COSMIC RADIATION IN COMMERCIAL AVIATION Professor

This paper reviews the current knowledge of cosmic radiation and its applicability to commercial aviation. Galactic cosmic radiation emanates from outside the solar system, while occasionally a disturbance in the sun’s atmosphere leads to a surge in radiation particles. Protection is provided by the sun’s magnetic field, the earth’s magnetic field, and the earth’s atmosphere. Dose rates are dependent on the altitude, the geomagnetic latitude and the solar cycle. For occupational exposure to ionising radiation, which includes aircrew, the International Commission on Radiological Protection recommends maximum mean body effective dose limits of 20 mSv per year (averaged over 5 years, with a maximum in any one year of 50 mSv). Radiation doses can be measured during flight or may be calculated using a computermodelling program such as CARI, EPCARD, SIEVERT or PCAIRE. Mean ambient equivalent dose rates are in the region of 4 – 5 μSv per hour for long-haul pilots and 1 – 3 μSv per hour for short-haul, giving an annual mean effective exposure of the order 2 – 3 mSv for long-haul and 1 – 2 mSv for short-haul pilots. Epidemiological studies of flight crew have not shown any increase in cancer mortality or cancer incidence that could be directly attributable to ionising radiation exposure. Whilst it is accepted that there is no level of radiation exposure below which effects do not occur, all the current evidence indicates that the probability of airline crew or passengers suffering any abnormality or disease as a result of exposure to cosmic radiation is very low.