For years airline passengers and cabin crew have blamed a range of health problems on the air quality inside modern passenger jets. Now a scientific panel says they may have a point and has recommended further study of the problem.
The environmental factors and cabin air quality could be responsible for health problems like skin irritations and respiratory trouble among air travelers and crew. While it was "extremely difficult" to link environmental conditions and air quality on passenger planes to a broad range of health complaints, researchers did find evidence suggesting a connection in four areas.
Ozone pollution may cause respiratory problems, and decreased oxygen pressure may present a health risk for people with preexisting conditions, such as cardiac and respiratory diseases, the scientists said.
Dry air inside commercial aircraft may cause drying of the eyes, nasal membranes and skin, while pesticides, which are routinely sprayed on some international flights, might cause skin irritation.
Toxic substances that might contaminate cabin air, like engine oils, hydraulic fluids, de-icing solutions and pesticides, have not been monitored adequately to assess potential health risks.
Some of these substances can enter an aircraft cabin through the plane's air supply system, especially when on the ground.
The scientific panel recommended that the Federal Aviation Administration, which banned smoking on domestic flights more than a decade ago, conduct "rigorous scientific investigation" to ensure that air-quality regulations are adequate.
But the spread of infectious agents like influenza appears more closely linked to person-to-person transmission in crowded passenger cabins rather than aircraft ventilation systems, the panel found.
The number of air passengers worldwide has nearly quadrupled in the past 30 years to nearly 1.5 billion annually.
Over the years, many airline crew members -- especially flight attendants -- and passengers have blamed health problems like headaches, difficulty breathing, dizziness and eye and skin irritation on the air quality in planes.
The air on a modern jetliner is a mixture of outside and recirculated air, similar to that found in many homes and office buildings.
Airlines began to mix fresh air with recirculated air in the mid-1980s to save money and improve the efficiency of energy systems. A Boeing 737-300 recirculates about 40% of its air, while a 757 recirculates about 50%. Cabin air is filtered to remove viruses and bacteria.
Report by the National Academies' National Research Council Washington December 6, 2001
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