an apartment which allows air flow between units, so the air comes out of one unit, then goes into other units. This is unquestionably worse.... and it does happen in some buildings.

Not all buildings are the same. HVAC systems can be quite different, which is why I'm asking.


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## james4beach (Nov 15, 2012)

cainvest said:


> Which sources say this?


Earlier, I found some articles that said "don't worry about it". They were taking the (early and outdated) position that COVID-19 does not spread through the air.

The more current scientific opinion is that airborne transmission is possible. I spent hours looking for articles about risk of spread inside apartments and condos, and found very little -- this is just not something that is well understood right now.

Here are some resources:









HVAC and COVID-19 explained


There is considerable interest in the role that HVAC may play in the transmission of COVID-19.




www.thefifthestate.com.au





This article explains that many institutional HVAC systems (more like offices) are fundamentally air *recirculation* systems. It describes that viruses can move from one area to another, but thinks that the risk is reduced due to various factors (like some filtration). They give some recommendations on how the HVAC should be properly cleaned, filteres replaced, etc. *They also mention that the filters used in typical HVAC are not good enough to stop viruses.*

The professional body for heating & cooling has also released official statements on this topic:



> Transmission of SARS-CoV-2 through the air is sufficiently likely that airborne exposure to the virus should be controlled. Changes to building operations, including the operation of heating, ventilating, and air-conditioning systems, can reduce airborne exposures.
> 
> Ventilation and filtration provided by heating, ventilating, and air-conditioning systems can reduce the airborne concentration of SARS-CoV-2 and thus the risk of transmission through the air.


My understanding is that they are informing buildings that they should increase the % ventilation (fresh air intake, as opposed to recirculated air) and make sure filters are in good shape.









Can coronavirus spread through building's HVAC or plumbing?


'There is concerning evidence that there may be some hybrid form of transmission — not just droplets, but potentially airborne or aerosol transmission .'



realestate.boston.com





This article also cites experts who believe there is airborne transmission. The following is the only solid advice I have found about my question



> Fortunately, there’s a pretty simple solution, one Allen said would make sense even if we weren’t in the midst of a pandemic. “We can put in high-efficiency filters for the recirculated air, which can be really effective at capturing airborne particles,” he said.
> 
> If you live in a mechanically ventilated building, Allen suggested asking the landlord or manager about the HVAC system: Does it bring in fresh outdoor air? If air is being recirculated throughout the building, how is it being handled? “Make sure they have high-efficiency filters, a MERV 13 or greater,” he added, referring to the rating system for air filters.


This goes back to my earlier point, and something that Just a Guy doesn't seem to understand even though he's a real estate pro. Not every building has the same kind of air flow and HVAC systems. Some include more fresh outdoor air; others do more recirculation.

Some buildings may not circulate air at all. Perhaps these ones are the safest buildings?

Other things people can do are, as sags said, open the windows to get some fresh air yourself. You can also use portable HEPA air filters inside rooms.

From all my research, it seems that the key danger in apartments and condos is *recirculated air*. Not every building does this, but some do. So the questions are: how much fresh air is brought in? How does the building handle recirculated air?


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## james4beach (Nov 15, 2012)

I phoned the property manager for my last apartment building and asked some of these questions. Here is what I found out.

Their building does pressurize the hallways. I asked: do they recirculate air, or is that fresh air? The manager said that the air blowing into the hallways is fresh, taken from outside.

For individual apartments, it's electrical heating and air remains local to each unit. Air does not recirculate.

I think this ^ is an example of a pretty safe scenario.


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## james4beach (Nov 15, 2012)

And here's another example I heard from a friend. He lives in a townhouse kind of building, where one physical house contains 6 separate rentals.

They have central heating & air, which blows air, but air is only recirculated within their own home. Air does not mix with the neighbours. This is also pretty safe, because you're only dealing with your own air... it's not broadly recirculated.


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## Just a Guy (Mar 27, 2012)

Until You open your door and the two air chambers mix. I suggest, as before, you stop breathing. It’s the safest.


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## Topo (Aug 31, 2019)

I doubt the risk would be very high. The smell from cooking and smoking is a bit different, because these are gases that linger in the air for longer, until they get diffused. I find the smell of MJ especially sticky and permeating in apartment buildings, seeping in from around the windows. But droplets eventually fall or evaporate. Unless there is a high concentration of droplets and strong movement of the air, the risk should be relatively small.


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## cainvest (May 1, 2013)

james4beach said:


> Earlier, I found some articles that said "don't worry about it". They were taking the (early and outdated) position that COVID-19 does not spread through the air.
> 
> The more current scientific opinion is that airborne transmission is possible. I spent hours looking for articles about risk of spread inside apartments and condos, and found very little -- this is just not something that is well understood right now.


All the high level medical advice says airborne transmission is very low risk and close proximity only where droplets transfer. I mean if there was any serious airborne potential they would have had a 10m-50m buffer, not a 2m one. IMO, you're overthinking this but it's your call.


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## bgc_fan (Apr 5, 2009)

Well, there was an article recently, where spread via HVAC systems was being studied: Can COVID-19 spread through HVAC systems? Canadian researchers seek to find out

The article mentions some families eating at a restaurant, but fairly far apart. The thought is that the virus could be spread via airborne transmission. 

But study of the Princess Diamond cruise ship would say the opposite: Transmission routes of Covid-19 virus in the Diamond Princess Cruise ship


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## james4beach (Nov 15, 2012)

I certainly hope that building air / HVAC is not a common transmission route. Note that the engineering association for heating/cooling does express concern, and says pretty clearly: "Transmission of SARS-CoV-2 through the air is sufficiently likely that airborne exposure to the virus should be controlled."

Yes, realistically I might not be able to do anything, other than keep windows open, or use a portable air filter. Over the years, I have used small HEPA filters in my apartment because it helps with dust and allergens, anyway.


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## Retired Peasant (Apr 22, 2013)

If this is such a big concern to you, why not look for a small house to rent? Why are you set on a high-rise/multi-unit building?


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## GreatLaker (Mar 23, 2014)

The system that sends air into the corridors that then flows under doors into apartment units is called makeup air, so named because it makes up for air that flows out of a unit through the range hood, bathroom fan and dryer vent. I think it is required by building code in newer buildings. There is positive pressure in the halls that also tends to keep airflow and smells from moving out of units into the corridor. Makeup air should be fresh, filtered and heated or cooled according to the season. It's cheaper to send makeup air through the corridors than to build fresh air ducts unto each unit. Positives are fresh air reduces incidence of condensation, mold, mildew and CO in units. Negatives are sometimes it does not work properly. The system may need balancing to ensure all floors get adequate air flow. If someone on the windward side of the building opens a window the breeze may blow in, reversing the air flow from the unit into the corridor, and people tend to open window when they cook or smoke, sometimes exacerbating the smell to other units. Some people don't like the draft from under the door, so they weather strip the door bottom, thus resulting in stale inside air.

Many newer buildings also have a self contained HVAC system, with a heat pump or gas furnace + AC unit that draws in air from inside the unit, filters & heats/cools it and sends it out through ducts in the unit. The advantage of this is each unit owner controls their own temperature with separate electricity and/or gas billing per unit thereby encouraging conservation. They can also upgrade the air filters in some systems if they want, especially those with allergies.

A lot of older buildings I have seen have wimpy make up air systems resulting in humidity, condensation and possibility of mold and mildew buildup. I am guessing that building code has increased fresh air requirements over the years. 

Overall I think I prefer fresh constantly flowing air for a clean interior environment over the older systems, even if it means some (unknown) risk of a virus coming in from the corridor. The droplets that would carry the virus would have to move along the corridor, under a door, along the floor then up again to a surface or to the level of air you would be breathing. Sounds possible, but not super likely.


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## james4beach (Nov 15, 2012)

Thanks GreatLaker, this is great info. Your description matches the system in the last building I stayed in: the makeup air is fresh air, and is constantly flowing from the hallway into the units. Given that this air is not recirculated, and is probably keeping each unit's air from spilling back to the hallway, to me it sounds like a pretty safe configuration.


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## Mukhang pera (Feb 26, 2016)

I can't say I have a lot of interest in the topic, living out in the boonies, but I nonetheless appreciate GreatLaker's scholarly dissertation.


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## peterk (May 16, 2010)

cainvest said:


> All the high level medical advice says airborne transmission is very low risk and close proximity only where droplets transfer. *I mean if there was any serious airborne potential they would have had a 10m-50m buffer, not a 2m one*. IMO, you're overthinking this but it's your call.


Sounds like you're assuming the current 2m buffer was determined by a medical "methodology" in the first place...

More like it was some government ministers chatting about --- soo 10m? --- No that's crazy! --- OK 1m? --- Hey take this seriously! --- Fine, 2m? --- Perfect! Just think how nice and proportionate all the signs and posters we spend $50M on will look!


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## james4beach (Nov 15, 2012)

I agree with @peterk ... there is a lot of guesswork happening right now. I think health experts provide guidance, but they are guessing too. There was no time for controlled studies on these matters and we know very little about some of these matters.

I think it's worth being overly cautious at this point, because we still know so little. How airborne is this thing? I'd rather be safe than sorry.

Being cautious means things like mask usage, keeping lots of distance, and getting fresh air (not confined air) whenever possible.


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## :) lonewolf (Feb 9, 2020)

Krazzy governments were worried about CO2 now the scamdemic has caused a shortage of CO2


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## james4beach (Nov 15, 2012)

:) lonewolf said:


> Krazzy governments were worried about CO2 now the scamdemic has caused a shortage of CO2


lonewolf, this board wouldn't be the same without you!


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## cainvest (May 1, 2013)

peterk said:


> Sounds like you're assuming the current 2m buffer was determined by a medical "methodology" in the first place...


I'd imagine it is and I don't know why you'd think otherwise but you're free to make your own assessment.


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## :) lonewolf (Feb 9, 2020)

james4beach said:


> lonewolf, this board wouldn't be the same without you!


 James you cant make this stuff up Coronavirus-driven CO2 shortage threatens US food and water supply, officials say


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## bgc_fan (Apr 5, 2009)

:) lonewolf said:


> James you cant make this stuff up Coronavirus-driven CO2 shortage threatens US food and water supply, officials say


Except you did make it up. At least, you put a spin on the story, so let's look at the facts from the story:
1. CO2 is used primarily for drink carbonation and some food packaging to keep it sterile;
2. CO2 is generated as an ethanol by-product;
3. The Trump administration made exemptions so that gas refineries didn't have to blend ethanol, resulting in a crash in the ethanol market (more here: Trump's billion-dollar gambit: An ethanol deal to meet the demands of farmers and Big Oil);
4. Flood of cheap oil made ended up reducing the market for domestic oil, reducing the ethanol market even more; and
5. People start driving less due to COVID 19, so the market demands shrink even more.

But yes, let's blame it on COVID 19, and not the other 2 main factors that disrupted the ethanol market demand.


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## Longtimeago (Aug 8, 2018)

james4beach said:


> I agree with @peterk ... there is a lot of guesswork happening right now. I think health experts provide guidance, but they are guessing too. There was no time for controlled studies on these matters and we know very little about some of these matters.
> 
> I think it's worth being overly cautious at this point, because we still know so little. How airborne is this thing? I'd rather be safe than sorry.
> 
> Being cautious means things like mask usage, keeping lots of distance, and getting fresh air (not confined air) whenever possible.


LOL, maybe the thing to do rather than buying a condo then is to look at buying and living in a tent pitched in the middle of a field or forest in that case.


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## AltaRed (Jun 8, 2009)

Best I can tell is every building built since circa 1970 (and some before it) has pressurized corridors (positive pressure) such that there is no cross-contamination between units. The original purpose of this was to prevent, for example, cooking odours from one unit infiltrating other units.The first high rise we lived in, in 1971 in Mt Pleasant/Eglinton in Toronto had positive pressure, as did our second place at Scarlett Rd/Eglinton in Etobicoke.. My undestanding is these positive pressure systems bring in 'make up' fresh air with either zero or minimal recirculation from lobbies and corridors.

I would be a lot more worried about surface contamination of door handles and elevator buttons, or even sharing an elevator with other residents.


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## peterk (May 16, 2010)

cainvest said:


> I'd imagine it is and I don't know why you'd think otherwise but you're free to make your own assessment.


Yes I will, and I don't know why you WOULD imagine that it is.

How far does a cough, sneeze or moisture droplets from breath travel? 2m? Sure, maybe. Sounds low to me...
How wide are grocery store aisles? 2m
How far do you have to be apart before having a conversation is difficult? 2m
What makes for a good easy to read sign? 2 stick people separated by 2m

It's obviously just "the number" that was picked, likely as a compromise between competing desires among political influencers, and ultimately decided by someone based on those competing factors, practicality, and political calculation.

Same with the 50 > 15 > 5 people gatherings ban. Whatever sounds good and whatever is politically tenable for the particular politician who is trying to either convey that he is "taking this virus seriously" or that he is "sensitive to people's need for community and togetherness". Based on absolutely nothing other than "that sounds about right".

James, if you are so worried (I'm not FWIW), then I think this is the time to spend your money and rent a house. Your portfolio is up up up, you are successfully working contracts in your new career, all other living expenses are low. Rent the damn house, spend an extra 10-20k or whatever it costs over-and-above a little apartment, and live contently and isolated for the next 12 months until this is all past us. You are rich. There is absolutely no reason you need to expose yourself to dense, urban, box living like millions of people who have no choice in the matter and are just scraping by on temporary CERB.


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## james4beach (Nov 15, 2012)

@peterk I'm not actually that worried either. I'm in an age group that has few deaths from COVID-19. Just trying to be careful. Apartments can be OK, and as I mentioned up thread, I'm convinced that my last apt's ventilation system was safe. If I was still living there right now, I'd be OK with it.

Generally, I'm trying to optimize for 'good quality of life under normal circumstances'. I am not concerned enough to restructure my life around COVID-19. This is why I'm looking for an apartment in a city I like, even with the dense population. I'm generally planning for normal times.

I'm not rich, and can't afford renting a house as a single person. My contract income is extremely volatile.

Caution never hurt anyone. Being cautious is different than re-arranging everything due to risk.


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## cainvest (May 1, 2013)

peterk said:


> Yes I will, and I don't know why you WOULD imagine that it is.
> 
> How far does a cough, sneeze or moisture droplets from breath travel? 2m? Sure, maybe. Sounds low to me...
> How wide are grocery store aisles? 2m
> ...


I doubt it was just "picked" but rather a reasonable safety distance many could understand. Actually, many have said 1 meter over the course of the pandemic but that likely increases your chances of contact (bumping into,brushing clothes,etc) with others to much so generally 2m is stated as a buffer.

Yes if someone does cough, sneeze, etc at you within 2 meters (or more) you are pretty much doomed, it will travel farther. But what is more likely, having someone do that when you are out shopping or picking up the virus from contact? If 100 people have walked down a shopping aisle before you and one of them sneezes they infect all the products 2-4m in front of them with the spray. IMO, product (or common contact points) like this are a much greater threat and not direct transfer like a sneeze or cough within 2m of you.


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## james4beach (Nov 15, 2012)

In Mississauga, there's a cluster of COVID cases at a condo building. All the cases are the same variant from South Africa, which strongly suggests that it has been spreading within the building.



https://www.cbc.ca/news/canada/toronto/variant-cases-mississauga-condo-testing-1.5914529



I wonder how it spread. Elevator buttons? Doorknobs?


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## sags (May 15, 2010)

Worse case scenario..........ventilation system.


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## james4beach (Nov 15, 2012)

sags said:


> Worse case scenario..........ventilation system.


Yeah, I really hope it isn't spreading through the ventilation. It's possible there is a malfunction in the building's HVAC. If the air is flowing from units back into the hallway, that might do it.

Normally, there should be pressurized hallways which flows into each unit. That keeps everyone's air isolated and separate.

It might also be spreading in crowded elevators, if people are really packing tight in there.


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## GreatLaker (Mar 23, 2014)

Most of the community spread I have read about is person to person via aerosols. In an apartment it could be people in close proximity in elevators or stairs, passing in the corridors, passing each other through the entrance and exit doors, front desk, mail rooms, fitness rooms (if still in operation). Or touching a contaminated surface like elevator buttons or common element door handles recently touched by a carrier. So wear a mask in common areas and wash hands when you get home.

If a COVID carrier coughed or sneezed in the corridor outside your condo unit, the air in the hallway containing their virus laden respiratory droplets could pass under your door (via the positive pressure corridors) into your unit along the floor. Then up onto a surface you touch, or up into the air at head level you are breathing. This mechanism of transmission seems less likely than what I mentioned in the above paragraph.


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## sags (May 15, 2010)

It will interesting to see how the COVID experience effects the popularity of communal living.


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## Mukhang pera (Feb 26, 2016)

AltaRed said:


> The first high rise we lived in, in 1971 in Mt Pleasant/Eglinton in Toronto


My high school high school gf lived in that area then. A lot of high-rise buildings on Broadway in them days. Would you have been in one? She was in "The Algonquin" at 66 Broadway. I knew someone renting at 88 Erskine Ave., just behind the Algonquin, at that time.


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## AltaRed (Jun 8, 2009)

Close but not quite. We were right on Eglinton, right around Mt Pleasant I believe. I forget the name of the high rise. After a few years, we moved to a brand new high rise right at the intersection of Eglinton and Scarlett Rd on the banks of the Humber. Loved the walking options there. Then decided to have a family and we bought a house in Burlington and I commuted.


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## gibor365 (Apr 1, 2011)

james4beach said:


> I'm looking to rent a condo or apartment (in a building with many occupants) but am concerned about air circulation and COVID-19. The scientific picture is not clear. Some sources say that building HVAC systems are not a significant COVID-19 threat, but I don't want to take any chances. Officials have been very slow catching on that COVID-19 is airborne.
> 
> The dangerous situation I want to avoid is where air flows from someone else's unit into the hallway, then into mine. I've previously been in apartments where I can smell someone else's cooking or cigarette smoke. Clearly, that also means that if they are coughing up a storm, those particles are coming into my home.


Just go back to Oregon ... they gonna vaccinate everyone very soon...
P.S. Still regret when we decline amazing Oregon relocation offered be INTC


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## Beaver101 (Nov 14, 2011)

james4beach said:


> In Mississauga, there's a cluster of COVID cases at a condo building. All the cases are the same variant from South Africa, which strongly suggests that it has been spreading within the building.
> 
> 
> 
> ...


 ... people not wearing masks and inviting friends over I bet.


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## james4beach (Nov 15, 2012)

gibor365 said:


> Just go back to Oregon ... they gonna vaccinate everyone very soon...
> P.S. Still regret when we decline amazing Oregon relocation offered be INTC


gibor maybe you didn't see the emails I posted, but clinics in Oregon don't have vaccine available for the general population. Maybe at some point, but they don't know when.

Curious, did Intel offer to relocate you from Israel to the Hillsboro Oregon location?


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## gibor365 (Apr 1, 2011)

james4beach said:


> gibor maybe you didn't see the emails I posted, but clinics in Oregon don't have vaccine available for the general population. Maybe at some point, but they don't know when.
> 
> Curious, did Intel offer to relocate you from Israel to the Hillsboro Oregon location?


In any case Oregon gonna vaccinate much much earlier than ON. Vaccination rate per hundred people higher in Oregon 470% comparing to Canada

They offered us to relocate to OR, AZ or CA (city with major site ) from Toronto, when Intel Toronto was just down ...we even went to CA and OR to check out houses, schools etc, but at the end decided not to go mostly because of our moms and kids. Also AFAIR they were giving L1A Visa for 7 years, but couldn't guarantee that we gonna get green card (just help with it).
But our friends relocated to Intel in OR and later in AZ directly from Intel Israel


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## james4beach (Nov 15, 2012)

I was ahead of the game here, thinking about how the building's airflows affect the spread of COVID.

Now that scientists know that COVID is airborne, they are talking about fundamentally rethinking indoor ventilation systems

As we discussed in this thread a full year ago, different buildings have different kinds of ventilation systems and it can be hard to figure out if a building's air is actually safe. The experts in this article are saying that the time has come to step up the standards we expect for indoor air.

Just as we currently expect clean tap water, the time has come to expect clean indoor air ... which can protect us from influenza and all kinds of things.

People used to deal with contaminated drinking water without a second thought. After recognizing how disease was spread through it, new norms were established, and new infrastructure to assure clean drinking water in cities. This is pretty exciting because we might now be coming to similar realizations about indoor air; something that was just ignored until now.

This is also a lesson in thinking for yourself and doing your own research. In post #10 I pointed to the research I had done, and said it was very unclear (people seemed to really have no idea how HVAC systems relate to virus spread). Then of course I've read constantly mocking, sneering and ignorant posts like the one from @Just a Guy where he jokes that one should just stop breathing. Apparently this "real estate guy" has absolutely no understanding of HVAC and how it relates to disease spread.


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## james4beach (Nov 15, 2012)

GreatLaker said:


> Most of the community spread I have read about is person to person via aerosols. In an apartment it could be people in close proximity in elevators or stairs, passing in the corridors, passing each other through the entrance and exit doors, front desk, mail rooms, fitness rooms (if still in operation).


In recent months, I've seen some examples of how this community spread might happen in an apartment/condo.

In my building, when large groups of 20 year olds have parties (which happens frequently, violating provincial laws) they gather in common areas. So you will see groups of several young adults, some without masks, talking loudly in lobbies hallways, and elevators. This is a great way to contaminate the common areas and infect other people. Whether masked or not, lots of loud talking will emit enough particles and leave aerosols hanging in the air.

If five people linger in a corridor, and contaminate it with viruses, that aerosol may remain for quite a while after they are gone. I think this could infect other people coming or going through the hallways and lobby.

The other example I've seen is people exercising in confined areas, like the stairwells. A couple times, I caught some 20 year olds exercising (without masks) going up and down the stairs, in very poorly ventilated areas. Especially with the exercise and heavy breathing, this can leave virus aerosols in the air and could infect other people for some time.

Just some examples to think about. We should all be actively thinking about this, because we don't know how variants will change over time, and we shouldn't rule out that we might be dealing with another dangerous 2021 winter, if mutant strains turn out to be more dangerous.


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## MrMatt (Dec 21, 2011)

james4beach said:


> I was ahead of the game here, thinking about how the building's airflows affect the spread of COVID.
> 
> Now that scientists know that COVID is airborne, they are talking about fundamentally rethinking indoor ventilation systems
> 
> As we discussed in this thread a full year ago, different buildings have different kinds of ventilation systems and it can be hard to figure out if a building's air is actually safe. The experts in this article are saying that the time has come to step up the standards we expect for indoor air.


We knew this was an issue with SARS years ago.
Personally I think high density housing is unhealthy.


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## cainvest (May 1, 2013)

james4beach said:


> Just some examples to think about. We should all be actively thinking about this, because we don't know how variants will change over time, and we shouldn't rule out that we might be dealing with another dangerous 2021 winter, if mutant strains turn out to be more dangerous.


But by winter 2021 almost everyone (that wants it) should be fully vaccinated right?


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## Covariance (Oct 20, 2020)

james4beach said:


> In recent months, I've seen some examples of how this community spread might happen in an apartment/condo.
> 
> In my building, when large groups of 20 year olds have parties (which happens frequently, violating provincial laws) they gather in common areas. So you will see groups of several young adults, some without masks, talking loudly in lobbies hallways, and elevators. This is a great way to contaminate the common areas and infect other people. Whether masked or not, lots of loud talking will emit enough particles and leave aerosols hanging in the air.
> 
> ...


You can measure CO2, CO with inexpensive handheld units. This will give you a proxy for the level of exhaled gas in the surrounding area. Small and or poorly ventilated areas with lots of people will exhibit much higher levels of detectable, emitted gas. Doesn't mean there are virus particles but it does give one a sense of the inhalation risk.


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## james4beach (Nov 15, 2012)

cainvest said:


> But by winter 2021 almost everyone (that wants it) should be fully vaccinated right?


Yes we should be OK, but there is still a slim possibility that we get a new variant that starts evading vaccines. I don't expect that will happen though.

In any case, figuring out how to improve indoor air quality is critical for many other reasons. Think of stores and offices... people are soon going to be back in offices spending all their time there. Indoor air quality matters. How about all the workers who spend their whole days in stores, warehouses and factories?


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## MrMatt (Dec 21, 2011)

james4beach said:


> Yes we should be OK, but there is still a slim possibility that we get a new variant that starts evading vaccines. I don't expect that will happen though.
> 
> In any case, figuring out how to improve indoor air quality is critical for many other reasons. Think of stores and offices... people are soon going to be back in offices spending all their time there. Indoor air quality matters. How about all the workers who spend their whole days in stores, warehouses and factories?


I expect we will have a variant that evades current vaccines, and soon.

Hopefully this pushes people to look at air quality overall, maybe even outdoor air quality. Not just this insane preoccupation with CO2


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## andrewf (Mar 1, 2010)

MrMatt said:


> We knew this was an issue with SARS years ago.
> Personally I think high density housing is unhealthy.


Suburban housing is unhealthy--it makes you fat and inactive.


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## MrMatt (Dec 21, 2011)

andrewf said:


> Suburban housing is unhealthy--it makes you fat and inactive.


Didn't notice. I like being only a few hundred meters from multiple parks and playgrounds, with forests, trails and fishing ponds within a 10 minute bike ride.
Way more ability to be active here than in the city center.


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