The air you breathe on an aircraft may not be as good as you had hoped for.
Coming to this page, you probably know already.
However, if it is all new to you, read my
German Memo or
Video in English.
A detailed look at the design of jet engines with their bearings, lubrication and sealing reveals that jet engines leak small amounts of oil by design.
This oil gets into the engine compressor and the bleed air.
Almost all passenger jet aircraft today use this potentially contaminated bleed air for cabin ventilation.
2020-07-31: JetBlue Pilot Wins Major Worker Compensation for Toxic Fume Exposure
The airline got accused of being "more concerned about keeping planes in the air than worker safety."
The toxic fumes incident, or more specifically, "acute chemical inhalation" and "acute toxic inhalation,"
took place aboard an Airbus A320 and led to Captain Myers’devastating health problems.
2020-01-28: ARD/SWR (German Television): Polluted Cabin Air
YouTube-Video with English Subtitles (inspired by Prof. Scholz, realized by Markus Steinhausen after month of dedicated hard work)
See more information related to this documentary below!
Reporting by Aviation Herald
Far too often there is a CACE (Cabin Air Contamination Event) somewhere in the world to allow me to offer here an exhaustive list of such events.
I have added here just a few quite extreme events once I came accross them and found time to look into them a little.
In most cases, I just refer to Aviation Herald. Only occasionally, I have added something on my own.
Aviation Herald is a good source, but also at times struggles to report about all CACEs. As I said, CACEs are just far too often. We need to change that!
2019-03-29: Five UK Airlines Sued Over Toxic Cabin Air Including British Airways and EasyJet
EasyJet, British Airways, Thomas Cook Airlines, Jet2 and Virgin Atlantic have all been served lawsuits by the union Unite,
with a total of 51 cases to be heard. Four of the lawsuits involve pilots while the rest are being brought by members of cabin crew.
Court actions involve crews who claim to have suffered chronic illness as a result of being exposed to toxic fumes.
It could take up to a year before they’re heard in court.
Sensors have been demanded by pilots and cabin crew for years, but they are still not introduced on board.
There may be good reasons for NOT introducing air quality sensors on passenger aircraft.
However, every individual on an aircraft may decide to get informed and this can not be denied.
Therefore, immediate action could be taken without waiting for the ultimate industry solution of the problem - which may never come.
This is especially important in failure cases like fume events.
Failures compromising cabin air quality may alert people on board, but it may need some kind of objective confirmation before action can be taken.
Situations with cabin air quality problems could also pass unnoticed without sensing.
If cabin air is contaminated, it will show a mixture of many substances. Carbon monoxide (CO) will most probably be one of these substances.
Simple logic tells us that it is sufficient to trace one bad gas in an abnormal quantity to conclude that the cabin air is not ok.
CO is taken from the cocktail to be measured, because inexpensive and small CO detectors are available on the market.
Pilots (cabin crew, passengers) should read the carbon monoxide (CO) concentration from a personal CO detector
as an objective indicator in addition to the observations from their senses (nose and eyes).
It is known from CO measurements on the BAe 146 that the CO concentration will be low even in a fume event .
For this reason, the CO concentration should not be compared against the limit value of 50 ppm (CS 25.831),
but rather against values obtained under normal conditions (e.g. 2 ppm; as a frequent flyer you will find out for yourself soon).
 Global Cabin Air Quality Executive: Carbon Monoxide Database Collated on 345 BAe 146 Flights in UK, 2003-2004, 2006
(access difficult, but contact GCAQE for more information if you are desperate)
Feel free to report/share your findings. E.g. take a picture of your CO detector with its reading (maybe with a fume filled cabin in the background)
and report about what happened to people during that flight. We may all learn from this collected information.
I have expressed the above view in my presentations and have been asked where inexpensive(!) CO detectors can be bought.
Looking on the Internet myself, I discovered these links:
Not considered to be an alarm/safety/warning device
Battery about 100 hours service life
Operating pressure unkown
These very affordable CO detectors are offered by Chinese wholesale and retail online shops e.g.
You can find mixed online reviews about both shops. I have no stakes in these sales. You purchase at your own risk.
The main disadvantage of these inexpensive products is that they will automatically shut off if they are not operated for 10 minutes.
This is necessary, because the batteries will not last sufficiently long otherwise. The holder has to check the air for CO at regular intervals or when being suspicious.
Do not worry about a loud alarm on your CO detector going off.
The CO concentration in the cabin is much lower than the typical fixed threshold of 50 ppm. Some sensors even allow setting the threshold.
In the very unlikely event where the alarm is triggered, you should be thankful for it!
Not considered to be an alarm/safety/warning device
3 month logging life (data storage & battery)
Operating pressure range 900 hPa ... 1100 hPa (up to 3300 ft cabin altitude; required would be 8000 ft or 750 hPa)
It is left to the user to set the light and sound alarms indicating the presence of CO
Device with USB interface and PC software for data visualization
EL-USB-CO300: ±5ppm / ±4% (whichever is greater); EL-USB-CO: ±7ppm / ±6% (whichever is greater); => select EL-USB-CO300
Each member of the cockpit crew is protected by one onboard oxygen mask. Oxygen comes from a bottle and is available for the rest of the flight.
Cabin crew have (at best) a smoke hood for their protection. The chemical oxygen supply in the smoke hood is intended only for short duration.
A private breathing mask can protect people in the cabin in the very rare event of air contamination.
A breathing mask filters the air and will do so for the rest of the flight.
Inexpensive are the army standard breathing masks. Buy only new masks. Germany: "Bundeswehr Schutzmaske M65" (by Dräger).
Better suited is a civil mask like the "Dräger X-plore 6300 Full Mask".
It has a standardized 40 mm threaded filter connection.
A suitable filter would be the "Dräger X-plore A2B2E2K2HGP3". This is a "combined filter" for "organic gases and vapours" (A),
"inorganic gases and vapours" (B), and other substances.
Also this information is provided here; because I have been ask for it.
Cabin crew members are increasingly concerned. Some already have a personal breathing mask in their carry-on baggage or intend to do so.
By asking cabin crew members to consider to carry a breathing mask (in order to be prepared for a very unlikely event),
I do NOT state that cabin air can be compared to the air after an attack with chemical weapons.
What I argue is only this: A breathing mask (with a suitable filter) will protect people in "harsh environments".
I do NOT consider the aircraft cabin such a "harsh environment".
Therefore, a breathing mask will give sufficient protection in such cases
where people have (claimed to) become ill in the aircraft cabin due to (potentially) contaminated cabin air.
Employers have a legal duty to protect their employees.
If employers do not act accordingly, cabin crew have the right to take measures themselves as deemed necessary.
Type of Work
No of Pages
Hochschule RheinMain (Lufthansa Technik)
Entwicklung eines Versuchsaufbaus zur Detektierung von Triebwerksöl und Enteisungsflüssigkeit im Bleedsystem
Vortrag zur Bachelorarbeit
Dynamic Cabin Air Contamination Calculation Theory
Analyse der Entstehungsmechanismen von Ölnebel in Flugzeugkabinen
Copyright of student contributions is with the respective author. Thanks to the students for their enthusiasm to advance the topic! Thanks for giving me permission to upload the documents.
Find individual papers in the proceedings via the Index on page 2 and 3 (click on name or title).
The PDF Table of Contents shows author's names (alphabetically by last name) and also links to the paper.
Citation of Individual Article (ISO 690):
LastName, FirstName, 2019. ArticleTitle. In: Proceedings of the International Aircraft Cabin Air Conference 2017. Journal of Health and Pollution, Vol. 9, No. 24 (Dec. 2019), pp. StartPage - EndPage. - URL:
Citation of Proceedings (ISO 690):
Global Cabin Air Quality Executive (GCAQE), 2019. Proceedings of the International Aircraft Cabin Air Conference 2017. Journal of Health and Pollution, Vol. 9, No. 24 (Dec. 2019). - URL: