Department of Global Public Health and Primary Care, Centre for International Health, University of Bergen, Bergen, Norway.
Department of Environmental and Occupational Health, Muhimbili University of Health and Allied Sciences, Dar es salaam, Tanzania.
Ann Work Expo Health. 2018 Nov 12;62(9):1109-1122. doi: 10.1093/annweh/wxy071.
Machines, processes, and tasks in the iron and steel factories may produce noise levels that are harmful to hearing if not properly controlled. Studies documenting noise exposure levels and related determinants in sub-Saharan Africa, including Tanzania are lacking. The aim of this study was to document noise exposure and to identify determinants of noise exposure with a view to establishing an effective hearing conservation programme.
A walk-through survey was conducted to describe the working environment in terms of noise sources in four metal factories (A-D) in Tanzania. Noise measurements were conducted by both personal, full-shift noise measurements (8 h) using dosimeters and area measurements (10-s measurements) using a sound level meter. A total of 163 participants had repeated personal noise measurements (Factory A: 46 participants, B: 43, C: 34, and D: 40). Workers were randomly selected and categorized into 13 exposure groups according to their job. Linear mixed effects models were used to identify significant determinants of noise exposure in the furnace section and the rolling mill section.
The average personal noise exposure in the four factories was 92.0 dB(A) (range of job group means; 85.4-96.2 dB(A)) (n = 326). Personal exposure was significantly higher in the rolling mill section (93.0 dB(A)) than in the furnace section (89.6 dB(A)). Among the job groups, the cutters located in the rolling mill section had the highest noise exposure (96.2 dB(A)). In the furnace section, furnace installation (below the ground floor), manual handling of raw materials/billets/crowbars, and billet weighing/transfer were significant determinants explaining 40% of the total variance in personal noise exposure. In the rolling mill section, the size of the cutting machine, steel billet weight and feeding re-heating furnace explained 46% of the total variance in personal noise exposure. The mean noise level of the area measurements was 90.5 dB(A) (n = 376).
Workers in the four iron and steel factories in Tanzania were exposed to average noise of 92.0 dB(A), without using hearing protection, implying a high risk of developing hearing loss. Task and factory level determinants were identified in the furnace and the rolling mill sections of the plant, which can inform noise control in factories with similar characteristics.
如果钢铁厂的机器、流程和任务没有得到适当控制，可能会产生危害听力的噪声水平。缺乏记录撒哈拉以南非洲（包括坦桑尼亚）噪声暴露水平和相关决定因素的研究。本研究的目的是记录噪声暴露情况，并确定噪声暴露的决定因素，以期建立有效的听力保护计划。
进行了一次步行调查，以描述坦桑尼亚四家金属厂（A-D）的工作环境中的噪声源。噪声测量是通过个人、全班噪声测量（使用剂量计进行 8 小时）和区域测量（使用声级计进行 10 秒测量）进行的。共有 163 名工人接受了重复的个人噪声测量（工厂 A：46 名参与者，B：43 名，C：34 名，D：40 名）。工人是随机选择的，并根据其工作分为 13 个暴露组。线性混合效应模型用于确定炉区和轧机区噪声暴露的显著决定因素。
四家工厂的平均个人噪声暴露量为 92.0 dB(A)（各作业组平均值范围；85.4-96.2 dB(A))(n=326)。轧机区的个人暴露量（93.0 dB(A))明显高于炉区（89.6 dB(A))。在作业组中，位于轧机区的刀具工人噪声暴露量最高（96.2 dB(A))。在炉区，炉体安装（低于底层）、原材料/钢坯/撬杠的手动搬运以及钢坯称重/转运是个人噪声暴露总方差的 40%的显著决定因素。在轧机区，切割机器的大小、钢坯的重量和喂入再加热炉解释了个人噪声暴露总方差的 46%。区域测量的平均噪声水平为 90.5 dB(A)(n=376)。
坦桑尼亚四家钢铁厂的工人暴露在平均噪声为 92.0 dB(A)的环境中，没有使用听力保护设备，这意味着他们有很高的听力损失风险。在工厂的炉区和轧机区确定了任务和工厂层面的决定因素，这可以为具有类似特点的工厂的噪声控制提供信息。
