Knowledge of noise pollution, noise pollution and its hazards

Noise is the sound emitted when the emitter vibrates irregularly. It is a general term for those sounds that are particularly chaotic and unpleasant to the ear and dissonant. Noise above 140 decibels can cause physical discomfort, damage people's hearing in severe cases, and even induce a variety of diseases.

So make as little noise as possible.

1) Traffic noise includes the noise of motor vehicles, ships, subways, trains, airplanes, etc. Due to the rapid increase in the number of motor vehicles, traffic noise has become the main source of noise in cities.

2) Industrial noise: Noise generated by various equipment in the factory. Industrial noise levels are generally high, which has a greater impact on workers and surrounding residents.

3) Construction noise is mainly the noise emitted by construction machinery. Construction noise is characterized by high intensity, and most of them occur in densely populated areas, so it seriously affects the rest and life of residents.

4) Social noise includes the noise emitted by people's social activities and household appliances and audio equipment. Although the noise level of these devices is not high, because of their close connection with people's daily life, people cannot be quiet when resting, which is particularly annoying and easy to cause neighborhood disputes.

Classification: Noise pollution can be divided into noise caused by gas disturbance, noise generated by solid vibration, noise generated by liquid impact and electromagnetic noise generated by electromagnetic action according to the mechanical characteristics of the sound source.

According to the frequency of sound, the noise can be divided into: < 400Hz low-frequency noise, 400 1000Hz medium-frequency noise and 1000Hz high-frequency noise.

Characteristics: Noise is not only a public nuisance, it has the characteristics of public pollution, but also as a kind of sound, it also has acoustic characteristics.

1) Pollution characteristics of noise.

Since noise is a sensory nuisance, it is different from other harmful and toxic substances. First of all, it has no pollutants, that is, the noise does not leave any toxic substances in the surrounding environment when it travels through the air; Secondly, the impact of noise on the environment is not cumulative and long-lasting, and the distance of propagation is also limited; The noise source is dispersed, and once the sound source stops sounding, the noise disappears. Therefore, noise cannot be processed centrally and needs to be controlled in a special way.

2) Acoustic characteristics of noise.

To put it simply, noise is sound, and it has all the characteristics and laws of acoustics. However, the impact of noise on the environment is related to its strength, and the stronger the noise, the greater the impact. The physical quantity that measures the intensity of noise is the noise level.

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The harm of noise is mainly manifested in: disturbing sleep, impairing hearing, affecting human physiology and the development of children and fetuses.

Experiments have shown that noise can cause the body's nervous response ** adrephrin secretion, which causes heart rate changes and blood pressure rises, so some people believe that noise in life is an important reason for the worsening of heart disease and the increase in incidence; Relevant studies have pointed out that noise will reduce the secretion of saliva and gastric juice and reduce gastric acid, which will make people prone to ulcers and duodenal ulcers, and the incidence of ulcers in some noisy industrial enterprises is 5 times higher than that in quiet environments; Noise has an effect on a person's endocrine function.

In addition, noise causes damage to animals and buildings. For example, strong noise will cause birds to shed their feathers, not lay eggs, and even bleed internally, and eventually die. In the 50s, there were reports of a high-speed airplane flying at a low altitude of 60 meters, and the noise caused damage to a building on the ground. 

1) Traffic noise. From various means of transportation such as cars, trains, airplanes, etc., with the increase of urban vehicles, urban traffic noise will also become more and more serious. Among the current traffic noise in China's cities, the most serious is honking. 

2) Factory noise. Factory noise not only directly harms production workers, but also has a significant impact on nearby residents. Among the industrial noise, the noise of the general electronics industry and light industry is below 90 decibels, the noise of textile factories is between 90 and 100 decibels, and the machinery industry is between 8 0 and 120 decibels, and industrial noise is the main cause of occupational deafness.

3) Construction noise. During the construction of houses and roads, all kinds of construction machinery and transport vehicles produce noise, which is very disturbing to the surrounding residents. 

4) Social noise. Noise from social activities and family life is also widespread, such as noise from entertainment venues, stations, vegetable markets, schools, etc. There are stereos, TVs, etc. in the home. 

The propagation of noise is generally divided into three stages: noise source, propagation path, and receiver. The propagation route includes reflection, diffraction, and other forms of sound wave travel.

The principle of noise control is to take seven major measures before the noise reaches the eardrum, such as sound blocking, vibration isolation, sound absorption, muffler, personal protection and building layout. try to reduce or reduce the vibration of the sound source, or absorb the sound energy in the propagation; Or set up a barrier to make the sound reflect out in whole or in part and weaken the effect of noise on the eardrum, so as to achieve the purpose of controlling noise.

1. The most direct harm of noise to the human body is hearing damage. When people enter a noisy environment and are exposed to it for a period of time, they will feel uncomfortable in both ears and even have headaches. Leave the noisy environment and rest in a quiet place for a while, and your hearing will gradually return to normal.

This phenomenon is called temporary hearing threshold shift, also known as auditory fatigue.

2. Noise can induce a variety of diseases. Neurasthenia such as headaches, brain swelling, tinnitus, insomnia, general fatigue and weakness, and memory loss may occur due to noise. People who work in high-noise environments for a long time have twice the incidence of hypertension, arteriosclerosis and coronary heart disease compared to those who work in low-noise environments.

Visible noise can cause diseases of the cardiovascular system. Noise can also lead to digestive system dysfunction, causing indigestion, loss of appetite, nausea and vomiting, and increasing the incidence of gastrointestinal diseases and ulcers.

3. Noise pollution interferes with people's life and work. Noise has a great impact on people's sleep, which can lead to dreaminess, easy awakening, and decreased sleep quality, etc., and the impact of sudden noise on sleep is more prominent. Noise can interfere with people's conversation, work, and study.

Experiments have shown that when a person is disturbed by a sudden noise, he or she loses 4 seconds of concentration. Noise can distract people, leading to sluggish reactions, easy fatigue, decreased productivity, and increased error rates. Noise can also mask safety signals, such as alarm signals and vehicle driving signals, which can cause accidents.

4. Impact on animals. Noise can cause pathological changes to the auditory organs, visual organs, internal organs and central nervous system of animals. Noise has a certain impact on the behavior of animals, which can make animals lose their ability to control their behavior, appear irritable, lose normalcy and other phenomena, and strong noise will cause animal death.

Birds will lose their feathers during noise, which will affect the egg laying rate, etc.

Noise pollution mainly includes:

1) Traffic noise, including the noise of motor vehicles, ships, Yufeng subway, trains, airplanes, etc.;

2) Industrial noise: Noise generated by various equipment in the factory.

3) Construction noise is mainly the noise emitted by construction machinery.

4) Social noise, including noise emitted by social activities and household appliances and audio equipment.