Can Air Conditioners Spread COVID-19?

[Ohiogal]

From NPR

Among scientists, there is ongoing debate about the extent to which aerosol transmission causes infection. However, it has been generally accepted that it does occur, especially in closed indoor settings. Consequently, there's a possibility that air conditioning may be a potential route of transmission — sucking in virus particles breathed out by an infected person and then blowing those infectious particles back out in the same room or even another room several floors away.

In fact, other infectious diseases such as measles, tuberculosis, chickenpox, influenza, smallpox and SARS have all been shown to spread through heating, ventilation and air conditioning systems.

(snip)

“We didn't focus on ventilation as much early on as we probably should have," says Abraar Karan, a physician and global health researcher at Harvard Medical School.

What we do know is this: HVAC systems primarily recirculate air in a room or a building and don't bring in any fresh air from outside. So yes, theoretically virus-containing aerosols could be sucked into an air conditioning system and then circulated around a building.

More

https://www.npr.org/sections/goatsandsoda/2020/08/15/897147164/can-air-conditioners-spread-covid-19

[Wounded Bear]

1. Typical air filters are for dust and other particulates...

largely through static attraction and cling. They don't really do anything for water droplets or mists.

While they may "de-humidify" the air they circulate, that doesn't mean they will eradicate viruses or other pathogens. That takes some special conditioning.

[fescuerescue]

2. AC systems can be fitted with UV sterilizers

If Trump had any brains, he would require all commercial buildings closed until they can be fitted with them.

Also all new AC systems should be required to have one as well.

[FoxNewsSucks]

4. "If Trump had any brains"

HAHAHAHAHAHAHAHAHAHAHAHAHAHAAHAAA!



Good one!

[Ohiogal]

5. Absolutely!

But I won’t hold my breath (no pun intended) for this weak, do-nothing administration to require it. Dumpy is only interested in playing golf and the rest of the lame brains in his cabal don’t care.

[PoindexterOglethorpe]

13. Which would probably take years and cost billions of dollars.

[fescuerescue]

14. So a couple % more.

We are spending trillions right now.

SPend a couple % more and save 167,000 lives.

[Rstrstx]

22. Prediction: they'll be mandatory in new commercial construction in a few years

They’ll add a slight cost to a new building but if an office complex or restaurant can’t afford it then their project is probably not viable to begin with. We will benefit from them as a whole long after CV-19 is gone; they should also help reduce seasonal flu, common colds, etc. I believe most hospitals already have them, it would be borderline criminal if they didn’t.

Some states may even require retrofits every time an HVAC unit needs major work. I’m surprised more places didn’t proactively install them when they were shut down, it would have made people feel a little more comfortable going back into their businesses.

We’ve known AC units can circulate the virus ever since that paper came out that showed which tables at a restaurant in China were infected from a case of someone who had the virus.

[PoindexterOglethorpe]

23. I'd be willing to predict that, also.

However, mandatory in new construction in a few years is hardly comforting. Nor is that "Some states may even require retrofits every time an HVAC unit needs major work" seem particularly helpful.

On the up side I read something earlier today that it's beginning to look as if even a mild case of Covid-19 confers long-lasting immunity. I can't seem to find the precise article I read, alas.

So in the long run herd immunity may well be a thing.

[DeminPennswoods]

31. Exactly, even if a business has to borrow,

the cost of money is practically 0 right now. I'd've had it installed, done a demonstration of effectiveness for health officials, then asked for a waiver of capacity reductions. You can bet when other businesses saw that, they'd want to do the same.

[DeminPennswoods]

15. Thank you!

Have been saying this for awhile, fix HVAC and it would allow the hospitality industry and schools to open back up.

This is should be part of the national building code going forward, but states can act, too. I'd bet the cost of retrofit would be less, even if the federal govt picked up the entire cost, than what's been spent in the relief bills that have already been passed and signed into law.

There are plenty of people within the Army Corps of Engineers who could figure out how to do this in a cost effective way.

[nolabear]

25. My dentist outfitted his office with those.

He’s amazingly careful, not crowding the appointments, all the PPE, and new high overturn air system with UV light. It can be done!

[Throck]

3. Closed HVAC systems are typically found in residential sytems.

Commercial HVAC system must include provisions for ventilation air per building codes. Better HVAC systems allow 100% outside air, called economizer.

[TheBlackAdder]

7. The problem is during the wintertime, when it's too inefficient to draw in a lot of outside air.

[SlogginThroughIt]

6. Even if the system has filtration or UV

Even if the system has filtration or UV I have read where the ventilations systems exacerbate the issue with creating air currents which carry the virus further than typical breathing before it gets sucked up in the return of the system.

[JudyM]

19. It may carry farther but increased ventilation is also believed to help by dispersing the particles

so that the viral load inhaled would be less.

[SlogginThroughIt]

24. Yep it is all MAY and MIGHT.

We just do not know enough

[Ohiogal]

10. The building

that serves as my kids’ Jr. High building was built to accommodate air conditioning, but the school ran out of money and never installed it. This was back in the 60s so it’s been that way a long time. The classrooms each have one skinny window that can’t be opened. In warm weather, it’s utterly miserable inside. Most teachers bring their own floor fans to stir the air, but when you’ve got 35 kids in a room full of hot stale air, on a hot day, who knows what kind of particles are floating around. I don’t know how they endure it. Of course, the front office and principal’s office have air conditioners.

[DeminPennswoods]

16. I can't imagine a school building having windows that

do not open regardless of when it was built. Why isn't this a safety issue?

[Ohiogal]

17. I have gone to new student orientation there

Three times with three kids. In the afternoon, it’s like walking into a pizza oven. Kids always said it didn’t get real bad until after noon. But, yeah, windows that don’t open and no air conditioning.

[appalachiablue]

21. Contact local/state health & fire depts. Inexcusable & potentially

lethal-- no air cooling, no window access to escape if there's a fire, chem spill, shooter or other emergency, & since the 1960s?

I'm almost certain a Fire Dept. would issue a real strong message or citation. Exits, doorways and other areas have to be clear and easily accessible in event of an emergency.

At a govt. dept. where I worked we always had the stairwells, interior and exterior doors and more working and clear of obstacles as required by the yearly Fire Dept. inspectors. No dangerous, unsecured containers of paint, cleansers or chemicals laying around and messy either.

[DeminPennswoods]

28. Actually OSHA, even under the current WH, would come in

with thermometers, check the ambient temperature and if it's over a certain threshhold, they would close the school.

[appalachiablue]

33. Tx, that's reassuring. This situation sounds very unsafe.

[DeminPennswoods]

29. One of the local high schools

was built in the late 70s. Although inside, it's an open design, I don't think the windows open. In what was the former HS, all the windows open and I'll bet the teachers assigned there are glad about it. They'll be able to open their classroom windows when students return on a hybrid schedule.

[JudyM]

20. Same with hotels.

[Iliyah]

9. Dr. S. Gupta talked about this months ago . .

Air conditioners recycle air and most filters are not equipment to deal with droplets. It was also advised to open slightly windows to allow air from outside to flow inside as well while also allowing air conditioner air to flow outward.

At this point in time, COVID-19 constantly is mutating.

[crickets]

12. Yep. Canadian researchers also were talking about this in April.

https://www.democraticunderground.com/100213356943

[ProfessorGAC]

26. Only A Minor Dispute

HVAC systems almost always bring in outside air to:
1. Compensate for air loss due to leakage. This is a bigger deal in the winter where the higher temperature inside is warmer, hence higher pressure.
2. Maintain a constant positive pressure so exit doors are easy to open. Building codes generally require entry doors open out.
3. To freshen the air.
It's a small amount, so it doesn't dispute their overall point. But, HVAC systems almost never recirculate 100% of the air.

[Hekate]

27. Wasn't Legionnaire's Disease found in AC systems? I seem to remember that.

[DeminPennswoods]

30. Yes

In fact, when businesses were getting ready to reopen, they were recommended to clean and purge their water systems to ensure no legionella bacteria was present.

[Hekate]

32. That's what I thought. smh

[roamer65]

34. Yes they can.

For the person in said building, it’s all about virus concentration, duration of exposure and immune system strength.

[appalachiablue]

35. Legionnaires Disease:

https://en.wikipedia.org/wiki/Legionnaires%27_disease

[Buckeye_Democrat]

36. Well, I'm certainly assuming it does. The A/C is off here...

... because I'm still dealing with contractors after a major pipe leak under the foundation of my apartment.

I originally suggested to the landlord that he just bypass the leaking underground pipe with an above-ground pipe, but nooooo!

So a plumber jack-hammered the foundation of the restroom and then realized that's not where the leak was located! I told him it sounded louder in the utility room near the water heater, but he said otherwise and I deferred to his "years of experience" despite how he seemed a bit like a redneck. (And he certainly didn't approach it like a scientist or something, using special equipment to locate the leak precisely.)

The landlord later called me to say he and the plumber decided to bypass that pipe from the utility room to the restroom with an above-ground flexible pipe -- forgetting that I made that suggestion in the first place -- and that fixed THAT problem.

Just had a guy today who replaced the restroom tiles. So I went through my routine of turning off the A/C, covering my bedroom vent, having zippered plastic barriers closed off near the restroom, etc.

I briefly looked at the finished tile while wearing my N100 mask; sprayed Lysol in the air; sprayed alcohol mist on the doorknobs, light switches, etc.

Will be less cautious later, since the virus can't remain viable without a host forever!

And the damn work isn't done yet. Still awaiting yet ANOTHER GUY to replace the restroom sink and vanity.

I'd obviously prefer to have nobody else in here! I don't even let family members in here! Ugh.

Edit: I'll probably "lose my shit" if I get infected from these mask-less yahoos coming in here. Yeah, they don't even do that despite the statewide mandate. After my extreme caution and sacrifices for months, I will be furious. (I haven't raised a fuss about them not wearing masks because I figure some of their droplets and aerosols would get out anyway, and the bigger issue is them being in my apartment for so long.)

[Igel]

37. That's been a bit of speculation.

COVID took off in Texas when it got hot.

Where I grew up, around April or May you start going outside more. It's warmer, pleasant. Parks start filling up, pools open.

Where I live now, near Houston, in April and May you seriously start avoiding outside more. It's warmer, unpleasant. Parks start emptying out unless there's a source of cool water. By August, add some bubbles to most pools and they're found to be very large hot tubs.

I go outside to water the yard, get to the car, and water plants. Otherwise ... I'd like to be out and have a garden going, but seriously, it's in the upper 90s and it just looks unpleasant outside. Bright, sunny, blue sky, green everywhere. < cringe >