Sometimes, All I Need is the Air that I Breath...

…at 30,000 feet.

To save money, airlines in the United States are circulating less fresh air into the cabins of many airplanes. As a result, flight attendants, as well as some passengers, have begun to complain that the practice is causing headaches, nausea and other health problems, especially after long flights.

The reduction of fresh air is done only on newer planes. Older aircraft built before the mid-1980's provided cabins with 100 percent fresh air that was circulated every three minutes. But the newer models provide half fresh air and half recirculated air that is freshened every six or seven minutes or longer. The recirculation system enables the planes to use less fuel to cool the outside air, which is heated by the engines as it is drawn in.

This is similar to a common problem with Building Related Illness or its more severe and newsworthy sister, Sick Building Syndrome. In the 1970’s, due to energy efficiency concerns buildings were built with the air conditioning bringing in less fresh air.

In the same article, the New York Times describes some of the problems attributed to poorly circulated air.

Studies have also found that passengers with respiratory problems can infect their fellow passengers unless enough outside air is supplied to dilute the contagious effects of coughs and sneezes.

"Reducing the amount of fresh air from outside the cabin and increasing the length of time between cleaning of the vent system increases the amount of contamination in the air that passengers and flight attendants breathe," said Mr. Witkowski of the flight attendants union.

Several Government studies have shown relatively high levels of carbon dioxide in airplane cabins. At the request of flight attendants, the National Institute of Occupational Safety and Health studied MD80's used by Alaska Airlines last February. The agency found that carbon dioxide averaged 4,882 parts per million, more than four times the 1,000 p.p.m maximum set by the American Society of Heating Refrigeration and Air-Conditioning Engineers.

King 5 News out of Seattle reports another problem with air in airplanes.

Mysterious illnesses have been reported by flight crews around the world, who believe they are exposed to dangerous fumes aboard aircraft.

Scientists believe they have found the culprit.

Researchers have zeroed in on a chemical found only in airplanes, a jet engine oil additive called tricresyl phosphate, or TCP.

Here's how TCP could find its way from a jet engine into humans. All commercial jetliners, from both Boeing and Airbus, use air sucked in by the engine and then fed to the cabin in what's called a "bleed air" system.

Oil and hydraulic fluid leaks in the engine, which flight crews say happen more often than airlines admit, can send toxic vapors into the breathing air system and throughout the plane.

Dr. Clement Furlong of the University of Washington genetics lab has been studying this problem for the last three years.

There have been documented cases of sick passengers, but that's usually when there's a big leak and obvious smell and vapors in the cockpit.

Dr. Furlong's team suspect that flight crews, who spend 750 hours on a plane a year, suffer from lower level exposures to TCP. They're trying to find out if it accumulates in the body.

Boeing's new 787 does not use bleed air technology.