Measuring Virus Exposure Risk Using a CO2 Sensor While Traveling (isi.edu) 61
hardaker writes: I wrote up the results from studying graphs of CO2 measurement data during a trip I took from Sacramento, California to London to attend the IETF-115 conference. Since CO2 is considered to be a potential proxy for measuring exposure to airborne viruses, it provided me with a rough guess about how safe (or not) I was at various points of my travel.
TL;DR: big conference rooms: good, busses: bad, everything else: in between.
"Numbers alone do not effectively measure risk absolutely," the page concludes. "You must combine numbers with logic and common sense. Airlines with good filtering systems are likely ok. But do aim the fans at you with maximum air flow..."
"Hallways and crowded coffee tables are where we need to worry the most. Unfortunately, the masking policy at IETF-115 was sort of backward: in the rooms the circulation was quite good, but in all my graphs you can see a spike as I wandered from one room to another, and this is where masking policies were more lax allowing participants to remove their masks."
TL;DR: big conference rooms: good, busses: bad, everything else: in between.
"Numbers alone do not effectively measure risk absolutely," the page concludes. "You must combine numbers with logic and common sense. Airlines with good filtering systems are likely ok. But do aim the fans at you with maximum air flow..."
"Hallways and crowded coffee tables are where we need to worry the most. Unfortunately, the masking policy at IETF-115 was sort of backward: in the rooms the circulation was quite good, but in all my graphs you can see a spike as I wandered from one room to another, and this is where masking policies were more lax allowing participants to remove their masks."
Proximity to hairless apes... (Score:2)
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It's not just the concentration of people. Lots of people at the airport, but good ventilation so low CO2.
Airlines and Boeing have pointed out that during flight the cabin air is replaced every 3 minutes. Yet the CO2 level remains high.
I wonder if the cabin gets better airflow. The levels of CO2 in the cabin are enough to degrade a human's performance during take-off and landing.
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Masking has proven effective in reducing the transmission of COVID-19 and other airborne illnesses through many studies. Masks vary in how well they work, with N95 and surgical masks outperforming cloth masks, which are more common due to supply shortages, but even cloth masks, with their variability in fabric type and mask fit, provide wearers with substantial protection from particles carrying COVID-19.
Source: Face masks during the COVID-19 pandemic https://en.wikipedia.org/wiki/... [wikipedia.org]
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Knock off the gaslighting already, Mr. Fauci. Nobody with two brain cells to rub together believes you anymore.
Hypochondriacs moment in the spotlight (Score:3, Insightful)
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These people are rational. COVID can really screw you up, even if you are fully vaccinated. You might be lucky and get a mild case, you might end up with Long COVID. We don't yet understand the reasons why some people get Long COVID, but it doesn't seem to be related to general health. People who are young and fit get it, much like ME which it seems to be similar to.
Therefore it makes sense to limit your risk where possible. Of course you have to strike a balance that allows you to e.g. visit these kinds of
Re: Hypochondriacs moment in the spotlight (Score:3)
Re: Hypochondriacs moment in the spotlight (Score:4, Insightful)
The point is that this is a obvious outcome of being in a closed space with lots of people.
The point is that not all closed spaces are alike, and the difference is quantifiable. CO2 is a tolerably reliably proxy in this case, although it will be unsurprising if some people fail to account for non-breathing sources.
Re: Hypochondriacs moment in the spotlight (Score:5, Insightful)
It's kind of disturbing that people have now reached the point where they get angry at people simply gathering data.
Not asking them to wear a mask, not complaining to the airline. Literally just gathering some data and taking their own precautions.
Re: Hypochondriacs moment in the spotlight (Score:4, Interesting)
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Maybe I'm too generous, I tend to think they just want things to go back to normal and anything like this is basically triggering a kind of mild PTSD.
I do get it, it was a nightmare for me too. Doesn't justify this kind of reaction though.
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I don't think there will be a fix for long COVID in the foreseeable future. We don't even understand what causes it or the mechanism by which it works, let alone what we need to do to treat it.
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"He disagrees with me!" has been a prelude to "Burn the heretic!" since ... well, Socrates was far from the first to be executed for asking - or answering - uncomfortable questions. It's part of that lovely thing called "human nature".
You've got me thinking now, who was the first questioner to get killed for asking the wrong questions? Silenus, perhaps, with his wisdom [wikipedia.org]? Or Prometheus with his
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Can you explain the gaslighting part?
You missed the point here. This debunks some of the airline claims. It gives the conference organizers some data that suggests ways to improve safety.
Sometimes these places are hard to avoid. Are you just going to quit your job because you don't want to fly? Or can you fly with reasonable safety?
This data suggests that wearing an FFP3 mask and avoiding eating during the flight is potentially worth doing, but more research is needed to understand it fully.
Nobody is being
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Evidence is that masking is effective. Japan is a good example. Never had a lockdown, just masking and some other precautions. Vaccination started later than Europe and the US.
Death rate about 1/10th European countries, even with the Olympics.
You need to understand different types of masks. FFP3 will protect you and stop you getting COVID. You need to fit it properly to be effective. It's medically proven to be effective against airborne viruses.
Surgical masks only protect other people.
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If the "strengthening the immune system" argument, which sounds like Russian roulette, is true, people living in Africa should have a longer life expectancy and lower morbidity than someone living in the West because they have exposure to a bunch of pathogens. Maybe playing Russian roulette builds character .. in 5 out of 6 people, but then there's the 1 in 6 that lost. The vaccine allows you to train your immune system with lower risk than actual will virus exposure.
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48% of people who get covid have some sort of long term impact [nature.com]
So you feel free to blunder around and take all that damage. I will mind for myself and my family.
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Modeling based on hundreds of previous studies: https://link.springer.com/arti... [springer.com]
Still, CO2 proxy is an interesting alternative measure imho so I'd say this guy did good work.
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How much CO2 is frorm nearby combustion (Score:2)
Re:How much CO2 is frorm nearby combustion (Score:5, Insightful)
but in an aircraft how much of the cabin air includes some CO2 from the engines?
Depends on the aircraft but it varies between none and none. Some aircraft (e.g. 787) don't even use the engine bleed-air, they pull in fresh air only and then compress it with an electric compressor and run it through a heat exchanger. Basically every other aircraft uses bleed air from the LP compression stage of the engine. This is a long way away from any combustion, the products of which are entirely ejected from the rear of the engine. Not even trace amounts are carried forward in a turbine. Better still the LP bleed air is too hot and too high of a pressure for the cabin so it is mixed with fresh air as well.
During departure aircraft may also be flying in the path of previous departures and measuring CO2 exhaust frmom the flight that followed the same path just a minute
At best you may be getting some CO2 from the plane in front of you while taxiing if there's a takeoff queue. Aircraft may look like they are close together but only if you look at them in a line. On approach and takeoff the visual separation rules mean aircraft can be closer than 3km to each other, but overriding rules is that an aircraft may not take off until the one in front is airborne and has cleared the runway. That is 6000-8000ft minimum (2-2.5km-ish) that aircraft are apart when taking off.
Bottom line is the concentration in the air is effectively atmospheric. On the ground it's a different matter.
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reason CO2 rises during takeoff (Score:2)
A few factors missing (Score:2)
While hard to do, you would need to monitor time-exposure data along with a few other statistics to develop meaningful conclusions. Going directly between rooms (~2 minutes) with a higher exposure rate might not be as bad as 60 minutes in a low exposure setting.
I think the best you could really do is compare different individuals' risk over a similar time frame and activities-- two different people at the same conference as an example.
Fans? (Score:2)
"Airlines with good filtering systems are likely ok. But do aim the fans at you with maximum air flow..."
Aim the fans at you in a closed ventilation system. Right. Won't that just concentrate particles?
What a nonsense article...
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Won't that just concentrate particles?
Modern airliners have pretty good HEPA filtering systems. So the particles aren't really the problem. Viruses still can be, as they can make it through some filters. The only solution in this case is lots of air changes per hour. And that both flushes out the viruses but the exhaled stale air as well. So CO2 levels are a good proxy for air changes per hour.
Not all airplanes are closed systems. Cabin pressure is controlled by pumping in conditioned outside air and then regulating the position of an outflow
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My point was, that the air stream from the fan will also draw (polluted) air from the surrounding area onto you.
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I've been doing some research on this. The cabin air is cycled about once every 3 minutes, but most aircraft mix outside and recycled air. The recycled air gets filtered. HEPA filters will remove a lot of virus particles that are bound to droplets, but not all of them. The ratio varies but is typically 50/50 outside air and recycled.
I'm a little surprised it isn't a better ratio for safety reasons. High CO2 concentration doesn't help the pilots do a good job. The fact that CO2 spikes during boarding/take-of
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A HEPA filter will remove 99.95% of particles 0.3 microns in diameter in a single pass. If the particles are larger or smaller, it will remove a greater percentage of the particles. That's pretty close to all the virus particles, whether bound to droplets or not.
It won't, of course, remove suspended particles from the coughing passenger in the air that hasn't been recycled through the filters yet.
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The fact that CO2 spikes during boarding/take-off and landing
You really, really do not want to be breathing the fumes of a bunch of other aircraft queuing up for takeoff. Or the ones you are following down on final approach and landing.
There's also that detail about bleed air reducing maximum engine output right when you need it.
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Aim the fans at you in a closed ventilation system. Right. Won't that just concentrate particles?
Aircraft recircle only about 50% of the air through the aircon system, the other half is fresh air. All of the recircled air goes through a HEPA filter first. There should be nothing left to concentrate.
At best your risk is the guy behind you sneezing and the AC blasting that sweet sweet virus right into your face.
Where all the ftx grant money went (Score:1)
Stupid (Score:2)
If you were worried about being safe, which did you bother getting on a plane, buses or going to a conference ?