Document np5bQbeZKEvMrzOVjrbojg4e6

Mr. E. H. Fcierabend -2- March 11, 1376 of their size and aerodynamic characteristics, and remain suspended indefinitely. The Ht. Sinai representatives stated that they have regularly been finding street level concentra tions of from 1 to 100 fibers per cubic centimeter. Ac a comparison, the tentative ambient Mr quality criteria proposed by the SPA is .04 fibers per cubic centimeter. They were emphatic In their assertions that braking systems which they have investigated to date do not readily convert all the asbestos through dehydroicylatton to forBterite. They claim that micron and subraieron particles are readily detectable both under laboratory and street conditions. This would suggest braking surface temperatures of around 500C or below. This is counter to previous research which has revealed light braking temperatures of 300-900 C and heavy braking temperatures of 1700-1S00C. Although I have not yet been able to confirm their assertion, it appears that the Federal Government has extended a large grant to Mt. Sinai with which to complete their dausati.o study of cancer induction by asbestos, with the grant, Mt Sinai has recruited researchers from a wide variety of dis ciplines to concentrate their efforts to this end. This not only includes medical research teams, but environmentalists as well to document the pervasiveness of the problem. - They are also very aware of the problems associated with the use of baghousas for asbestos collection purposes. The state ment was made that they have observed high levels of submicron particles in the vicinity of asbestos manufacturing plants utilizing these systems. The explanation is as follows. When considering baghouse efficiency on a weight basis, it is relatively easy to get high efficiency with particles whose size is in excess of 5 microns. However, efficiency falls off with a decrease in particle size, and apparent high effi ciencies are much less meaningful, in terms of numbers of fibers. It can be assumed that 103 average fibers of asbestos weigh approximately 1 nanogram. If 1 gram cf asbestos material approaches a baghouse filter rated even as high as 09.999% efficiency, then the quantity passing through will be 0.00001 grams or 10^ nanograras. And since 1 nanogram is approximately ogual tc 10^ fibers, then a total of 107 (10 million) fibers will pass through the filter for every 1 gram SPNY 006290