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 disorder and changes in peripheral blood flow. 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 decibels.
(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 economic and technical feasibility. 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) To reduce the noise of sound source, industry and transportation can choose low-noise production equipment and improve production technology, or change the motion mode of noise source (such as damping and vibration isolation to reduce the vibration of solid sound generator).
(2) Reduce the noise in the sound propagation path, control the noise propagation, change the noise propagation path that has been emitted by the sound source, such as taking measures such as sound absorption, sound insulation, sound barrier and vibration isolation, and rationally plan the layout of cities and buildings.
(3) When the noise protection of the receiver or the receiver fails to take measures in terms of sound source and transmission route, or the acoustic measures still fail to achieve the expected effect, it is necessary to take protective measures for the receiver or the receiver. For example, workers who have been exposed to occupational noise for a long time can wear ear protectors such as earplugs, earmuffs or helmets.
Although noise control is technically mature now, many enterprises and places adopt noise control because of the large scale of modern industry and transportation. Therefore, in the aspect of noise prevention, we must make a comprehensive balance from the aspects of technology, economy and effect. Of course, specific problems should be analyzed in detail. In outdoor, design room, workshop or places where employees work for a long time, the noise intensity should be low; Warehouses or workshops with few people or open places are slightly noisy. In a word, the treatment of noise should be different at different time, place, nature and duration.