Identification of the minimum noise level capable of producing an asymptotic temporary threshold shift
Stephenson, M.R.; Nixon, C.W.; Johnson, D.L.
Aviation Space and Environmental Medicine 51(4): 391-396
1980
ISSN/ISBN: 0095-6562 PMID: 7369977 Document Number: 155556
The minimum noise level capable of producing an asymptotic temporary threshold shift (ATTS) was studied. At some level below 85 dBA, probably 70-80 dBA, an exposure level apparently exists where no ATTS would occur. If a long-duration noise does not produce temporary changes in hearing levels, then it would not produce permanent changes. This level would define an exposure condition below which personnel could be exposed for indefinite periods of time without adverse auditory effects. Subjects were exposed to continuous pink noise for 24 h at levels of 65, 70, 75, 80 and 85 dBA. TTS growth and recovery was measured at specific intervals throughout each condition. At the most sensitive frequency (4000 Hz), the ATTS threshold level was in the region of 75-80 dBA.