Materials and Methods
We assessed hearing impairment in a large wagon
manufacturing factory in the capital of Iran in 2007 by a
cross-sectional and descriptive-analytic study.
A team of occupational hygienist working in Health and Safety
Executive (HSE) managed noise monitoring. Digital Sound
level meter (EXAIR, model 9104) was placed in 25 various
stations according to ISO 1999. In this study, after measuring
sound level in different parts of the factory, areas with high
levels of noise were selected; eventually five areas of the
factory with the highest levels of noise were selected as noisy
areas. Minimum and maximum noise levels at different stations
of these five parts were 88 dBA and 96dBA, respectively (The
8 h time weighted averaged means = 91 dBA).