Ask Captain Lim

Although ozone has been an useful element by forming a protective layer in the upper atmosphere and shielding human beings from the effect of ultra violet radiation, it is an unpleasant poison. A US House of Representatives Hearing Report of 1979, Adverse Health Effects of In-flight Exposure to Atmospheric Ozone, states that repeated exposure to ozone can lead to permanent lung scarring and loss of lung function. Exposure to ozone is greatest the higher the airplane flies.

The good news of the grounding of the Concorde by Air France in May 2003 and British Airways in October 2003 is that, high altitude (60,000 feet) air travelers are now less affected by ozone 'poisoning'. At that altitude, they received 6 parts per million ozone level. This is 60 times more than the recommended maximum dosage. In the Concorde, catalytic converters were installed in the airplane to break up the ozone and turn them into harmless oxygen.

Ultra violet radiation is also another problem. According to the Federal Aviation Administration, at about 37,000 feet (12,000 meters) air travelers are exposed to as much as 265 times the radiation dose they receive on the ground. Those who fly long-haul frequently receive an average of about three chest x-rays exposures.

Maria Blettner, head of Germany Radiation Protection Commission, is finishing a large-scale mortality study on cancer among flight crews. Germany's Cockpit Association warns the finding will reveal breast cancer rates may be twice as high, and skin cancer rates may be as high as 15 times as those of the general populace.