Document B8mnbJa5we7zjJj6Ep5Qy5RBE

v.y.>r is m *1 ..vl IV * Wi . ijtl V \ -.' t COMPARISON OF- 1MPWGEB AND MEMBRilNE^^ v^'v-A. study. (if t FILTER TECHNIQUES FOR EV/flAJATINC_ AIR SAMPLES,.',,j : ^beingcartledL^cs Julius H. Fantiey l^jyH^th-Servic*.' ^-..Department*. T " ? ;.(: ''.; Divttion of Occupational Hbolth, Public Health Service Department of Health, Education and Welfare ' " Cincinnati, Ohio if;membrane filter :J^'elze and other cl only one aspect ^sampling to fibc ijyicioMcopq 6bje. __ ^ft'ahpuld 1ee ^'v-Although data' had'been pre*ent*d[ by. a- number of otheF'aiithors^Sv Ji^-plnger counts a ; the more definitive studies of hesith hazards in the United States asbestos ''' being proposed industry are probably those of the Pennsylvania Department of Labor presented, rath* and Industry in 1936* and the U. S. Public Health Service and the .^ort^'Iplnger. count* t< Carolina State Board of Health In 1987.* These studU*'\bf-aati<wfi^>lMr{i`,1jK&'<dicatloc' of th i correlated exposure to asbestos dust with the incidence of asbeatosis amonf y ... membrane filter.workers. The exposure was evaluated by the same instruments and methods f ' of better infom used in studies of other dusty trades (e.g., granite finishing, cement manu facturing).1 The sampling instrument used was the Greenburg-Smith .dust exposure. impinger, and samples obtained were counted in the sampling liquid using a 1 mm. deep counting cell, allowing the particles to settle for at least 20 minutes and counting the settled particles with a microscope equipped with a 13 mm. lOx objective. In the studies which correlated dust exposure with ssbestosis it was found that the incidence and severity of asbestosii Impinpm The impinger in siiicosiR-prodi of quartz and i increased with increasing dust exposure, and that those workers exposed to dust concentrations of less than 6 million particles per cubic fo*ot larger. The aaac objective to ; (mppcf) did not develop asbeatosis even after long-continued exposure Because epidemiologic studies In the U. S. are based on the impinger method, this method has been adopted as a standard by those concerned with prevention of aabestosia. Using the impinger to evaluate effectiveness of environmental controls, it hss been possible to notably reduce the inci dence and aeverity of asbestosia. or 1 mm. depth -' ' " minimum size. * eKscntialiy the s *tquently-by th- . glenists.V the A [Textile Institut, In Great Britain a customary procedure In monitoring air in asbestos sampling mediu: processing plants has been to count only the fibers collected in air samples. ! may be used. In The thermal precipitator, Owens jet sampler and other instruments have f . at -the sampling been used for sampling, but the moat common air sampling method at th* / I plnger. When 0 present time is probably membrane filtration. After aampllng, the filter is ' . , plants, few a*be treated to render It transparent, and fiber* ore counted using a microscope j-. 'doubtedly been equlp|Kxl with a 2 mm. or d mm. objective. Fiber concentration* determined by-these methods have not been compared to crltoria developed in the . ts> when all particle as fibers, the fib- U.R.A.. because these fiber-counting methods do not yield results directly plnger dust cou> comparable tu those obtained b.v the impinger sampling and counting method. I- methods .reveal dlamoter --7 hund 9000 0994 -fci.. SCF-FA-0030 PRODUCED BY FORD