Not sure about any filters, but the pressurized planes I have flown have outflow valves located in the aft part of plane. Cabin air is replaced many times per minute when in flight. Not familiar with Boeing or Airbus pressurization systems.
Per my company’s procedure I was wearing a mask when my charter passengers showed and during loading of baggage. Now I am far from being in top physical shape so after loading several typical charter passenger bags I felt a little “light” headed and took mask off and waited to catch my breath. Using a mask (especially the N95 ones) require breathing in a lot more CO2 than you would be normally without the mask. I found out on Google that this is a training method some athletes use to simulate a higher altitude for their competitions, giving them an edge in any competitions they participate in. Not trying to be offensive to any flight attendant, I have seen my share of those flight attendants (male or female) who are in just the same physical condition as myself or worse. Imagine one loading several passenger carryons then passing out from lack of O2 due to the mask. How about using a mask at cruise altitude (most airliner cabin altitudes are from 6000 to 8000 ft). The effects of higher altitude will magnify any hypoxia effects along with anyone who smokes. How fast can you take the mask off so you can put on supplemental O2 in a pressurization failure? This possible emergency was discussed at my company and procedure is once in the cockpit the mask comes off, period. With the FAA emphasis on pilots not having a beard when flying pressurized airplanes kind of makes me think the SAFO referred in this article is a cop out. Why does the FAA just come out and say without proper training wearing any face covering is not safe for flight crews? These same issues have been discussed at the 2 drop zones that I fly jumpers at. I will not fly skydivers if they wear any mask covering their faces during the climb to altitude. Sorry about the long response but there has not been anyone thinking about the issues that come up with N95 mask use in airplane cabins whether pressurized or not.
As I understand it, the whole mask thing is supposed to retain your own virus-laden saliva, sputum, and snot against your own face and not spewed into the atmosphere at large where somebody else as yet unexposed could pick it up.
The opposition, agreements and disagreements of when to wear masks in aviation may be about the unknown - untested crews, traveling public and the general population at large everywhere. This pandemic is spread invisibly by inadvertent carriers without symptoms, no different to catching a cold or flu with one exception. The cold is recognized and treated with little to no deaths associated with the common cold. The flu is recognized and yearly flu shots reduce chances of deaths from it by having a readily available vaccine. Flu deaths still occur but to a lesser degree than compared to the flu pandemic of 1918, killing millions around the world. Covid-19 is the new killer kid on this little orb we call earth. No vaccine exists as this invisible contagion is carried by anyone anywhere and spread inadvertently due to a near total lack of testing. Until massive testing can ramp up to cover, say the 327 million untested Americans from a million tested, it’s a guessing game of establishing permanent or temporary procedures about masks since the very idea of wearing it is not so much against contracting this virus but against spreading one’s own bodily fluids possibly containing Covid-19 from being given to anyone whether by droplet transfer or depositing it on surfaces like door handles, trays, handling goods while shopping - everyday tasks we all do without regard to passing on this monstrous cooties that kills indiscriminately. We’re scrambling to acknowledge the presence of this invisible contagion and attempting to establish some form of health control. Testing to determine who’s carrying and who’s not can go a long way towards safeguarding the general public while allowing recognition of those inadvertently carrying to be segregated, quarantined or if a disinfectant can help, to lessen the time of self/forced quarantine to rid this virus from persons not having signs of being infected in order to show returning them back to a normal life.
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HEPA filters apparently filter out particles as small as 0.3 micrometers.
Thank you Fred B and Yars. The faster the US understands, develops , and manufactures a low cost, easily available Covid-19 test , the faster we can go back to work. And do it safely. As Yars points out, we need to be tested several times, let alone at least once. Until we know who presently has it, those who have had it, and those who don’t have Covid-19, our only defense is social distancing, wearing masks, and isolation/quarantine. Crude, archaic, but the only way to at least slow the spread. As Fred notes, the mask is designed to protect others from you spewing the disease you don’t know you might have to those around you…who don’t know anymore than you, if they are a contributor and/or a receiver. Adds a new dimension to the phrase, “the blind leading the blind”.
Since we have not yet focused or concentrated on the US development of, combined with US manufacturing power for, an affordable, readily available, home use, and accurate Covid-19 test, we are spending buccoo bucks on sheer guess work regarding where, when, and how to ease present Covid-19 restrictions. Hence, the use of masks for passengers and crew until these tests become available in the numbers needed.
Without knowing who is infected with a disease that has killed 60K+ and counting US citizens in a matter of 7 weeks are not the kind of stats that suggests getting on an airliner soon is a wise choice. Masks combined with seating arrangements that offers some minimal distance between the unknown disease carriers, is better than not doing anything. But no one knows what the real odds are of being sick, getting sick, and the outcome if infected.
However, every carrier knows what kind of load factor will be profitable or not. So flying with 25-50% load factors will be a losing proposition for most if not all airlines. For profitability, the airlines, the politicians, and medical community will have to convince you that it is safe to be sitting shoulder to shoulder, face to face, back to back, in an aluminum tube…when none of them have any idea who has the disease, those that don’t, and those who have had it, never knew it, and gave, or are presently giving the gift that keeps on giving. Maybe staying at home is worse than critically looking at the still unknown odds of being around strangers who are equally clueless to their own condition. Not for me, though.
If I go anywhere via airplane, it will be in my airplane. Flight planning in this new normal will also have to take considerations on what to do regarding Covid-19 when we get to our destinations. Makes touching the steering wheel of the well used crew car today another game of Russian Roulette. Self-serve gas never looked so good.
You have to think positive. If you test positive on
Monday and then self-quarantine for two weeks (asymptotic or not), then you can reasonably conclude that you are no longer a viable host and that you will not spread the bug.