Tiếng ồn và âm thanh biến động áp lực âm thanh trong không khí. Cả hai đều là đặc trưng bởi mức độ âm thanh trong decibel và nội dung tần số hertz. Mặc dù âm thanh là quan trọng đối với truyền thông, tiếng ồn là một trong những vấn đề lớn nhất của chúng tôi. Cố ý tạo ra tín hiệu âm thanh bao gồm cả lời nói và âm nhạc thường được gọi là âm thanh. Tiếng ồn là một thuật ngữ được sử dụng để xác định âm thanh không mong muốn, bao gồm cả âm. | NOISE Noise and sound refer to audible pressure fluctuations in air. Both are characterized by sound level in decibels and frequency content in hertz. Although sound is vital for communication noise is one of our greatest problems. Intentionally generated acoustic signals including speech and music are usually referred to as sound. Noise is a term used to identify unwanted sound including sound generated as a byproduct of other activities such as transportation and industrial operations. Intrusive sound including speech and music unwelcome to the hearer are also considered noise. Thus the distinction between noise and sound is subjective and the two terms are often used interchangeably. When a body moves through a medium or vibrates some energy is transferred to that surrounding medium in the form of sound waves. Sound is also produced by turbulence in air and other fluids and by fluids moving past stationary bodies. In general gases solids and liquids transmit sound. Well-documented effects of noise include hearing damage interference with communication masking of warning signals sleep interruption and annoyance. Noise detracts from the quality of life and the environment it contributes to anger and frustration and has been implicated as a contributor to psychological and physiological problems. The National Institute for Occupational Safety and Health NIOSH named hearing loss as a priority research area noting that noise-induced hearing loss is 100 preventable but once acquired it is permanent and irreversible. The Occupational Safety and Health Administration OSHA noted that hearing loss can result in a serious disability and put employees at risk of being injured on the job. The World Health Organization WHO notes that noise-induced hearing impairment is the most prevalent irreversible occupational hazard and estimates that 120 million people worldwide have disabling hearing difficulties. In developing countries not only occupational noise but also .
