Carbon Monoxide in the Cabin

Emergence of Carbon Monoxide (CO)

Burning Hydrocarbon Compounds (like oil, gasoline or kerosene), will result in Carbon Dioxide (CO2) and Water (H2O) as end products, on condition that sufficient Oxygen (O2) is present for a complete combustion. When however a lack of Oxygen occurs, this will result in an incomplete combustion. Under these conditions Carbon Monoxide (CO) will also be formed, a colourless, odourless and toxic gas.

Dangers of CO

The problem with CO in breathing air is, that CO is much easier absorbed by our blood than Oxygen (O2). As a result, CO seemingly supplants the O2 in the air we breathe, which causes hypoxia. On top of that, getting rid of the absorbed CO again is a difficult and time consuming process, so the body will only slowly recover from this hypoxia. With low concentrations of CO, the patient will develop complaints like headaches, fatigue, dizziness and loss of concentration. In higher concentrations, it will even be lethal. The flu-like complaints that normally come with CO-poisoning, are often not immediately recognised as such, even by GP's, which can potentially lead to life-threatening situations. In the Netherlands, several hundreds of people end up in hospital each year as a result of CO-poisoning, e.g. by polluted chimneys of poorly maintained central heating installations.

Fire Brigade Campagne spring 2018

In February 2018, the Dutch National Fire Brigade started  a  campagne to point people to the importance of precautions like mounting CO-detectors in their homes and timely maintenance of heating equipment, but also to make GP's more aware of the risks of CO-poisoning.

 

CO in aircraft

Also on board of aircraft, CO unfortunately is not uncommon, it is one of the gases that strongly pollutes the cabin air during Fume Events. The air for the cabin is bled from the engine compressors. In that process, the air gets heated up to around 400ºC. The (oil) pollutants that end up in that same air, are also heated up to that temperature, resulting in incomplete combustion/pyrolysis, and therefore the emergence of CO, plus a wide range of other toxic substances.

Self-measuring on board?

While measuring the many toxic combustion products that occur in the cabin air is difficult and requires specialist measuring equipment, a CO-meter is cheap and widely available. And even though the measurement with e.g. a simple, handheld CO-meter would never be formally recognised, the indication can certainly give a good impression of the level of cabin air contamination.
After all, one can safely assume that when high levels of CO are measured, several other toxic substances are very likely to be present as well. So, wearing a suitable facial mask (e.g. from Cambridge Masks) during periods when the CO-meter indicates high values (typically during engine start, Take off/climb and descent/approach/landing), can significantly reduce the risks of contaminated cabin air.