Cosmic radiation is radiation coming from the Sun and from stars. On average, we receive an equivalent dose from cosmic radiation of about 0.27 mSv per year whereas crewmembers and frequent flyers can receive much higher doses. High doses increase the chance of getting cancer; cosmic radiation is a key health issue for air crews.
What is cosmic radiation?
Radiation is the transport of energy through space. Radiation can be either particulate radiation or electromagnetic radiation. Cosmic radiation is radiation exposure received from the sun and stars. This is one component of our external background radiation exposure; the other component is terrestrial radiation.
An equivalent dose is a quantity used to measure radiation dose based on the biological damage expected. Unit used to describe equivalent dose is called sievert. One millisievert (mSv) is one-thousandth of a sievert.
What are the risks of cosmic radiation for crewmembers?
The dose of radiation at the cruising altitude of jetliners is between 200 and 400 times greater than at sea level. Radiation doses received by pilots and flight attendants are often greater than those received by radiation workers in the heavily regulated nuclear industry. Medical research has documented a significant correlation between overexposure to cosmic radiation and certain types of cancer - including breast and skin cancer.
What does ICAO say?
ICAO Annex 6 6.12 requires all aircraft intended to be operated above 49,000ft to carry equipment to measure and indicate continuously the dose rate of total cosmic radiation being received and the cumulative dose on each flight. ICAO Annex 6 18.104.22.168 requires the operator to maintain records of flights above 49,000ft so that the total cosmic radiation dose received by each crewmember over a period of 12 consecutive months can be determined.
What does the EU legislation say?
The main legal reference is the Art. 42 of the EU Council Directive 96/29/EURATOM, which was recently complemented by the Art. 35 of the EU Council Directive laying down basic safety standards for protection against the dangers arising from exposure to ionising radiation.
The EU legislation sets out two different thresholds:
A. Where the effective dose to the crew is liable to be exceed 1 mSv per year, the parties shall take appropriate actions to:
- assess the exposure of the crew concerned
- take into account the assessed exposure when organising working schedules with a view to reducing the doses of highly exposed crew
- inform the workers concerned of the health risks their work involves and their individual dose
- special consideration for pregnant air crew.
The JAR-OPS 1.390 Cosmic radiation directly transpose the requirements of the EU legislation into aviation specific regulations.
What does ICRP say?
The International Commission on Radiological Protection (ICRP) is the primary body in protection against ionizing radiation. ICRP acknowledges aircrew to be occupationally exposed to radiation. The recommended effective dose limit is 20 mSv per year, averaged over defined 5-year periods (100 mSv in 5 years), with the further provision that the effective dose should not exceed 50 mSv in any single year.
In addition, the recommendation for pregnant crewmembers is 1mSv from declaration of pregnancy for the remainder of the pregnancy. For the general public (e.g. passengers) the annual limit is 1mSv. ICRP assumes that occupationally exposed people have chosen to accept the risks of their radiation exposure in exchange for the benefits of employment.
What does the FAA says?
There are no binding regulations concerning radiation within FAA rules. However, the FAA considers aircrews to be occupationally exposed to ionising radiation and has the same recommended limits as ICRP recommendations, i.e. a 5-year average effective dose of 20 mSv per year, with no more than 50 mSv in a single year.
For pregnant crewmembers, starting when the pregnancy is reported to management, the recommendation is 1mSv limit for the remainder of the pregnancy.
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