[fffernan]

Even better is to wear a mask (not to prevent virus from coming in that's silly air gets around it) but to keep your nasal passages moist during a high altitude flight. Japanese have known this for years and why they wear masks so much.

[jonpurdy]

On this topic, I recently got officially fit-tested for N95 masks (specifically 3M 9210+). They put a cover over your head and spray in a bitter substance; if you taste it, the mask fit fails. (You can also do this test at home if you have the supplies.)

I started wearing N95s on flights since KF94 ear loop masks would hurt my ears after a few hours. Inadvertently realized during fit-testing that the KF94s let so much air around the edges that they were much less effective than I had assumed, so I basically just use my N95 when needed indoors anywhere. Also found that other 3M mask models didn't fit my face as effectively (failed the test almost immediately).

Highly recommended to go with fit-tested N95s (if not already using something even better like a respirator).

Edit: I should mention I've flown SF to Toronto a few times since the pandemic started and air quality on planes is quite terrible despite what airlines say. Lowest CO2 concentration around 1800 ppm, and highest I've seen has been 3000+ ppm (during boarding). (420ppm outdoor average at sea level, and anything about 1000ppm I'd wear a mask indoors.)

[MobileVet]

How are you testing air quality on the plane?

I am also curious how you connect CO2 levels to pathogen levels. Would a carbon filtration system adjust the CO2 levels at the same rate as pathogens?

[sneak]

co2 levels are an inverse proxy for incoming fresh air fraction. this is of course inversely correlated with pathogen concentration (presuming that fresh incoming air from outside is relatively pathogen-free).

they aren’t directly correlated, it’s just a proxy. ventilation reduces both.

[MobileVet]

Makes sense, thanks for the reply

[jonpurdy]

aranet4 CO2 monitor that I bring with me. 2xAA batteries allow it to go for a year or more, and I can pull the readings via Bluetooth to my phone to look at historical data.

As sneak also replied, it's just a proxy: higher CO2 correlates to higher chance of breathing in pathogens, but doesn't take into consideration filtration.

[btown]

Physically, the probability that an aerosolized particle enters your body is lower with a mask than without one, as at least some airflow will go through the mask and carry particles onto the mask surface. How much lower, of course, is difficult to predict.

It’s worth noting in this context that masks have been shown to protect the wearer, not just to prevent the wearer transmitting viruses. See e.g. https://www.cdc.gov/mmwr/volumes/71/wr/mm7106e1.htm

[hnarn]

> Even better is to wear a mask (not to prevent virus from coming in that's silly air gets around it)

That obviously depends on how you define a "mask", a "medical mask" has a very different efficacy from an N95.[1]

[1]: https://www.mayoclinic.org/diseases-conditions/coronavirus/i...

[wrp]

I wear masks on planes for this reason, also with goggle-style glasses. Through inadvertent A/B testing, I have some support that they are effective. I also use eye and nose moisturizers rather than just rely on covering up. I used to catch a bug every time I flew but have now mostly eliminated that.

[Krssst]

For a high altitude flight, going straight for the N95 would make sense to me. In such a situation one probably paid good money for the flight and spent time organizing the trip to wherever it was, having it be all for nothing because of catching something would be a waste.

[jerlam]

From a cost/benefit perspective, it's definitely slanted towards wearing the N95.

Given all the other discomforts of flying, wearing a respirator is a minor problem. Passengers are not likely to have long, emotional conversations during a flight where a mask might be uncomfortable or inhibit communication. But there is the food/drink issue, if someone considers those to be important.

[trog]

Fit-tested respirators - not masks - do not allow unfiltered air in, which helps prevents the virus from entering your system at all. People need to differentiate between the generic term "mask" and "respirator".

[amelius]

Isn't it much more comfortable to use a nose-spray once every hour or so?

[rob_c]

Can't disagree to doing that for that benefit.

If only we had better air systems to go with these $1,000 tickets , but that's demanding a lot from the makers of 737max and such :p

[mrguyorama]

Airplanes have about 12-15 air changes per hour they are flying, and the air that is recycled, less than half, is going through standard HEPA filters and are rated to capture virus and bacteria particles.

My less empirical info is that airflow in a plane mostly goes from being input above your head, and exhausted from the pressurized cabin at your feet, meaning you have less exposure to anyone not in your row.

Remember that aircraft pressurization systems were designed to be smoked in, other than the newest designs. They needed enough airflow to not totally choke out passengers on a cross country or cross atlantic trip.

[rob_c]

If only saving a quick dime wasn't the main goal and maybe improving the comfort of cattle class.

Most systems lead to a dry throat due to bad filter designs and improper humidity regulation which is a shame.

[wnissen]

Are you able to square the levels of CO2 on planes, which are 1000-1800 ppm, so over 2-3x atmospheric air, with the 12-15 ACH? I don't understand how those two things can be true.

[reureu]

ACH often refers to filtration and not ventilation; that is, recycled air counts for ACH calculations but won't decrease CO2 because that's not scrubbed by the filters. So it's possible you can have high CO2 levels but also no virus or particulate matter in the air; this is why some places will report PM2.5 as well as CO2, as a proxy for filtration. To make it more complicated, you can also use UV-C to inactivate pathogens, which may not decrease PM2.5 and won't decrease CO2.

I'm not saying this is the case necessarily for planes, but I'm just trying to provide context for how proxy measures of air quality may not tell the full story.

[ein0p]

IIRC the airlines did improve filtering of air in the cabin, but I think this is basically moot - you’re stuck in a hermetic, pressurized can with hundreds of other people and some percentage of them is exhaling viral droplets into the air that’s force circulated through the cabin. Unless you’re wearing a hazmat suit, you’ll be exposed.

[rob_c]

I'm not talking about viral/bacterial factors here, clearly a better filter with a better humidity system doesn't cause you to end up with a dry throat. I'm not talking about exposure to people your in the same goldfish bowl as, that's a guaranteed to happen when you bump into people getting your bags outside...

[abc123abc123]

In summary, while wearing a face mask might offer minimal benefits in terms of retaining some moisture around your nasal passages due to breath capture and reduced airflow exposure to dry cabin air, it does not effectively keep them moist during high altitude flights. The primary concern remains that airplane cabins are inherently dry environments that can lead to discomfort regardless of whether one wears a mask.

Thus, wearing a face mask will not effectively keep your nasal passages moist during a high altitude flight.

[amelius]

In summary? You just said the complete opposite of what was said before.

[evertedsphere]

isn't that an llm tic

[cujo]

Why wouldn't it keep nasal passages moist? If I wear a mask very long, the environment under it becomes a relative sauna.