Environmental Engineering
S. Sinworn; N. Viriyawattana
Abstract
BACKGROUND AND OBJECTIVES: The fishery workers are affected by the noise produced by motorboats, which is caused by long-term (more than 7 hours per day), exposure to high frequencies and hazardous noise levels. The detrimental impact of the loud noise emitted by small boat engines affects the hearing ...
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BACKGROUND AND OBJECTIVES: The fishery workers are affected by the noise produced by motorboats, which is caused by long-term (more than 7 hours per day), exposure to high frequencies and hazardous noise levels. The detrimental impact of the loud noise emitted by small boat engines affects the hearing abilities of fishermen in Thailand has been well-documented. In light of this, the primary aim of the present study was to assess the potential hazards associated with noise exposure and develop an effective silencer that can effectively mitigate the noise generated by fishing boats. The study was conducted in Songkhla Lake, located in Thailand, providing a suitable setting for the current study.METHODS: During an 8-hour work period, 300 sample fishers were monitored using sound-level and noise-dose meters. Their response to noise was evaluated through an audiometry test and a questionnaire. Furthermore, a silencer was engineered to decrease the noise emissions from boat engines. Utilizing the solid work technique, the exhaust silencer was designed based on a model of the internal exhaust pressure. The sound level at the end of the exhaust silencer pipe was determined by employing a sound meter and recording it at a speed of 4,000 revolutions per minute. The designed silencer was installed on the exhaust pipe of the boat engine to align with the current operation of the engine. The objective was to measure the variation in noise levels before and after the installation of the silencer. The sound level meter of type I, equipped with a weighted circuit incorporating an A network (weight A), closely resembles the auditory response of the human ear to sound. Prior to assessing the noise produced by the engine, it was ensured that the engine had been running for a minimum of 5 minutes. The sound level of the small boat's engine was then measured using a type I sound-level meter positioned at a 45-degree angle behind the engine, and at a distance of 0.5 meter.FINDINGS: The results indicated that evaluating the risks associated with being exposed to high levels of noise from boat engines had an impact on the auditory capacity of fishermen. The right ear was more severely damaged than the left at frequencies of 6,000 (23 people) and 8,000 (20 people) Hertz at sound levels of 85 decibels A and above. This data is valuable for the development of a silencer aimed at mitigating sound pressure levels that impact the loudness of sound across different frequency levels, considering a boat engine's maximum acceleration of 4,000 revolutions per minute through the application of solid design principles. Subsequently, the silencer will be tested on Thai fishermen who are regularly exposed to noise, demonstrating a reduction in engine noise of over 23 decibels A within the frequency range of 100 to 10,000 Hertz.CONCLUSION: The auditory abilities of fishermen are adversely impacted by the intensity and high pitch of the noise emitted by small boat engines. The solid design technique is employed to create a silencer for a boat engine with a maximum acceleration of 4000 revolutions per minute, operating at frequency levels of 2000, 3,000, 4,000, 6,000, and 8,000 Hertz. Exposure to loud noise can pose a significant risk to the hearing health of fishermen. However, their safety can be ensured by implementing effective measures to reduce the loudness by more than 23-42 decibel A. By employing such work practices, the noise levels experienced by fishermen can be kept below the hazardous threshold of > 85 decibels A.
Environmental Engineering
N. Robinah; A. Safiki; O. Thomas; B. Annette
Abstract
BACKGROUND AND OBJECTIVES: The effect of infrastructure equipment is taking a toll on the health and economic well-being of residents all around the world. This is mainly because it contributes to ambient air pollution, noise, and vibration in the surroundings. The study aimed at analyzing the ...
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BACKGROUND AND OBJECTIVES: The effect of infrastructure equipment is taking a toll on the health and economic well-being of residents all around the world. This is mainly because it contributes to ambient air pollution, noise, and vibration in the surroundings. The study aimed at analyzing the effects of the road infrastructure equipment on the surroundings in Uganda. The emissions of carbon dioxide, carbon monoxide, nitrogen dioxide, hydrocarbons, and particulate matter were analyzed.METHODS: Six road infrastructure equipment were sampled consisting of an excavator, roller, grader, concrete mixer, tamper, and wheel loader, obtained from a case study project in Kampala city, Uganda. The diesel exhaust air emissions were computed and analyzed using the emissions rate equation model for non-road equipment, developed by Environmental Protection Agency. This was based on the horsepower and power rating of the equipment. Noise and vibrations levels were obtained using a sound level meter, seismometers, and accelerators, while following the National Environment Regulations.FINDINGS: The greenhouse gas of carbon dioxide was the most predominant accounting for 84.1 percent of the total emissions. The grader was the highest emitter of this greenhouse gas, at 1,531.5 g/h, representing 37.1%. The lowest air pollutant emission was nitrogen dioxide at 1.43 g/h for the concrete mixer, representing 1.4%. Overall, the equipment emitted more greenhouse gases than air criteria pollutants at 88.8% and 11.2% respectively. The highest criteria air pollutant was particulate matter at 100.5 g/h, emitted by the grader. Most of the emissions met the standards stipulated by Environmental Protection Agency, for reducing emissions back to the environment, except particulate matter. However, the concentrations of some pollutants like carbon monoxide and nitrogen dioxide did not satisfy the limits required for ambient air quality that is safe for workers. All the equipment had noise levels way above the recommended 70.00 decibel, except for the wheel loader. Only the excavator produced vibrations higher than permissible vibration limit by 4%.CONCLUSION: The criteria air pollutants of carbon monoxide, nitrogen dioxide, and particulate matter emitted by the equipment were all not safe to the workers. They exceeded the permissible limits of 50 ppm, 5 ppm, and 0.02 g/kW/h respectively. This partly shows why ambient air pollution had been reported in urban centers in Uganda. The study shows the need for strengthening the regulations and monitoring of the construction equipment being used, in order to protect the surroundings.
