Advertisement

Radioaktive Aerosole

Chapter

Summary

A I. For the radon and thoron decay products, the main sources of natural radioactivity in the atmosphere, natural aerosols act as carriers. The main features of these aerosols are discussed, especially the size distribution and concentration under various geographical conditions, including some data on chemical composition and distribution with altitude. Several processes, predomi-nantly those connected with the formation and evaporation of cloud droplets, will modify the size distributions by growth of individual particles.

A II. The decay products of radon and thoron, RaA and ThA are atoms, which readily become molecular clusters (primary particles) similar to small ions and then in turn become attached to the aerosols (secondary particles). The theory of Smoluchowsky can be applied to this process of attachment and various parameters, such as the half live time of primary particles, the activity ratio of primary to secondary particles and the activity distribution with particle size can be calculated. The agreement with the data available in literature is fair and indicates that the presented model is a good approximation. For longer lived decay products, the removal of aerosols from the atmosphere has to be incorporated in the calculations. Data on the atmospheric residence time of aerosols obtained by the use of radon decay products are critically reviewed.

B. Similar to the decay products of the emanations, the isotopes induced by cosmic radiation can only exist as particles. New data on stratospheric aerosols allows similar calculations as for the radon decay products. It is concluded that most of the isotopes must be attached to particles between 0.02 and 0.2 microns and that the half live of the primary particles is of the order of hours as compared to fractions of a minute in the troposphere.

CI. The structure and chemical composition of close in fallout particles of atomic tests depends considerably on the type of test, i.e., if it is a ground, tower, water or air burst. If no surface material enters the fireball, the particles are formed by condensation and consist of iron oxide with the activity uniformly distributed within them. Surface or tower material may only partly be evaporated or melted, and the result is a variety of particles with the activity primarily deposited on the surface.

CII. The particles of medium range fallout can be characterized by the fact that they are small enough to be carried over large parts of the globe in the first few months after tests, but still large enough to fall out primarily by sedimentation. Activities up to 10−9 C are observed in these “hot” particles, which at times may represent a considerable fraction of the activity in air. Their activity is roughly proportional to their volume and they form only the tail of a size distribution which extends to much smaller particles and represents already part of the long range fallout.

CII. The long range fallout particles are so small that they behave like a gas with respect to meteorological processes. They have residence times in the stratosphere of about a year and are removed from the troposphere primarily by precipitation. The few measurements available from the stratosphere indicate average sizes of a few hundred microns to the tenth of a micron range. After penetration into the troposphere these particles are modified in their size, composition and structure by the same processes which influence the natural aerosols.

CIV. A problem of special interest in the area of reactor aerosols is the absorption of radioactive gases on aerosols. This phenomenon was studied in more detail for Iodine 131, which was released in considerable quantities at the Windscale accident. It appears that absorption of Iodine on aerosols becomes important, when its concentration by weight is about 10−3 the concentration of the aerosol.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Schrifttum

  1. Adams, C.E., N.H. Farlow and W.R. Schell: Compositions, structure and origins of radio- active fallout particles. U.S. Naval Radiological Defense Laboratory Technical Report, USNRDL-TR-209 (1958).Google Scholar
  2. Anderson, A.D.: A theory for close-in fallout. U.S. Naval Radiological Defense Laboratory Technical Report, USNRDL-TR-249, 1–55 (1958).Google Scholar
  3. Aron, A., U. B. Gross: Eine Beobachtung über die von Kernbombenversuchen herrührende Radioaktivität der Luft. Z. Naturforsch. 12a, 944–945 (1957).ADSGoogle Scholar
  4. Blifford I.H., L.B. Lockhart and H.B. Rosenstock: On the natural radioactivity in the air. J. Geophys. Res. 57, 499–509 (1952).ADSCrossRefGoogle Scholar
  5. Brewer, A.W.: Evidence for a world circulation provided by the measurements of helium and water vapor distribution in the stratosphere. Quart. J. Roy.Meteor. Soc. 75, 351–363 (1949).ADSCrossRefGoogle Scholar
  6. Bullrich, K.: Streulichtmessungen in Dunst und Nebel. Meteor. Rdsch. 13, 21–29 (1960).Google Scholar
  7. Burton, W.M., and N. G. Stewart: Use of long-lived natural radioactivity as an atmospheric tracer. Nature, Lond. 186, 584–589 (1960).ADSCrossRefGoogle Scholar
  8. Chamberlain, A.C.: Deposition of iodine-131 in northern England in October 1957. Quart. J. Roy. Meteor. Soc. 85, 350–361 (1959).ADSCrossRefGoogle Scholar
  9. Chamberlain, A. C., and M.T. Dunster: Deposition of radioactivity in north-west England from the accident at onidscale. Nature, Lond. 182, 629–630 (1958).ADSCrossRefGoogle Scholar
  10. Chamberlain, A. C and E.D. Dyson: The dose to the trachea and bronchi from the decay products of radon and thoron. Brit. J. Radiol. 29, 317–325 (1956).CrossRefGoogle Scholar
  11. Chamberlain A. C, W. J. Megaw and R.D. Wiffen: Role of condensation nuclei as carriers of radioactive particles. Geofis. pura e appi. 36, 233–242 (1957).ADSCrossRefGoogle Scholar
  12. Chamberlain, A. C and R.D. Wiffen: Some observations on the behaviour of radio-iodine vapour in the atmosphere. Geofis. pura e appi. 42, 42–48 (1959)•Google Scholar
  13. Chambers L.A., J.F.Milton and C.E. Cholak: A comparison of particulate loadings in the atmospheres of certain American cities. Paper presented at the Third National Air Pollution Symposium, Pasadena, California 1955Google Scholar
  14. Chambers, L.A., E.C. Tabor and M.J. Foter: The characteristics and distributions of organic substances in the air of some American cities. Paper presented at 48th Annual Meeting of the Air Pollution Control Association, Detroit, Michigan 1955Google Scholar
  15. Chan, H. K.: Activity-size relationship of fallout particles from two shots, operation redwing. U.S. Naval Radiological Defense Lab. Technical Report, USNRDL-TR-314, 1–71 (1959).Google Scholar
  16. Dobson, G. M. B.: Origin and distribution of the polyatomic molecules in the atmosphere. Proc. Roy. Soc. Lond. A 236, 187–193 (1956).ADSCrossRefGoogle Scholar
  17. Facy, L.: La capture des noyaux de condensation par choes moléculaires air cours des pro-cessus de condensation. Arch. Meteor. Geophys. u. Bioklim. A 8, 229–236 (1955).CrossRefGoogle Scholar
  18. Friedlander, S. K.: On the particle size spectrum of atmospheric aerosols. Paper submitted to the J. Meteorology I960.Google Scholar
  19. Georgii, H. W.: Ein Beitrag zum Größenverteilungsgesetz des atmosphärischen Aerosols über dem Kontinent. Meteor. Rdsch. 11, 33–34 (1958).Google Scholar
  20. Goel, P. S., N. Narasappaya, C. Prabhakara, Thor RAMA, and P. K. Zutshi: Study of cosmic ray produced short-lived isotopes P32, P33, Be7, and S35: in tropical latitudes. Tellus 11, 91–100 (1959).ADSCrossRefGoogle Scholar
  21. Haxel, O., u. G.Schumann: Selbstreinigung der Atmosphäre. Z. Physik 142, 127–132 (1955).ADSCrossRefGoogle Scholar
  22. Israël, H.: Radioactivity of the atmosphere. Compendium of meteorology. Amer. Met. Soc. 1951, P-155–161.Google Scholar
  23. Jacobi, W., A. Schraub, K. Aurand U. H. Muth: Über das Verhalten der Zerfallsprodukte des Radons in der Atmosphäre. Beitr. Phys. Atmosph. 31, 244–257 (1959).Google Scholar
  24. Jones, S.: Persönliche Mitteilung I960.Google Scholar
  25. Junge, C.E.: Austausch und großräumige Vertikalverteilung von Luftbeimengungen. Ann. Meteor. 380–392 (1952).Google Scholar
  26. Junge, C.E.: The size distribution and aging of natural aerosols as determined from electrical and optical data on the atmosphere. J. Meteorology 12, 13–25 (1955)CrossRefGoogle Scholar
  27. Junge, C.E.: Remarks about the size distribution of natural aerosols. In: Artificial stimulation of rain. New York: Pergamon Press 1957.Google Scholar
  28. Junge, C.E.: Recent investigations in air chemistry. Tellus 8, 127–139 (1956).ADSCrossRefGoogle Scholar
  29. Junge, C.E.: Air chemistry. Adv. Geophys. 4, 1–109 (1958).ADSCrossRefGoogle Scholar
  30. Junge, C.E.: Sulfur in the atmosphere. J. Geophys. Res. 65, 227–237 (I960).Google Scholar
  31. Junge, C.E.: C.W. Chagnon and J.E. Manson: Stratospheric aerosols. J. Meteorology (in Press I960).Google Scholar
  32. Junge, C.E.:, and J.E. Manson: Unpublished I960.Google Scholar
  33. Kalkstein, M.I., P.J. Drevinsky, E.A. Martell, C.W. Chagnon, J.E. Manson and C.E. JUNGE: Natural aerosols and nuclear debris studies, progress report II. GRD Research Notes No. 24, Geophysics Research Directorate, AF Cambridge Research Center, 1–36, Nov. 1959.Google Scholar
  34. Keefe, D., P.J.Nolan and T.A.Rich: Charge equilibrium in aerosols according to the Boltzmann law. Proc. Roy. Ir. Acad., Sect. A 60, No. 4, 27–450 (1959).Google Scholar
  35. Kientzler, C.F., A.B. Arons, D.C.Blanchard and A. H. Woodcock: Photographic investigation of the projection of droplets by bubbles bursting at a water surface. Tellus 6, 1–7 (1954).ADSCrossRefGoogle Scholar
  36. King, P., L.B. Lockhart, R.A. Baus, R.L. Patterson, H. Friedman and J.H. Blifford: RaD, RaE, and Po in the atmosphere. Nucleonics 14, 78–84 (1956).Google Scholar
  37. Kumai, M.: Electron-microscope study of snow-crystal nuclei. J. Meteorology 8, 151 (1951)CrossRefGoogle Scholar
  38. Lal, D.: Cosmic ray produced radioisotopes for studying the general circulation in the atmos-phere. Indian J. Meteor, and Geophys. 10, 147–154 (1959).Google Scholar
  39. Lal D., P. K. Malhorta and B. Peters: On the production of radioisotopes in the atmosphere by cosmic radiation and their application to meteorology. J. Atmosph. Terr. Phys. 12, 306–328 (1958).CrossRefGoogle Scholar
  40. Lassen, L.: Die Anlagerung von Zerfallsprodukten der natürlichen Emanation an elektrisch geladene Aerosole (Schwebstoffe). Z. Physik 163, 363–376 (1961).ADSCrossRefGoogle Scholar
  41. Lassen, L., U. G. Rau: Die Anlagerung radioaktiver Atome an Aerosole (Schwebstoffe). Z. Physik 160, 504–519 (1960).ADSCrossRefGoogle Scholar
  42. Lassen, L., u. H. Weicksel: Die Anlagerung radioaktiver Atome an Aerosole (Schwebstoffe) im Größenbereich 0,7–5 f (Radius). Z. Physik 161, 339–345 (1961).ADSCrossRefGoogle Scholar
  43. Lehmann, L., U. A. Sittkus: Bestimmung von Aerosolverweilzeiten aus dem RaD und RaF- Gehalt der atmosphärischen Luft und des Niederschlages. Naturwissenschaften 46, 9–10 (1959).ADSCrossRefGoogle Scholar
  44. Lodge, J.P., J.E. Mcdonald and F. Baer: An investigation of the Melander effect. J. Meteorology 11, 318–322 (1954).CrossRefGoogle Scholar
  45. Machta, L.: Symposium über Luftchemie und Radioaktivität, Helsinki, Aug. I960.Google Scholar
  46. Machta, L. and H.F. Lucas jr.: Radon in the upper atmosphere. Science 135, 296–299 (1962).ADSCrossRefGoogle Scholar
  47. Mason, B. J.: Bursting of air bubbles at the surface of sea water. Nature, Lond. 174, 470–471 (1954).ADSCrossRefGoogle Scholar
  48. Mason, B. J.: The oceans as source of cloud-forming nuclei. Geofis. pura e appl. 36, 148–155 (1957).ADSCrossRefGoogle Scholar
  49. May, R., U. H. Schneider: Verteilung der künstlichen Radioaktivität in Staubproben undRegenwasserrückständen. Atomkernenergie 4, 28–29 (1959).Google Scholar
  50. Metnieks, A. L.: The size spectrum of large and giant sea-salt nuclei under maritime conditions. Geophys. Bull. No. 15, School of Cosmic Physics, Dublin, 1–50 (1958).Google Scholar
  51. Mordy, W. A.: Computations of the growth by condensation of a population of cloud droplets Tellus 11, 16–44 (1959).Google Scholar
  52. Penndorf, R.: The vertical distribution of Mie particles in the troposphere. Geophysics Research Papers, No. 25, Geophysics Research Directorate, AF Cambridge Research Center 1954.Google Scholar
  53. Robbins, R.C., R.D. Cadle and D.L.Eckhardt: The conversion of sodium chloride to hydrogen chloride in the atmosphere. J. Meteorology 16, 53–56 (1959).CrossRefGoogle Scholar
  54. Rosinski, J., and J. Stockham: Preliminary studies of scavenging systems related to radioactive fallout. Summary Report ARF 3127–12, Armour Research Foundation, Chicago, 111. 1–51 (I960).Google Scholar
  55. Sagalyn, R.C., and G.A. Faucher: Aircraft investigation of the large ion content and conductivity of the atmosphere and their relation to meteorological factors. J. Atmosph. Terr. Phys. 5, 253–272 (1954).CrossRefGoogle Scholar
  56. Schumann, G.: Untersuchungen der Radioaktivität der Atmosphäre mit der Filtermethode. Arch. Meteor. Geophys. u. Bioklim. A 9, 204–223 (1956).CrossRefGoogle Scholar
  57. Sisefsky, J.: A method for photographic identification of microscopical radioactive particles. Brit. J. Appl. Phys. 10, 526–529 (1959)ADSCrossRefGoogle Scholar
  58. Sisefsky, J.: Autoradiographic and microscopic examination of nuclear-weapon debris particles. Fors- varets Forskningsaustalt, Stockholm, FOA 4 Rapport A 4130–456, 1–37 (I960).Google Scholar
  59. Stern, S.: The sampling of radioactive debris in the stratosphere. Paper presented at the A.M.S. Symposium on Stratospheric Meteorology, Minneapolis, Minnesota, July 1959.Google Scholar
  60. Stewart, K.: The condensation of a vapour to an assembly of droplets or particles (with particular reference to atomic explosion debris). Trans. Faraday Soc. 52, 161–173 (1956).CrossRefGoogle Scholar
  61. Stewart, N.G., R.N. Crooks and E.M.R. Fisher: The radiological dose to persons in the U.K. due to debris from nuclear test explosions. Report for the M.R.P. Committee on the medical aspects of nuclear radiation. A.E.R.E., Harwell, 1–22, June 1955.Google Scholar
  62. Strahlenschutz Nr. 12, Schriftenreihe des Bundesministeriums für Atomkernenergie und Wasserwirtschaft, S. 1–204. Braunschweig: Gersbach & Sohn 1959.Google Scholar
  63. Sumi, L., A. Corkery and J.L. Moukman: Calcium sulfate content of urban air. In: Atmospheric chemistry of chlorine and sulfur compounds. J. P. LODGE ed. American Geophysical Union No. 652, 69–80 (1959).Google Scholar
  64. Turner, J.S.: The salinity of rainfall as a function of drop size. Quart. J. Roy. Meteor. Soc. 81, 418–429 (1955).ADSCrossRefGoogle Scholar
  65. Twomey, S., and K.N. Mcmaster: The production of condensation nuclei by crystallizing salt particles. Tellus 7, 458–461 (1955).ADSCrossRefGoogle Scholar
  66. Volz, F.: Die Optik und Meteorologie der atmosphärischen Trübung. Ber. dtsch. Wetterd. US-Zone, No. 13, 2, 1–47 (1954).Google Scholar
  67. Wasson, J.: Persönliche Mitteilung I960.Google Scholar
  68. Wexler, H., L. Macuta, D.H.Pack and F.D. White: Atomic energy and meteorology. Intern. Conference Atomic Energy, vol. 13, p. 333–344 (1956).Google Scholar
  69. Whytlaw-Gray, R., and M.S.Patterson: Smoke: A study of aerial disperse systems. London: E. Arnold & Co. 1932.Google Scholar
  70. Wigand, A.: Die vertikale Verteilung der Kondensationskerne in der freien Atmosphäre. Ann. Phys. 59, 689 - 742 (1919).CrossRefGoogle Scholar
  71. Wilkening, M.H.: Natural radioactivity as a tracer in the sorting of aerosols according to mobility. Rev. Sei. Instrum. 23, 13–16 (1952).ADSCrossRefGoogle Scholar
  72. Woodcock, A.H.: Salt nuclei in marine air as a function of altitude and wind force. J. Meteorology 10, 362–371 (1953).CrossRefGoogle Scholar
  73. Zebel, G.: Zur Theorie der Koagulation elektrisch ungeladener Teilchen. Kolloid-Z. 156, 102–107 (1958).CrossRefGoogle Scholar

Copyright information

© Springer- Verlag OHG / Berlin · Göttingen · Heidelberg 1962

Authors and Affiliations

There are no affiliations available

Personalised recommendations