Cosmic radiation is an ionized radiation in the atmosphere that emerges through the impact of the galactic-cosmic radiation onto our atmosphere (particle collision with oxygen, nitrogen,...). Neutron and Electron radiation are examples for this secondary radiation. Its intensity depends on:

• altitude (flight level) and duration of stay at this altitude
• latitude (from latitude 60° toward the polar ice caps, the intensity of the radiation remains the same)
• solar activities.

Other factors of influence are Earth's magnetic field and the solar cycles. The solar activity, following an 11-year cycle, has an influence on the radiation insofar that high solar activity causes a stronger magnetic field around the Earth with a weaker effect of the cosmic radiation.

The dose capacity (dose per time unit) is, depending on travel altitude, flight duration, latitude (increasing from the Equator toward the polar ice caps) and solar activity, up to 10 µsv per hour. Brief solar activities are not taken into consideration. The established dose on the route from Frankfurt to New York is about 30 µsv. The staff is submitted to 2-5 msv per year, which is clearly below the limit for staff exposed to radiation on the job, subject to flown routes (re. EU basic norm).

The ICRP (International Commission Radiation Protection) has calculated the risk of cancer for flight personal - referred to an annual exposure of 5 msv and 25 years of flying - and established an additional probability to fall ill with cancer of approx. 0.5 % to 1 %. At our latitude, the general probability to get cancer is around 25 %. For flight personal, it is 25.5 % to 26 %

For pregnant women, the limit of exposure in the plane is 1 msv.

Frequent Flyers rarely reach the amount of annual flight hours comparable to the flight personal. In general, they record approx. 20 % less than the annual flight hours of the flight personal. Numerous scientists estimate their risk - according to current knowledge - as largely insignificant.