Increased efficiency of production and improved quality have contributed to the development of ultrasonic technological applications, in which low frequency ultrasounds are generated to operate, accelerate as well as to facilitate technological processes. Technological ultrasonic devices (i.e. sources of ultrasonic noise in the work environment, e.g. ultrasonic washers, ultrasonic welding machines) have relatively high power and their nominal frequencies are in the range from 18 kHz to 40 kHz. In Poland, ultrasonic noise (defined as noise containing high audible and low ultrasonic frequencies from 10 kHz to 40 kHz) is included in the list of factors harmful to health in the work environment and therefore the admissible values of ultrasonic noise in the workplaces are established. The admissible values of ultrasonic noise and the new ultrasonic noise measurement method make it possible to perform the assessment of occupational risk related to ultrasonic noise. According to this method, the scope of the measurements includes the determination of the equivalent sound pressure levels in the 1/3 octave bands with the centre frequencies from 10 kHz to 40 kHz. This paper presents the description of both, i.e. the method for ultrasonic noise measurements and the method of the assessment of occupational risk related to ultrasonic noise. The examples of the results of the assessment of occupational risk related to exposure to ultrasonic noise are also discussed.
The constant growth of energy demand, as well as the accompanying increase in environmental pollution resulting from the prevailing use of fossil fuels, has led to a rising use of energy from renewable sources. The use of wind turbines to generate electricity has many obvious advantages, such as lack of fuel costs during operation and lack of harmful pollutants, including carbon dioxide. Despite advantages, the use of wind turbines constantly raises questions concerning the impact of wind farms on humans. This impact includes many factors related to the operation of wind farms, and in particular noise emitted by these farms. The wind turbine noise impact on humans has been studied by the Central Institute for Labour Protection - National Research Institute. A test bench to conduct noise annoyance tests of different types of wind turbine noise in laboratory conditions have been developed. During exposures to 6 different virtual acoustic environments, representing different wind turbine noise, 40 participants assessed wind turbine noise annoyance. The paper describes the results of the studies concerning the assessment of wind turbine noise annoyance.
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