Why aren’t we talking more about airborne transmission? • Hacker News Board

Re: Why aren’t we talking more about airborne transmission?

#181

Post by graeme » Mon, Aug 03, 2020, 5:23 PM UTC

newsbinator wrote: post #117

graeme wrote: post #22

If anyone is in an indoor environment and wants to gauge risk, a portable co2 meter can be had for about $100-$150. Cod2 is a good proxy for indoor pollutants/air exchange, and I’m assuming it is a good proxy for aerosols too. I use one of these, you can use a portable battery to power it. https://www.amazon.com/AutoPilot-APCEMDL-Desktop-Data-Storag...

Is there a reliable portable Co2/Pm2.5 logger? I've heard the accuracy on the Pm2.5 ones at least is way off. I just moved to a place where I need to keep an eye on Pm2.5 in particular.

It doesn’t log pm2.5. Only co2. For pm 2.5 I recommend a laseregg

Re: Why aren’t we talking more about airborne transmission?

#182

Post by jansan » Mon, Aug 03, 2020, 5:23 PM UTC

mensetmanusman wrote: post #166

jansan wrote: post #163

Earlier quoted context omitted.

Opening the windows more often may also help a lot. This is a very simple method to reduce risk of spreading. It is free and especially useful for places like schools. But I do not think I read about this in mainstream media. It's all about masks and social distancing.

I am concerned about winter, because we have to prep now for that.

On the northern hemisphere we still have a few months (actually, two or three only). That's why the article is correct, we urgently need to talk about airborne transmission.

Re: Why aren’t we talking more about airborne transmission?

#183

Post by tomrod » Mon, Aug 03, 2020, 5:23 PM UTC

SkyPuncher wrote: post #118

jennyyang wrote: post #32

After this pandemic, doctors and scientists are going to have to come up with more media-friendly terms from now on. The problem is that "airborne droplets" and "airborne" sound too similar and it's very hard for regular people to understand what that means. "Airborne droplets" means that viruses need saliva to transmit between people. "Airborne" means that the virus only needs dust particles to transmit to other peo…

> If someone with coronavirus sneezes in a room, the large heavy droplets will quickly fall to the ground. This is the slightly incorrect part with COVID. Traditionally, this would be an appropriate description for other droplet transmission (like the flu). However, it seems COVID has an above average ability to survive in extremely fine droplets - think mist-sized particles that CAN float in the air for an extended…

True. And I am curious whether things can be done in most building's HVAC systems to account for this.

The ideal would be:

- Heavy external air exchange OR heavy filtering (think N95-level filtration on the return air exchange

- Diffusers are at foot level (not common)

- Return air in ceiling

- People wear masks

My fear of school spread is that folks are basing their mental models on the flu, and if this hangs in the air for an appreciable amount of time then classrooms are difficult to keep sanitized.

Good luck out there. Thanks for the knowledgeable comment.

Re: Why aren’t we talking more about airborne transmission?

#184

Post by graeme » Mon, Aug 03, 2020, 5:25 PM UTC

graeme wrote: post #22

If anyone is in an indoor environment and wants to gauge risk, a portable co2 meter can be had for about $100-$150. Cod2 is a good proxy for indoor pollutants/air exchange, and I’m assuming it is a good proxy for aerosols too. I use one of these, you can use a portable battery to power it. https://www.amazon.com/AutoPilot-APCEMDL-Desktop-Data-Storag...

Can’t edit: co2 is a good proxy for VOC’s. CO2 is not a good proxy for pm 2.5, to be clear: this depends on the pm 2.5 in your outdoor air.

In other words co2 is a proxy for indoor/outdoor air exchange, and thus should be a proxy for how fast aerosols are sent outdoors.

Re: Why aren’t we talking more about airborne transmission?

#185

Post by mensetmanusman » Mon, Aug 03, 2020, 5:25 PM UTC

war1025 wrote: post #180

mensetmanusman wrote: post #164

Earlier quoted context omitted.

It is all about virion particles per cubic meter (similar to how they classify class ## cleanrooms for the semiconductor, but in that case they talk about dust particles). Outdoor air works through dilution (‘the solution to pollution is dilution’ is the phrase often used). Indoor air being purified is often much cleaner than outdoor air (assuming CO2 levels are not of any concern), this is especially true during wil…

> this is especially true during wildfire season Curious what if any effect that would have over here in Iowa. I would guess negligible, but we do get high-level haze occasionally when there are wildfires in Canada. > If you purchase a PM2.5 sensor I have been curious about these in the past. Do you have any recommendations? I couldn't find enough info to feel comfortable that whatever I bought might actually tell me…

Ideally people would be outside more if the air is good. When they have to be indoors, it is better to purify so we aren’t being exposed to ‘unnatural’ environments, i.e. lots of skin flakes floating around with dust mites, etc.

Also, many people in South America have shortened lives because they are indoors with wood burning stoves that are giving them lung cancer.

Re: Why aren’t we talking more about airborne transmission?

#186

Post by R0b0t1 » Mon, Aug 03, 2020, 5:26 PM UTC

hashtagjohnt wrote: post #155

R0b0t1 wrote: post #138

Earlier quoted context omitted.

>By strict definition, COVID is not airborne since it seems to require a host material (e.g. water droplet). You are wrong. Read: 1. https://www.who.int/news-room/commentaries/detail/transmissi... . 2. https://www.nature.com/articles/s41586-020-2342-5_reference.... . Aerosol transmission is the main vector. Consider posing your statement in the reverse: SARS-CoV-2 does not disperse in droplets, and/or is not infectio…

In the first article you posted it reads: > To date, transmission of SARS-CoV-2 by this type of aerosol route has not been demonstrated; much more research is needed given the possible implications of such route of transmission. That seems to be in direct opposition to your statement, correct? Or am I missing something.

Well, I forgot the WHO still does not think aerosol transmission is likely. But they do have a section on airborne spread that exceeds most people's expectations.

The thing is -- why assume it can't form aerosols and that those aerosols aren't infectious? By demanding evidence for aerosol formation that is what they are stating. It makes no sense. Most viruses do form aerosols, and those aerosols do seem to be infectious.

Re: Why aren’t we talking more about airborne transmission?

#187

Post by mensetmanusman » Mon, Aug 03, 2020, 5:27 PM UTC

yellow_postit wrote: post #172

ogre_codes wrote: post #149

Earlier quoted context omitted.

My wife works in a doctors office which has stayed open through the pandemic. She sees a few people a day in a small room. The very first thing she did after the pandemic hit the US, was buy an air purifier and she runs it continually. I'm quite surprised that they aren't more common in medical offices in general. The benefits of the air filter are cumulative with other protections—particles caught by the filter can'…

Expect we will see a repeat of the bungled rush for air purifiers as we did with ventilators.

Here would could at least prioritize schools? Ventilators was only bungled because it turned out to be the wrong therapy... air purifiers is a win win win

Re: Why aren’t we talking more about airborne transmission?

#188

Post by throwaway_pdp09 » Mon, Aug 03, 2020, 5:27 PM UTC

jennyyang wrote: post #120

jtbayly wrote: post #68

Earlier quoted context omitted.

> we would have to implement extremely strict lockdowns... if we assume that the goal is not to flatten the curve but to completely stop the virus in its tracks. Most people and countries don't have this goal. Edit: To those downvoting, I'll just say that my statement is factual, so argue the facts. Long-term, we want a vaccine, yes. In the meantime, most people and countries are simply not willing to do what it take…

If the virus were truly airborne, which it isn't, then simply walking through an empty room could get you infected. The levels of people getting infected, and subsequently getting hospitalized would be far worse than the worst scenes we saw in Italy and NYC. Lockdowns absolutely would have been mandatory for months upon months. Coronavirus is not by itself a tremendously deadly disease. The problem is how infectious…

> If the virus were truly airborne, which it isn't

why do you say this? The article is saying otherwise, quite literally "The coronavirus reproduces in our upper and lower respiratory tracts, and is emitted when we breathe, talk, sing, cough, or sneeze"

> then simply walking through an empty room could get you infected

You're presuming it has to be empty.

If you walked through a full room without touching anyone or anything and you caught covid, would you accept that it is airborne? Or are you saying that is impossible?

Do I misunderstand you?

Re: Why aren’t we talking more about airborne transmission?

#189

Post by R0b0t1 » Mon, Aug 03, 2020, 5:27 PM UTC

frenchy wrote: post #156

R0b0t1 wrote: post #138

Earlier quoted context omitted.

>By strict definition, COVID is not airborne since it seems to require a host material (e.g. water droplet). You are wrong. Read: 1. https://www.who.int/news-room/commentaries/detail/transmissi... . 2. https://www.nature.com/articles/s41586-020-2342-5_reference.... . Aerosol transmission is the main vector. Consider posing your statement in the reverse: SARS-CoV-2 does not disperse in droplets, and/or is not infectio…

So I read those, and at least according to the WHO document, it seems to be the case that while viral RNA is detectable in a non-aersolized state in the air, they haven't been able to find any cases of this causing infection (See section labelled "Airborne transmission").

The thing is -- why assume it can't form aerosols and that those aerosols aren't infectious? By demanding evidence for aerosol formation that is what they are stating. It makes no sense. Most viruses do form aerosols, and those aerosols do seem to be infectious.

Are you really prepared to make the bet that they aren't infectious?

Re: Why aren’t we talking more about airborne transmission?

#190

Post by graeme » Mon, Aug 03, 2020, 5:27 PM UTC

CogentHedgehog wrote: post #31

Short-distance aerosol transmission changes things a bit: * Social distancing isn't enough to guarantee safety in indoors spaces: bad news for bars, clubs, gyms, concerts, and restaurants * Outdoors spaces are probably safer than we previously thought * Indoor mask-wearing becomes CRITICAL in public spaces * Indoor ventilation becomes extra important, using fresh air from outside or filtered/UV-sanitized air * Indoor…

Indeed. Governments have been slow to draw these lessons unfortunately. My local government (quebec) lets you remove masks at indoors events when seated.