—= -* Ne an hee “ : es ~ . 7 4 wd fe one, it was recommended in the January 20, 1954 meeting to strike from the record the past recommendations for maximum permissible air concentrations, It was recermended thet an sir monitor’ng program be continued for documentery may mt 8 meee oe purposes end for whetever velue tho Gata inicht have in the future vien new In RpaRRaELe apie apagee HH rn SE agaioe era4 arriving at the recommendation “4. nor is it desirable that any individual particle in this size range have activity greater than 10° microcuries cal- an A further discussion of the single particle problem may be made, Ce analyses might be made in the light of additional Imovwledge. culated four hours efter the blast" a computation was made that the averag redietion dose from such a perticle to a sphere one-half a milliuster in radius vould be 325 reps.* However, ths conclusions may be mislonding. In the ccse of a single particle, relutively large doses are delivered necr the porticle and smcll doses ata grerter di:tsnce. a> possible estimete of this phenerenon. many and citricult to evaluate. Pants Appendix L susrests The parameters involved hers sie For oxannic, how long will a particle romain in one place in the lung and what dera will be delivered during tht t272? It has been sugzested** that in the uprir reepiratory passage 20-mieron diameter particles are the upper linit of size for deposition and thet "Cilia sweep 4 to 6 cycles per second. The protability of a particle rezaining within one millimeter sone fer as much as cno~half hour seppears to be vanishing small, eee Protection will also te provided by the mucus lining e Accepting the estizates above and the methods illustrated in appendices E and F, it may be computed that about 8 reps would be delivered to the surface of an imaginary stationary sphere one millimeter in radius by a 20-micron particle (0.5 *Minutes, Meeting of Committee to Consider the Feasibility and Conditions For A Preliminary Radiologic Safety Shot for Jangle. LASL. May 21-22, 1951. **HW-33068, A status report. Sept. 15, 1954. (CONFIDENTIAL), 51 | wit ae mee wae ce ee I a which is itself renewed several times ean hour." _ = ey Hel Rees peanriAiuto RETGSO op hagHESPERIA GRRanapa RE ee otae a eate gem indicates that the external gamma hazerd is more limiting than the inhalation