A number of possible health hazards of air travel have been investigated.

Infection

On an airplane, people sit in a confined space for extended periods of time, which increases the risk of transmission of airborne infections. For this reason, airlines place restrictions on the travel of passengers with known airborne contagious diseases (e.g. tuberculosis). During the severe acute respiratory syndrome (SARS) epidemic of 2003, awareness of the possibility of acquisition of infection on a commercial aircraft reached its zenith when on one flight from Hong Kong to Beijing, 16 of 120 people on the flight developed proven SARS from a single index case. There is very limited research done on

contagious diseases An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmiss ...

on aircraft. The two most common respiratory pathogens to which air passengers are exposed are parainfluenza and

influenza Influenza, commonly known as "the flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms ...

. In one study, the flight ban imposed following the attacks of September 11, 2001 was found to have restricted the global spread of seasonal influenza, resulting in a much milder influenza season that year, and the ability of influenza to spread on aircraft has been well documented. There is no data on the relative contributions of large droplets, small particles, close contact, surface contamination, and no data on the relative importance of any of these methods of transmission for specific diseases, and therefore very little information on how to control the risk of infection. There is no standardisation of air handling by aircraft, installation of HEPA filters or of hand washing by air crew, and no published information on the relative efficacy of any of these interventions in reducing the spread of infection. Air travel, like other forms of travel, radically increases the speed at which infections spread around the world, as viruses rapidly spread to large numbers of people living across the world. Human and cargo traffic greatly facilitates the spread of pathogens across the world, for example during the COVID-19 pandemic.

Deep vein thrombosis

Deep vein thrombosis (DVT) is the third most common vascular disease next to stroke and heart attack. It is estimated that DVT affects one in 5,000 travellers on long flights. Risk increases with exposure to more flights within a short time frame and with increasing duration of flights. According to a health expert in Canada, even though the risk of a blood clot is low, given the number of people who fly, it is a public health risk. It is reported in 2016 that the average distance between seat rows has declined to , from over , while the average seat size has shrunk to from in the previous two decades.

Radiation exposure

Flying high, passengers and crews of jet airliners are exposed to at least 10 times the cosmic ray dose that people at sea level receive. Every few years, a geomagnetic storm permits a solar particle event to penetrate down to jetliner altitudes. Aircraft flying polar routes near the

geomagnetic pole The geomagnetic poles are antipodal points where the axis of a best-fitting dipole intersects the surface of Earth. This ''theoretical'' dipole is equivalent to a powerful bar magnet at the center of Earth, and comes closer than any other poin ...

s are at particular risk. There is also increased radiation from space.

Other possible health hazards

Other possible hazards of air travel that have been investigated include airsickness and chemical contamination of cabin air.

In pregnancy

In low risk pregnancies, most health care providers approve flying until about 36 weeks of gestational age.Page 173
in: Most airlines allow pregnant women to fly short distances at less than 36 weeks, and long distances at less than 32 weeks.Page 57
in: Many airlines require a doctor's note that approves flying, specially at over 28 weeks.

References