Sound above 75 decibels is harmful to human body! Noise (1) A sound whose tone and sound intensity change out of order, which sounds disharmonious. It is produced by the irregular vibration of the pronunciation body. From a physical point of view, noise is the sound made when the pronunciation body vibrates irregularly. Generally refers to noisy and harsh sounds. From the point of view of environmental protection, any sound that interferes with people's normal rest, study and work, as well as the sound that interferes with people's listening, belongs to noise, which is a kind of sound that causes people's irritability or is too loud and harms human health. Noise pollution mainly comes from social noise such as traffic, vehicle horn, industrial noise, building construction, concert hall, tweeter, morning market and people talking loudly. Noise is the sound that the body makes when it does something irregular. The physical and psychological harm of noise mainly includes the following aspects: the damage to hearing. Experiments have shown that people's hearing will be impaired after 8 hours of continuous listening to motorcycle sounds; If you are in a rock concert hall, your hearing will be impaired in half an hour. It is harmful to people's cardiovascular system. According to the survey of urban noise and residents' health in China, the incidence of hypertension increases by 3% for every increase of 1 decibel in regional noise. It affects people's nervous system and makes them irritable. Affect sleep and cause fatigue. From the perspective of psychoacoustics, noise, also known as noise, generally refers to inappropriate or uncomfortable auditory stimulation. It is a compound sound with many frequencies and aperiodic vibration. In short, noise is an aperiodic sound vibration. Its sound wave shape is irregular and it sounds harsh. From the social and psychological point of view, any sound that interferes with people's study, work and rest and makes people feel uncomfortable is called noise. For example, the sound of running water, knocking, rustling and the roar of machines are all noises. It is measured in decibels. Zero decibel is the lowest intensity of audible sound. Noise can be divided into high intensity and low intensity. Low-intensity noise is generally harmless to people's physical and mental health, and it is also beneficial to improve work efficiency in many cases. High intensity noise mainly comes from industrial machines (such as looms, lathes, air compressors, pickaxes, blowers, etc.). Modern means of transportation (such as cars, trains, motorcycles, tractors, airplanes, etc.). ), loudspeakers, noise generated by construction sites, shopping malls, sports and entertainment places, etc. These high-intensity noises do harm to people's health, make people feel tired, produce negative emotions and even cause diseases. High-intensity noise not only damages people's hearing, but also affects the nervous system, cardiovascular system, endocrine system, digestive system, vision and intelligence to varying degrees. If people work and live in a noise environment of 95 decibels for a long time, about 29% people will lose their hearing; Even if the noise is only 85 decibels, 10% people will be deaf; 120~ 130 db noise can make people feel ear pain; Strong noise will damage the hearing organs. In the nervous system, strong noise can cause headache, dizziness, burnout, insomnia, emotional anxiety, memory loss, increased EEG slow waves, autonomic nervous system dysfunction and other symptoms. In the cardiovascular system, strong noise will cause changes in pulse and heart rate, elevated blood pressure, arrhythmia, conduction block, changes in peripheral blood flow and so on. In the endocrine system, strong noise will cause hyperthyroidism, adrenal cortex function enhancement, basal metabolic rate increase, sexual dysfunction, menstrual disorder and so on; In the digestive system, strong noise will cause digestive dysfunction, gastric dysfunction, gastric acid reduction, loss of appetite and so on. In a word, strong noise will lead to a series of physiological and pathological changes in human body. Someone once investigated 202 people who worked in an environment with noise as high as 95 decibels. The results show that 39% of them are dizzy, 32% suffer from insomnia, 27% have a headache, 27% have a stomachache, 27% are flustered, 27% have poor memory, 22% are upset, 65,438+08% have anorexia and 65,438+have high blood pressure. Therefore, we should not take strong noise for granted, and take measures to prevent it. Of course, people are sensitive to noise, and there are great differences among individuals. Some people are sensitive to noise, and some people have strong adaptability to noise, which is also related to psychological factors such as people's needs and emotions. No matter how different people are, strong noise always needs to be prevented. In order to prevent noise, Professor Ma, a famous Chinese vocalist, summarized and studied the hazards and standards of various noises at home and abroad, and put forward three suggestions: (1) In order to protect people's hearing and health, the allowable value of noise is 75~90 dB. (2) Ensure conversation and communication, and the allowable value of environmental noise is 45~60 decibels. (3) It is recommended to sleep at 35~50 decibels. Psychologists in China believe that the control of noise environment should not only consider human factors, but also consider the feasibility of economy and technology. Adequate noise control must consider the whole system composed of noise source, sound propagation mode and sound receiver. Noise control measures can be aimed at the above three parts or any of them. The contents of noise control include: (1) reducing sound source noise. Industry and transportation industry can choose low-noise production equipment and improve production technology, or change the motion mode of noise source (such as reducing the vibration of solid sound generator through damping and vibration isolation). (2
Which sounds are sometimes harmful and sometimes beneficial to the human body?