wn methods of estimating gamma doses anc sinoe there are uncertainties in evaluating the hasards of such transitory air concentrations es from fallout, ani experieneed sinee the preponderance of evidence from pest suelear test series indicates that the external gamca hazard is more limiting than the inhalation one, it was recommended in the January 2C, 1954 meeting to strike from the record the past reeomendiations for maxizun permissible air concentrations. I[t was recommende: thet an air monitoring program be continued for documentary surposes and for whatever value the data might have in the future uben new analyses aight be sade in the light of additional knowledge. 4 further discussion of toe single article problem may be sade. In arriving st the reeommencetion '.. user ta kt deatrable that any indivie Cin, particle in this s.se range have activity greater than Lo™* eieroeuries celicuiated four hours after the bliast” «a computation vas asde that the arer- age radiation dose from such a particle to e« sphere one-half a aillineter in raciuz would be 3c* reps.* However, the conclusions may be misleading, in the sage of a singie ,artiele, relativeiy large doves are delivered near the particle anc smal’ doses at a greater distance. one }ousible estimate of tris nhenomenon. many and diffieuls to evaluate Appendix | suggests fhe parameters involved here are Por examjle, how long will a particle remain in one place in the lung and what doce wil. be delivered during that tine? It has been suggested** that 4: the sapper respiratory passage 2O—mteron dianeter particles are the upper linit of aise for deposition and that "Cilia #.inutes, Meeting of Committee to Consider the Peastbility and Conditions For a Preliminary Radiologie »cafsty shot for Jangle. iL.a.3.L. May 21 and 22, 1951, 84H 4233060, A status report. Sept 16, 195. CONFIDENTIAL; .