Depends on the actual scan. A head CT can be as little as one sievert while a full blown angiogramm can be more than ten sievert. A pilot can accrue 40k flight hours over his career. If 90% of that is at cruising altitude (meaning 3-6 microsievert/hour), that would be 100-200 mSv in total. That would be equivalent to more than a hundred head CTs or a dozen angios. If you need that many CTs, your lifetime cancer risk is probably your smallest concern. But you still wouldn't expose any normal human to that level of radiation.
For general comparison astronauts are exposed to approximately 72 millisieverts (mSv) while on six-month-duration missions to the International Space Station (ISS).
According to linear no-threshold model (LNT model) the incidence of cancers due to ionizing radiation can be modeled as increasing linearly with effective dose at a rate of 5.5% per sievert, so a flight crew member receiving 200 mSv lifetime dose should have 1.1 % higher lifetime chance of cancer then general population. LNT is quite good model for high doses, but there is much less confidence for LNT at low doses, there both studies which confirm LNT at low doses and reject LNT at low doses.
For the overall US population risk of developing any cancer is 39.9% for men, 39.0 % for women.
Wonderful work by Mr. XKCD (Randall Munroe).
This was published in 2011 when there was "some" misinformation in the U.S. press about the Fukushima nuclear accident.
Based on this chart some proposed to use "bananas" as unit of radition (equivalent to 0.1 uSv).
So (from this chart) one flight from New York to LA exposes you to 400 bananas worth of radiation.
Attendants have higher risk than pilots. This kind of makes sense, as my understanding is they don't have pilots fly too often. Meanwhile, attendants are flying all the time.
In my search, I found that they spend almost an equal number of hours in air like you said - 75-100 hours per month. If that's the case, after adjusting for sex, these numbers holding would throw some uncertainty into the radiation hypothesis.
Older flight attendants look really damaged by the job. The combination of irregular sleep, quite likely too much alcohol and sun in layover locations when younger. Plus radiation, and biological hazards like being around sick people and smelling farts all day. Being in an enclosed space is not that great for the lungs either, just being around people wearing perfume, is likely bad for the lungs
Your comments makes problematic suggestions, but I found it funny that the more childish one —farts– is actually very true: with the lower pressure, people do fart more on airplanes.
> Older flight attendants look really damaged by the job.
First off, this is just anecdotal and I know FAs who do _not_ look "damaged by the job". So, we're off to a bad start.
> The combination of irregular sleep, quite likely too much alcohol and sun in layover locations when younger.
Not all FAs fly crazy schedules. This comment then makes assumptions about where younger FAs fly, and suggests they all drink too much. More conjecture to back up a weak claim without any evidence provided.
> Plus radiation, and biological hazards like being around sick people and smelling farts all day. Being in an enclosed space is not that great for the lungs either, just being around people wearing perfume, is likely bad for the lungs
OK, so this article is about radiation. That is at least addressing the topic. Calling "smelling farts" a biological hazard is borderline ridiculous. "Being around sick people" is what nurses do all day. There are _many_, _many_ professions where _being around a lot of people_ is part of the job. It does not seem particularly notable here.
They end by saying that being in an enclosed space is bad for your lungs. Uh, ok. Maybe? Probably? How bad? Compared to what? Being outdoors in an area prone to air pollution?
Boeing, Bombardier, Learjet, Embraer and Airbus should be forced to clean up aircraft cabin air they poison us with.
For people who don’t know how GROSS this is: on almost every modern passenger jet, the air you breathe is pulled through the engine’s Bleed-Air system before entering the cabin. As oil, hydraulic fluid, or other contaminants leak into that system, those superheated fumes can be pumped directly into the cockpit and cabin. These incidents are literally called "fume events" and are the basis of the "gym sock" smell you can detect when in airports or on a plane, especially during takeoff and landing. This is so pervasive you'll see airline attendants spraying glycol-based air fresheners during these times to COVER UP the smell of this toxic stuff.
And no, the HEPA filter people like to point to does not make this problem disappear. HEPA filtration primarily cleans recirculated particles. It does not magically remove every gas, vapor, or contaminant entering through the aircraft’s air-supply system.
The absurd part is that we already know how to avoid this architecture. The Boeing 787 is the major commercial exception: its cabin air is supplied by dedicated electric compressors rather than engine bleed air.
So this is not some unsolved engineering problem. The industry made a DESIGN choice to KEEP using a system capable of feeding contaminated engine air into a sealed tube full of passengers, pilots, and flight attendants. Zero regard for their well-being in order to save a few pounds and eck-out more miles per gallon.
Flight crews spend thousands of hours breathing this air over their careers. Passengers have no meaningful ability to know when contamination occurs or opt out. Manufacturers and airlines alike are afraid to put contamination sensors on their planes because it exposes them to liability - it shows the true extent of the problem.
That is not an acceptable health standard in 2026, and it wasn't when these decisions were made. Fix the source, stop pretending filtration alone solves it, and make bleed-air-free cabin ventilation the standard for new aircraft. Demand this from your regulator or determine who is responsible for your health effects.
> This is so pervasive you'll see airline attendants spraying glycol-based air fresheners during these times to COVER UP the smell of this toxic stuff
I've never once seen a flight attendant do that. Flown hundreds and hundreds of times. You'd think something that's "so pervasive" would have been common enough that I'd have seen it dozens of times?
Feels like youre defensive about this would love to know why. If you havent seen aerosols on a flight youre being disengenous or are not looking up/around. They are used for lavoratories and pest fumiagation during passengered flights regularly - and those are uses we agreed to as a society. Ive seen firsthand them sprayed during takeoff and landing at the time fume events are most noticed by passengers.
Disclaimer: I am an aviation enthusiast and loves planes and their design. I am unaffiliated with any airline or manufacturer. I want everyone to breathe ok.
> Feels like youre defensive about this would love to know why.
It couldn't possibly be that someone else has real-world experiences that differ from your own?
> If you havent seen aerosols on a flight youre being disengenous or are not looking up/around.
Or they just actually really weren't used on any of the flights GP was on?
> Ive seen firsthand them sprayed during takeoff and landing
GP hasn't, and neither have I.
Your experiences are not universal and it is impolite to accuse others of being "disingenuous" simply for reporting experiences that differ from your own.
> These incidents are literally called "fume events"
Your first FAA link says that these 'fume events' are rare: "The report found that the rate of cabin air quality events is less than 33 events per million aircraft departures." This is about one event every 30,000 flights.
I have a pretty sensitive sense of smell, and I regularly smell oil/smoke/hydrocarbon smell after they're starting the engines. It also sticks on your clothes after the plane ride, and I'm quite sure it's not just stinky seat smell.
It's probably good old "normalization of deviance". Smelling exhaust/fumes is common enough that it would not get reported unless someone has a medical event. And reporting it would require investigation and downtime which management would frown upon.
I usually smell it too. I've noticed its when they switch from the air handler provided by the jetway (big yellow hose) to the plane's onboard system. Perhaps there's some sequencing procedure that the staff is moving through too quickly trying to get the plane out on time, or it's just an acceptable amount of cross-contamination.
If you think of the last 10 flights you were on, how many had the gym sock smell? That's the real occurence rate. I'd say in my experience across all airlines its around 7/10 flights I can detect via smell a fume event.
There is one specific plane type (Airbus A320) that has significantly more fume events than all other plane types, suggesting that plane type or associated engine has a design or procedural flaw.
Since airlines consolidate on specific types, it is possible that some travelers experience this problem often and others very rarely.
Through no choice of my own, I seem to only fly on Boeing 737s, but the one recent time I was on an Airbus (A321neo) there was a distinct exhaust odor upon engine startup.
In my experience, a large fraction of flights have very stinky air during a substantial portion of the time from when the engines start until takeoff. Whether this is “gym sock” or something else has never been entirely clear to me.
I think airplanes reek too, but mostly because the cleaning done on the seats/cabin is pathetic by overworked and underpaid cabin crew, the average American doesn't wash their asshole (no bidet culture in the USA) so they have smeared shit stains on most of their undergarments, standard BO, etc
Coincidentally, when I am flying anywhere in Asia, I get none of this. I'd unironically rather be on an Indian airline for most flights because for all the flack that Indian people get about cleanliness, they're far more likely than the average gringo to have used a bidet at some point in their lives.
I don’t think I’ve noticed gym socks smells, but I can certainly smell kerosene basically every time when outdoors at the airport, and often in the plane.
We're not talking about stinky passengers, those are normal, expected smells :)
Politely, I don't believe you haven't noticed the smell - this statistically is impossible when at an airport with multiple planes. You can smell it daily, at any airport terminal of your choosing, impossible to ignore when closer to the gates. It's a smell powerful enough to not get eaten by the various encapulation, ozone generators, and air fresheners used in public commerical environments like airports. The smell comes through from the planes and gangways into the terminal itself.
Next trip: With a clear nose, smell the air at the airport entrance and then compare this with the smell closer to your gate. The contaminated airs smell it's very similar to a wet locker room or gym bag that was left for days without cleaning. You won't ever miss it again, and your stat will flip to detected in 50 out 50 visits.
Quite interesting. My reaction is that one of these is much more easily controlled and an input for cancer than the other. Radiation shielding is a tougher solve due to weight and other factors, where air quality is an easy, known fix.
Would love both to be solved, which would lead to good outcomes. Any thoughts on why attendants have different outcomes?
Off topic: when did using solve as a noun take off? There are so many good nouns that work there (challenge, task, etc...) or use the verb form (is tougher to solve).
In the bay area this trend of nounifying verbs is common amongst VCs and C-level startup execs. I'm not sure if it's arisen due to peacocking or a higher incidence of ESL in those communities.
That's interesting to know (thanks for calling it out!), and makes me feel extra glad I've worn a mask during the entire flight on every flight I've been on since 2020 (not that I've been on many)... turns out I was avoiding a lot more than just COVID etc. heh >_<
I believe the pilots air source works differently than the rest of the cabin - at least on the 737. Maybe that explains the difference between the pilots and the flight attendants.
Like others, I have zero experience with any of the things you are mentioning, but I want flying to be more expensive, more luxurious, and far more comfortable in general for everyone so please keep giving them a hard time about this.
In general, 50% or more of the people flying should not be flying, and going back to the pre-privatization era alongside much stricter regulations on seat sizes would be awesome as it would force actual economics of scale to kick in for the good seats and keep the burger king crown wearing crowd ( https://www.youtube.com/watch?v=onib3bDo6Z0 ) off these airplanes for good.
I read once that a CT scan is roughly equivalent to 1000 hours of flight WRT radiation exposure. I've had about 6 or 8 of those over the years.
Depends on the actual scan. A head CT can be as little as one sievert while a full blown angiogramm can be more than ten sievert. A pilot can accrue 40k flight hours over his career. If 90% of that is at cruising altitude (meaning 3-6 microsievert/hour), that would be 100-200 mSv in total. That would be equivalent to more than a hundred head CTs or a dozen angios. If you need that many CTs, your lifetime cancer risk is probably your smallest concern. But you still wouldn't expose any normal human to that level of radiation.
Air crew radiation exposure depends strongly on cruising altitude and Latitude, for example flight Tokyo JP – New York NY is about 67 microsievert.
https://www2.ans.org/pubs/magazines/nn/docs/2000-1-3.pdf
For general comparison astronauts are exposed to approximately 72 millisieverts (mSv) while on six-month-duration missions to the International Space Station (ISS).
https://en.wikipedia.org/wiki/Effects_of_ionizing_radiation_...
According to linear no-threshold model (LNT model) the incidence of cancers due to ionizing radiation can be modeled as increasing linearly with effective dose at a rate of 5.5% per sievert, so a flight crew member receiving 200 mSv lifetime dose should have 1.1 % higher lifetime chance of cancer then general population. LNT is quite good model for high doses, but there is much less confidence for LNT at low doses, there both studies which confirm LNT at low doses and reject LNT at low doses.
For the overall US population risk of developing any cancer is 39.9% for men, 39.0 % for women.
https://www.cancer.org/cancer/risk-prevention/understanding-...
This chart has the flight & CT scan scenarios (among many other): https://xkcd.com/radiation/
Wonderful work by Mr. XKCD (Randall Munroe). This was published in 2011 when there was "some" misinformation in the U.S. press about the Fukushima nuclear accident.
Based on this chart some proposed to use "bananas" as unit of radition (equivalent to 0.1 uSv).
So (from this chart) one flight from New York to LA exposes you to 400 bananas worth of radiation.
Cancers rates among Orthopedic surgeons are also much higher than those faced by non surgeon doctors.
This is due to exposure to the radiation from intra operative x rays.
Our company shared a wall with an xray lab next door. My coworkers and I were always curious what impacts it would have to our health.
Probably nothing if the wall was lead lined.
And then there’s the inverse square law too.
Attendants have higher risk than pilots. This kind of makes sense, as my understanding is they don't have pilots fly too often. Meanwhile, attendants are flying all the time.
> as my understanding is they don't have pilots fly too often
From a quick search, I can’t find evidence of this. If anything, pilots are in the air more of their week/lives vs. flight attendants.
In my search, I found that they spend almost an equal number of hours in air like you said - 75-100 hours per month. If that's the case, after adjusting for sex, these numbers holding would throw some uncertainty into the radiation hypothesis.
The fuselage probably has a lot less attention to shielding even if the cockpit seems very exposed.
This is peak HN. Two engineers running google searches without any primary sources speaking up about the issue.
Account created 2021
I guess I am going off when a pilot spoke at my high school for career day. (Decades ago...)
Older flight attendants look really damaged by the job. The combination of irregular sleep, quite likely too much alcohol and sun in layover locations when younger. Plus radiation, and biological hazards like being around sick people and smelling farts all day. Being in an enclosed space is not that great for the lungs either, just being around people wearing perfume, is likely bad for the lungs
Your comments makes problematic suggestions, but I found it funny that the more childish one —farts– is actually very true: with the lower pressure, people do fart more on airplanes.
What problematic suggestions?
Why is this comment downvoted? This is objectively true. HN is a worse orange reddit.
I handed it a downvote. Here's why:
> Older flight attendants look really damaged by the job.
First off, this is just anecdotal and I know FAs who do _not_ look "damaged by the job". So, we're off to a bad start.
> The combination of irregular sleep, quite likely too much alcohol and sun in layover locations when younger.
Not all FAs fly crazy schedules. This comment then makes assumptions about where younger FAs fly, and suggests they all drink too much. More conjecture to back up a weak claim without any evidence provided.
> Plus radiation, and biological hazards like being around sick people and smelling farts all day. Being in an enclosed space is not that great for the lungs either, just being around people wearing perfume, is likely bad for the lungs
OK, so this article is about radiation. That is at least addressing the topic. Calling "smelling farts" a biological hazard is borderline ridiculous. "Being around sick people" is what nurses do all day. There are _many_, _many_ professions where _being around a lot of people_ is part of the job. It does not seem particularly notable here.
They end by saying that being in an enclosed space is bad for your lungs. Uh, ok. Maybe? Probably? How bad? Compared to what? Being outdoors in an area prone to air pollution?
I've wondered if billionaires get their jets lined with lead.
Lead is notoriously heavy, but if you buy a 737 and it only ever has to fly you and a couple other people, it might be feasible.
Or I guess they could just line one section where they spend the majority of the time.
hmmm...
looks like there's something called ultra-high-molecular-weight polyethylene.
"UHMWPE/hydrogen-rich benzoxazine composite (UHC) exhibits excellent cosmic radiation shielding."
maybe that should be a thing.
Don't forget your lead body armor when going on long flight trips (which they can't charge you extra for).
Boeing, Bombardier, Learjet, Embraer and Airbus should be forced to clean up aircraft cabin air they poison us with.
For people who don’t know how GROSS this is: on almost every modern passenger jet, the air you breathe is pulled through the engine’s Bleed-Air system before entering the cabin. As oil, hydraulic fluid, or other contaminants leak into that system, those superheated fumes can be pumped directly into the cockpit and cabin. These incidents are literally called "fume events" and are the basis of the "gym sock" smell you can detect when in airports or on a plane, especially during takeoff and landing. This is so pervasive you'll see airline attendants spraying glycol-based air fresheners during these times to COVER UP the smell of this toxic stuff.
[FAA overview](https://www.faa.gov/newsroom/cabin-air-quality-0)
And no, the HEPA filter people like to point to does not make this problem disappear. HEPA filtration primarily cleans recirculated particles. It does not magically remove every gas, vapor, or contaminant entering through the aircraft’s air-supply system.
[FAA research](https://www.faa.gov/sites/faa.gov/files/data_research/resear...)
The absurd part is that we already know how to avoid this architecture. The Boeing 787 is the major commercial exception: its cabin air is supplied by dedicated electric compressors rather than engine bleed air.
So this is not some unsolved engineering problem. The industry made a DESIGN choice to KEEP using a system capable of feeding contaminated engine air into a sealed tube full of passengers, pilots, and flight attendants. Zero regard for their well-being in order to save a few pounds and eck-out more miles per gallon.
Flight crews spend thousands of hours breathing this air over their careers. Passengers have no meaningful ability to know when contamination occurs or opt out. Manufacturers and airlines alike are afraid to put contamination sensors on their planes because it exposes them to liability - it shows the true extent of the problem.
That is not an acceptable health standard in 2026, and it wasn't when these decisions were made. Fix the source, stop pretending filtration alone solves it, and make bleed-air-free cabin ventilation the standard for new aircraft. Demand this from your regulator or determine who is responsible for your health effects.
> This is so pervasive you'll see airline attendants spraying glycol-based air fresheners during these times to COVER UP the smell of this toxic stuff
I've never once seen a flight attendant do that. Flown hundreds and hundreds of times. You'd think something that's "so pervasive" would have been common enough that I'd have seen it dozens of times?
https://farahandfarah.com/blog/toxic-airplane-fumes-workers-...
Feels like youre defensive about this would love to know why. If you havent seen aerosols on a flight youre being disengenous or are not looking up/around. They are used for lavoratories and pest fumiagation during passengered flights regularly - and those are uses we agreed to as a society. Ive seen firsthand them sprayed during takeoff and landing at the time fume events are most noticed by passengers.
Disclaimer: I am an aviation enthusiast and loves planes and their design. I am unaffiliated with any airline or manufacturer. I want everyone to breathe ok.
> Feels like youre defensive about this would love to know why.
It couldn't possibly be that someone else has real-world experiences that differ from your own?
> If you havent seen aerosols on a flight youre being disengenous or are not looking up/around.
Or they just actually really weren't used on any of the flights GP was on?
> Ive seen firsthand them sprayed during takeoff and landing
GP hasn't, and neither have I.
Your experiences are not universal and it is impolite to accuse others of being "disingenuous" simply for reporting experiences that differ from your own.
> These incidents are literally called "fume events"
Your first FAA link says that these 'fume events' are rare: "The report found that the rate of cabin air quality events is less than 33 events per million aircraft departures." This is about one event every 30,000 flights.
I have a pretty sensitive sense of smell, and I regularly smell oil/smoke/hydrocarbon smell after they're starting the engines. It also sticks on your clothes after the plane ride, and I'm quite sure it's not just stinky seat smell.
It's probably good old "normalization of deviance". Smelling exhaust/fumes is common enough that it would not get reported unless someone has a medical event. And reporting it would require investigation and downtime which management would frown upon.
I usually smell it too. I've noticed its when they switch from the air handler provided by the jetway (big yellow hose) to the plane's onboard system. Perhaps there's some sequencing procedure that the staff is moving through too quickly trying to get the plane out on time, or it's just an acceptable amount of cross-contamination.
I don't have a sensitive sense of smell and I still smell it.
https://www.cbsnews.com/sanfrancisco/news/study-shows-toxic-...
If you think of the last 10 flights you were on, how many had the gym sock smell? That's the real occurence rate. I'd say in my experience across all airlines its around 7/10 flights I can detect via smell a fume event.
There is one specific plane type (Airbus A320) that has significantly more fume events than all other plane types, suggesting that plane type or associated engine has a design or procedural flaw.
Since airlines consolidate on specific types, it is possible that some travelers experience this problem often and others very rarely.
Through no choice of my own, I seem to only fly on Boeing 737s, but the one recent time I was on an Airbus (A321neo) there was a distinct exhaust odor upon engine startup.
In my experience, a large fraction of flights have very stinky air during a substantial portion of the time from when the engines start until takeoff. Whether this is “gym sock” or something else has never been entirely clear to me.
I think airplanes reek too, but mostly because the cleaning done on the seats/cabin is pathetic by overworked and underpaid cabin crew, the average American doesn't wash their asshole (no bidet culture in the USA) so they have smeared shit stains on most of their undergarments, standard BO, etc
Coincidentally, when I am flying anywhere in Asia, I get none of this. I'd unironically rather be on an Indian airline for most flights because for all the flack that Indian people get about cleanliness, they're far more likely than the average gringo to have used a bidet at some point in their lives.
I’ve never noticed this in 35 years and I have an unusually sensitive sense of smell.
I don’t think I’ve noticed gym socks smells, but I can certainly smell kerosene basically every time when outdoors at the airport, and often in the plane.
43 years for me, and in addition to being notably smell-sensitive, I’ve also taken a probably close to 500 long haul flights
Of the last 50 flights I took, none had gym sock smell.
If anything smelled it's usually due to a passenger. But nothing from the aircraft itself
We're not talking about stinky passengers, those are normal, expected smells :)
Politely, I don't believe you haven't noticed the smell - this statistically is impossible when at an airport with multiple planes. You can smell it daily, at any airport terminal of your choosing, impossible to ignore when closer to the gates. It's a smell powerful enough to not get eaten by the various encapulation, ozone generators, and air fresheners used in public commerical environments like airports. The smell comes through from the planes and gangways into the terminal itself.
Next trip: With a clear nose, smell the air at the airport entrance and then compare this with the smell closer to your gate. The contaminated airs smell it's very similar to a wet locker room or gym bag that was left for days without cleaning. You won't ever miss it again, and your stat will flip to detected in 50 out 50 visits.
I assure you I'm very sensitive to smells and I haven't smelled anything like that in a plane
That sounds awful; it means 3+ times a day a whole plane of a passengers is getting sprayed with this stuff.
The article specifically says flight attendants are only at increased risk of radiation related cancers, but not others.
Quite interesting. My reaction is that one of these is much more easily controlled and an input for cancer than the other. Radiation shielding is a tougher solve due to weight and other factors, where air quality is an easy, known fix.
Would love both to be solved, which would lead to good outcomes. Any thoughts on why attendants have different outcomes?
Off topic: when did using solve as a noun take off? There are so many good nouns that work there (challenge, task, etc...) or use the verb form (is tougher to solve).
It’s no different than “a big ask” or a “tough sell”.
Also "invite" instead of invitation.
In the bay area this trend of nounifying verbs is common amongst VCs and C-level startup execs. I'm not sure if it's arisen due to peacocking or a higher incidence of ESL in those communities.
Physicists noun-ified work
ESL/clevel exec, guilty!
That's interesting to know (thanks for calling it out!), and makes me feel extra glad I've worn a mask during the entire flight on every flight I've been on since 2020 (not that I've been on many)... turns out I was avoiding a lot more than just COVID etc. heh >_<
I believe the pilots air source works differently than the rest of the cabin - at least on the 737. Maybe that explains the difference between the pilots and the flight attendants.
The Boeing 787 has a bleedless system. It uses dedicated electric compressors for the cabin air.
Like others, I have zero experience with any of the things you are mentioning, but I want flying to be more expensive, more luxurious, and far more comfortable in general for everyone so please keep giving them a hard time about this.
In general, 50% or more of the people flying should not be flying, and going back to the pre-privatization era alongside much stricter regulations on seat sizes would be awesome as it would force actual economics of scale to kick in for the good seats and keep the burger king crown wearing crowd ( https://www.youtube.com/watch?v=onib3bDo6Z0 ) off these airplanes for good.
Oh how the middle class hates having to share with the poor.
We don’t mind the rich flying private jets, but for the love of god don’t put a poor person next to us on a plane.
This but unironically.
The rich smell better than I do. I can learn from them.
The CNN article has more info on the study, for those without access to download it:
https://www.cnn.com/2026/08/19/health/flight-attendants-pilo...
Thanks! I've put that link at the top and moved the paper link to the toptext.
[stub for offtopicness]
(We've since changed the top link.)