There are no sensors or warning devices to tell flight crew when this (= fume event, cotaminated toxic air) is happening, nor will the high efficiency particulate air filters that 'scrub' cabin air have any effect since this is a gas. Passengers and crew might detect a burning smell, or dirty socks or wet dog smells. In an extreme case smoke might fill the cabin, known as a fume event.
Passengers and crew whose health is affected as a result of exposure to this contaminant in the aviation environment have been described as suffering from aerotoxic syndrome, and the effects can be long-term and life-threatening. Symptoms include fatigue, blurred vision, nausea, breathing difficulties, headache, memory loss, convulsions, tremors and cognitive impairment, which includes the inability to carry out routine tasks, not a skill you want your pilot to lose. Aerotoxic syndrome is a little-known term used to describe the symptoms of exposure to contaminated air.
Campaigners and expert scientists believe it is responsible for long-term sickness, and even death, in a disproportionate number of people who work as cabin crew and pilots. Aerotoxic syndrome has also been cited as the reason for ill health in passengers in a number of cases.
Aerotoxic syndrome was so named by a small team of medical researchers in 1999. In their report, Dr Harry Hoffman, Professor Chris Winder and Jean-Christophe Balouet suggested that exposure to contaminated cabin air could result in long-term ill health, and needed further investigation. Since the 1950s, aircraft have used what’s known as the “bleed air” system to filter air through cabins.
Air is sucked into the engine compressor (the cold part of the engine) before it is siphoned off into the air-conditioning units, where it mixes with the recirculated cabin air. Problems occur when the oil used to lubricate the combustion parts of the engine heat up and chemicals leak back through damaged or inefficient seals into the compressor – and from there into cabin air. Filters in the air-conditioning units are designed to remove bacteria, viruses and dust.
Obvious leaks, identified by smoke or “dirty sock” smells, are known as fume events and can cause acute toxicity, with symptoms likened to CO-poisonings, ranging from runny nose to memory loss, severe headaches, loss of balance, muscle weakness, instant cognitive issues and more. But the constant low-level, “silent” presence of toxic substances are, crew and pilots claim, just as much of a problem, even more so, since it cuases a gradual, unnoticed build-up of toxic body burden, until suddenly the break-down happens.