Noise in the city and means of protection. Methods for controlling environmental noise pollution Cut roads are usually well shielded by the edge of a shield wall, although reflections from a distant wall may reduce the shielding performance.

Noise is any sound that is unwanted by humans. Under normal atmospheric conditions, the speed of sound in air is 344 m/s.

A sound field is a region of space in which sound waves propagate. When a sound wave propagates, energy transfer occurs.

The noise level is measured in units expressing the degree of sound pressure - decibels (dB). This pressure is not perceived infinitely. Noise of 20–30 dB is practically harmless to humans and constitutes a natural background sound, without which life is impossible. As for “loud sounds,” here the permissible limit rises to approximately 80 dB. A noise of 130 dB already causes pain in a person, and when it reaches 150 dB it becomes unbearable for him. It was not for nothing that in the Middle Ages there was execution - “to the bell”; the ringing of a bell killed a man.

If in the 60s and 70s of the last century the noise on the streets did not exceed 80 dB, now it reaches 100 dB or more. On many busy highways, even at night, the noise does not drop below 70 dB, while according to sanitary standards it should not exceed 40 dB.

According to experts, noise in large cities increases annually by approximately 1 dB. Considering the level already achieved, it is easy to imagine the very sad consequences of this noise “invasion”.

Depending on the level and nature of the noise, its duration, as well as the individual characteristics of a person, noise can have various effects on him.

Noise, even when it is small, creates a significant load on the human nervous system, having a psychological effect on him. This is especially common in people engaged in mental activity. Low 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's attitude towards it. Thus, the noise produced by the person himself does not bother him, while small extraneous noise can cause a strong irritating effect.

Lack of necessary silence, especially at night, leads to premature fatigue. High-level noises can be good soil for the development of persistent insomnia, neuroses and atherosclerosis.

Under the influence of noise from 85 – 90 dB, hearing sensitivity at high frequencies decreases. A person complains of feeling unwell for a long time. Symptoms: headache, dizziness, nausea, excessive irritability. All this is the result of working in noisy conditions.

11. Measures to combat noise problems.

Noise protection equipment is divided into collective and individual protection equipment.

Measures to reduce noise should be included at the design stage of industrial facilities and equipment. Particular attention should be paid to the removal of noisy equipment to a separate room, which allows reducing the number of workers in conditions of high noise levels and implementing noise reduction measures with minimal costs,

equipment and materials. Noise reduction can only be achieved by silencing all equipment with high noise levels.

Work on noise reduction of existing production equipment in a room begins with the compilation of noise maps and noise spectra of equipment and production premises, on the basis of which a decision is made regarding the direction of work.

Combating noise at its source - the most effective way to combat noise. Low-noise mechanical transmissions are being created, and methods are being developed to reduce noise in bearing units and fans.

Architectural and planning aspect of collective noise protection is associated with the need to take into account noise protection requirements in planning and development projects for cities and neighborhoods. It is expected to reduce the noise level through the use of screens, territorial breaks, noise protection structures, zoning and zoning of sources and protection objects, and protective landscaping strips.

Organizational and technical means of noise protection are associated with the study of noise generation processes in industrial installations and units, transport machines, technological and engineering equipment, as well as with the development of more advanced low-noise design solutions, standards for maximum permissible noise levels of machines, units, vehicles, etc.

Acoustic noise protection are divided into means of sound insulation, sound absorption and noise mufflers.

12. Electromagnetic field and man.

An electromagnetic field is a special form of matter, which is an interconnected electric and magnetic field.

The effect of electromagnetic radiation on the human body is mainly determined by the energy absorbed in it. It is known that radiation falling on the human body is partially reflected and partially absorbed in it. The absorbed part of the electromagnetic field energy is converted into thermal energy. This part of the radiation passes through the skin and spreads in the human body depending on the electrical properties of tissues (absolute dielectric constant, absolute magnetic permeability, specific conductivity) and the frequency of oscillations of the electromagnetic field.

In addition to the thermal effect, electromagnetic radiation causes the polarization of molecules in human body tissues, the movement of ions, the resonance of macromolecules and biological structures, nervous reactions and other effects.

From the above it follows that when a person is irradiated with electromagnetic waves, the most complex physical and biological processes occur in the tissues of his body, which can cause a disruption in the normal functioning of both individual organs and the body as a whole.

People working under excessive electromagnetic radiation usually get tired quickly and complain of headaches, general weakness, and pain in the heart area. Their sweating increases, irritability increases, and their sleep becomes disturbed. In some individuals, with prolonged irradiation, convulsions appear, a decrease in memory is observed, and trophic phenomena are noted (hair loss, brittle nails, etc.).

Group II:

I. Selected sources.

Single vehicles, electrical transformers,

Intake or exhaust openings of ventilation systems,

Installation of industrial or energy plants.

II. Complex sources.

Traffic flows on the streets and roads,

Train flows on the railway,

Industrial plants with multiple noise sources,

Sports or playgrounds.

From a physical point of view, most of the individual noise sources are point emitters of sound energy.

4.2 City zones by noise level.

1. Transport highways.

2. Industrial zones.

3. Nature protection zones.

4. residential development.

4.3 Basic methods of protecting residential buildings and premises in residential and other buildings from external noise.

1. Zoning of the territory.

When using line building techniques on highways of regional and general district importance, between the ends of buildings facing the roadway → structures are installed to shield the distribution of noise into the intra-block space (shops, canopy walls, noise protection strips).

2. Organization of intracity transport by organizing loop (ring) or chord express roads around the central zone.

Provide for the routing of expressways and freight roads bypassing residential areas and recreation areas.

3. Green spaces.

Noise-proof qualities are improved when formed in the form of special multi-row plantings.

Particular attention is paid to the improvement and landscaping of the territory of sanitary protection zones, industrial and household facilities.

4. Shielding structures.

1.-bioprotective noise walls.

Green noise protection screens are multifunctional structures in which noise protection functions are enhanced by greening the front surface and top of the wall.

2.noise barriers and screens.

The relief (hills, embankments, towers) has a great influence → a sound shadow is formed behind such natural screens.

3. Soundproof houses.

Such a house has a considerable length and can protect an entire neighborhood from noise.

I. Orientation towards noise sources from windows and utility rooms, apartments and non-apartment communications premises, as well as no more than one common room in multi-room apartments.

II. By increasing the sound insulation of external enclosing structures.

5. Architectural and planning methods for reducing noise levels from internal sources in premises for various purposes.

1. The structure of noise-proof buildings of the first type is orientation towards the noise source of the windows of the utility rooms of the apartments.

2. Frame-panel residential building.

1 type is divided into: - multi-section

Bellhops

Corridor-sectional.

Development of noise-proof block sections of multi-section residential buildings.

The presence of only vertical non-residential connections.

Placement of most utility rooms near the outer wall, facing the noise source.

The location of the staircases with their long sides along the outer wall facing the sound source.

The use of different spans for residential and utility rooms, ensuring, when the areas of residential and utility rooms differ, some leveling of their light? (sound) front.

Soundproof windows.

Multilayer fencing.

Zoning is the main method.

Rice. 70. Noise from various sources (dB)

operating frequencies 63, 125, 250, 500, 1000, 2000, 4000, 8000 Hz. An approximate noise assessment can also be made using sound levels measured on the A scale of a sound level meter (dB A).
Intermittent noise is rated in equivalent sound levels, which is the average sound level of intermittent noise that has the same impact on a person as constant noise of the same level.
Natural sounds do not affect human environmental well-being: the rustling of leaves and the measured noise of the sea surf correspond to approximately 20 dB. Sound discomfort is created by anthropogenic noise sources with high (more than 60 dB) noise levels, which cause numerous complaints. Noise levels below 80 dB do not cause any danger to hearing, at 85 dB some hearing impairment begins, and at 90 dB serious hearing impairment occurs; at 95 dB the probability of hearing loss is 50%, and at 105 dB hearing loss is observed in almost all persons exposed to noise. A noise level of 110-120 dB is considered the pain threshold, and above 130 dB is a destructive limit for the hearing organ.
The human hearing organ can adapt to certain constant or repetitive noises (auditory adaptation). But this adaptability cannot protect against hearing loss, but only temporarily delays its onset. In urban noise conditions, the auditory analyzer is constantly stressed. This causes an increase in the hearing threshold by 10-25 dB. Noise makes it difficult to understand speech, especially at noise levels greater than 70 dB.
Currently, more than half the population of Western Europe lives in areas with noise levels of 55-65 dB: in France - 57% of the population, in the Netherlands - 54%, Greece - 50%, Sweden - 37%, Denmark and Germany - 34%. In Moscow, areas where the permissible noise level is periodically exceeded reach 60%.
Noise as an environmental factor leads to increased fatigue, decreased mental activity, neuroses, increased cardiovascular diseases, noise stress, impaired vision, etc. Constant noise can cause overstrain of the central nervous system, which is why residents of noisy areas of the city are on average 20% more likely to suffer from cardiovascular diseases and 18-23% more likely to suffer from atherosclerosis and nervous system disorders. Noise has a particularly negative effect on the functional state of the cardiac system in children.
Excessive street noise is the cause of 80% of migraines in France, about 50% of memory disorders and the same number of spoiled characters.
Noise contributes to the development of neuroses, which affect a quarter of men and a third of women in the UK. According to French psychiatrists, a fifth of all psychiatric patients lost their minds as a result of exposure to loud noise. In New York, children have been noted to have stunted growth and mental development due to excessive noise.
Noise in big cities shortens human life expectancy. According to Australian researchers, noise causes 30% of the aging of city residents, reducing life expectancy by 8-12 years, pushing people to violence, suicide, and murder.
Currently, noise irritation is an important cause of sleep disorders, and such disturbances affect the efficiency of rest and can lead to a state of chronic fatigue, drowsiness with all the ensuing consequences for performance and susceptibility to disease. At night, noise can accumulate cumulatively. Night noise of 55 dB causes the same physiological effects as daytime noise of 65 dB; noise of 65-67 dB, repeated more than 5 times a night, has significant harm to human health. The threshold value of the noise level that can cause sleep disturbance is, depending on various reasons, on average 40-70 dB: in children it reaches 50 dB, in adults - 30 dB, and in older people - much lower. Noise has the greatest concern on people engaged in mental work, compared to those working physically.
Depending on the origin, they distinguish between household noise, industrial noise, industrial noise, transport noise, aviation noise, street traffic noise, etc. Household noise arises in residential premises from the operation of television and radio equipment, household appliances and human behavior. Industrial noise is created in industrial premises by operating mechanisms and machines. The source of industrial noise is industrial enterprises, among which are power plants, compressor stations, metallurgical plants, and construction enterprises that create high noise levels (more than 90-100 dB). Somewhat less noise occurs during the operation of machine-building plants (80 dB), printing houses, clothing factories, woodworking plants (72-76 dB).
Traffic noise is created by the engines, wheels, brakes and aerodynamic features of vehicles. The noise level generated by the operation of road transport (buses, cars and trucks) is 75-85 dB. Railway transport can increase the noise level to 90-100 dB. The strongest noise - aviation - is created by the operation of the engine and the aerodynamic characteristics of the aircraft - up to 100-105 dB above the air transport route. In airport areas, there is a statistically significant increase in the number of stillbirths and congenital anomalies. Aircraft noise also leads to an increase in mental disorders. The maximum permissible level of this noise at the surface of the earth is determined to be 50 dB.
Traffic noise is a combination of traffic noise and all sounds of the street (traffic controllers' whistles, pedestrian footsteps, etc.).
Transport noise arising from vehicle traffic accounts for up to 80% of all city noise. In recent decades, noise levels in large cities have increased by 10-15 dB. Traffic flows on regional highways near large cities during peak hours reach 2,000 cars per hour, on urban highways - up to 6,000 cars per hour. The increase in noise in large cities is associated with an increase in the power and carrying capacity of transport, an increase in engine speed, the introduction of new engines, etc. Rio de Janeiro is considered the noisiest city in the world; the noise level in one of its districts (Capacabana) significantly exceeds 80 dB. The noise level in Cairo, the largest city in Africa and the Middle East, is 90 dB, and on the main streets of the city it reaches 100 dB. On the roads of Moscow, St. Petersburg and other large cities of Russia, the noise level from transport during the daytime reaches 90-100 dB and even at night in some areas does not fall below 70 dB. Overall, about 35 million people in Russia, representing 30% of the urban population, are significantly affected by traffic noise.
To protect the population from the harmful effects of urban noise, it is necessary to regulate its intensity, spectral composition, duration of action and other parameters. Standards for permissible levels of external noise from various sources are being developed.
During hygienic standardization, a noise level is established as acceptable, the effect of which for a long time does not cause changes in a set of physiological indicators that reflect the reactions of the body systems most sensitive to noise.
Standard sound pressure levels and sound levels for residential and public buildings, residential areas, and recreational areas are established in accordance with sanitary standards for permissible noise (Table 42).
The permissible traffic noise near the walls of houses should not exceed 50 dB during the day and 40 dB at night, and the general noise level in residential premises should not exceed 40 dB during the day and 30 dB at night.
Permissible noise levels in areas of different
for economic purposes
Table 42

Maximum sound levels of 75 dB at night and 85 dB during the day and equivalent sound levels of 55 dB at night and 65 dB during the day can be accepted as acceptable parameters for aircraft noise in residential areas.
A noise map gives an idea of ​​the location of noise sources and the spread of noise in a city. Using this map, you can judge the state of the noise regime of streets, neighborhoods, and the entire urban area. The city noise map makes it possible to regulate the noise level in residential areas of the city, and also serves as the basis for the development of comprehensive urban planning measures to protect residential buildings from noise.
When compiling a city noise map, they take into account traffic conditions on main streets, the intensity and speed of traffic, the number of units of freight and public transport in the flow, the location of industrial facilities, transformer substations, external transport, the payment of housing stock, etc. The map must contain information about the types of buildings being constructed, the location of medical institutions, research institutes, and parks. Existing noise sources with their levels obtained by field measurements are plotted on the city map.
Using the map, you can judge the state of the noise regime on highways and residential areas immediately adjacent to them, and identify the most acoustically dangerous areas. Maps from different years allow us to judge the effectiveness of measures aimed at reducing noise.
In Fig. 71 shows a fragment of a noise map of one of the districts of Karaganda.

Rice. 71. Fragment of a noise map of the city:
1-6 - city streets; noise levels: I - 80 dB A; II - 76 dB A;
III - 65 dB A; IV - 79 dB A; V - 78 dB A; VI - 70 dB A

The presented area is mainly influenced by transport highways (streets 1-2, 4-6) with high traffic intensity, especially freight transport. The area surrounded by these streets is exposed to high intensity noise (78-80 dB A) throughout the day. Even at a distance of 100 m from the roadway, the noise intensity reaches 65 dB A.
Analysis of the noise map shows that the constant growth of the vehicle fleet in the presence of a large number of narrow streets and sidewalks, the lack of necessary landscaping and isolation of microdistricts and blocks from penetrating traffic noise have created the preconditions for increased noise levels in the city. To ensure acoustic comfort for the population, the width of the highway with such intense traffic should be at least 100-120 m.
The noise map makes it possible to identify a set of factors influencing the acoustic regime and recommend the rational placement of functional zones of the city, which makes it possible to weaken or completely eliminate the influence of the main noise sources.
The most common reasons for increased noise levels are: insufficient territorial separation to ensure noise protection of populated areas, public recreation areas, resorts, and treatment centers; violation of regulatory documents or failure to take into account sanitary standards during the construction and design of main roads and railways, and airport locations; an increase in noise levels from year to year due to the lack of new silent modes of transport and an increase in the power of aircraft jet engines; high cost of noise protection structures, lack of technical and economic developments in this area.
These reasons mainly determine the promising set of measures for noise protection.
Of greatest importance is the method of reducing noise along the path of its propagation, which includes various measures: organizing the necessary territorial gaps between sources of external noise and zones for various economic purposes with standardized noise conditions, rational planning and development of the territory, using the terrain as natural screens, noise-proof landscaping .
Special territorial breaks make it possible to significantly reduce noise levels in residential areas. Sanitary norms and rules provide for the creation of sanitary protection zones between production facilities, transport routes, airfields, sea and river ports and residential buildings. Within the sanitary protection zones, it is allowed to place shielding buildings for non-residential purposes, in which a noise level of 55-60 dB A is allowed. The noise protection properties of screen houses are quite high. Long buildings such as shopping arcades are especially effective. They reduce traffic noise by 20-30 dB A and reliably protect the area within the block. Screen buildings can house garages, workshops, reception centers for consumer service enterprises, canteens, cafes, restaurants, studios, hairdressers, etc. You just shouldn’t place pharmacies, libraries and other institutions in this area, where the noise level should not exceed 40 dB A.
Optimal planning and development of the territory, which helps reduce noise levels, provides for the rational routing of transit highways, laying them outside populated areas and recreation areas; construction of ring and semi-ring roads and bypass railway lines in suburban areas of cities with a population of more than 250 thousand people; localization of intense noise sources in the territory under consideration and separation of residential areas, public recreation areas, tourism from industrial and factory zones and transport sources; removal of the most powerful noise sources outside the territory under consideration or, conversely, removal of housing from the high noise zone.
Highways of categories I and II and railway lines, creating, respectively, an equivalent noise level of 85-87 and 80-83 dB A, should not cross the territory of the suburban area where forest parks, holiday homes, boarding houses, children's camps and medical institutions and sanatoriums, universities and research institutes. Rest houses must be located at a distance of at least 500 m from roads and industrial enterprises and 1 km from the railway.
Industrial enterprises, districts or industrial zones that are sources of noise at elevated levels (70-80 dB A) must be separated from residential buildings by protective zones and located taking into account the prevailing wind direction. At the same time, other factors that negatively affect the environment are also taken into account.
Industrial enterprises whose equivalent noise levels are less than 60 dB A may be located in industrial and residential areas if they do not cause other negative impacts.
Airports should be located outside the city, outside recreation areas. The distance from the boundaries of the airfield runways to the boundaries of the residential area depends on the class of the airfield, the intersection of the flight route with the residential area, and can range from 1 to 30 km.
To reduce noise in urban planning practice, natural shielding structures are used, based on the use of the terrain - excavations, embankments, ravines, etc.
Trees and shrubs planted along highways have an exceptional ability to delay and absorb noise impacts. A multi-row strip of trees and shrubs 5-6 m high can significantly reduce noise levels; Wide stripes have the greatest effect - with a stripe width of 25-30 m, a decrease in noise level by 10-12 dB A is observed. However, in winter, the protective function of green spaces decreases by 3-4 times.
When developing detailed planning projects and highway development, a protective effect can be achieved through zoning of residential areas. In the zone immediately adjacent to the highway, low-rise buildings for non-residential purposes should be located, in the next zone - low-rise residential buildings, then - high-rise residential buildings, and in the zone furthest from the highway - children's institutions, schools, clinics, hospitals, etc.
A significant reduction in noise level is achieved with a closed type of development (Table 43).
Efficiency of gas-noise development and relief elements
Table 43

Every year, noise pollution in large cities is constantly growing. The main sources of noise are automobiles, air and rail transport, and industrial enterprises. 80% of the total noise comes from vehicles.

Normal background noise is considered to be sounds of twenty to thirty decibels. A sound background of about 80 decibels is considered acceptable for human perception. Noises of 140 decibels cause pain in people. And with a sound louder than 190 decibels, metal structures begin to collapse.

Health effects of noise

It is difficult to overestimate the impact of noise on people's health. Noises depress the nervous system, interfere with concentration, tire, and cause irritability. Constantly being in an area of ​​noise pollution leads to sleep disturbances and hearing impairment. Noise exposure can even cause mental disorders.

The amount of noise exposure varies for each person. Those at maximum risk are children, the elderly, people suffering from chronic diseases, residents of 24-hour busy areas of the city, living in buildings without sound insulation.

When spending a long time on busy avenues, where the noise level is about 60 dB, for example, while standing in a traffic jam, a person’s cardiovascular activity may be impaired.

Noise protection

To protect the population from noise pollution, WHO recommends a number of measures. Among them is a ban on construction work at night. Another ban, according to WHO, should concern the loud operation of any acoustic devices, both at home and in cars and public institutions located not far from residential buildings.
You need and can fight noise!

Methods to combat noise pollution include acoustic screens, which have recently been widely used near highways, especially in Moscow and the region. Soft asphalt and electric cars, unfortunately not yet widespread, are also ways to combat acoustic pollution in cities. To this list we can add soundproofing insulation of apartment buildings and landscaping of city squares.

Legislative acts in the field of noise control

In Russia, from time to time, interesting studies of the problem of noise in urban settlements appear, but at the federal, regional and municipal levels there are no special-purpose regulations adopted to combat noise pollution. Today, the legislation of the Russian Federation contains only separate provisions on protecting the environment from noise and protecting people from its harmful effects.

In many European countries. America and Asia have special laws. It's time for our turn to come. In the Russian Federation, a special law and by-laws should be adopted on noise and economic instruments to combat it.

It is still possible to resist noise

If the residents of the house understand that background noise and vibrations exceed the maximum permissible level (MAL), they can contact Rospotrebnadzor with a complaint and a request for a sanitary and epidemiological examination of the place of residence. If, based on the results of the inspection, an increase in the maximum limit is established, the violator will be asked to ensure the operation of the technical equipment (if it was the one that caused the excess) in accordance with the standards.

It is possible to contact regional and local administrations of settlements with a requirement for noise-proof reconstruction of the building. Problems of combating sound pollution of the environment can also be solved at the level of individual enterprises. Thus, anti-acoustic systems are built near railway lines, close to industrial facilities (for example, power plants) and protect residential and park areas of the city.

Rice. 70. Noise from various sources (dB)

operating frequencies 63, 125, 250, 500, 1000, 2000, 4000, 8000 Hz. An approximate noise assessment can also be made using sound levels measured on the A scale of a sound level meter (dB A).
Intermittent noise is rated in equivalent sound levels, which is the average sound level of intermittent noise that has the same impact on a person as constant noise of the same level.
Natural sounds do not affect human environmental well-being: the rustling of leaves and the measured noise of the sea surf correspond to approximately 20 dB. Sound discomfort is created by anthropogenic noise sources with high (more than 60 dB) noise levels, which cause numerous complaints. Noise levels below 80 dB do not cause any danger to hearing, at 85 dB some hearing impairment begins, and at 90 dB serious hearing impairment occurs; at 95 dB the probability of hearing loss is 50%, and at 105 dB hearing loss is observed in almost all persons exposed to noise. A noise level of 110-120 dB is considered the pain threshold, and above 130 dB is a destructive limit for the hearing organ.
The human hearing organ can adapt to certain constant or repetitive noises (auditory adaptation). But this adaptability cannot protect against hearing loss, but only temporarily delays its onset. In urban noise conditions, the auditory analyzer is constantly stressed. This causes an increase in the hearing threshold by 10-25 dB. Noise makes it difficult to understand speech, especially at noise levels greater than 70 dB.
Currently, more than half the population of Western Europe lives in areas with noise levels of 55-65 dB: in France - 57% of the population, in the Netherlands - 54%, Greece - 50%, Sweden - 37%, Denmark and Germany - 34%. In Moscow, areas where the permissible noise level is periodically exceeded reach 60%.
Noise as an environmental factor leads to increased fatigue, decreased mental activity, neuroses, increased cardiovascular diseases, noise stress, impaired vision, etc. Constant noise can cause overstrain of the central nervous system, which is why residents of noisy areas of the city are on average 20% more likely to suffer from cardiovascular diseases and 18-23% more likely to suffer from atherosclerosis and nervous system disorders. Noise has a particularly negative effect on the functional state of the cardiac system in children.
Excessive street noise is the cause of 80% of migraines in France, about 50% of memory disorders and the same number of spoiled characters.
Noise contributes to the development of neuroses, which affect a quarter of men and a third of women in the UK. According to French psychiatrists, a fifth of all psychiatric patients lost their minds as a result of exposure to loud noise. In New York, children have been noted to have stunted growth and mental development due to excessive noise.
Noise in big cities shortens human life expectancy. According to Australian researchers, noise causes 30% of the aging of city residents, reducing life expectancy by 8-12 years, pushing people to violence, suicide, and murder.
Currently, noise irritation is an important cause of sleep disorders, and such disturbances affect the efficiency of rest and can lead to a state of chronic fatigue, drowsiness with all the ensuing consequences for performance and susceptibility to disease. At night, noise can accumulate cumulatively. Night noise of 55 dB causes the same physiological effects as daytime noise of 65 dB; noise of 65-67 dB, repeated more than 5 times a night, has significant harm to human health. The threshold value of the noise level that can cause sleep disturbance is, depending on various reasons, on average 40-70 dB: in children it reaches 50 dB, in adults - 30 dB, and in older people - much lower. Noise has the greatest concern on people engaged in mental work, compared to those working physically.
Depending on the origin, they distinguish between household noise, industrial noise, industrial noise, transport noise, aviation noise, street traffic noise, etc. Household noise arises in residential premises from the operation of television and radio equipment, household appliances and human behavior. Industrial noise is created in industrial premises by operating mechanisms and machines. The source of industrial noise is industrial enterprises, among which are power plants, compressor stations, metallurgical plants, and construction enterprises that create high noise levels (more than 90-100 dB). Somewhat less noise occurs during the operation of machine-building plants (80 dB), printing houses, clothing factories, woodworking plants (72-76 dB).
Traffic noise is created by the engines, wheels, brakes and aerodynamic features of vehicles. The noise level generated by the operation of road transport (buses, cars and trucks) is 75-85 dB. Railway transport can increase the noise level to 90-100 dB. The strongest noise - aviation - is created by the operation of the engine and the aerodynamic characteristics of the aircraft - up to 100-105 dB above the air transport route. In airport areas, there is a statistically significant increase in the number of stillbirths and congenital anomalies. Aircraft noise also leads to an increase in mental disorders. The maximum permissible level of this noise at the surface of the earth is determined to be 50 dB.
Traffic noise is a combination of traffic noise and all sounds of the street (traffic controllers' whistles, pedestrian footsteps, etc.).
Transport noise arising from vehicle traffic accounts for up to 80% of all city noise. In recent decades, noise levels in large cities have increased by 10-15 dB. Traffic flows on regional highways near large cities during peak hours reach 2,000 cars per hour, on urban highways - up to 6,000 cars per hour. The increase in noise in large cities is associated with an increase in the power and carrying capacity of transport, an increase in engine speed, the introduction of new engines, etc. Rio de Janeiro is considered the noisiest city in the world; the noise level in one of its districts (Capacabana) significantly exceeds 80 dB. The noise level in Cairo, the largest city in Africa and the Middle East, is 90 dB, and on the main streets of the city it reaches 100 dB. On the roads of Moscow, St. Petersburg and other large cities of Russia, the noise level from transport during the daytime reaches 90-100 dB and even at night in some areas does not fall below 70 dB. Overall, about 35 million people in Russia, representing 30% of the urban population, are significantly affected by traffic noise.
To protect the population from the harmful effects of urban noise, it is necessary to regulate its intensity, spectral composition, duration of action and other parameters. Standards for permissible levels of external noise from various sources are being developed.
During hygienic standardization, a noise level is established as acceptable, the effect of which for a long time does not cause changes in a set of physiological indicators that reflect the reactions of the body systems most sensitive to noise.
Standard sound pressure levels and sound levels for residential and public buildings, residential areas, and recreational areas are established in accordance with sanitary standards for permissible noise (Table 42).
The permissible traffic noise near the walls of houses should not exceed 50 dB during the day and 40 dB at night, and the general noise level in residential premises should not exceed 40 dB during the day and 30 dB at night.
Permissible noise levels in areas of different
for economic purposes
Table 42

Maximum sound levels of 75 dB at night and 85 dB during the day and equivalent sound levels of 55 dB at night and 65 dB during the day can be accepted as acceptable parameters for aircraft noise in residential areas.
A noise map gives an idea of ​​the location of noise sources and the spread of noise in a city. Using this map, you can judge the state of the noise regime of streets, neighborhoods, and the entire urban area. The city noise map makes it possible to regulate the noise level in residential areas of the city, and also serves as the basis for the development of comprehensive urban planning measures to protect residential buildings from noise.
When compiling a city noise map, they take into account traffic conditions on main streets, the intensity and speed of traffic, the number of units of freight and public transport in the flow, the location of industrial facilities, transformer substations, external transport, the payment of housing stock, etc. The map must contain information about the types of buildings being constructed, the location of medical institutions, research institutes, and parks. Existing noise sources with their levels obtained by field measurements are plotted on the city map.
Using the map, you can judge the state of the noise regime on highways and residential areas immediately adjacent to them, and identify the most acoustically dangerous areas. Maps from different years allow us to judge the effectiveness of measures aimed at reducing noise.
In Fig. 71 shows a fragment of a noise map of one of the districts of Karaganda.

Rice. 71. Fragment of a noise map of the city:
1-6 - city streets; noise levels: I - 80 dB A; II - 76 dB A;
III - 65 dB A; IV - 79 dB A; V - 78 dB A; VI - 70 dB A

The presented area is mainly influenced by transport highways (streets 1-2, 4-6) with high traffic intensity, especially freight transport. The area surrounded by these streets is exposed to high intensity noise (78-80 dB A) throughout the day. Even at a distance of 100 m from the roadway, the noise intensity reaches 65 dB A.
Analysis of the noise map shows that the constant growth of the vehicle fleet in the presence of a large number of narrow streets and sidewalks, the lack of necessary landscaping and isolation of microdistricts and blocks from penetrating traffic noise have created the preconditions for increased noise levels in the city. To ensure acoustic comfort for the population, the width of the highway with such intense traffic should be at least 100-120 m.
The noise map makes it possible to identify a set of factors influencing the acoustic regime and recommend the rational placement of functional zones of the city, which makes it possible to weaken or completely eliminate the influence of the main noise sources.
The most common reasons for increased noise levels are: insufficient territorial separation to ensure noise protection of populated areas, public recreation areas, resorts, and treatment centers; violation of regulatory documents or failure to take into account sanitary standards during the construction and design of main roads and railways, and airport locations; an increase in noise levels from year to year due to the lack of new silent modes of transport and an increase in the power of aircraft jet engines; high cost of noise protection structures, lack of technical and economic developments in this area.
These reasons mainly determine the promising set of measures for noise protection.
Of greatest importance is the method of reducing noise along the path of its propagation, which includes various measures: organizing the necessary territorial gaps between sources of external noise and zones for various economic purposes with standardized noise conditions, rational planning and development of the territory, using the terrain as natural screens, noise-proof landscaping .
Special territorial breaks make it possible to significantly reduce noise levels in residential areas. Sanitary norms and rules provide for the creation of sanitary protection zones between production facilities, transport routes, airfields, sea and river ports and residential buildings. Within the sanitary protection zones, it is allowed to place shielding buildings for non-residential purposes, in which a noise level of 55-60 dB A is allowed. The noise protection properties of screen houses are quite high. Long buildings such as shopping arcades are especially effective. They reduce traffic noise by 20-30 dB A and reliably protect the area within the block. Screen buildings can house garages, workshops, reception centers for consumer service enterprises, canteens, cafes, restaurants, studios, hairdressers, etc. You just shouldn’t place pharmacies, libraries and other institutions in this area, where the noise level should not exceed 40 dB A.
Optimal planning and development of the territory, which helps reduce noise levels, provides for the rational routing of transit highways, laying them outside populated areas and recreation areas; construction of ring and semi-ring roads and bypass railway lines in suburban areas of cities with a population of more than 250 thousand people; localization of intense noise sources in the territory under consideration and separation of residential areas, public recreation areas, tourism from industrial and factory zones and transport sources; removal of the most powerful noise sources outside the territory under consideration or, conversely, removal of housing from the high noise zone.
Highways of categories I and II and railway lines, creating, respectively, an equivalent noise level of 85-87 and 80-83 dB A, should not cross the territory of the suburban area where forest parks, holiday homes, boarding houses, children's camps and medical institutions and sanatoriums, universities and research institutes. Rest houses must be located at a distance of at least 500 m from roads and industrial enterprises and 1 km from the railway.
Industrial enterprises, districts or industrial zones that are sources of noise at elevated levels (70-80 dB A) must be separated from residential buildings by protective zones and located taking into account the prevailing wind direction. At the same time, other factors that negatively affect the environment are also taken into account.
Industrial enterprises whose equivalent noise levels are less than 60 dB A may be located in industrial and residential areas if they do not cause other negative impacts.
Airports should be located outside the city, outside recreation areas. The distance from the boundaries of the airfield runways to the boundaries of the residential area depends on the class of the airfield, the intersection of the flight route with the residential area, and can range from 1 to 30 km.
To reduce noise in urban planning practice, natural shielding structures are used, based on the use of the terrain - excavations, embankments, ravines, etc.
Trees and shrubs planted along highways have an exceptional ability to delay and absorb noise impacts. A multi-row strip of trees and shrubs 5-6 m high can significantly reduce noise levels; Wide stripes have the greatest effect - with a stripe width of 25-30 m, a decrease in noise level by 10-12 dB A is observed. However, in winter, the protective function of green spaces decreases by 3-4 times.
When developing detailed planning projects and highway development, a protective effect can be achieved through zoning of residential areas. In the zone immediately adjacent to the highway, low-rise buildings for non-residential purposes should be located, in the next zone - low-rise residential buildings, then - high-rise residential buildings, and in the zone furthest from the highway - children's institutions, schools, clinics, hospitals, etc.
A significant reduction in noise level is achieved with a closed type of development (Table 43).
Efficiency of gas-noise development and relief elements
Table 43