Your worst fears about breathing bad air on planes are probably unfounded.
A recent European study that monitored air on 69 flights found cabin air quality was less polluted than that of office buildings, schools and residences. Contaminants that were found were “detected at levels considered not unusual for indoor air environments,” the study commissioned by the European Aviation Safety Agency said.
That’s good news for travelers, but unlikely to eliminate fears some hold, particularly in Europe, that oil fumes in airplanes are a toxic health problem.
Airlines and aircraft manufacturers have struggled for decades to eliminate contamination from “bleed air” systems that compress air just inside the engine, before that air comes in contact with burning fuel. The fresh, compressed air mixes with filtered air recirculated within the cabin. Problems, such as leaky seals or overfilling the oil in the engine during maintenance, can arise. That can lead to pumping chemicals from hot oil to passengers.
“There’s nothing between the engine and the people breathing that air,” says Judith Anderson, an industrial hygienist who works on health and safety issues for the Association of Flight Attendants. The organization has researched this issue for decades and pushed for improvements of aircrafts and airline procedures.
Still, such events are rare. The flight attendants union says it gets two or three reports a week out of tens of thousands of flights. The lead author on the European study, Sven Schuchardt of the Fraunhofer Institute for Toxicology and Experimental Medicine in Hannover, Germany, says research that distinguishes between minor “smell events” and more-serious “fume events” show fume events happen only a few times per one million takeoffs.
Oil-related toxins “can enter the cabin more often than you think, but in amounts that are not worth mentioning,” Dr. Schuchardt says.
The study, funded by EASA, the European equivalent of the U.S. Federal Aviation Administration, measured air on 69 flights and recorded no fume events. Still, Dr. Schuchardt says in an interview that the research team calculated the maximum concentrations in a fume event and concluded there’s not enough oil in an engine to be harmful. Being behind exhaust from a stinky car or truck in traffic would be worse.
“Our opinion is: OK, it’s not nice to have a fume event, because it’s oily mist in the cabin air. But if this occurs, it’s only for a few minutes, maximum three to five minutes, and the amount of toxic compounds is never critical. No way,” he says. “I think it’s no problem to breathe cabin air in every situation.”
The aviation world doesn’t dispute that fume events happen, but there is disagreement over whether they are harmful. In some cases, some scientists believe, exposure can cause neurological issues such as loss of memory or balance, and onset of problems is often delayed. Crew members may be more susceptible to getting sick right away, because repeated exposure weakens resistance.
Boeing’s newest design, the 787 Dreamliner, is made without a bleed air system, using an electric system for heating and compressing fresh air. The EASA study included eight 787 flights and found slightly lower levels of chemical vapors.
Since the 1990s, airplanes have been equipped with filters used in hospital operating rooms and high-tech clean rooms called High Efficiency Particulate Air (HEPA) filters. Recirculated air passes through the filters to capture viruses, bacteria, pollen and other contaminants. Air on a plane recirculates in high volume—a good health tip is open up your air vent and aim it in front of your face so you’re breathing filtered air, not the germs from the person two rows behind you.
The FAA has studied used HEPA filters and found a few samples had some contaminants, or TCP. TCP is a toxic oil additive that can cause neuropathy and gastrointestinal disorders. But the FAA says there were no high levels of TCP or other contaminants.
The European study detected TCP on three of its 69 flights. All three were on aircraft with bleed air systems. Crews didn’t smell anything unusual on those flights, the study said, and the levels weren’t considered high enough to be a risk.
The FAA plans to release a report later this year on research that began a number of years ago collecting air samples aboard 100 airplanes. Results have been delayed because researchers involved have changed jobs.
AFA’s Ms. Anderson thinks progress is being made, since several companies are trying to develop bleed air filters and sensors. And some airlines have taken a more active approach to prevention.
Ms. Anderson credits Spirit Airlines with making improvements after some serious fume events several years ago. Spirit changed pilot procedures to isolate and shorten any fume events and trained crews on better recognition of problems. In addition, Spirit is working with a filtration company on some engineering solutions.
Preventing fume events can be a cost-savings measure for airlines, reducing unscheduled emergency landings, bad publicity, workers comp claims and maintenance and ground time.
“There are some changes. It’s slow,” she says.
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