Levels and influencing factors of noise pollution from small-scale industries (SSIs) in a developing country.

A study was carried out to determine levels and factors that influence noise pollution from small-scale industries (SSIs) in Dar es Salaam City Tanzania. Two sites for wood- and metalworks industries were investigated. Both sites exhibited equivalent noise levels higher than 90.0 dBA, the permissible exposure level limit for occupational noise. At a woodworks SSI, noise levels were found to correlate well with machine-use age, wood-feed speed, and wood-cut depth. Additionally, noise emanating from both types of SSIs was found to influence the level of environmental noise in the neighborhood of the SSIs. One woodworks SSI was found to have a circle of influence of about 140 m. The study concluded that SSIs present a serious source of environmental noise pollution in their neighborhoods. Noise pollution from SSIs is greatly influenced by the type of SSIs and the activities they carry out, the type and age of machines they use, their location relative to residential areas in their vicinity, and in-house noise control measures.