What to expect when flying
Pressure, oxygen content and gas expansion
Contrary to popular belief, cabin pressure is not maintained at sea level pressure. Air pressure in the cabin is equivalent to the outside air pressure at 1,800–2,400 metres (6,000–8,000 feet) above sea level. As a result, the blood takes up less oxygen and gases within the body will expand. The effects of reduced cabin air pressure are usually well tolerated by healthy passengers. Passengers with certain medical conditions, in particular heart and lung disorders and diseases such as anaemia, may not tolerate this reduced oxygen level. These passengers will need to apply for medical clearance before travelling.
As the aircraft climbs, the decreasing cabin air pressure causes gases to expand. Gas expansion during ascent causes air to escape from the middle ear and the sinuses, usually without causing problems. This airflow can sometimes be perceived as a "popping" sensation in the ears. As the aircraft descends, air must flow back into the middle ear and sinuses in order to equalise pressure differences. If this does not take place, the ears or sinuses may feel as if they were blocked and, if the pressure is not relieved, pain can result. Swallowing, chewing or yawning will usually clear the ears and relieve any discomfort. If the problem persists, a short forceful expiration against a pinched nose and closed mouth (Valsalva manoeuvre) will usually help. In the same way, gases in the abdominal cavity also expand and travellers are advised to vent gases freely if they feel discomfort in their abdomen. For infants, feeding or giving a pacifier to stimulate swallowing may reduce the symptoms.
Individuals with ear, nose and sinus infections should avoid flying because pain and injury may result from the inability to equalise pressure differences.
Cabin humidity is relatively low, usually less than 20 percent and may cause relative discomfort for those travelling. Dry, itchy or irritated eyes, dry stuffy nose, dry throat and skin dryness are common complaints but present no health risk. Using a skin moisturising lotion, saline nasal spray to moisturise the nasal passages and wearing spectacles rather than contact lenses can relieve or prevent discomfort.
Cabin air quality
Cabin air is replenished with fresh air around 10–15 times every hour by dilution. Almost 50 percent of the cabin air is re-circulated to maintain a comfortable level of humidity and temperature. The air is passed through HEPA (highly efficient particulate air) filters which remove 99 percent of the bacteria and viruses particles in the cabin air to increase the comfort and safety of our passengers.
Many countries require disinsection (i.e. treatment for the removal of insects) of aircraft arriving from countries where vector-borne diseases, such as malaria and yellow fever, occur. This is to prevent the inadvertent introduction of infection by insects carried on board. Disinsection is a public health measure that is mandated by the International Health Regulations. Disinsection involves treatment of the interior of the aircraft by the application of insecticides. The different procedures in use include:
- Treatment of the interior of the aircraft by application of a quick-acting pyrethroid insecticide spray, with the passengers on board, immediately prior to take-off.
- Treatment of the interior of the aircraft on the ground before passengers come on board, using a residual insecticide aerosol containing permethrin, plus additional in-flight treatment with a quick-acting insecticide spray shortly before landing.
- Regular application of a residual insecticide to all internal surfaces, except in food preparation areas.
Travellers are sometimes concerned about their exposure to insecticide sprays while travelling by air. They should be reassured that disinsection is a safe procedure. There is no evidence of any toxic hazard to passengers or crew resulting from the use of the recommended methods and products for disinsection.
General tips while travelling
The travel to the airport and checking-in procedures are a tiring time for all passengers. The walk from the check-in area to the gate is usually quite a distance and does not cause any problems for healthy passengers. However, those who are elderly and suffer from heart and lung diseases may find this a trying time. It is advisable to carry some drinking water to prevent dehydration, which is more common in the old and infirm. Passengers are also advised to wear loose comfortable clothing. Flight delays, lack of information and separation from luggage affect almost everyone sooner or later. It is advisable to carry a spare change of clothes, essential toiletries and any medication with a doctor's note in your hand luggage at all times.