Traditional Rating of Noise Versus Physiological Costs of Sound Exposures to the Hearing (Biomedical and Health Research)

Description

In occupational safety and health acts, ordinances, regulations, directives, standards and guidelines, A-weighted sound exposures, varying in level and duration, are traditionally converted to an 8-hour-average sound level by applying the 3-dB exchange rate. Under the prerequisite that the energy equivalent rating level does not exceed 85 dB(A)/8 h, even impulse noise exposures of up to 140 dB are declared harmless. Indeed, the mutual settlement of level and duration based on the concept of energy equivalence is correct as far as sound energy or physical dose is concerned. However, between this principle and work physiological and work psychological, i.e. ergonomics paradigms, some decisive discrepancies do exist, and the dose maxim cannot be accepted from an ergonomics point of view. People react to exposures according to human characteristics rather than 'function' according to the laws of physics as they apply to inert matter. This has been demonstrated by a series of new experimental approaches, in which temporary threshold shifts and their restitution associated with various energy equivalent noise exposures have been measured. Also the impact of various types of loud music has been investigated. In addition to the conventionally determined maximum threshold shift, TTS2, and the time it takes to reach the resting hearing level again, the area under the restitution curve, i.e. the integrated restitution temporary threshold shifts, indicate the total physiological costs the hearing has to pay for a preceding sound exposure. Quite different statistically significant physiological responses to equally rated and legally tolerated sound exposures (94 dB(A)/1 h / 85 dB(A)/8 h) have repeatedly been measured. These refute the concept of energy-equivalence along virtually all dimensions, for example, substantially underestimating the risk of impulse noise, legalizing the 'filling' of resting periods with noise, ignoring the fact that short-term, high continuous noise is even quite favourable for the hearing, or prognosticating drastic losses in attenuation after short time periods of not wearing hearing protective devices, making them sound worse than they are. This book is an attempt to increase the transparency in existing evaluation methods and - in the interest of pertinent disclosure of risks associated with common procedures - to work towards the elimination of unacceptable simplifications and dangerously erroneous assessments.IOS Press is an international science, technical and medical publisher of high-quality books for academics, scientists, and professionals in all fields. Some of the areas we publish in: -Biomedicine -Oncology -Artificial intelligence -Databases and information systems -Maritime engineering -Nanotechnology -Geoengineering -All aspects of physics -E-governance -E-commerce -The knowledge economy -Urban studies -Arms control -Understanding and responding to terrorism -Medical informatics -Computer Sciences