Air crew monitoring of occupational exposure to ionising radiation

1. Air crew monitoring of occupational exposure to ionising radiation Gerhard Frasch Ralf Stegemann Lothar Kammerer Bundesamt für Strahlenschutz Germany European ALARA-Network 9th Workshop on Occupational Exposure to Natural Radiation, Augsburg, 18.-21.10.2005

2. Nature of cosmic radiation • Radiation in high altitudes and dosimetry • Radiation protection for air crews • Air crew monitoring and exposure in Europe • ALARA for air crews • Air crews and health risk • Air crews and risk communication

3. Discovery of cosmic radiation Victor Hess 1883 - 1964 Nobel Prize 1936

4. Galactic radiation Solar wind Geomagnetic field Cosmic radiation Steady particle flux from galaxy protons, helium nuclei, electrons Continuous radiation emitted from the corona of the sun periodically changing during an 11-years cycle Variation in dependence of latitude, longitude and time

5. Solar wind

6. Solar cycle

7. Solar cycle at Oct. 2005

8. Solar events - solar flares . Very seldom solar events with high dose rates in high altitudes: e.g. Feb. 1956: ~50 mSv h-1 at 20 km, ~10 mSv h-1 at 10 km

9. Magnetosphere of the earth

10. Ambient dose rate in atmosphere Different longitudes and latitudes at 11 km, Dec. 2002

11. Particle shower in high altitudes Proton (> 1 GeV) pions, neutron myons Cruising altitudes 11 - 15 km electrons neutrinos gamma

12. Global neutron monitoring

13. Measurement of route doses Reference instrument for ambient equivalent dose H*: Tissue-equivalent proportional counter (TEPC)

14. Calculation of route doses • Computer programs • e.g. EPCARD, CARI, FREE, SIEVERT, PC-AIRE • Calculation codes are based on • particle fluence rates (analytical) or radiation transport (Monte Carlo) • solar potential • geomagnetic conditions • experimental validations on flight • grids of ambient dose rate measurements in atmosphere • cruising altitude and duration.

15. Uncertainty of route doses • EURADOS working group on aircraft crew exposure: • “Calculated E-values agree within ± 25%” • “Measurements and calculations of H* agree within 25%” • van Diyk, NRG, ESOREX 2005 • ICRP: Person dosimetry • 1 • ---- Hp(true) < Hp(measured) < 1.5 * Hp(true) • 1.5

16. Effective doses on selected flight routes Dose range caused by solar cycle and variation of cruising altitudes, EPCARD 3.1

17. Radiation protection for air crews 1990: ICRP-Recommendations 1996: Council Directive 96/29 EURATOM, Art. 42: Protection of air crew > 2000: National regulations in Member States

18. Air crew monitoring • Who is monitored: • air crew personnel employed by aircraft operator (i.e. airline) • annual effective dose from cosmic radiation > 1mSv

19. Duties • Calculate and accumulate individual route doses • Keep doses low by • mission scheduling (personnel) • flight planning (routes) • Instruct air crew members • nature of cosmic radiation exposure • risk of adverse health effects

20. Air crew monitoring in Europe ESOREX 2005

21. Dose calculation programs in use ESOREX 2005

22. Monitored air crew personnel and doses ESOREX 2005

23. Air crews and other work sectors: mean doses

24. Air crews and other work sectors: dose distributions

25. Air crew members by gender Germany 2003/2004

26. Air crew members by work categories Germany 2003/2004

27. Dose distribution of air crew members Germany 2003/2004 female male

28. Dose distribution of air crew members Germany 2003/2004 cabin cockpit

29. Air crew members by age and dose bivariate frequency distribution, Germany 2003/2004 male female

30. Problems of ALARA airborne

31. ALARA approach for air crews • ALARA by mission planning • e.g. appropriate mix of short-range and long-haul flights • ALARA by routes and flight profile • e.g. cruse without final climb-up

32. Air crews and health risks Work- and life-style-specific risk factors: • radiation exposure • electromagnetic fields • air-conditioned work place • smoky air (in former times) • noise • long-hour shift work • irregular rest and mealtimes • jet-lag • often and rapid climate change • exotic nutrition • UV exposure • ...

33. Air crews and health risks Epidemiological findings in air crew cohort studies: • clear healthy worker effect • enhanced or slightly enhanced risk for • air crash, • AIDS (male flight attendants), • malignant melanoma, • female breast cancer, • cataract of eye lens (elderly pilots). • no enhanced risk for • leukaemia, • other forms of cancer. • difficult to control: many work- and life-style-specific risk factors.

34. Risk communication Majority of air crew personnel: young and female • exposure before or during pregnancy • accumulation of comparatively high life-time dose

35. Risk communication Sensitive topic for public media • frequent flyers • members of public

36. Risk communication New stakeholders • pilots, flight attendants, air lines • internationally organised

37. Risk communication • New territory for risk communication • Lessons learned from the past • reliable dose monitoring (QM for programs and procedures) • trustful co-operation (authorities - air lines - stakeholders) • transparency instead of secrecy • comprehensible information • reasonable dose evaluation and comparisons (cosmic radiation vs. other natural and man-made sources).