Improving ventilation will help curb SARS-CoV-2 • Hacker News Board

Re: Improving ventilation will help curb SARS-CoV-2

#71

Post by schoen » Mon, May 31, 2021, 2:31 AM UTC

nradov wrote: post #50

pyk wrote: post #10

Earlier quoted context omitted.

If you have forced air, you can get a UV bulb that all air passes by for $200-300 - just requires drilling some holes and an AC plug. Also helps with killing mold and bacteria as an added benefit (and some of the original intention for the devices, e.g., OdorStop).

Are there any independent test results to show how effective those UV bulbs are at killing pathogens?

I would particularly want guidance about

* what UV frequencies to use

* what intensity of light to use

* what volume of air can flow past it per second

I totally believe that UV light is great at killing pathogens and that UV belongs in ventilation systems, but we presumably need to know how much UV light is needed.

The UV doses needed also seem to depend on a lot on the type of pathogen. For example, viruses require a higher dose than bacteria. In

https://www.sciencedirect.com/science/article/pii/S019665531...

it required up to 6 times as much UV to inactivate viruses compared to bacteria.

Re: Improving ventilation will help curb SARS-CoV-2

#72

Post by xaduha » Mon, May 31, 2021, 2:32 AM UTC

myroon5 wrote: post #52

xaduha wrote: post #44

I believe Home Automation needs to start with proper climate control (not with iKettles) because just bringing fresh air from outside probably isn't enough, it depends on many things. There's so much wasted heat, varying humidity, overabundance of co2 and particulate matter due to pollution in some places - keeping it all at optimal levels throughout the year is no small task. Everyone knows about air conditioning, b…

I've been thinking the same and mainly found this so far: http://wyndflow.com/

There are some DIY recuperator videos on youtube https://www.youtube.com/results?search_query=diy+recuperator

Re: Improving ventilation will help curb SARS-CoV-2

#73

Post by throwaway879 » Mon, May 31, 2021, 2:33 AM UTC

whatshisface wrote: post #18

tinus_hn wrote: post #16

Earlier quoted context omitted.

It’s not about having a monopoly on good information. It’s about a monopoly on attention. What use is it if the WHO is wrong and someone else is right, but everybody listens to the WHO?

Who's going around listening to the WHO?

Their Tommy album was pretty good.

Re: Improving ventilation will help curb SARS-CoV-2

#74

Post by deugo » Mon, May 31, 2021, 2:33 AM UTC

SllX wrote: post #6

> The who therefore played down the risks of aerosols, issuing guidance via its Twitter and Facebook pages at the end of March 2020 that the general public need not worry. “FACT: #COVID19 is NOT airborne,” it said, adding that any claims to the contrary were “misinformation”. Not quite the money quote, but on reading this I wanted to point out one little thing. This is also a form of authoritarianism, not the splashy…

https://www.who.int/docs/default-source/coronaviruse/transcr...

Coronavirus press conference 11 February, 2020

Tedros gives the money quote:

> That was exactly what we were trying to do in DRC so we don't want, as WHO, to go into speculation. Okay, people can have projections. We prefer, what can be done with the equipment or the solutions at hand and do our best to contain it at the source without undermining its gravity, without undermining the serious consequences it may have. That's what we did and that's what we want for this one.

> Of course Ebola and this are not the same. Ebola is lousy. This is airborne, corona is airborne, it's more contagious and you have seen how it went into 24 countries although it's a small number of cases. In terms of potential to wreak havoc the corona is very different from Ebola; corona has more potency, virulence. We take it more seriously but still the position should be instead of speculation really to focus at the source, to do everything at the source, slow the spread, stop the spread, invest more in containment and based on the situation move into other strategies if necessary.

> Meaning we have to be realistic; we have to be calm [?] but we have to take also serious measures.

This was when the WHO was pressured into saying not to ban flights from China, as it would be useless [?!] against fighting the pandemic. Not blaming them too hard, as these were difficult decisions. But somehow this got retconned hard, and we, and the media, let it, not even bringing it up again when debating COVID being airborne or not.

Re: Improving ventilation will help curb SARS-CoV-2

#75

Post by viraptor » Mon, May 31, 2021, 2:38 AM UTC

krona wrote: post #21

kiba wrote: post #13

Earlier quoted context omitted.

Yes, health authorities can be wrong, but if you want to prevent, stop, or aliemoriate a pandemic, you need cooperation. You can't just have Joe Sixpack decided to not quarantine himself or not wear masks. Yes, the authority figures can be wrong. Fauci can be wrong. People can die when health authorities make mistakes, whether through indecision or decision. I myself keep wearing masks after the CDC says I don't need…

> you need cooperation Sure. > You can't just have Joe Sixpack decided to not quarantine himself or not wear masks. So, cooperation, via coercion? Got it. I guess the ends justify the means.

At some point... yes. Otherwise, what's your idea for dealing with people who know they're sick but still go into crowded places? We've had examples of people who knew they were infected trying to board planes for example. If not coercion, then what?

Re: Improving ventilation will help curb SARS-CoV-2

#76

Post by mike529 » Mon, May 31, 2021, 2:48 AM UTC

timr wrote: post #69

Izkata wrote: post #63

Earlier quoted context omitted.

> (and before anyone says it: yes, it's entirely possible to have conducted clinical trials of masks. a cluster randomized trial, for example, could have been used to establish efficacy early in the pandemic. That we didn't even consider doing these "because it's a pandemic" is one of the biggest scientific lost opportunities of our lifetime.) There were studies done; all the way back in March 2020 there was an infog…

There have been a number of laboratory studies performed that show varying levels of effectiveness for different kinds of masks and materials (where "effectiveness" is defined in all sorts of different ways that may or may not be relevant). Prior to Covid-19, there was a low-quality evidence base that didn't provide much signal either way: https://www.cebm.net/covid-19/masking-lack-of-evidence-with-... Strapping a ma…

This good cluster RCT is in the midst of being done.

https://www.nber.org/papers/w28734

In this paper they demonstrated an intervention in Bangladesh that increased mask usage by 30 percentage points (from ~10% to ~40%). In the follow-up paper they are doing random antibody testing between the two groups.

Re: Improving ventilation will help curb SARS-CoV-2

#77

Post by darkteflon » Mon, May 31, 2021, 3:02 AM UTC

beisner wrote: post #32

darkteflon wrote: post #12

Earlier quoted context omitted.

Can I ask why you chose this brand and this model? I’m looking for an air filter but have no idea which brands to trust.

Wirecutter recommends Coway

Thanks, [this](https://www.nytimes.com/wirecutter/reviews/best-air-purifier...) was a great read from a trustworthy source.

The AP-1512HH sounds like a great buy for most cases, although if you're particularly concerned about VOCs including exhaust fumes (we are - we live in a dense city, close to a main road), the Austin Air HealthMate HM400 is probably what you want. Used by "FEMA and the Red Cross ... for deployment at Ground Zero and the surrounding areas in the aftermath of 9/11", apparently.

Re: Improving ventilation will help curb SARS-CoV-2

#78

Post by dwaite » Mon, May 31, 2021, 3:24 AM UTC

bsder wrote: post #41

kevin_nisbet wrote: post #27

Earlier quoted context omitted.

I certainly don't think you should be ridiculed for the notion, although I think my counter thought would be why should it be one or the other, and how confident are we in the engineering side of the solution at a wide scale. To my knowledge masks are a low cost / lost risk way to reduce the spread, and countries that had faster uptake and higher rates of compliance in mask usage did see lower overall case counts. Th…

> And how can we be sure that businesses don't just try and cheat As someone who knows an HVAC inspector, they WILL cheat. He has appalling stories. The most appalling was him having to hold up opening a memory care facility because the HVAC was all shared when it was all supposed to be isolated. This was completely on the HVAC contractor as the plans were quite explicit about what needed to be done--which means that…

> So, don't hold your breath.

Or, do.

Re: Improving ventilation will help curb SARS-CoV-2

#79

Post by xxpor » Mon, May 31, 2021, 3:34 AM UTC

BurningFrog wrote: post #58

SllX wrote: post #6

> The who therefore played down the risks of aerosols, issuing guidance via its Twitter and Facebook pages at the end of March 2020 that the general public need not worry. “FACT: #COVID19 is NOT airborne,” it said, adding that any claims to the contrary were “misinformation”. Not quite the money quote, but on reading this I wanted to point out one little thing. This is also a form of authoritarianism, not the splashy…

It's important to understand that what CDC & FDA etc say is not "science". These are federal regulatory agencies whose mission is to enforce regulations. This is part of a political process, and their leaders ultimately serve at the pleasure of the president. When the prominent scientists who work there speak on issues, they are speaking as employees of that organization, not giving their best scientific estimation.…

>The WHO is a UN agency that's probably even more politicized, but I don't know much about it.

Tedros was hand picked by China. He was a communist during his time in Ethiopia. This was a big controversy years before covid. I was wondering why China would possibly care so much, I thought it was just them trying to increase their international clout however possible...

Re: Improving ventilation will help curb SARS-CoV-2

#80

Post by bootlooped » Mon, May 31, 2021, 3:35 AM UTC

kardos wrote: post #25

exabrial wrote: post #23

I suggested this as an alternative to mask enforcement months ago and was ridiculed on hacker news. I'm happy to see the idea come up again as it has a lot of solid science behind it.

Retrofitting the world's buildings for better ventilation all at the same time during a pandemic? Seems like a project measured in decades

I have almost never even seen a business' window or door propped open where it was normally closed before. I have never seen an air purifier in a public area of a business. If HVAC systems were modified or upgraded, I wouldn't have any way of knowing that, but I bet not many were. A lot of businesses won't do things for their patrons' safety unless they're forced to. Could you imagine what fire safety would be like if there were no laws or regulations about it?