We all do it! Well quite a few of us do...
According to the Internation Air Transport Association (IATA) in a recent press release the world was well on the way to 3.3 billion passenger journeys by air during 2014 and it estimated that there would be 7.3 billion per year by 2034.
That is an amazing number of people taking 1 or more journeys by air and being subjected to a number of short-term risks during the travel event and potentially having other issues to contend with later.
All's well that ends well
When we reach our destination, we generally relax a bit, recover from the travel experience and then get back to daily life. For the vast majority of passengers and crew-members the flighst go well and they safely reach their destination. We may consider them to be safe travel events that have ended well.
I'm not referring to Winston Churchill's speech following the Battle of Britain in the Second World War. Instead I am focusing on the few (number unknown) for whom it doesn't necessarily end well at the end of the flight.
Since before 1999 and a study undertaken by Dr Harry Hoffman, Professor Chris Winder and Jean Christophe Balouet, Ph.D, there have been concerns regarding the possibility of negative long-term health effects from air travel. However, in their report Aerotoxic Syndrome: Adverse health effects following exposure to jet oil mist during commercial flights. they coined a term that has come to be adopted within parts of the industry of "Aerotoxic Syndrome". Others prefer, possibly rightly, to refer to Cabin Air Quality problems.
A few people become unwell following continued air travel and in February 2015 a UK Coroner put British Airways and the UK Civil Aviation Authority on notice through requesting their attention to Prevention of Future Deaths through a formal notice in his findings relating to the death of a 42 year old British Airways pilot, Richard Westgate. There have also been reported deaths of cabin crew where similar symptoms and loss of life have occurred.
Moreover, for every death there seem to be 10s of people who are suffering from the symptoms of aerotoxic syndrome.
The investigations to date
The aviation industry has not ignored the issue and have set up investigations and inquiries into the possible causes - in the main they have been linked to a specific source of possible contamination in the form of compressed air from the aircraft engines (engine bleed air) being used to ventilate and pressurise the aircraft. It is known that from time to time there can be contamination of this air source through 'fume events' where there is the smell of burning oil in the aircraft.
A desktop review was carried out by the Australian Civil Aviation Safety Authority and reported in 2009 Contamination of aircraft cabin air by bleed air – a review of the evidence based on an the collaboration of an Expert Panel on Aircraft Air Quality.
From the report, the problem was described as:
Irritant effects: itchy, red, weeping eyes: “scratchy” sensation in throat, swelling of throat (sometimes with altered taste): respiratory symptoms, tightness in chest, red and itchy skin.
Central Nervous System (CNS) effects: loss of recent memory, poor concentration, increased lethargy, neuromuscular incoordination, confusion and headaches.
With the report noting that "Despite the large amount of information available to the Panel, there remain many unanswered questions in seeking to understand the potential for exposures to engine oil in aircraft cabins and the acute and chronic effects on a person’s health as the result of such exposures", it suggested "Carbon monoxide (CO) and organophosphate derivatives remain the most likely contaminants documented"
The Panel limited the scope of this review to cabin air contamination due to internal leakage of chemicals into the air conditioning system. The review excluded consideration of the health effects of allergens, microorganisms and chemical contamination from external sources.
What was missing from the reviews?
It seems that the first thing missing was human physiological data. The hunt for the cause didn't include collection and interpretation of data relating to the human impact.
The second thing that was missing was a systems thinking approach to the problem. It seens that the cause had been determined as being the bleed air and the evidence was being sought around that predetermined 'fact'.
The Aviation eco-system has many more facets and potential sources of contaminaton that such a narrow focus might lead to a failure to find the facts.
Having taken a look through some of the reports to date and with some practical knowledge of testing that can measure human uptake of Carbon Monoxide, we have the opportunity to think differently and to consider better evidence and seek to find the real smoking 'gun(s)' in Aerotoxic Syndrome.
Advances in diagnosis and monitoring of patients with Carbon Monoxide poisoning and Firefighters at major incidents mean that there may now be further ways to assess the causes and complex ecosystems surrounding Aerotoxic syndrome.