Energy, Electrical and Electronic System Laboratory, Research and Training Unit of Physics, University of Yaoundé I- Cameroon, B.P. 812, Yaoundé, Cameroon.
Laboratory of Applied Physics, Department of Physics, Higher Teacher Training College Yaounde, University of Yaounde I - Cameroon, B.P. 47, Yaoundé, Cameroon.
Environ Monit Assess. 2019 Nov 21;191(12):765. doi: 10.1007/s10661-019-7940-z.
To be able to geographically map, model and evaluate noisy sound emissions from industrial motors, emphases have been laid on various phenomena linked to the propagation of sound waves and their effects on the environment. The failure to respect factory-servicing norms coupled with the depreciation of parts of an industrial motor lead to additional sound production, which due to an accumulation in acoustic power and pressure levels contributes to environmental noise pollution. In this work, a study has been carried out on environmental noise pollution from a thermal power plant in Cameroon, using empirical, diagrammatic, analytical and noise map elaboration methods, with the aim of proposing an optimal protection of the surroundings of the thermal plant from the noise pollution. The results obtained show a similarity in propagation of acoustic pressure and power levels for the different types of frequencies considered. Besides these, the study has revealed that the inhabitants are exposed to sound levels higher than the upper limit of 50 dB and above the alert threshold level of 80 dB. At the geo-localized motors of the plant, the primary sources of acoustic power levels were found to fall within the range from 60 to 98 dB, which is very close to the acoustic pressure levels of between 60 and 95 dB. Due to dispersion of sound, the acoustic power levels are also felt at different points around the plant, considered here as secondary sources. From a general point of view, the observed distribution of the iso-sound contours from the collected data and their general NE-SW orientations show the development of new sources due to cumulative effects and superposition of sound waves at regular intervals. At the same time, the acoustic power and pressure levels have been found to be higher than 80 dB, which is the threshold value for human hearing. This therefore is considered detrimental to human health and wellbeing, provoking the need for a more profound investigation on the existing correlation between levels of sound due to stationary sources and frequency in a high sound medium and elaborating a strategic noise map for the town of Mbalmayo and its environs.
为了能够对工业电机的噪声排放进行地理绘图、建模和评估，人们已经重点关注了与声波传播及其对环境影响有关的各种现象。未能遵守工厂维护规范，再加上工业电机部件的折旧，会导致额外的噪声产生，而由于声功率和声压级的积累，这会导致环境噪声污染。在这项工作中，我们对喀麦隆一座火力发电厂的环境噪声污染进行了研究，使用了经验、图表、分析和噪声图编制方法，目的是提出一个从噪声污染方面对火力发电厂周边环境进行最佳保护的方案。研究结果表明，不同类型的频率的声压和声功率水平的传播具有相似性。此外，研究还表明，居民们所暴露的噪声水平高于 50dB 的上限值和 80dB 的警报阈值。在工厂的地理定位电机处，发现声功率级的主要声源在 60 到 98dB 之间，这非常接近 60 到 95dB 的声压级。由于声音的分散，在工厂周围的不同位置也能感受到声功率级，这些位置被认为是二次声源。从总体上看，从收集的数据中观察到的等声线的分布及其大致的 NE-SW 方向，表明由于累积效应和声波的定期叠加，新的声源正在发展。同时，发现声功率和压力级高于 80dB，这是人类听力的阈值。因此，这被认为对人类健康和福祉有害，需要对固定声源和高频介质中声音的水平之间的现有相关性进行更深入的研究，并为姆巴尔马约镇及其周边地区编制一份战略噪声图。
