The impact of strong noise on a person leads to. The effect of sound and noise on the human body

Schelmanova Ekaterina Alexandrovna

The project examines what noise and noise pollution are, how noise affects human health, presents the results of a survey of teachers and school students on the impact of noise on their health, and presents the results of practical work to determine the hearing acuity of students in grades 9 and 11.

Download:

Preview:

MUNICIPAL BUDGET EDUCATIONAL INSTITUTION "Secondary school No. 19 with in-depth study of individual subjects."

Ecology project

"Impact of noise on human health"

Completed by a student of 11 "A" class

Schelmanova Ekaterina Alexandrovna

Project Manager:

Teacher of chemistry and ecology Khripunova T.V.

Zavolzhye, 2012

Introduction …………………………………………….3
Relevance of the work………………………………5
The purpose of the work…………………………………………5
Sound characteristic…………………………….5
Noise…………………………………………………..6
The influence of sounds on the human psyche…..8
Practical part:

Practical №1…………………………………9

Practical №2………………………………...12

Conclusion………………………………………..13
Application……………………………………….14

10. Literature……………………………………….15

Introduction

In nature, loud sounds are rare, the noise is relatively weak and short. The combination of sound stimuli gives animals and humans time to assess their nature and form a response. Sounds and noises of high power affect the hearing aid, nerve centers, can cause pain and shock. This is how noise pollution works.

The quiet rustle of leaves, the murmur of a stream, bird voices, a light splash of water and the sound of the surf are always pleasant to a person. They calm him, relieve stress. But the natural sounds of the voices of Nature are becoming more and more rare, disappearing completely or are drowned out by industrial traffic and other noises.

Prolonged noise adversely affects the organ of hearing, reducing the sensitivity to sound.

It leads to a breakdown in the activity of the heart, liver, to exhaustion and overstrain of nerve cells. Weakened cells of the nervous system cannot clearly coordinate the work of various body systems. This results in disruption of their activities.
The noise level is measured in units expressing the degree of sound pressure - decibels. This pressure is not perceived indefinitely. The noise level of 20-30 decibels (dB) is practically harmless to humans, this is a natural background noise. As for loud sounds, here the permissible limit is approximately 80 decibels. A sound of 130 decibels already causes a painful sensation in a person, and 150 becomes unbearable for him. Not without reason in the Middle Ages there was an execution “under the bell”. The hum of the bell ringing tormented and slowly killed the convict.

The level of industrial noise is also very high. In many jobs and noisy industries, it reaches 90-110 decibels or more. Not much quieter in our house, where new sources of noise appear - the so-called household appliances.

Noise

Noise acts on the body as a stress factor, causes a change in the sound analyzer, and also, due to the close connection of the auditory system with numerous nerve centers at the most diverse levels, profound changes occur in the central nervous system.

The most dangerous is long-term exposure to noise, in which the development of noise disease is possible - a general disease of the body with a predominant lesion of the hearing organ, the central nervous and cardiovascular systems.

Noise levels in residential apartments depend on:

Location of the house in relation to urban noise sources

Internal layout of premises for various purposes

Soundproofing of building envelopes

Equipping the house with engineering and technological and sanitary equipment.

Noise sources in the human environment can be divided into two large groups - internal and external.

External sources: underground, heavy trucks, railway trains, trams

Internal: elevators, pumps, machine tools, transformers, centrifuges

Noise sources	Level noise	Effect on the body
whisper	20dB	harmless
Quiet conversation	30-40 dB	Sleep worsens
Loud talk	50-60 dB	Decreased attention, poor vision
Change at school	80dB	Change in blood flow of the skin, excitation of the body
Motorbike Bus In production Reactive plane	86 dB 91 dB 110dB 102 dB	Hearing loss, fatigue, headache, heart disease
explosion	130-150 dB	Pain, death

The relevance of the work

Wherever we are, whatever we do - we are accompanied everywhere by a variety of sounds. Each of our movements causes a sound - a rustle, a rustle, a creak, a knock. Man has always lived in a world of sounds and noise. The sounds of nature are always pleasant for him, they calm him down, relieve stress. But in everyday life, we are more confronted with the noise of household appliances, industrial, transport noise. And we notice that our body gets tired more and more. What is the reason for this, do the sounds around us really influence the state so much, in what way does it manifest itself?

Goal of the work

Find out what noise is, what effect sounds can have on a person, what noise pollution is and what are its sources, how noise disease manifests itself.
Learn from the literature about the effects of noise on humans and the environment
Determine the level of hearing of students when performing practical work, methods of dealing with noise pollution.

Study plan:

Sound characteristic
Noise and its impact on human health
Research work with students and teachers
Conclusion
Reminder: What needs to be done to make the house quieter

Sound characteristic

Man has always lived in a world of sounds and noise. Sound is called such mechanical vibrations of the external environment, which are perceived by the human hearing aid (from 20 to 20,000 vibrations per second). Vibrations of a higher frequency are called ultrasound, a smaller one is called infrasound. Noise - loud sounds that have merged into a discordant sound.

For all living organisms, including humans, sound is one of the environmental influences.

Noise

For a long time, the effect of noise on the human body was not specially studied, although already in ancient times they knew about its harm and, for example, in ancient cities, rules were introduced to limit noise.

Currently, scientists in many countries of the world are conducting various studies to determine the impact of noise on human health. Their studies have shown that noise causes significant harm to human health, but absolute silence frightens and depresses him. So, employees of one design bureau, which had excellent sound insulation, already a week later began to complain about the impossibility of working in conditions of oppressive silence. They were nervous, lost their working capacity. Conversely, scientists have found that sounds of a certain intensity stimulate the process of thinking, especially the process of counting.

Each person perceives noise differently. Much depends on age, temperament, state of health, environmental conditions.

Some people lose their hearing even after brief exposure to noise of comparatively reduced intensity.

Constant exposure to strong noise can not only adversely affect hearing, but also cause other harmful effects - ringing in the ears, dizziness, headache, increased fatigue.

Very noisy modern music also dulls the hearing, causes nervous diseases.

Noise has an accumulative effect, that is, acoustic irritation, accumulating in the body, increasingly depresses the nervous system.

Therefore, before hearing loss from exposure to noise, a functional disorder of the central nervous system occurs. Noise has a particularly harmful effect on the neuropsychic activity of the body.

The process of neuropsychiatric diseases is higher among persons working in noisy conditions than among persons working in normal sound conditions.

Noises cause functional disorders of the cardiovascular system; have a harmful effect on the visual and vestibular analyzers, reduces reflex activity, which often causes accidents and injuries.

Studies have shown that inaudible sounds can also have harmful effects on human health. So, infrasounds have a special effect on the mental sphere of a person: all types of intellectual activity are affected, mood worsens, sometimes there is a feeling of confusion, anxiety, fright, fear, and at high intensity - a feeling of weakness, as after a strong nervous shock.

For example, a well-known American physicist suggested that the director of the performance use very low, rumbling sounds, which, the scientist believed, would create an atmosphere of something unusual and frightening in the auditorium. To get an alarming sound, the physicist designed a special pipe that is attached to the organ. And the very first rehearsal frightened everyone. The trumpet did not make audible sounds, but when the organist pressed the key, the inexplicable happened in the theater: the window panes rattled, the crystal pendants of the candelabra rang. Even worse, everyone who was present at that moment in the hall and on the stage felt an unreasonable fear! And the culprit was infrasound, inaudible to the human ear!

Even weak infrasound sounds can have a significant impact on a person, especially if they are of a long-term nature. According to scientists, it is precisely by infrasounds, inaudibly penetrating through the thickest walls, that many nervous diseases of the inhabitants of large cities are caused.

Ultrasounds, which occupy a prominent place in the range of industrial noise, are also dangerous. The mechanisms of their action on living organisms are extremely diverse. The cells of the nervous system are especially susceptible to their negative effects.

Noise is insidious, its harmful effect on the body is invisibly, imperceptibly. Violations in the human body against noise is practically defenseless.

Currently, doctors are talking about noise disease, which develops as a result of exposure to noise with a primary lesion of hearing and the nervous system.

The influence of sounds on the human psyche

Cat's purring promotes normalization:

Of cardio-vascular system

blood pressure

Classical music (Mozart) contributes to:

General reassurance

Increased milk production (by 20%) in a nursing mother

Rhythmic sounds due to a direct effect on the brain contribute to:

Release of stress hormones

memory impairment

Bell ringing quickly kills:

typhoid bacteria

Viruses

Practical work No. 1

A sociological survey conducted among students and teachers of school No. 19 on the impact of noise on health:

Teachers Pupils

Conclusion: According to teachers and students, noise affects human health

2. Where do you think noise pollution is increased on school grounds?

Teachers Pupils

Conclusion: The main sources of noise are floors, gyms and canteen

3. Do you consider noise to be the cause of absent-mindedness, distraction of students in the lesson?

Teachers Pupils

Conclusion: Most teachers and students believe that noise affects the concentration in the lesson.

4. And what personally prevents you from concentrating on the lesson?

Teachers Pupils

Conclusion: According to the majority, the noise in the corridor interferes with the lesson

5. What do you feel about noise pollution? How does noise affect you?

Teachers Pupils

Conclusion: For the majority of respondents, noise causes headaches and fatigue.

6. Where is the big noise pollution?

Teachers Pupils

Conclusion: Most of the respondents believe that the greatest noise pollution in the school

Thus, according to students and teachers, noise can be a source of illness, fatigue, can interfere with the normal rhythm of life, and the school is the object of increased noise levels.

Practical work №2

"Determination of hearing acuity"

Purpose: to determine the acuity of students' hearing.

Equipment: ruler, clock.

Hearing acuity is the minimum volume that can be perceived by the subject's ear.

9th grade students

	1distance	2distance	Average distance
1 student
2 student			26,5
3 student

Conclusion: all students have good hearing

11th grade students

	1 distance	2 distance	Average distance
1 student
2 student			24,5
3 student

Conclusion: 11th grade students also have good hearing.

Conclusion: the students of the school have good hearing, but the students of the 9th grade are slightly better.

Conclusion

Sounds have a negative impact on human health, especially in the modern world, when there is a lot of carrier noise around. Based on a survey of students and teachers, it was found that: noise affects human health, the main sources of noise are floors, gyms and canteens, noise affects concentration in the lesson, noise in the corridor interferes with the lesson, noise causes headaches and fatigue, and what is the most noise pollution in the school.

The opinion of teachers and students is similar to the table given before practical work. During the work on the project, it was also possible to determine the level of hearing among students in grades 9 and 11, which showed that so far there are no particular hearing problems, but which may arise later, since in grade 11 the level of hearing is already lower.

All this is due to the fact that teenagers very often listen to loud music in headphones and the fact that a lot of equipment has appeared that negatively affects people's health (mobile phones, cars)

Application

memo

What you need to do to make the house where you live quieter:

External walls must be soundproofed
Double glazing significantly reduces noise
Plant trees between the house and the road
Replace thin doors with more solid ones
Lay thick, well-padded carpets
Choose the Quietest Appliance Model
If household appliances make a lot of noise, call a specialist
Use soft shoes at home

Literature

http://tmn.fio.ru/works/40x/311/p02.htm Effect of noise on human health.
http://schools.keldysh.ru/labmro/web2002/proekt1/zaklych.htm - health factors
Kriksunov E.A. Ecology 9 cells. M. Bustard 2007
Mirkin B.M., Naumova L.G. Ecology of Russia 9-11 cells.
Kuznetsov V.N. Ecology M. Bustard 2002

Slides captions:

Project on ecology"Impact of noise on human health"
MUNICIPAL BUDGET EDUCATIONAL INSTITUTION "SEVERAGE SCHOOL №19 WITH IN-DEPTH STUDY OF INDIVIDUAL SUBJECTS".
Completed by: student of 11 "A" class Shchelmanova Ekaterina Alexandrovna Project leader: teacher of chemistry and ecology Khripunova T.V.
Zavolzhye, 2012
Rationale for the choice of topic
Wherever we are, whatever we do - we are accompanied everywhere by a variety of sounds. Each of our movements causes a sound - a rustle, a rustle, a creak, a knock. Man has always lived in a world of sounds and noise. The sounds of nature are always pleasant for him, they calm him down, relieve stress. But in everyday life, we are more confronted with the noise of household appliances, industrial, transport noise. And we notice that our body gets tired more and more. What is the reason for this, do the sounds around us really influence the state so much, in what way does it manifest itself?
Goal of the work
Find out what noise is, what effect sounds can have on a person, what noise pollution is and what are its sources, how noise disease manifests itself. Learn from the literature about the impact of noise on humans and the environment. Determine the level of hearing of students when performing practical work, methods of combating noise pollution. The health of the nation must come first in any country. Therefore, much attention is paid to the study of the influence of various factors on human health. Knowing the problem is the first step in solving it
Study plan:
Characteristics of soundNoise and its effects on human healthInfluence of sounds on the human psycheResearch work with students and teachersConclusion Memo: What needs to be done to make the house quieter
Sound characteristic
Man has always lived in a world of sounds and noise. Sound is called such mechanical vibrations of the external environment, which are perceived by the human hearing aid (from 20 to 20,000 vibrations per second). Vibrations of a higher frequency are called ultrasound, a smaller one is called infrasound. Noise - loud sounds, merged into a discordant sound. For all living organisms, including humans, sound is one of the environmental influences.
Noise and its impact on human health
Noise is an unpleasant or unwanted sound or a combination of sounds that interfere with the perception of useful signals, break silence, have a harmful or irritating effect on the human body, reduce its performance. Noise is a general biological stimulus and, under certain conditions, can affect all organs and systems of the whole organism, causing various physiological changes.
Noise sources
Noise levels in residential apartments depend on: the location of the house in relation to urban noise sources; the internal layout of premises for various purposes; Noise sources in the human environment can be divided into two large groups - internal and external.
Impact of noise level on human health
External sources are vehicles that create large dynamic loads during operation, which cause the propagation of vibration in the ground and building structures of buildings. These vibrations are often also the cause of noise in buildings. centrifuge transformers
Noise units
The noise level is measured in units expressing the degree of sound pressure - decibels (dB). This pressure is not perceived indefinitely. The noise level of 20-30 dB is harmless, it is a natural background. Loud sound -80 dB. 130 dB - pain, 150 - the sound becomes unbearable
The influence of sounds on the human psyche
Cat's purring contributes to the normalization of: Cardiovascular system Blood pressure Classical music (Mozart) contributes to: General sedation Increased milk secretion (by 20%) in a nursing mother Rhythmic sounds due to direct effects on the brain contribute to: Release of stress hormones Memory impairment Bell ringing quickly kills: Typhoid bacteria Viruses
Appointment of the area, development, territories, premises
Permissible sound level, dB
7-23 h
23-7 h
Resort and health-improving (zones)
40
30
Territories and zones of mass recreation (outside resort areas)
50
-
Industrial or residential areas
65
55
Doctors' offices of hospitals, sanatoriums, polyclinics, pharmacy pharmacies
35
35
Living rooms of apartments
40
30
Sleeping quarters in preschool institutions
40
30
Classes at school
40
-
School plots
50
-
Sport halls
50
-
Practical work No. 1
A sociological survey conducted among students and teachers of school No. 19 on the impact of noise on health: 1. Can noise be considered an invisible killer Teachers Pupils
2. Where do you think noise pollution is increased on school grounds?
Teachers Pupils
According to teachers and students, noise affects human health
The main sources of noise are floors, gyms and dining rooms.
3. Do you think the noise is the reason for the absent-mindedness, distraction of students in the lesson? Teachers Pupils
4. And what personally prevents you from concentrating on the lesson
Teachers Pupils
Most teachers and students believe that noise affects the concentration in the lesson.
According to the majority, the noise in the corridor interferes with the lesson
5. How do you feel about noise pollution? How does noise affect you? Teachers Pupils
6.Where is the most noise pollution?
Teachers Pupils
For the majority of respondents, noise causes headaches and fatigue.
The majority of respondents believe that the greatest noise pollution in the school
Practical work No. 2 "Determination of hearing acuity"
Purpose: to determine students' hearing acuity. Equipment: ruler, watch. Hearing acuity is the minimum volume that can be perceived by the subject's ear. WORK PROCEDURE: 1. Bring the watch closer to you until you hear a sound. 2. Attach the watch tightly to your ear and move it away from you until the sound disappears. 3. Measure the distance (in cases 1 and 2) between the ear and the watch in cm. 4. Find the average of the two indicators. Make a conclusion.
The project involved students of grades 9 and 11. Pupils of grade 9: Pupils of grade 11: Conclusion The intensity of the sound varies significantly depending on the distance of the sound source (noise), the closer the clock, the higher the noise level, and vice versa. If the sound of the clock is heard at a distance of 15-20 cm - satisfactory (minor problems), 5 cm is already a sign of hearing loss (in the future, complete deafness is possible). As a result of practical work, it turned out that the hearing of 9th grade students is not much better than that of 11th grade.

1 student
2 student
3 student
1
26
24
23
2
28
25
29
3
27
24,5
26
1 student
2 student
3 student
1
27
25
24
2
29
28
28
3
28
26,5
26
Conclusion
Sounds have a negative impact on human health, especially in the modern world, when there is a lot of carrier noise around. Based on a survey of students and teachers, it was found that: noise affects human health, the main sources of noise are floors, gyms and canteens, noise affects concentration in the lesson, noise in the corridor interferes with the lesson, noise causes headaches and fatigue, and what is the most noise pollution in the school. The opinion of teachers and students is similar to the table given before practical work. During the work on the project, it was also possible to determine the level of hearing among students in grades 9 and 11, which showed that so far there are no particular hearing problems, but which may arise later, since the level of hearing is already lower in grade 11. All this is due to the fact that teenagers very often listen to loud music in headphones and with the fact that a lot of technology has appeared that negatively affects people's health (mobile phones, cars)
memo
What you need to do to make your house quieter: Exterior walls should be soundproofed Double glazing significantly reduces noise Plant trees between the house and the road Replace thin doors with more solid ones Install thick carpeting with good padding Choose the quietest model of household appliances If household appliances are very noisy, call SpecialistUse soft shoes at home
Literature
http://tmn.fio.ru/works/40x/311/p02.htm Impact of noise on human health . Ecology 9 cells. M. Bustard 2007 Mirkin B.M., Naumova L.G. Ecology of Russia 9-11 class Kuznetsov V.N. Ecology M. Bustard 2002

The influence of noise on a person has not been the object of special studies until some time. Now the impact of sound, noise on body functions is studied by a whole branch of science - audeology. Currently, scientists in many countries of the world are conducting various studies to determine the impact of noise on human health.

The mechanism of action of noise on the body is complex and insufficiently studied. When it comes to the influence of noise, usually the main attention is paid to the state of the hearing organ, since the auditory analyzer primarily perceives sound vibrations and its damage is adequate to the effect of noise on the body. Along with the organ of hearing, the perception of sound vibrations can also be partially carried out through the skin by vibration sensitivity receptors. There are observations that people who are deaf, when touching sources that generate sounds, not only feel the latter, but can also evaluate sound signals of a certain nature.

The possibility of perception and evaluation of sound vibrations by the receptors of vibration sensitivity of the skin is explained by the fact that in the early stages of the development of the organism they performed the function of an organ of hearing. Then, in the process of evolution, a more perfect hearing organ was formed from the skin, which reacted to acoustic impact.

Among the sense organs, hearing is one of the most important. Thanks to him, we are able to receive and analyze the whole variety of sounds of the external environment around us. Hearing is always awake, to a certain extent even at night, in sleep. He is constantly exposed to irritation because he does not have any protective devices, similar, for example, to the eyelids that protect the eyes from light. The ear is one of the most complex and subtle organs: it perceives both very weak and very strong sounds.

Under the influence of strong noise, especially high-frequency noise, irreversible changes occur in the hearing organ. Changes that occur in the organ of hearing, some researchers explain the traumatic effect of noise on the inner ear. There is an opinion that the effect of noise on the organ of hearing leads to overstrain and, in the absence of sufficient rest, leads to a violation of the blood supply to the inner ear.

At high noise levels, hearing sensitivity drops after 1-2 years, at medium noise levels it is detected much later, after 5-10 years, that is, hearing loss occurs slowly, the disease develops gradually.

The sequence in which hearing loss occurs is now well understood. At first, intense noise causes temporary hearing loss. Under normal conditions, hearing is restored in a day or two. But if noise exposure continues for months or, as is the case in industry, for years, there is no recovery, and the temporary shift in hearing threshold becomes permanent.

First, nerve damage affects the perception of the high-frequency range of sound vibrations (4 thousand hertz or higher), gradually spreading to lower frequencies. The high sounds "f" and "s" become inaudible.

The nerve cells of the inner ear are so damaged that they atrophy, die, and do not recover.

Each person perceives noise differently. Much depends on age, temperament, state of health, environmental conditions.

Some people lose their hearing even after brief exposure to noise of comparatively reduced intensity.

Constant exposure to strong noise can not only adversely affect hearing, but also cause other harmful effects - ringing in the ears, dizziness, headache, increased fatigue.

Noise, even when it is small, creates a significant load on the human nervous system, exerting a psychological impact on him. This is especially often observed in people engaged in mental activity. Weak noise affects people differently. The reason for this may be: age, health status, type of work. The impact of noise also depends on the individual attitude to it. So, the noise produced by the person himself does not bother him, while a small extraneous noise can cause a strong irritating effect.

The lack of necessary silence, especially at night, leads to premature fatigue. Noises at high levels can be good ground for the development of persistent insomnia, neurosis and atherosclerosis.

Noise has an accumulative effect, that is, acoustic stimuli gradually, like poison, accumulate in the body, increasingly depressing the nervous system. The strength, balance and mobility of nervous processes change - all the more, the more intense the noise. The reaction to noise is often expressed in increased excitability and irritability, covering the entire sphere of sensory perceptions. People who are constantly exposed to noise often become difficult to communicate with.

Therefore, before hearing loss from exposure to noise, a functional disorder of the central nervous system occurs. Noise has a particularly harmful effect on the neuropsychic activity of the body.

The process of neuropsychiatric diseases is higher among persons working in noisy conditions than among persons working in normal sound conditions.

Noises cause functional disorders of the cardiovascular system, have a harmful effect on the visual and vestibular analyzers, reduce reflex activity, which often causes accidents and injuries.

So, we can single out the following consequences of the influence of noise on a person:

1. Noise causes premature aging. In thirty cases out of a hundred, noise reduces the life expectancy of people in large cities by 8-12 years.

2. Every third woman and every fourth man suffers from neurosis caused by increased noise levels.

3. Sufficiently strong noise already after 1 minute can cause changes in the electrical activity of the brain, which becomes similar to the electrical activity of the brain in patients with epilepsy.

4. Diseases such as gastritis, gastric and intestinal ulcers are most often found in people who live and work in noisy environments. Variety musicians have a stomach ulcer - an occupational disease.

5. Noise depresses the nervous system, especially with repeated action.

6. Under the influence of noise, there is a steady decrease in the frequency and depth of breathing. Sometimes there is arrhythmia of the heart, hypertension.

7. Under the influence of noise, carbohydrate and fat changes. protein, salt metabolism, which is manifested in a change in the biochemical composition of the blood (blood sugar levels decrease).

From this we can conclude: from excessive noise (over 80 dB) not only the hearing organs suffer, but also other organs and systems (circulatory, digestive, nervous, etc.), vital processes are disrupted, energy metabolism begins to prevail over plastic, which leads to to premature aging.

Noise is insidious, its harmful effect on the body is invisibly, imperceptibly. A person is practically defenseless against noise.

Currently, doctors are talking about noise disease, which develops as a result of exposure to noise with a primary lesion of hearing and the nervous system.

So, noise has its destructive effect on the entire human body. The fact that we are practically defenseless against noise also contributes to its disastrous work. A blindingly bright light makes us instinctively close our eyes. The same instinct of self-preservation saves us from being burned by moving our hand away from the fire or from a hot surface. But a person does not have a protective reaction to the impact of noise.

Noise and its impact on health. Noise is a disorderly combination of sounds of different strength and frequency. Household noise is understood as any unpleasant, unwanted sound or a set of sounds that break the silence, have an irritating or pathological effect on the human body.

Sound as a physical phenomenon is a mechanical oscillation of an elastic medium (air, liquid and solid) in the range of audible frequencies. The human ear perceives vibrations with a frequency of 16,000 to 20,000 Hertz (Hz). Sound waves propagating in the air are called air sound. Oscillations of sound frequencies propagating in solids are called structural sound or sound vibration.

Noise has a specific frequency or spectrum, expressed in hertz, and an intensity level of sound pressure, measured in decibels (dBA). By type, the noise spectra can be divided into low-frequency from 16 to 400 Hz, mid-frequency from 400 to 800 Hz and high-frequency over 800 Hz. Noises are divided into constants, the sound level of which changes over time by no more than 5 dBA, and non-constant, or intermittent, the sound level of which changes over time by more than 5 dBA. There may also be impulse noise. Constant noise in residential areas is the sound of a clock or the sound of rain coming from the street. The intermittent noise includes traffic noise, the noise of the turning on refrigerator unit, impulse noise includes slamming doors.

Effect of noise on the human body. Human response to noise is different. Some people are tolerant of noise, for others it causes irritation, a desire to get away from the source of noise. The psychological assessment of noise is mainly based on the concept of perception, and internal adjustment to the noise source is of great importance. It determines whether the noise will be perceived as disturbing. Often the noise produced by the person himself does not disturb him, while a small noise caused by neighbors or some other source has a strong irritating effect. An important role is played by the nature of the noise and its frequency.

The degree of psychological and physiological susceptibility to noise is influenced by the type of higher nervous activity, the nature of sleep, the level of physical activity, the degree of nervous and physical overstrain, bad habits (alcohol and smoking). Sound stimuli create a prerequisite for the emergence of foci of stagnant excitation or inhibition in the cerebral cortex. This leads to a decrease in working capacity, primarily mental, as the concentration of attention decreases, the number of errors increases, and fatigue develops.

This condition adversely affects the cardiovascular system: the heart rate changes, blood pressure rises or falls, the tone rises and the blood filling of the cerebral vessels decreases. There is a relationship between the incidence of the central nervous system and the cardiovascular system, noise levels and the duration of living in noisy urban environments. An increase in the general morbidity of the population is noted after 10 years of residence with constant noise exposure with an intensity of 70 dBA and above.

Consequently, urban noise can be attributed to risk factors for hypertension, coronary heart disease. Under the action of noise, such an important function of the body as sleep is most vulnerable. The threshold for the effect of noise on sleepers for different people lies in the region of the spectrum from 30 to 60 dBA. Constant exposure to intense noise (80 dBA or more) can cause gastritis and even peptic ulcer disease, as the secretory and motor functions of the stomach can be disturbed.

Loud music (on the radio, TV, reproduced by special equipment) can reach 100 dBA, and at concerts using electro-acoustic equipment up to 115 dBA. Prolonged exposure to high intensity and high frequency sound can cause permanent hearing loss (deafness). To prevent the adverse effects of noise on human health, measures to develop hygienic standards for permissible noise levels and to eliminate noise are of decisive importance.

The impact of noise on a person depends on the noise level, its characteristics and spectrum, exposure time, resonance phenomena. It also depends on the state of health, the adaptability of the body, the individual characteristics of the person and other factors.

The unpleasant effect of noise affects the emotional mood, motivation of actions, initiative, maybe, but, as a rule, does not manifest itself in the deterioration of work; in any case, it causes inconvenience to a person.

The disturbing effect of noise adversely affects the work of a person in that it causes strong concomitant irritations that negatively affect the main work of a person; increases the workload.

The harmful effects of noise cause pathological changes in the organ of hearing, worsen the state of the nervous system and the whole organism as a whole. It has a negative effect on certain types of human activity associated with changing certain situations, long-term management work and unforeseen reception of information that require attention. Short-term mental and physical activity is essentially independent of uniform exposure to noise of high intensity or high frequency.

Noise distracts a person's attention and thus has a negative effect in cases where it is necessary to monitor the flow of information or random changes.

Strong industrial noise adversely affects the human body. It reduces his working capacity, labor productivity, increases the susceptibility to heart attacks, increases the likelihood of neuroses and nervous diseases, worsens eyesight, causes headaches, mental depression, fatigue, causes a decrease in attention and psychological focus on work and an increase in reaction time. Noise disrupts relationships between people, a calm working environment. It causes a sharp deterioration in health in certain types of diseases, nervousness, a tendency to conflict situations. The unpleasant effects of noise have a stronger effect on mental than physical work.

According to the studies of E. Weil (France), exposure to strong noise causes the following mental disorders: disorders of the nervous system and the system of internal secretion, changes in the instinct of self-preservation, intellectual degeneration and inability to self-control, unwillingness to work, disturbance of a balanced state, conflicts between workers based on mental irritation.

The noise is more unpleasant, the narrower the frequency band and the higher the intensity. Noise, which has high tones in its composition, has the most harmful effect.

Noise above 500 Hz is more disturbing (error causing) than lower frequency noise. Intermittent chaotic noise is more harmful than constant noise. Noise with variable intensity (eg 40-70 dB) is more harmful than sound with constant intensity (eg 80 dB).

Unexpectedly occurring intense noise and sound (for example, impact) are very dangerous and have a significant impact on the decrease in productivity.

Rhythmically fluctuating and stepped noise, hissing, thunder and creaking can be unpleasant; they reduce the ability to perform coordinated movements quickly and accurately.

Strong noise causes difficulties in estimating distance and time, in recognizing color signals, reduces the speed of color perception, visual acuity, visual reaction at night, and disrupts the perception of visual information.

Labor productivity decreases by 5-12%. By reducing the noise level by 20%, it is possible to achieve an increase in labor productivity by 5-10%. Prolonged exposure to noise with an intensity of about 90 dB reduces labor productivity by 30-60%.

Monotonous monotonous sound or noise causes fatigue and increases the feeling of monotony. Noise and signaling sounds such as telephone ringing, loudspeaker sound, etc. interfere with operation.

Production noise, especially associated with pleasant and necessary work, is perceived normally and does not irritate. The worker, as a rule, is not annoyed by the noise of his own machine, but is annoyed by unpleasant, uncontrollable noise that appears unexpectedly from other machines.

A person aged 20-40 years tolerates strong noise worse than a person older or younger than this age, women tolerate noise better than men. People suffering from hypertension tolerate loud noise worse than healthy people.

A person does not perceive the normal noise of the living space. He just needs it. A quiet and noiseless environment negatively affects the human psyche, since absolute silence is not habitual for a person.

Rice. 1. Human exposure to noise

Noise levels are given and not included!. noe, interfering and harmful effects on the body of a working person, on his thinking, actions, on the reception of information and a decrease in labor productivity.

- Impact of noise on humans

Noise under certain conditions can have a significant impact on human health and behavior. It can cause irritation and aggression, arterial hypertension (increased blood pressure), tinnitus (tinnitus), hearing loss. Noise in the frequency range of 3000 - 5000 Hz causes the greatest irritation.

Chronic exposure to noise above 90 dB can lead to hearing loss.

With noise at a level of more than 110 dB, a person experiences sound intoxication, which, according to subjective sensations, is similar to alcohol or drugs.

At a noise level of 145 dB, a person's eardrums rupture.

Women are less resistant to loud noise than men. In addition, susceptibility to noise also depends on age, temperament, health status, environmental conditions, etc.

Discomfort is caused not only by noise pollution, but also by the complete absence of noise. Moreover, sounds of a certain strength increase efficiency and stimulate the thinking process (especially the counting process) and, conversely, in the absence of noise, a person loses working capacity and experiences stress. The most optimal for the human ear are natural noises: the rustle of leaves, the murmur of water, the singing of birds. Industrial noise of any power does not contribute to the improvement of well-being.

Scientists distinguish the following gradations of noise action: 1. Interfering action. It increases with increasing volume, but depends on individual perception and on the specific situation. Even a barely audible sound can become a hindrance, for example, the ticking of a clock, the buzzing of a fly, the dripping of water from a tap. The stronger the volume of a sudden noise interference differs from the level of the general background noise, the more unpleasant it is for the ear. Here is how the director of the Institute for Occupational Hygiene and Occupational Medicine at the Essen Clinic, Professor Werner Klosterketter, says about the impact of noise on the human body: irritation, resentment. This means that the psychological and social well-being of a person is violated. Depending on the strength of the unpleasant emotions caused by the noise, the autonomic nervous system also more or less reacts to the noise. Through habituation, the unpleasant psychological effects of noise can be reduced or completely eliminated. This fact must be taken into account when planning districts of the city. Being on the street or at the workplace, due to habit, they are ready to endure noises louder than at home, where, according to many studies, the upper limit of habituation is about 40 dB (A) during the day, in any case not more than 45 dB (A), and at night - 35 dB(A)”. 2. Activation, that is, excitation of the central and autonomic nervous system, sleep disturbance, impaired ability to relax, a marked increase in reactions associated with fear. This type of noise exposure is characterized by a slight increase in blood pressure, dilated pupils, decreased stomach motility, secretion of gastric juice and saliva, increased respiratory rate and pulse rate, increased muscle activity and skin electrical resistance, and increased release of hormones that play a role in the functioning of the autonomic nervous system. . The threshold for some of these reactions is quite high (eg skin blood flow changes from 70-75 dB(A)); in other reactions it is very low (for the electrical resistance of the skin - starting from 3-6 dB(A) above the background noise level). As far as we know, in a sleeping person the threshold of auditory perception is 10-14 dB lower than in the waking state. When resting, the nervous system is at an average level of activation. Sound stimuli can sharply raise this level, prevent the release of tension. Noise is especially disturbing during the rest period, especially during sleep. Now many people complain about sleep disturbance, and there are more and more cases of insomnia caused by noise. Noise makes it difficult and slows down falling asleep, can wake a person at night, and even if it doesn’t come to that, night noise still has a bad effect on sleep. Since there is an activating effect of noise. Non-monotonic noise with large volume jumps, for example, from airplanes, passing cars, as well as information-carrying noises (conversations, radio, TV) are especially disturbing. Sudden short-term noises, for example, slamming doors, gunshots, barking dogs, and so on, the level of which exceeds the background noise by more than 10-15 dB(A), should also be attributed to especially interfering ones. But continuous noise that does not give pauses for rest is also very unpleasant. The probability of awakening from noise depends on the phase of sleep. 3. Impact on performance. There have been many scientific studies on the effect of noise on performance. Almost all of them showed that habitual and expected noises do not worsen, and sometimes even improve their performance due to the activation reaction, but noise, especially unexpected, unusual and undesirable, can reduce the performance of tasks that require a lot of concentration. Simply put, while music at low to moderate volumes can have a positive effect on us at work, unwanted noise can reduce or impair our productivity and ability to concentrate.

4. Interference for the transmission of information and violation of the general orientation in the sound environment.Speech intelligibility, acoustic orientation in the environment and the perception of warning signals are impaired by noise the stronger, the higher its level. For example, noise interference during a conversation should be at least 10 dB(A) quieter than the speech of the interlocutors. A particular problem in industrial, residential and educational premises is communication interference with extraneous noise (industrial noise, traffic noise, etc.), which mask the sounds of speech. Thus, information-carrying noise can be combated by means of neutral noise. 5. Constant exposure to noise can cause deafness due to damage to sound-sensitive cells in the inner ear. The danger of permanent deafness occurs if a person is exposed to noise with an average level of more than 85 dB(A) for many years every day for 8 hours. This level, as a rule, is achieved only in production. It is estimated that approximately 10-15% of industrial workers are exposed to noise levels above 85 dB(A). People working in ferrous and non-ferrous metallurgy, in the textile industry and in underground construction suffer the most from noise. Noises with an intensity of over 100 dB(A) are noted here. Dangerous and construction noise produced by machines that work on construction sites, as well as trucks delivering materials. The noise of the mechanisms used here is very diverse. So a jackhammer at a distance of 7 m creates a noise of 90-100 dB (A), which is almost twice as loud as the noise of a truck. Outside the workplace, hearing damage can be caused mainly by too noisy leisure activities, shooting sports or musical hobbies. The traumatic effect of noise on the human body consists of several components. The changes that occur in the organ of hearing are associated with the damaging effect of noise on the peripheral part of the auditory analyzer - the inner ear. The primary localization of the lesion is the cells of the internal spiral groove and the organ of Corti.

Along with this, in the mechanism of the effect of noise on the organ of hearing, an overstrain of the inhibitory process plays a significant role, which, in the absence of sufficient rest, leads to the depletion of the sound-receiving apparatus and the redistribution of the cells that make up its composition.

Prolonged exposure to noise causes persistent disturbances in the circulatory system of the inner ear. This is the cause of subsequent changes in the labyrinth fluid and contributes to the development of degenerative processes in the sensitive elements of the organ of Corti.

In the pathogenesis of occupational damage to the organ of hearing, the role of the central nervous system cannot be excluded. Pathological changes that develop in the nervous apparatus of the cochlea during prolonged exposure to intense noise are largely due to overwork of the cortical auditory centers.

The auditory analyzer has extensive anatomical and physiological connections with various parts of the nervous system. An acoustic stimulus, acting through the receptor apparatus of the auditory analyzer, causes reflex shifts in the functions of its cortical section and other organs and systems of the human body.

The symptom complex that develops in the body under the influence of noise is called noise disease .

Clinical picture . Clinical manifestations of noise disease consist of specific changes in the organ of hearing and non-specific changes in the central nervous and cardiovascular systems. Occupational hearing loss is usually bilateral and proceeds according to the type of cochlear neuritis.

As a rule, persistent changes in hearing are preceded by a period of adaptation to noise. During this period, there is an unstable hearing loss that occurs immediately after the action of an acoustic stimulus and disappears after the termination of its action. Adaptation is a protective reaction of the auditory analyzer. The development of persistent hearing loss occurs gradually.

The initial stage of the disease may be preceded by a sensation of ringing or noise in the ears, dizziness, headache. The perception of spoken and whispered speech during this period is not disturbed.

A special place in the pathology of the organ of hearing is occupied by lesions caused by exposure to superintense noise and sounds. Even with a short-term effect, they can cause complete death of the spiral organ and rupture of the eardrum, accompanied by a feeling of congestion and sharp pain in the ears. The outcome of such an injury is complete hearing loss.

Nonspecific manifestations of noise disease are the results of functional disorders of the nervous and cardiovascular systems. They occur during prolonged systematic exposure to intense noise. The nature and degree of disturbances largely depend on the intensity of the noise.

Prolonged exposure to intense noise develops asthenovegetative syndrome, vegetative vascular dysfunction.

In the neurological picture, the main complaints are a headache of a dull nature, a feeling of heaviness and noise in the head, appearing at the end of a work shift or after work, dizziness when changing body position, irritability appears, working capacity, memory and attention decrease, sleep disturbance (drowsiness during the day, disturbed sleep or insomnia at night). Increased sweating is also characteristic, especially when agitated.

When examining such patients, a small tremor of the fingers of outstretched hands, a tremor of the eyelids are observed, tendon reflexes are reduced, pharyngeal, palatine and abdominal reflexes are depressed, a decrease in the excitability of the vestibular apparatus, and muscle weakness are noted. Pain sensitivity in the distal extremities is disturbed, vibration sensitivity is reduced. A number of functional and endocrine disorders are revealed, such as hyperhidrosis, persistent red dermographism, coldness of the hands and feet, depression and perversion of the oculocardial reflex, an increase or inhibition of the orthoclinostatic reflex, and an increase in the functional activity of the thyroid gland.

Changes in the cardiovascular system in the initial stages of the disease are functional. During the stay in noise conditions, instability of the pulse and blood pressure is observed. After a working day, bradycardia is noted, diastolic pressure rises, functional heart murmurs appear. Patients complain of palpitations, discomfort in the region of the heart in the form of tingling.

The electrocardiogram reveals changes that indicate extracardiac disorders: sinus bradycardia, bradyarrhythmia, a tendency to slow intraventricular or atrioventricular conduction. Sometimes there is a tendency to spasm of the capillaries of the extremities and the vessels of the fundus, as well as to an increase in peripheral resistance.

Functional shifts that occur in the circulatory system under the influence of intense noise, over time, can lead to persistent changes in vascular tone, contributing to the development of hypertension.

Diagnostics. The professional nature of the damage to the organ of hearing is established on the basis of the clinical picture of the gradual development of the disease according to the type of bilateral cochlear neuritis. The length of service in conditions of exposure to intense noise, the possibility of developing the disease due to infectious diseases (neuroinfection, influenza, meningitis), contusion or taking certain medications (such as streptomycin, quinine, etc.)

Treatment. Hearing loss syndrome is not always treatable, and full recovery of hearing cannot be expected. Perhaps only a slight improvement in hearing after the cessation of work in conditions of exposure to noise with persistent drug treatment. They use vasodilators (nicotinic acid, reserpine), drugs that improve neurotrophic regulation in the inner ear. Fortifying agents (aloe), vitamin therapy are used.

In the complex of therapeutic measures, physiotherapeutic methods are used: diathermy, paraffin, silt, mud therapy on the area of the mastoid processes, ionogalvanization with potassium iodide ions, local darsonvalization, hydrochloric-coniferous and hydrogen sulfide baths.

Prevention. Measures to prevent the harmful effects of noise on the human body should primarily be aimed at reducing the noise level. This can be achieved by improving the design of machines, tools and other equipment, using sound-absorbing and sound-insulating materials. If these measures do not reduce the noise level to safe limits, it is advisable to use personal protective equipment (headphones, helmets).

Preliminary (when applying for a job) and periodic medical examinations are important. Depending on the time of exposure, noise can lead to more or less severe stress, and stress can upset a person's “internal clock”.

Diseases caused by occupational noise exposure (noise disease) Noise disease is understood as persistent, irreversible morphological changes in the organ of hearing, due to the influence of industrial noise. At acute heavy-duty noise exposure and sounds, the death of the spiral (Corti) organ, rupture of the eardrums, and bleeding from the ears are observed. At chronic exposure to occupational noise there is atrophy of the spiral organ with its replacement by fibrous connective tissue. There may be no changes in the auditory nerve. There is stiffness in the joints of the auditory ossicles.

Accident, illness, exposure to noise can seriously impair the function of the ears. A foreign body can rupture the eardrum, and a blow to the head can damage the middle or inner ear. The disease can affect the middle ear or destroy the sensitive hair cells on the basilar membrane, but worst of all, when the auditory nerve is damaged and its connections with the brain are disrupted, deafness of perception occurs.

With all types of deafness, except for the last one, medicine is able to help the victim: the damaged eardrum and auditory ossicles are replaced by transplantation or implantation of artificial plastic bones. If the hair cells in the cochlea begin to lose sensitivity, amplifying the sound entering the external auditory canal may help; but when the auditory nerve dies, the ear as a sense organ becomes completely useless.

The most common and serious cause of noise-induced hearing loss is exposure to high noise levels in workplaces, whether in the cab of a diesel truck, a foundry, or anything from a print shop to a synthetics factory. If we exclude explosions and shooting, then hearing damage from noise outside of work is an unlikely event. No matter how irritating a person is the noise of aircraft or ground transportation, it is unlikely to cause physiological hearing damage. Perhaps the exceptions are motorcycles of some brands and, as we have already said, pop music orchestras. How exactly does noise affect its victims? What noise level should be considered dangerous? Is hearing damage reversible?

Noise can affect hearing in three ways: cause instant deafness or hearing damage; with prolonged exposure - sharply reduce sensitivity to sounds of certain frequencies, and, finally, noise can reduce hearing sensitivity for a limited time - minutes, weeks, months, after which hearing is restored almost completely.

The first type of injury, acoustic trauma, is usually caused by exposure to very high intensity noise, such as an explosion. For obvious reasons, it is impossible to establish experimentally the minimum level of noise that leads to damage of this kind; but it appears that impulsive noise in excess of 150 dB causes injury instantly. In this case, the eardrum may be irreparably torn, and the auditory ossicles may be broken or displaced. However, it is possible that the snail will still survive, since damage to the ossicles can prevent the transfer of all noise energy to the perilymph.

Explosions are not the only source of impulsive noise. Hitting a steel plate with a hammer also produces a significant pulse of noise, although not as high as an explosion. Impulses of lower intensity also injure hearing, but cause damage not in the middle, but in the inner ear, as well as continuous noise, which will be discussed later. As we already know, there are two protective devices in the human ear: one of them is the ear reflex. Unfortunately, it fires within about 10ms (milliseconds), during which time the impulse noise can already cause injury. But such impulsive noise with a very short rise time is almost never found in nature, it is generated only by man.

Another powerful source of impulsive noise is the sonic boom produced by aircraft. First of all, however, it should be said that, according to the generally accepted opinion, a peak overpressure of 35,000 N/m 2 is required to rupture the eardrum, and 100,000 N/m 2 to damage the lungs. The excess pressure created by supersonic aircraft very rarely exceeds 100 N/m 2 .

However, hearing damage from impulsive noise is not the main cause for concern. Much more detrimental to hearing are long periods of continuous exposure to high-intensity noise. This type of noise acts in two ways, and the first type of impact may not cause serious harm. Thus, if a person is exposed for more than a few minutes to medium or high frequency sound with a level of about 90 dB or a little higher, he then experiences a so-called "temporary threshold shift". The normal hearing threshold is the lowest level at which a given person can still hear a sound of one frequency or another; after exposure to strong noise, this threshold increases markedly. However, this decrease in hearing will last no more than half an hour, after which the residual threshold shift will become imperceptible.

With an increase in exposure time and with an increase in the noise level, the time shift of the threshold increases and the recovery period lengthens. If, for example, a noise of 100 dB at frequencies of 1200-2400 Hz lasted 100 minutes, then the temporal threshold shift will exceed 30 dB, and it will take about 36 hours to restore normal hearing.

If exposure to high noise does not occur systematically, then the residual effect is so small that it can be neglected. However, many people around the world are constantly exposed to high levels of noise in production or other work; the effect ceases to be temporary, and over the years, hearing loss becomes severe and chronic. Usually noise victims tend to deny that they are not all right with their hearing.

Not all people react the same way to noise. The same dose of noise exposure causes hearing damage in some people, not in others, and in some this damage can be more severe than in others. Therefore, any acceptable noise limit should always be assessed in terms of the number of people (percentage) who suffer less damage after exposure to noise than some chosen limit. The limits taken from the code guarantee that in 90% of people the specified noise doses will cause a residual hearing loss of less than 20 dB after 50 years of work at the specified noise exposure dose. Lowering the limits by 5 dB will increase this figure to 93%, and lowering by 10 dB will increase this figure to 96%. Hearing loss of more than 20 dB begins to seriously interfere with a person when age-related hearing changes are added to this. Hearing loss less than 20 dB is not very significant, but 10 dB is almost imperceptible.

As a rule, a noise so loud that it is impossible to talk without turning into a scream already carries the risk of hearing damage. It can be argued that if a person who does not systematically work in a noise zone receives a temporary shift in the hearing threshold after being in it, then the noise level in the zone is likely to exceed 90 dBA. In general, regardless of the duration of exposure, leaving the ears unprotected at a noise level of 120 dB is unreasonable, and at a level reaching 135 dB it is dangerous. Even with ear protectors, the absolute noise limit is 150 dBA, and since many types of protectors only reduce levels by 20 dBA or less, wearing them does not eliminate the risk of hearing damage if you are in a noisy area all day.

Occupational noise-induced hearing loss, in other words, occupational hearing loss, is perhaps the most serious exposure to noise, but it is not the only one. Noise has many other harmful effects on a person: certain types of noise and vibration cause diseases; noise can seriously disrupt communication, it often leads to accidents; with a constant irritating effect, noise can cause mental disorders; noise interferes with sleep and interrupts sleep, and the results of this can be quite serious. In short, noise worsens the human condition.

Not all the harmful effects of noise and its accomplice - vibrations have been fully disclosed yet. People who work with vibrating hand tools are known to suffer from diseases known as "white fingers", "dead hand", "Raynaud's phenomenon". The symptoms are pain, numbness, and cyanosis of the fingers, as from exposure to cold. Very often there is damage to the joints and bones of the hands, and the joints swell and lose mobility. It is possible that damage to bones and joints occurs as a result of repeated sharp blows to which the hands are exposed when working with impact mechanisms, and other symptoms are caused by high-frequency vibrations.

Other harmful effects of noise and vibration on the body are not currently considered serious, with the exception of exposure to sounds of very high or very low frequencies, as well as very high intensity. Noise of very high intensity can cause resonance in the semicircular canals, the organs of balance in the inner ear, leading to dizziness and nausea. Ultrasonic noise with a frequency above the limit of hearing can also cause nausea, and infrasound and very low-frequency audible noise excite resonances in the internal organs, including the heart and lungs. Acoustic excitation with a certain frequency and a sufficiently large amplitude can stop the pulsation of the heart. Strong low-frequency noise makes it difficult to breathe.

The psychological and other non-pathological effects of noise exposure are also important, but they are not always measurable. How to measure the degree of irritation experienced by a person? How much harm does a bad mood do? Annoyed people sometimes become unnaturally quick-tempered or make completely wrong decisions, which can sometimes lead to disastrous consequences. Noise victims may develop depression or psychosomatic susceptibility; families are destroyed, accidents occur, relations at work are complicated.

Noise causes both normal fatigue and an inability to concentrate, also leading to reduced productivity and accidents. It is not easy to measure the dependence of labor productivity on noise: as soon as we select a group of subjects and begin to experiment, changing the surrounding conditions, whether it be acoustics, lighting or heating, the productivity of the subjects immediately increases simply because they feel that they are taking care of their health and trying to help them in some way. However, few will dare to deny that people who work in conditions of strong noise are more likely to make mistakes and, consequently, their work is less productive and efficient. It has also been found that when the noise level decreases, the number of absenteeism decreases.

Sleep disturbance is probably the most serious damage that noise brings to a person, excluding, of course, hearing damage. To perform effectively, mentally and physically, almost everyone needs adequate sleep. It should be remembered that when a person sleeps, his senses, including the ears, remain "on". If during sleep we do not hear low-level sounds, this does not mean at all that our ears do not pick them up, but that the brain simply reacts differently to auditory stimuli. As you know, even under anesthesia, nerve impulses continue to be transmitted to the higher centers of the brain. Low-level noise may not have a visible effect on sleep, but the fact that noise is perceived is revealed by careful analysis of the electroencephalogram (EEG). During deep sleep, a click of 50-60 dBA causes an easily identifiable cortical response. Noises of higher levels cause very pronounced changes in the EEG.

The easiest way to consider that the effect of noise on sleep is that a person wakes up under the influence of noise. Of course, this is a very important point, but many underestimate the importance of a forced shift in the depth of sleep that does not yet lead to awakening. As experiments show, if a sleeping person, who has barely reached the stage of the deepest sleep, is influenced in such a way that, without waking up, he is transferred to a stage of less deep sleep, the result is the same as with full awakening.

Sudden awakening from deep sleep may be accompanied by palpitations. If a person is awakened every time he reaches the stage of dreaming (easily identified by rapid eye movements), and thus deprived of dreams, he develops symptoms that eventually lead to hallucinations and disorientation.

Noise causes both shifts in the depth of sleep and full awakening. It is well known that people over the age of 60 are more easily awakened or put into a state of less deep sleep than children or middle-aged people. Differences in reaction are sharply expressed; It has been established that noise, which wakes up only 5% of children aged 7-8, causes a complete awakening of 70% of people aged 69-72 years. An older person who is awakened has a harder time falling asleep again than a child or a middle-aged person. It has also been proven that women wake up more easily from noise than men.

If we compare the changes in sleep caused by noise with the normal sleep process, it is easy to understand how significant the role of ambient noise is. It is known that for the sleeper the most beneficial stage of deep sleep, and in order to reach it, it takes an adult about an hour, and it is obvious that a few short-term noise stimuli during the night are enough to cause a serious disturbance of full sleep. Of the same importance is the stage of dreams, frequent awakenings during which can greatly affect the quality of sleep.

A secondary manifestation of the effect of ambient noise on sleep was also studied, namely, the lengthening of the period necessary for the onset of the stage of deep sleep. Within certain limits, the brain is able to compensate for disturbances in the quality of sleep in noisy conditions and to compensate for the lack of deep sleep at the beginning of the night by increasing the duration of the deep sleep stage and its greater stability in the later hours (reverse normal order).

In terms of acceptable nighttime noise limits, it should be noted that noise at a constant level has less effect on sleep than noise with fluctuating levels or intermittent noise. So it's more important to try to prevent a few short "bursts" of noise than to try to reduce the overall noise level. Here, as in other situations, the presence of a suitable background can be of great help in cases where high-level intermittent noise cannot be avoided. In the tropics, where noisy air-conditioning devices built into windows are very common, it is certainly much easier for a person to sleep if such a device is not controlled by a thermostat, but operates continuously.

With a background noise of 35 dBA, individual noise peaks with a level of 45-50 dBA, although they seem too high, are practically quite acceptable for 80% of sleeping people; as the number of noise maxima increases, this limit should be lowered.

Finally, noise creates another problem - communication disruption. In many everyday situations it is very important that one person can quickly and accurately convey information to another. Communication disruption can lead, firstly, to a decrease in labor efficiency and, secondly, to much more serious and even fatal consequences. Often, accidents can be prevented by shouting: “Look out!”. Obviously, if the ambient noise prevents such warnings from being heard, people will die from causes that could have been prevented.