Carbon monoxide in passenger cabin?
Join Date: Nov 2015
Location: BRS/GVA
Posts: 342
Likes: 0
Received 0 Likes
on
0 Posts
... or, there was CO on the plane and the low cabin pressure aggravated the effects of the CO poisoning.
e.g. Oxygen is perfectly healthy for us at atmospheric pressure, but breath it whilst diving and it becomes toxic at a certain depth corresponding to the partial pressure rising above a certain value.
CO poisoning can be related to partial pressure. The partial pressure is independant of atmospheric pressure or altitude, but as cabin pressure falls to say 8000 ft the effect of a set percentage of CO in the cabin will fall as the pp falls.
This is separate from the effects on oxygen delivery. CO displaces oxygen from haemaglobin. The partial pressure of oxygen in the blood falls with decompression so the effect of CO on oxygen delivery vs oxygen requirements will be magnified in respect of the tissues.
So yes you may get increased headache with altitude but conversely you should become symptom free more rapidly when back on the ground
Smokers will already have some CO on board from their cigarette so theoretically need less additional CO to produce symptoms
Of course all hypothetical as no CO demonstrated in any passenger nor any fault in the aircraft. But the Fire Chief had his moment of fame and possibly will be able to persuade the city to increase his budget next year to avoid thousands of future imaginary mass incidents.
This is separate from the effects on oxygen delivery. CO displaces oxygen from haemaglobin. The partial pressure of oxygen in the blood falls with decompression so the effect of CO on oxygen delivery vs oxygen requirements will be magnified in respect of the tissues.
So yes you may get increased headache with altitude but conversely you should become symptom free more rapidly when back on the ground
Smokers will already have some CO on board from their cigarette so theoretically need less additional CO to produce symptoms
Of course all hypothetical as no CO demonstrated in any passenger nor any fault in the aircraft. But the Fire Chief had his moment of fame and possibly will be able to persuade the city to increase his budget next year to avoid thousands of future imaginary mass incidents.
Join Date: Jun 2016
Location: Singapore
Posts: 72
Likes: 0
Received 0 Likes
on
0 Posts
Seriously? Smoking????
What makes me suspicious of the CO diagnosis is the method of recovery. Normally, the patients would be given oxygen to breath and that would reduce their CO levels by 50% every 80 minutes. Walking around in fresh air (as is reported) reduces CO levels (actually, the COHb level) by 50% every 320 minutes (https://en.wikipedia.org/wiki/Carbon...ning#Treatment).
I think we need to consider this scenario: Many passengers smoked before boarding the plane - and those smokers had a lower tolerance for the reduced cabin air pressure. Some of these passengers and perhaps some others got sick during the flight so the flight landed. On landing, many of the sick passengers had elevated CO levels from smoking - but not elevated so much that the were offered oxygen therapy.
Regarding CO levels: Home detectors can detect 1 or 2 parts per million (ppm), flu-like symptoms start at 35 ppm, loss of judgement starts at 200 ppm, convulsions within 45 minutes at 800 ppm, death in less than 2 hours at 1600 ppm.
During a power outage in my town that lasted several days, I was with a volunteer group that worked with the Fire Department. We went home to home checking on the use of generators. Improperly positioned generators resulted in levels of 35 and 50 ppm at two homes. In both of those cases, fumes could be easily smelled. No symptoms were reported.
... or, there was CO on the plane and the low cabin pressure aggravated the effects of the CO poisoning.
I think we need to consider this scenario: Many passengers smoked before boarding the plane - and those smokers had a lower tolerance for the reduced cabin air pressure. Some of these passengers and perhaps some others got sick during the flight so the flight landed. On landing, many of the sick passengers had elevated CO levels from smoking - but not elevated so much that the were offered oxygen therapy.
Regarding CO levels: Home detectors can detect 1 or 2 parts per million (ppm), flu-like symptoms start at 35 ppm, loss of judgement starts at 200 ppm, convulsions within 45 minutes at 800 ppm, death in less than 2 hours at 1600 ppm.
During a power outage in my town that lasted several days, I was with a volunteer group that worked with the Fire Department. We went home to home checking on the use of generators. Improperly positioned generators resulted in levels of 35 and 50 ppm at two homes. In both of those cases, fumes could be easily smelled. No symptoms were reported.
... or, there was CO on the plane and the low cabin pressure aggravated the effects of the CO poisoning.
The CO diagnosis may turn out to be a red herring.... But smoking? No... We do not need to consider that. It is nonsense.
Join Date: Feb 2015
Location: New Hampshire
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
My point was that the fire chief could have detected COHb even if there was no CO on the plane. We both hold as suspect the suggestion that cabin CO caused the problem. But there are portable devices that can check for COHb - either from breath or from blood.
One passenger reported that pax from different parts of the plane actuated their call buttons at about the same time. This suggests that CO or not, there may have been a real (non-psychosomatic) cause for the illnesses.
One passenger reported that pax from different parts of the plane actuated their call buttons at about the same time. This suggests that CO or not, there may have been a real (non-psychosomatic) cause for the illnesses.
Join Date: Sep 2001
Location: Connecticut, USA
Age: 64
Posts: 251
Likes: 0
Received 0 Likes
on
0 Posts
Could passengers have been exposed before getting on the plane? Perhaps a malfunctioning cooking appliance or a vent that wasn't turned on in the terminal, and they didn't feel the effects until the pressure dropped on the aircraft?
Join Date: Jun 2016
Location: Singapore
Posts: 72
Likes: 0
Received 0 Likes
on
0 Posts
I think the post that followed, about exposure on the ground exacerbated by lower pp of oxygen at altitude, is much more plausible.
Re: other posts. I believe A/C have electric ovens not gas ones! Oven linings do not contain carbon, hence not a possible source of CO. Not a lot of CO from electrical fires. As for a smouldering fire somewhere, I think the pax might have noticed the smell of smoke (and perhaps a smoke alarm might have gone off) long before enough CO reached them.
As I have said, the CO call might be a red herring. But if real, then the only likely source is the engines or APU. There is a lot of fuel, it is burnt, and said fuel is mostly carbon... Occam's razor applies.
I had a bad air fill when scuba diving ,my tank had been the first fill that day and vehicles were parked near the compressor intake.If you get CO poisioning you will certainly know about it!After about ten minutes into the dive I had a splitting headache which lasted all day !
The CO component of the story has zero credibility:
For one, CO is the product of incomplete combustion of carbon compounds under oxygen deprived conditions AND high temperatures. The only place on the aircraft where it may be produced in measurable quantities (barring an on-board fire, which was clearly not the case) are the combustion chambers of the engines and the APU. As stated several times above, if the engines are producing thrust and there is sufficient airspeed to maintain flight, it is physically impossible for any CO produced there to enter the cabin air supply.
The fire chief was more than likely influenced by cognitive bias. They would have received extensive training on the effects of CO poisoning, as in case of victims of building fires swift recognition and treatment is vital. Naturally he would 'recognise' any condition with similar symptoms as CO poisoning, without considering other options. Very similar to doctors with different specialisations tending to come up with varying diagnoses matching their fields of expertise for the same patient.
For one, CO is the product of incomplete combustion of carbon compounds under oxygen deprived conditions AND high temperatures. The only place on the aircraft where it may be produced in measurable quantities (barring an on-board fire, which was clearly not the case) are the combustion chambers of the engines and the APU. As stated several times above, if the engines are producing thrust and there is sufficient airspeed to maintain flight, it is physically impossible for any CO produced there to enter the cabin air supply.
The fire chief was more than likely influenced by cognitive bias. They would have received extensive training on the effects of CO poisoning, as in case of victims of building fires swift recognition and treatment is vital. Naturally he would 'recognise' any condition with similar symptoms as CO poisoning, without considering other options. Very similar to doctors with different specialisations tending to come up with varying diagnoses matching their fields of expertise for the same patient.
Join Date: Sep 2005
Location: Scotland
Posts: 177
Likes: 0
Received 0 Likes
on
0 Posts
Actually CO is produced from burning Hydrocarbons at too low a temperature, I tune Industrial Gas Turbines for low emissions for a living, and as an ex aircraft propulsion Tech i know a thing or three about Aero Derivatives, it seems unlikely that high CO (in excess of 50ppm) is produced from combustion in an Aero but it all depends on temperature really. As for how it would get into the cabin, i cant think of any mechanism unless there was an oil fire across the labyrinth seals of a bearing that would cause CO to enter the cabin. Oil would burn inefficiently and cold enough to produce tremendous amounts of CO - certainly in excess of 1000ppm
Join Date: Feb 2015
Location: New Hampshire
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
The symptoms are wrong for organophosphates - and you can't walk off that type of poisoning.
I mentioned psychosomatic earlier, but one passenger reported that many call buttons where pressed from different sections of the plane at about the same time. So, on the face of it, it would seem as though there was not enough opportunity for pax-to-pax communication to support mass hysteria.
I mentioned psychosomatic earlier, but one passenger reported that many call buttons where pressed from different sections of the plane at about the same time. So, on the face of it, it would seem as though there was not enough opportunity for pax-to-pax communication to support mass hysteria.
Join Date: Sep 2001
Location: Connecticut, USA
Age: 64
Posts: 251
Likes: 0
Received 0 Likes
on
0 Posts
It would be interesting to know if those who displayed symptoms were people who might have been more susceptible - smokers, elderly, pre-existing medical issues, small children, etc.
Join Date: Sep 2001
Location: Connecticut, USA
Age: 64
Posts: 251
Likes: 0
Received 0 Likes
on
0 Posts
Wow. I had no idea ethyl alcohol purges CO from the blood stream and sleeping increases CO levels in the blood stream.
