Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Why don’t we just open the windows? Covid-19 prevention lost in translation

bmj.com

Post reply on HN
Print view View original

61–70 of 298 posts

Re: Why don’t we just open the windows? Covid-19 prevention lost in translation

#61

Post by YZF »

mlyle wrote: post #48
nicoburns wrote: post #4

This agrees with my intuitive impression of everything I've read on Covid-19: that the primary transmission vector is through the being in unventilated or poorly ventilated enclosed spaces with an infected person for ~15 minutes or longer. I definitely feel like neither governmental policies or people's individual precautions and behaviours quite reflect that reality.

I'm a teacher at a school. - We eat outside. - We have filters upgraded to MERV-13 and the fans run the entire school day. - We have windows and doors open on all classrooms, except for A) a few that don't open outside, or B) when it's rainy/windy to the point it's not possible. We have small, secondary HEPA filters that we run in those circumstances. (Often, we're blaring AC or heat into a room with all doors and wi…

That's awesome but why isn't it universal?

Re: Why don’t we just open the windows? Covid-19 prevention lost in translation

#62

Post by doubled112 »

mlyle wrote: post #48
nicoburns wrote: post #4

This agrees with my intuitive impression of everything I've read on Covid-19: that the primary transmission vector is through the being in unventilated or poorly ventilated enclosed spaces with an infected person for ~15 minutes or longer. I definitely feel like neither governmental policies or people's individual precautions and behaviours quite reflect that reality.

I'm a teacher at a school. - We eat outside. - We have filters upgraded to MERV-13 and the fans run the entire school day. - We have windows and doors open on all classrooms, except for A) a few that don't open outside, or B) when it's rainy/windy to the point it's not possible. We have small, secondary HEPA filters that we run in those circumstances. (Often, we're blaring AC or heat into a room with all doors and wi…

My kid's school doesn't have windows that open. It's too new for that.

Re: Why don’t we just open the windows? Covid-19 prevention lost in translation

#63

Post by nitrogen »

exclipy wrote: post #51
calsy wrote: post #47

Earlier quoted context omitted.

How are infections measured in seconds?

In Australia earlier this year when infections were happening the rate of single-digits per day, they could trace the source of an infection to a fleeting encounter of two people walking past each other in a shop. Source: https://www.abc.net.au/news/2021-06-22/covid19-cctv-footage-...

I haven't followed Australia's progress with COVID-19, so I hope these questions aren't too obvious or bothersome:

Were these single-digit infections all symptomatic, or were they detecting asymptomatic infections too? What is the false positive and false negative rate of the type of testing Australia is doing, and how many people were being tested during this time?

If some of the infections were asymptomatic, is it possible that some of them are false positives, and the fleeting encounter was also a false positive (either a false positive test, or that wasn't the true source of the infection) just due to random chance?

Re: Why don’t we just open the windows? Covid-19 prevention lost in translation

#64

Post by sjg007 »

doubled112 wrote: post #62
mlyle wrote: post #48

Earlier quoted context omitted.

I'm a teacher at a school. - We eat outside. - We have filters upgraded to MERV-13 and the fans run the entire school day. - We have windows and doors open on all classrooms, except for A) a few that don't open outside, or B) when it's rainy/windy to the point it's not possible. We have small, secondary HEPA filters that we run in those circumstances. (Often, we're blaring AC or heat into a room with all doors and wi…

My kid's school doesn't have windows that open. It's too new for that.

Your kids school should have a good HVAC then which should run 24x7 and will have a fresh air intake which does the required number of air exchanges per hour. Add in some local air cleaners too.

Re: Why don’t we just open the windows? Covid-19 prevention lost in translation

#65

Post by cryptodan »

anonporridge wrote: post #59
_delirium wrote: post #21

Earlier quoted context omitted.

I hope that's true. My experience so far has been pretty minor symbolic changes though. My employer sent emails about how they swapped their MERV filters for slightly better ones, and something hand-wavy about adjusting the external air percentage "when feasible" (with no numbers). I would be surprised if they do major retrofits, like a new heat exchange system allowing significantly higher percentage of outside air,…

It will eventually become just another element in economic selection. The wealthy and the high income earners will start avoiding buildings, businesses, and organizations that won't or can't sufficiently upgrade to be considered safe. Their money will flow and support the healthy/safe alternatives. Those that are left behind will be the dregs that the poor and desperate use and will gradually fall into disrepair unti…

It won't change my habits. I'm not going to ask every business owner to provide their facilities maintenance info before I go to a place of business. If I get sick I get sick. It may or may not be the fault of the business.

Re: Why don’t we just open the windows? Covid-19 prevention lost in translation

#66

Post by vondur »

anonporridge wrote: post #10
nicoburns wrote: post #4

This agrees with my intuitive impression of everything I've read on Covid-19: that the primary transmission vector is through the being in unventilated or poorly ventilated enclosed spaces with an infected person for ~15 minutes or longer. I definitely feel like neither governmental policies or people's individual precautions and behaviours quite reflect that reality.

A potentially fantastic outcome from all this is that many more public and private spaces will be designed and retrofitted with very good ventilation. Beyond curbing the spread of natural airborne diseases, it also may decrease the attack vector in our societies for airborne bio-terrorism/warfare. And even beyond all that, we're becoming increasingly aware of how important clean air is for our overall health even wit…

Ha, at the University where I work, they are "upgrading" the windows to more energy efficient (good) but they will no longer be able to open up to the outside. All of the occupants complained, but sorry too late to change the plans, even though we don't have a contractor picked yet. We also have a relatively mild climate where opening the windows 10 months out of the year would insure adequate cooling.

Re: Why don’t we just open the windows? Covid-19 prevention lost in translation

#67

Post by mlyle »

doubled112 wrote: post #62
mlyle wrote: post #48

Earlier quoted context omitted.

I'm a teacher at a school. - We eat outside. - We have filters upgraded to MERV-13 and the fans run the entire school day. - We have windows and doors open on all classrooms, except for A) a few that don't open outside, or B) when it's rainy/windy to the point it's not possible. We have small, secondary HEPA filters that we run in those circumstances. (Often, we're blaring AC or heat into a room with all doors and wi…

My kid's school doesn't have windows that open. It's too new for that.

Our newer buildings don't have windows that open and have interior hallways, so some rooms don't have doors to outside. They have better building ventilation and per-room standalone air filters, though.

Even just a single door open makes a big difference, IMO.

Re: Why don’t we just open the windows? Covid-19 prevention lost in translation

#68

Post by nitrogen »

newaccount74 wrote: post #42
Madmallard wrote: post #32

Earlier quoted context omitted.

? If your windows are open you will trend toward outside weather. If you’re in a dry climate then yeah it’ll be dryer but the reverse is also true. Outside air is far better than inside nearly everywhere in the world

Cold air can hold a lot less water vapor than warm air. If you open the window when it's cold outside, then the air will become very dry as it heats up. So even if you have 80% humidity outside on a cold winters day, once that air gets inside and heats up to room temperature it's going to be like 20% humidity.

Indeed, even in San Francisco I measured indoor humidity as low as 18% before I got a humidifier, and dryer+colder places (e.g. Salt Lake City) could be even lower inside. Humidity below 40-50% at indoor temperatures has noticeable negative effects for me.

As other comments have mentioned, in the long run for maximum health and maximum energy efficiency we really need to design our buildings to be air tight, with energy-recovering ventilation systems and humidity control.

Re: Why don’t we just open the windows? Covid-19 prevention lost in translation

#69

Post by geolqued »

calsy wrote: post #47
323 wrote: post #31

Earlier quoted context omitted.

There have been documented cases of infections happening in seconds. Yes, longer exposure time increases infection probability, but the 15 min threshold is arbitrary, like the 2 meter social distancing. A bit like the "you can pick up food from the floor if it sat there for less than 5 seconds" meme.

How are infections measured in seconds?

Up until about 2 months ago contact tracing in Australia was very effective. Contact tracing teams were able to trace who and where each person got infected. They were also notifying/testing/isolating first and sometimes secondary downstream contacts (up to 400 people in the case of one country town outbreak).

One of the infections was traced to a department store and the interaction between the two people was caught on cctv. They walked past each other and didn't talk. It was seconds.

Re: Why don’t we just open the windows? Covid-19 prevention lost in translation

#70

Post by sjg007 »

taeric wrote: post #34
nicoburns wrote: post #4

This agrees with my intuitive impression of everything I've read on Covid-19: that the primary transmission vector is through the being in unventilated or poorly ventilated enclosed spaces with an infected person for ~15 minutes or longer. I definitely feel like neither governmental policies or people's individual precautions and behaviours quite reflect that reality.

Annoyingly, my intuitive impression is that we are still far more ignorant than we'd care to admit. Being in a place where we all willingly wear masks to grocery shop, I get the impression we are far more cautious than most places. Still, I expect it is just a matter of time before we are exposed. Why? I honestly don't know. It isn't lack of wanting to be safer. But it has gotten fatiguing to try to keep up with what…

I have had the flu twice. The first was in college and then second was when my kids were in pre-school/elementary school.
Post reply on HN