[aaron695]

> neutralizing activity along the nasal muscosa.

Low humidity drying the nose out seems to be why planes and winter are when SARS-CoV-2 and flus are so contagious.

I've been using a generic nasal inhaler when flying, but it's not clear if that would work in practice.

> nitric oxide nasal spray as the nose is the major area to protect

Reading your comment you would believe a nitric oxide nasal spray would be a good preventative when flying?

[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.

[SideburnsOfDoom]

> winter is when SARS-CoV-2 and flus are so contagious

Influenza may be a seasonal virus, but SARS-CoV-2 is not. There can be and in fact are "summer waves" driven by new variants, not weather.

Source e.g.

https://www.bbc.com/future/article/20240719-why-covid-19-is-...

"Covid-19 doesn't follow normal seasonal patterns, like other respiratory viruses – waves of infection can happen at any time of year."

[Angostura]

Is there evidence for this? The typical theory is that during winter, you get more people indoors, in close proximity with poor ventilation- similarly planes is just about a large number of people sitting in close proximity for an extended period.

[jajko]

Its common knowledge in regions with stronger winters that indoor humidity needs to be well managed (aka avoid too dry air) since upper breathing tract is more prone to infections. I've experienced it myself numerous times, so did my family and literally everybody in that region I know. Nobody ever bothered to look for peer-reviewed study of something one experiences every winter during ones whole life (just like ie eating raw strong garlic works very well as prevention of infections, not so much once sick).

Now that's not the sole reason for transmissions of course, but weakened outer defenses help infections a lot.

[mschuster91]

> The typical theory is that during winter, you get more people indoors, in close proximity with poor ventilation

Covid by far is no longer a "winter only" thing. The US has a record covid wave [1], so does Germany [2] and the UK [3].

Unfortunately politicians worldwide have pretty much given up preventing Covid transmission, mostly due to the serious backlash from shortsighted large employers and the far-right - some places like Nassau County (NY, US) even ban people from wearing masks [4] to protect themselves. Not to mention large parts of the population itself - try wearing a mask in public these days, people will either look at you like you're some sort of madman or they'll just outright assault you [5].

And all of that despite serious indicators that even minor measures like air filters in kindergartens and schools massively reduce sick times... it's truly maddening, air filters don't impact anyone, they're cheap to operate. But people don't want any kind of reminder of the lockdown era, they sometimes even violently respond to that.

We regulate literally everything needed for survival... our water gets tested to make sure it's free of contaminants, food and medicine production of all kinds has to comply with very strict requirements, noise polluters such as cars, trucks and heavy machinery get regulated... but the air we breathe? Nothing except particulate emissions from cars and industry gets regulated. Children have to learn in schools no matter how hot, humid, CO2-overloaded or moldy it is. Workers enjoy barely any protection as well. And it takes a massive amount of mold for a residential building to be declared unfit for living, maintaining air-condition installations (especially filters) isn't a requirement, which means landlords can get away with a lot of shit... It's a disgrace how far we have all fallen.

[1] https://edition.cnn.com/2024/08/16/health/covid-largest-summ...

[2] https://www.wsws.org/en/articles/2024/07/17/bxrf-j17.html

[3] https://www.bbc.com/news/articles/ck5g2jk0730o

[4] https://www.washingtonpost.com/health/2024/08/27/nassau-mask...

[5] https://www.newsweek.com/will-keenan-attacked-wearing-face-m...

[trogdor]

The “record Covid wave” in the US is not evenly distributed across the country.

According to the CDC, “As of August 16, 2024, we estimate that COVID-19 infections are growing or likely growing in 27 states, declining or likely declining in 4 states, and are stable or uncertain in 17 states.”

Source: https://www.cdc.gov/cfa-modeling-and-forecasting/rt-estimate...

[treis]

Do you have a cite for the air filters? I'm under the impression that stand alone air filters don't move enough air to be effective.

[mschuster91]

In kindergartens it's 1/3rd less sick days [1], schools is 20% less [2]. That's the most recent I'm aware of.

[1] https://yle.fi/a/74-20062381

[2] https://www.newscientist.com/article/2398713-schools-cut-cov...