Extrapolation of experimental field study to a national occupational noise exposure standard

ABSTRACT

Proposing a Noise Standards should be considered seriously by the governmental authorities because of the prevalence of hazardous noise exposure and the seriousness of the effects. In a survey founded by World Health Organization's regional office in Iran, the existing as well as gathered data from field were applied to propose a National Occupational Noise Exposure Limit. The collected data plus the existing data were processed to propose a national occupational noise exposure limit and depict the major restrictions in application of existing field data in proposing a national occupational noise exposure limit. Results obtained from the present study shows that the occupational noise levels of 90 to 95 dBA can lead to hearing losses greater than 25 dBA. It was shown that occupational noise levels of 85 to 90 dBA would not lead to hearing losses greater than 20 dBA. The comparison of hearing losses shows that the noise levels of less than 80 dBA will not lead to any significant hearing loss. It was deduced that 85 dBA can be recommended for a national occupational noise limit in Iran. The study also showed that the application of existing field data to recommend a national occupational noise standard may have some restrictions