WASHINGTON -- That poorly ventilated conference room isn't the only place with the potential for sick-air syndrome.
Airliner cockpits can also have levels of carbon dioxide elevated enough that in simulations it causes pilots to fail test maneuvers at higher rates than normal, a new Harvard University study has found.
The first-of-its-kind research suggests that current regulations aren't adequate to assure there's enough fresh air in airline flight decks and raises questions about whether even moderately elevated carbon dioxide levels could impact safety, said Joseph Allen, an assistant professor at Harvard's School of Public Health and lead author of the study.
"It's clear that the air quality in the cockpit can have an impact on performance," Allen said. "It's clear we haven't been thinking about it too deeply in terms of the impact on pilot performance. Now that we know, I think we're obligated to ask those next sets of questions and really understand it."
In recent years, studies have shown that even an increase of a few hundred parts per million of carbon dioxide in the air we breath causes people to test lower for cognitive skills. But until the latest study, pilots and airline cockpits hadn't been examined.
Normal levels in the atmosphere are 400 parts per million. Concentrations of the colorless, tasteless gas can rise in poorly ventilated spaces where people exhale it -- such as crowded airliners.
Carbon dioxide levels reached as high as 1,400 parts per million on five percent of airline flights the European Aviation Safety Agency tested, according to data it released last year. The average was 603 parts per million, just slightly higher than levels found in the air.
Airliners replenish oxygen in a plane at high altitudes by pulling in the thin air and pressurizing it, mostly by scooping it from the front end of jet engines.
Because earlier studies showed people performed more poorly on tests of brain function at levels as low as 1,000 parts per million, the researchers thought it would make sense to examine pilot skills and carbon dioxide.