Noise exposure--sampling strategy and risk assessment.

Noise exposure surveys are performed to assess risk of hearing loss. Because of the large populations that are usually involved, there is a need for a sampling procedure that will ensure statistically significant results. After the survey has been performed, the risk has to be assessed in a meaningful manner so that management can easily evaluate the situation. In this study noise exposure levels were found to be normally distributed. As a result, the NIOSH sampling method could be applied for noise exposure surveys. Furthermore, it is shown how different degrees of risk can be assessed as the percentage of workers with exposure lower than 85 dBA, higher than 90 dBA or between 85 and 90 dBA. A numerical example in the Appendix shows how the procedure is applied in a practical situation.