Leeham writer Bjorn Fehrm has said that the aircraft recirculation system is effective in controlling spread of virus. Here is part 1 of a multi-part series.
In part 9, Fehrm says the HEPA filters in the cabin return path are hospital-grade and remove 99.9% of the viruses.
Fehrm also comments on the need to stay hydrated because the recirculated air is very dry.
Today Leeham has a different take, but not about the recirculation system. itself.
Why I Won’t be Flying Soon
Please consider Pontifications: Why I Won’t be Flying Soon by Scott Hamilton.
Some airlines block center seats. Others abandoned the practice recently or didn’t do so from the start. (When flights were operating 10% full, blocking seats didn’t matter.)
Blocking center seats really is cosmetic. Social distancing guidelines call for six feet between you and the next person. Blocking a center seat provides about 18 inches wide and 29-30 inches fore-and-aft.
The problem is not the airplane. It’s the people who fly. Passengers flying without masks put everyone at risk in those 2-4 minutes, as well as during enplaning and deplaning.
And most airlines aren’t enforcing a mask policy. The federal government won’t issue a rule requiring masks. Containing the virus requires passenger cooperation. It’s not there yet.
User’s Guide To Masks
NPR has User’s Guide To Masks that some may be interested in.
Mish
“Because of the high output the pressurization system is capable of, the volume of air in a modern airliner cabin is constantly exchanged at a rate of approximately every two to three minutes. This means that every two to three minutes, the air in the cabin has circulated in and out and fresh air has taken its place. “
For whatever reason, relatively low risk, actually.
Air tends to flow from front to back through the cabin before it gets sucked back into a filter. Air travel is famous for spreading the flu, can Covid-19 be much different?
Recirculation filters are the emphasis here, but what’s also important is that the air in the cabin is exchanged with outside air about 20 to 30 times an hour during flight, an exchange rate that is to hospital standards. This is inherent because much of the cabin air does not even recirculate but instead gets exhausted out into the atmosphere through outflow valves at the front and/or rear bulkhead, being continuously replaced by fresh air from outside, which is bled off of the engine compressor after is was sucked into the front of the engine. Modulation of these outflow valves is what regulates the cabin pressure.
So an aircraft cabin in flight is probably the safest confined space you can be in. Getting in and out of it is the risky part.
“So an aircraft cabin in flight is probably the safest confined space you can be in”
Per concentration of humans, it is.
It’s infinitely superior to the utter garbage passing for “ventilation” in the trashy shacks which is all that is built in societies where the sole and only overriding goal of everything, is to mediate crass theft fr the benefit of idle idiots, by way of housing rackets. The air handing infrastructures on airplanes, are at a minimum designed and built by literates.
But, you are still stuck with people stuffed into a tube like sardines in a can. Such that, netted out, a fully packed airplane is unlikely to be the spot on earth least likely to get you infected. Even a poorly ventilated cabin 50 miles into the Alaskan bush, is almost certainly still a safer spot from a contagion POV.
“Fehrm also comments on the need to stay hydrated because the recirculated air is very dry.”
I’ve been reading this for seems like decades. So why doesn’t someone finally attach a damn humidifier to airplane air rec-circulation? This wouldn’t require a huge store of heavy water, so can’t imagine that as a block.
So is it just the usual airline refusal to spend any additional money when they haven’t been ordered to do so? If so, then the FAA needs to make this a requirement.
You wouldn’t want to use heavy water, it costs about $1300 a kilogram.
Some answers here
Humidity condensing in dark corners of the cabin facilitates bacteria growth.
if you do fly here is my advice: https://askthepast.net/how-to-avoid-plague-1550/
Trumpists receive their marching orders–“just live with it”. It can’t get too bad, can it?
…White House officials also hope Americans will grow numb to the escalating death toll and learn to accept tens of thousands of new cases a day, according to three people familiar with the White House’s thinking, who requested anonymity to reveal internal deliberations. Americans will “live with the virus being a threat,” in the words of one of those people, a senior administration official….
…The goal is to convince Americans that they can live with the virus — that schools should reopen, professional sports should return, a vaccine is likely to arrive by the end of the year and the economy will continue to improve….
“Learn to live with the virus”
That’s what humanity has done with every other virus. What exactly is the alternative? Die trying to avoid it?
Everybody will be exposed sooner or later.
Don’t see how that is avoidable, unless you have a plan to eradicate it or have everybdoy quarantined forever.
People have to live with the fact that they will eventually die as well.
Doesn’t make reducing the risk of doing so at any given moment, not worth vile.
Of course, Trump gets tested every day, and have people screened before they get close to him. Exactly why should that not be the standard for everyone else as well?
Not really safe….measles transmission up to 17 rows from sick person.
Given the rarity of measles and unvaccinated person on the same flight–it’s pretty clear that in flight virus transmission occurs (17 rows wast the longest distance, median was 6 rows). The filters may be good, but air disturbance from people and people moving about and all of those jets of air blasting virus from one person to another (picture a water hose–the higher the velocity of water the further the water splashes…), transmission can and will occur.
Now picture a super-spreader with the diarrhea phase going back and forth to the toilet on the plane. A perfect storm of virus spreading.
Glad I am not flying, aircraft are crammed nowadays and you add wearing a mask it must feel even worse. Should be mandated by the airline I suppose though. In the replies in the link someone gives a tandofline link to a study that says airflow is in many directions in the aircraft, and personally I see masks only being part effective in that circumstance, where you are sat for an hour or more with that airflow, especially if the virus travels without droplets as has been suggested recently. Then there is using the rest room, people walking right next to you, how well the plane is disinfected from previous flight, etc. etc. etc. I guess air travel is just going to be due to nescessity, and for those those who are not fearful of catching the virus.
RESTROOMS
Bingo. The underestimated vector. Oral-fecal spread.
Airplanes and boats are incubators for airborne viruses. For a plane the longer the flight the dirtier the air becomes. You can wear masks and everything but if covid truly is airborne then it doesnt matter. It will penetrate the mask quickly.
Masks catch a pretty decent share of the viruses expelled by by those wearing them. Right when air is expelled, is when a mask like filter works the best: Airflow is directional right into the filter, and droplets are at their largest.
Sars-Cov2 is a large virus. Hence are filtered more effectively than smaller ones. And fall to the ground quicker. Hence are most likely to infect someone in the first few minutes after they are expelled.
Mask won’t catch them all, but between masks and air rapidly recirculated through (assuming a well designed, and maintained, air handling infrastructure) HEPA filters, the amount of steady “background” airborne virus will be much lower, than if contagious people didn’t wear masks. And that’s really the best you can hope for on an airplane. Not total freedom from even a single virus particle.
I have to wonder why they dont spray the plane during takeoff and landing the way they do when you are taking off or landing in Asia from Europe. I think you actually need cleaning agents in the air if you want to prevent transmission. In addition to masks and other precautions. You couldn’t pay me to get on a plane anytime soon.
Asians retain a greater tolerance for low, yet still not zero, risk possibly toxic chemicals than Westerners. As they are not yet fully de-industrialized, and are hence aware that the paint on their cars, and in their “homes,” didn’t just pop up all by itself because someone “designed it in California, “invested in it” and “voted for it” in a “democracy,” but is in fact one of those scary chemicals.
I’m not about to hop on an airplane, either. Not sure I’d risk solo crossing the Atlantic in a 40 footer to avoid it if I had to go to Europe, but doing so would at least be something I’d consider….
“Sars-Cov2 is a large virus. Hence are filtered more effectively than smaller ones. ” – I think what is being filtered by masks is not the virus itself, which is too small (even if large, like a tobacco mosaic virus, which you can easily see in a microscope) but rather the air droplets.