Can flying make you ill – really ill? This is a question of growing concern to travelers, pilots, cabin-crew unions and the authorities responsible for the health and safety of passengers.
We all know the symptoms: a dry throat, sore eyes, sinus pressure, throbbing head and swollen ankles. Call it airline cabin syndrome. It is caused by sitting for hours in cramped seats with low humidity (between zero and 15 percent) and a lack of fresh air.
We all know what to do even if we don’t do it. Drink plenty of water, avoid alcohol, coffee and tea, which promote dehydration, and eat sparingly. And there are aerobic exercises you’ll find in the back of the in-flight magazines. As the airlines force-feed us food and alcohol to justify outrageous business-class fares.
Quality of air has yet to compete with seat pitch and angle of recline and in-flight cuisine in the airlines’ battle for the hearts and minds of travelers in the glossy magazines. Airlines and their regulators worldwide seem reluctant to grant air quality higher status on their safety agendas.
Worries are now being expressed about the risk of passengers and crew catching serious airborne diseases – such as nasty strains of influenza, bronchitis, tuberculosis and Legionnaires’ diseases. This is because airlines are instructing pilots to save fuel by turning off one or more of their air-conditioning packs – especially after the meal when people are sleeping, thus reducing the amount of fresh air brought into the cabin and re-circulating more stale air.
But that’s only part of the story. The most sinister cause of ill health in the air is evidence now emerging that cabin air is dangerously contaminated with volatile organophosphates from the chemical breakdown of engine lubricants and hydraulic fluids. (Trimethylolpropane phosphate is a potent neurotoxin.) It is clear from copies of internal studies that aircraft manufacturers have known of this hazard for several years.
Organophosphates (OPs) – developed in World War 11 as a by-product of nerve gas technology – are used in pesticides. They work by interfering with the functioning of the central nervous system. People exposed to large doses are known to suffer a range of violent symptoms, some of them fatal, but chronic effects of low doses or of exposure over long periods of time are little understood. Many scientists are convinced that the mysterious Gulf War syndrome resulted from troops being exposed to OPs. Some are convinced that that the presence of OPs in our diet and in the environment – such as aircraft cabins – cause long-term damage to health.
An attorney for the Association of Flight Attendants in Seattle, says: ‘There are some very dirty aircraft out there and we have some very sick flight attendants. If they were Mexican farm workers in the Rio Grande, they’d have the right to be tested; but flight attendants and passengers don’t get that right: the airplane cabin is the only unregulated workplace in America with no standards that protect passengers and crew. The military have known of this problem for 20 years and have changed the type of hydraulic fluid they use. This is not being done in commercial aviation: the aerospace manufacturers, the airlines and the authorities have been keeping this dirty little secret.
‘Scientific studies going back to the late 1970s have demonstrated the problem of organophosphate contamination – including a 1983 FAA [U.S. Federal Aviation Administration] study. And there are thousands of cases of neuro-toxicity. But there’s been an active effort to keep this information out of the public eye. The Federal Government, the British and the Canadians, have all been sitting on this. Why? Because the authorities, along with NIOSH [National Institute for Occupational Safety and Health] and the airlines, have been in the hip pocket of the aerospace manufacturers.
‘There’s a parallel disinformation campaign to make airborne diseases the focus of concern about cabin air. Let’s talk about disease, that’s the plan; they want to hide the real cause. People think they’ve got flu – it’s not flu, it’s low-level organophosphate poisoning: respiratory problems, sinus infections, nausea, loss of memory and motor control, vomiting, diarrhoea and cramps. Physicians don’t recognize it because they’re not looking for it. They should give people a cholinesterase test for organophosphate poisoning.
At 30,000 feet (9,150 meters) the atmosphere in a plane has to be artificially created. At that altitude, the cabin is pressurized to 8,000 feet, the equivalent of sitting on a mountain top, except for the healthy breeze. Outside air is too cold and too thin for us to breathe. So the aircraft ventilation systems draw in air and bring it to the correct temperature and pressure (by mixing hot engine air with outside cold air) and remove a lot of moisture, as high humidity can cause aircraft corrosion.
Planes built before the early 1980s provided a complete change of fresh cabin air about once every three minutes. Modern aircraft supply a mix of fresh and re-circulated air, and the change rate can be as low as once every 10 minutes.
In some aircraft, such as Boeing 757s, the air is half fresh and half recycled, and the mix cannot be changed. In other aircraft, such as Boeing 747s, pilots can choose whether to operate the air-conditioning units at ‘normal’ or ‘reduced’ flow (reducing the amount of fresh air by a half to two thirds) or shutting off one of the three ventilation packs completely.
Airlines can save up to two percent of fuel costs, representing millions of dollars for a large airline, by cutting in half the amount of fresh air they bring into the cabin – thereby re-circulating 50 percent of cabin air. Turning a pack off not only saves fuel, but also reduces noise in the cabin.
Whatever class you fly, the quality of the air will be the same – although the cockpit crew gets a separate source of cold fresh air, partly because of the heat generated by instrument panels and electrically heated windows. Pilots get about 150 cubic feet of fresh air a minute per person; first class gets 50 cfm a person, and economy gets less than 7cfm.
The quality of re-circulated air depends on the efficiency of catalytic air filters and how often they are changed. (A short dry cough is typical of high ozone concentration – along with eye discomfort, nose and throat irritation and headache.) The new generation of HEPA (High Efficiency Particulate Air) filters are said to remove at least 99.97 percent of all air particles 0.3 microns in size – which includes large bacteria but excludes viruses.
Even HEPA filters cannot eliminate organophosphates from cabin air. There is evidence that the filters themselves can be a source of contamination when heavy molecules from, say, hydraulic fluid accumulate in the filters (and coat the inside of the air plenum, or air shafts), to be subsequently released into recirculated cabin air. There are cases where HEPA filters have caught fire in the plane, releasing contaminated air into the cabin.
Evidence that poor air quality may cause serious disease is mainly circumstantial. This is due to a lack of research and the difficulty of tracking passengers after a flight and an incubation period of three to four days, which means that people don’t always link illness with a particular flight. Plus, there are no international standards on air quality, except for levels of carbon monoxide, ozone and carbon dioxide.
The FAA has set the maximum concentration of carbon monoxide at 50 parts per million (and ozone at 0.1 ppm, with a 0.25 ppm ceiling) and has proposed lowering the maximum concentration of carbon dioxide from 30,000 parts per million to 5,000 parts. The Civil Aviation Authority in Britain says it will follow suit. But that figure is still five times higher than the comfort guidelines for buildings. Pilots report that carbon dioxide levels are rarely controlled.
Paradoxically, smoke-free flights may have exacerbated the problem. Smoke is a visible pollutant, so you needed much more air to disperse it. On nonsmoking flights people don’t notice the pollution so much, so you can turn down the air-conditioning.
Dr Richard Dawood, an expert on travel medicine and author of ‘Travelers’ Health,’ says: ‘Re-circulated air is filtered with varying degrees of efficiency in taking out tiny particles, depending on who you believe, the plane manufacturers or the airlines. But in the days of smoking flights you could still smell smoke in the front of the plane from re-circulated air, not just smoke wafting in through the open parts. So filters may not be terribly efficient.
‘The best documented cases of disease transmission have been when the plane has been on the ground for a long time, when you don’t even have enough power to get any fresh air coming in – it’s all re-circulated. You only need a few of those 200 or 300 people to have a transmittable disease and there’s a moderate chance of catching it.
‘Once you’re in the air, you are even more vulnerable to catching things because of removal of moisture in your respiratory passages due to the very low humidity – air comes in to the cabin at zero humidity and goes out at maybe five to 10 percent. Your mucous surfaces dry out, which makes it easier for germs to bed in and make themselves comfortable.’
A spokesman for the civil aviation section of the International Transport Workers Federation, in London, says: ‘We’re not alarmist, but cabin air quality is a growing problem. Air quality has been deteriorating consistently year on year. There is a breed of complaints of extreme dizziness, nausea, hypoxia, or breathlessness, headache and loss of motor control, during and after flights.
‘There’s no doubt that pilots do turn off air-conditioning packs to save fuel, but whether there are major health risks due to that is still an open question. None of the airlines will provide data on how much air is re-circulated. Pilots are not obliged to report this. And except for carbon dioxide levels, there are no legal limits for contaminants.
‘We’re establishing a worldwide task-force to look at cabin air standards. There has been a move in Congress for an enquiry into air cabin quality. The outcome is that we have reached an agreement with Boeing to put that legislative action on hold in return for a $2 million research study on cabin environment with independent experts, including us and the Association of Flight Attendants in the United States on an advisory panel to oversee that research.’
The report due by the end of 1999 has yet to appear.
Chris Witkowski at the Association of Flight Attendants in Seattle, says: ‘Boeing offered to do this study to create more time in view of the interest in Congress. I think they wanted to have a buy in from us, so that whatever they came up with, we’d be kind of backed into a corner to go along with whatever they came up with. In discussions with them about the study, they were never very forthcoming with this kind of information, which tells me that they’re just trying to cover up this problem. And by looking at other things, like seat comfort, trying to get away from health issues.
‘We’ve had this problem with air quality since the late 1970s, early 1980s, and there never seems to be a resolution. What we’re looking at right now are a large number of complaints for which the industry has professed they really don’t understand the cause. We have documentary evidence that the industry has known for a long time about the danger of organophosphate poisoning from the chemical breakdown of lubricating oils and hydraulic fluids. We are concerned that the FAA has trusted the industry to take care of these kind of problems instead of taking a more active role in the area of cabin-crew and passenger health.
‘I don’t know how this is going to play out, but certainly it is intolerable and unacceptable that the potential for chemical contamination has never been looked at. Around 60 percent of aircraft accidents are due to pilot error. The reason the military doesn’t use the same types of organic lubricants and fluids as civil aviation is because of the effect on pilots. Since the U2 incident with Gary Powers, they changed to synthetic fluids. ‘We have been in support of bringing more outside air into the cabin, so that you can dilute viruses, bacteria and so on. But we must make sure that the air we bring in is not contaminated by organophosphates. That is something that has to be addressed up-front and publicly. Airlines must produce maintenance records of engine systems and filtration and catalytic converters used to filter air coming into the cabin to determine if there has been loss or leakage of fluid. And then to see what corrective procedures were implemented.
‘We have to be careful not to jump into saying what needs to be done until we know more about the extent and nature of the problem. The bottom line is that we need to come up with regulations and policies that make sense on the quality of cabin air.’
Roger Collis 2000 New York Times