Clean atmospheric air at the Earth's surface is a mechanical mixture of various gases, among which nitrogen, oxygen, argon, carbon dioxide and a number of other gases are contained in descending order by volume, the total amount of which does not exceed 1%.

The composition of clean dry atmospheric air in volume percent is shown in fig. 1.2,

During the day at rest, an adult passes 13-14 m3 of air through the lungs - a significant volume that increases when performing physical activity. This means that the body is not indifferent to the air of what chemical composition it breathes.

Oxygen is the most important air gas for life. It is consumed in the body for oxidative processes, entering through the lungs into the blood, and delivered to the tissues and cells of the body as part of oxyhemoglobin,

Rice. 1.2. The chemical composition of atmospheric air at normal conditions.

In the environment, oxygen is also necessary for the oxidation of organic substances found in water, air and soil, as well as for supporting combustion processes.

The source of oxygen in the atmosphere is green plants, which form it under the action of solar radiation in the process of photosynthesis and releasing into the air during respiration, we are talking about the phytoplankton of the seas and oceans, as well as plants of tropical forests and evergreen taiga, which are figuratively called the "lungs of the planet".

Green plants form oxygen in very large quantities, and due to the constant mixing of atmospheric air layers, its content in atmospheric air remains practically constant everywhere - about 21%. Low oxygen concentrations, essential for the life of the human body, are observed when climbing to a height and when people stay in hermetically sealed rooms in case of emergencies when technical means of life support are violated. An increased oxygen content is noted under conditions of high atmospheric pressure (in caissons). At partial pressure over 600 mm Hg. it behaves like a toxic substance, causing pulmonary edema and pneumonia.

Atmospheric air contains a dynamic isomer of oxygen - triatomic oxygen - ozone, which is the strongest oxidizing agent. It is formed in natural conditions V upper layers atmosphere under the influence of short-wave ultraviolet radiation of the Sun, during lightning discharges, in the process of water evaporation.

Ozone plays an important role in protecting the biological objects of the planet from the harmful effects of hard ultraviolet radiation, retaining it in the stratosphere at an altitude of 20-30 km.

Ozone has a peculiar pleasant smell of freshness, and its presence can be easily detected in the forest after a thunderstorm, in the mountains, in a clean natural environment, where it is considered an indicator of the purity of the air. However, an excess of ozone is unfavorable for the life of the organism, and starting from a concentration of 0.1 mg/m3 it acts as an irritating gas.

The presence of ozone in the air of large industrial cities, polluted by emissions from vehicles and industrial facilities, in the light of recent scientific data, is considered an unfavorable sign, since under these conditions it is formed as a result of photochemical reactions during the formation of smog.

The high oxidizing power of ozone is used in water disinfection.

Carbon dioxide, or carbon dioxide, enters the air during the breathing of people, animals, plants (at night), the oxidation of organic substances during combustion, fermentation, decay, being in the environment in free and bound states.

The constancy of the content of this gas at the level of 0.03% in the atmosphere is ensured by its absorption in the light by green plants, dissolution in the water of the seas and oceans, and removal with atmospheric precipitation.

Significant amounts of CO2 are formed as a result of the work of industrial enterprises and vehicles that burn huge amounts of fuel, as a result of which last years there is evidence that the content carbon dioxide in the air of large modern cities approaches 0.04%, which causes concern among environmentalists about the formation of a "greenhouse effect", which will be discussed in more detail later.

Carbon dioxide is involved in the metabolic processes of the body, being a physiological causative agent of the respiratory center.

Inhalation of high concentrations of CO2 disrupts redox processes, and its accumulation in the blood and tissues leads to tissue anoxia. Long-term stay of people in enclosed spaces (residential, industrial, public) is accompanied by the release into the air of their metabolic products: carbon dioxide with exhaled air and volatile organic compounds (ammonia, hydrogen sulfide, indole, mercaptan), called anthropotoxins, from the surface of the skin, dirty shoes and clothes. There is also a slight decrease in the content of oxygen in the air. Under these conditions, people may complain of a deterioration in well-being, decreased performance, drowsiness, headache and other functional symptoms. What explains this symptom complex? It can be assumed that the reason lies in the lack of oxygen, the amount of which, as already mentioned, is somewhat reduced compared to its content in atmospheric air. However, it was found that its decrease in the most unfavorable conditions does not exceed 1%, since, due to the leakage of these rooms, oxygen easily penetrates from the atmosphere into the air of the rooms, replenishing its supply. The human body does not respond to such a decrease in oxygen content. Sick people note a decrease in oxygen in the air, if it is 18%, healthy people - 16%. Life is impossible with an oxygen concentration in the air equal to 7-8%. However, these oxygen concentrations never occur in leaky spaces, but they can be found in a sunken submarine, a collapsed mine, and other sealed spaces. Therefore, in non-hermetic rooms, a decrease in the oxygen content cannot cause a deterioration in people's well-being. Then, isn't this reason for the accumulation of excess carbon dioxide in the indoor air? However, it is known that the unfavorable concentration of CO2 for human health is 4-5% when headache, tinnitus, palpitations, etc. appear. When the content in the air is 8% carbon dioxide, death occurs. The indicated concentrations are typical only for sealed rooms with a faulty life support system. In ordinary enclosed spaces, such concentrations of carbon dioxide cannot be due to the existing constant air exchange with the environment.

However, the CO2 content in the air enclosed spaces has sanitary value, being an indirect indicator of air purity. The fact is that in parallel with the accumulation of CO2, usually not higher than 0.2%, other properties of the air worsen: temperature and humidity, dustiness, the content of microorganisms, the number of heavy ions increase, and anthropotoxins appear. This complex of changed physical properties of air, along with chemical pollution and makes people feel worse. Such a change in the properties of air corresponds to a carbon dioxide content equal to OD%, and therefore this concentration is considered the maximum allowable for indoor air.

In recent years, it has been found that this indicator is not enough to assess the sanitary condition of indoor air, since it is necessary to determine the content of some toxic chemicals released into the air from polymeric building materials widely used for interior decoration premises (phenol, ammonia, formaldehyde, etc.).

Nitrogen and other inert gases. Nitrogen in terms of quantitative content is the most significant part of atmospheric air, accounting for 78.1% and diluting other gases, primarily oxygen. Nitrogen is physiologically indifferent, does not support the processes of respiration and combustion, its content in the atmosphere is constant, its amount in the inhaled and exhaled air is the same. Under conditions of high atmospheric pressure, nitrogen can have a narcotic effect, and its role in the pathogenesis of decompression sickness is also known.

The nitrogen cycle is known in nature, carried out with the help of certain types of soil microflora, plants and animals, as well as electrical discharges in the atmosphere, as a result of which nitrogen is bound by biological objects, and then re-enters the atmosphere.

FEDERAL AGENCY FOR EDUCATION

State educational institution higher professional education

“St. Petersburg Trade and Economic Institute”

Department of Technology and Catering

Essay on the topic: air hygiene

Saint Petersburg

Air hygiene.

Physical properties of air

The chemical composition of air and its sanitary significance.

mechanical impurities.

Sanitary and hygienic standards for permissible levels of air ionization (SanPiN of June 16, 2003)

State and departmental control over compliance with sanitary norms and rules.

Air microflora.

Air pollution and environment.

Environmental protection.

State of atmospheric air quality and characteristics of atmospheric pollution sources.

We are not afraid of CO2.

Requirements for ventilation and heating

List of used literature:

The air environment consists of gaseous substances necessary for human life. It provides mechanisms for heat exchange and functions of human organs that orient it in space (vision, hearing, smell), and also serves as a natural reservoir in which gaseous metabolic products of living organisms and industrial waste are neutralized. Along with this, the air environment, with a significant change in its natural physical and chemical properties, bacteriological and dust pollution, can cause various human diseases. Sources of air pollution are toxic industrial waste, vehicle exhaust gases, pesticides used in agriculture, etc. In this case, toxic fogs (smog) associated with the accumulation of, for example, sulfur dioxide in the air, are of particular danger, which leads to acute and chronic mass poisoning.

In the hygienic assessment of the air environment, the requirements for atmospheric air and indoor air are considered. Take into account its physical properties, chemical and bacterial composition, the presence of mechanical impurities.

Physical properties of air

The physical properties of air include: temperature, humidity, mobility, barometric pressure, electrical state, intensity of solar radiation, ionizing radioactivity. Each of these factors has independent significance, but they have a complex effect on the body.

When characterizing the hygienic indicators of the air environment, special importance is attached to a complex of physical factors defined as climate. They play a decisive role in the regulation of human heat transfer. These include temperature, relative humidity and air velocity.

In the hygienic assessment of the indoor air, the factors characterizing the climate are united by the concept of indoor microclimate.

Human heat exchange consists of two processes: heat production and heat transfer. Heat production occurs due to the oxidation of nutrients and the release of heat during muscle contractions. Some of the heat enters the body from the outside due to solar energy, heated objects and hot food. Heat transfer is carried out by conduction, or convection (due to the difference in body and air temperatures), radiation, or radiation (due to the difference in body and object temperatures), and evaporation (from the surface of the skin, through the lungs and respiratory tract). In a state of rest and comfort, human heat loss is: convection - about 30%, radiation - 45, evaporation - 25%.

A person has the ability to regulate the intensity of heat production and heat transfer, due to which the temperature of his body remains, as a rule, constant. However, with significant changes in the meteorological factors of the environment, the state of thermal equilibrium can be disturbed and cause pathological changes in the body - overheating or hypothermia.

Optimal microclimate - These are indicators of the microclimate that, when exposed to a person for a long time, ensure the preservation of the normal thermal state of the body without straining the mechanisms of thermoregulation and provide a feeling of thermal comfort.

The optimal values ​​of meteorological conditions for a person in production conditions differ depending on the category of work according to the severity, i.e., depending on the total energy consumption of the body (in kcal / h) And period of the year. For example, when physical work medium severity (category II) with energy consumption in the range of 151-250 kcal / h (175-290 W) optimal microclimate values ​​in cold period year (the average daily temperature of the outside air is equal to or below 10 ° C) are characterized by the following indicators: temperature 17-20 "C, relative humidity 40-60%, air speed 0.2 m / s.

Thanks to the mechanisms of thermoregulation, a person relatively easily tolerates significant deviations in air temperature from a comfortable one and is even able to endure short-term exposure to air temperature. 100 in C and higher.

When the air temperature rises compensatory reactions of the body lead to some decrease in heat production and increased heat transfer from the skin surface. If an increase in air temperature is accompanied by a deviation from the norm and other meteorological factors (humidity, air movement, intensity of thermal radiation), then the violation of thermoregulation occurs much faster. So, under normal relative humidity air (40%), violation of the body's thermoregulation occurs at an air temperature above 40 "C, and at a relative humidity of 80-90% - already at 31-32" C. In conditions high temperatures and high humidity, a person is freed from excess heat mainly due to the evaporation of moisture from the surface of the skin. For example, moisture loss in a hot shop can reach about 10 liters per day for a worker. Together with sweat, salts, water-soluble vitamins B and C are removed from the body. The loss of chlorides and water with profuse sweating leads to tissue dehydration, inhibition of gastric secretion. In addition, the processes of inhibition in the central nervous system are intensifying, there is a weakening of attention, impaired coordination of movements, which increases industrial injuries. It is especially difficult for a person to endure elevated temperatures and humidity of still air. Under these conditions, all mechanisms of heat transfer are suppressed in the body.

Sudden overheating of the body can lead to the development of heat stroke, which manifests itself in the form of weakness, dizziness, tinnitus, palpitations, and in severe cases, fever, neuropsychic agitation or loss of consciousness. It should be noted that the presence of heated surfaces enhances the state of overheating of the body due to the characteristics of the biological effect of radiation heat. In accordance with the laws of heat radiation (Kirchhoff, Stefan-Boltzmann, Wien), the thermal radiation of a heated object is more intense than the increase in its temperature, and the spectral composition of the radiation, as the object heats up, shifts towards shorter waves and, therefore, causes a deeper penetrating effect heat to the body.

In the production shops of enterprises Catering The most important hygienic task is to prevent overheating of the body. To this end, it is planned to remove excess heat with the help of general and local ventilation, the use of advanced designs of thermal apparatus, the use of rational overalls.

Low air temperatures(especially in combination with high humidity and mobility) can lead to diseases associated with hypothermia. Under these conditions, the temperature of the skin decreases, the contractility of muscles, especially the hands, decreases, which affects the working capacity of a person. With deep cooling, reactions to painful stimuli are weakened as a result of the narcotic effect of cold, and the body's resistance to infectious diseases decreases. For example, local cooling of hands during prolonged unloading of frozen meat, fish, washing vegetables cold water leads to circulatory disorders, which is a cold factor.

In this regard, it is very important for enterprises to observe hygienic measures that prevent hypothermia of the body: a local ventilation device that excludes cold air flows (drafts) in the working area, organizing hand warming during prolonged work with cold objects, designing insulated vestibules, etc.

Air humidity affects the human body in combination with air temperature.

In order to prevent both overheating and hypothermia in industrial premises, special importance is attached to the normalization of allowable indicators of temperature, relative humidity and air velocity in the working area, depending on the categories of work by severity and period of the year (Table 1).

It should be remembered that in order to ensure acceptable microclimate indicators, it is necessary to use means of protecting workplaces from cooling due to the glazing of window openings during the cold period, and from falling into working area direct sunlight.

Of the above physical properties of the air environment, an important hygienic indicator is the nature and degree of its ionization.

Air ionization is understood as the transformation of neutral gases of molecules and atoms into ions that carry positive and negative charges. Ionization occurs by the redistribution of electrons between atoms and molecules of gases under the influence of radioactive radiation from the earth and cosmic radiation.

Carbon dioxide is a constituent ingredient of atmospheric air. The concentration of carbon dioxide in the atmospheric air outside the pollution zone is on average 0.03% by volume or 0.046% by weight, which is equal to 591 mg/m3 under normal conditions.

An increase in carbon dioxide in the air leads to irritation of the respiratory center. Prolonged inhalation of air with a high content (8-10%) of carbon dioxide leads to re-irritation of the respiratory center and death from paralysis of the latter. At 15% and above CO2 in the air, death occurs instantly from paralysis of the respiratory center. Humans are more sensitive to excess carbon dioxide than animals. Already at the content of CO2 in the air in the amount of 3%, respiration noticeably accelerates and deepens; at 4%, there is a feeling of squeezing the head, headache, tinnitus, mental agitation, palpitations, slowing of the pulse and increased pressure, less often - vomiting and fainting.

A further increase in the level of CO2 to 8-10% is accompanied by an increase in the severity of all symptoms and death occurs from paralysis of the respiratory center. The danger of a significant accumulation of CO2 in enclosed spaces is aggravated by the fact that it is accompanied by a simultaneous decrease in the oxygen content in the air.

From a hygienic point of view, carbon dioxide is an important indicator by which the degree of air purity in residential and public buildings is judged.

Carbon dioxide is released during the breathing of people, and the accumulation of large amounts of it in the air of enclosed spaces indicates the sanitary problems of this room (crowding of people, insufficient ventilation). Under normal conditions, with insufficient natural ventilation premises and infiltration of outdoor air through the pores of building materials, the content of carbon dioxide in the air of residential premises can reach 0.2%. Staying in such an atmosphere leads to a deterioration in well-being and a decrease in performance. This is explained by the fact that in parallel with an increase in the amount of carbon dioxide in the air, its properties deteriorate: temperature and humidity increase, foul-smelling gases appear, which are human waste products (mercaptan, indole, skatole, hydrogen sulfide, ammonia), and the content of dust and microorganisms increases. There is a change in the ionization regime of air, an increase in heavy and a decrease in light ions. However, of all the indicators listed above, associated with the deterioration of air properties, carbon dioxide lends itself to the most simple definition, which is why it is taken as a hygienic indicator of air purity in residential and public buildings.

The permissible concentration of carbon dioxide in the air is considered to be 0.07-0.1%. The last value is taken as a calculated one when determining the volume required ventilation and efficiency of ventilation in residential and public buildings.

Method for determining carbon dioxide in air using a photoelectric colorimeter.

The principle of the method is based on the measurement of the optical density of a colored absorbing solution (a mixture of bromthymol blue and NaHCO3) after the interaction of the test air with carbon dioxide. The sensitivity of the method is 0.025% vol.

Air sampling. An air sample for the determination of carbon dioxide is taken into gas pipettes with a capacity of 150-200 ml, pre-filled with a 26% sodium chloride solution. When taking an air sample, the gas pipette is in vertical position. Open the top faucet first, then the bottom faucet. The sodium chloride solution flowing out of the pipette sucks the test air into it. At the end of the air sampling, the latter is delivered to the laboratory.

Work progress. From a gas pipette, the test air in the amount of 50 ml is transferred saline solution in a 100 ml syringe. Then 5 ml of the absorption solution is sucked into the syringe from the burette. After 2 minutes of shaking the test air with an absorption solution, the liquid is placed in a cuvette with a layer thickness of 10 mm and photometered on an LMF-69 instrument at a wavelength of 600 nm (N4 light filter). On the calibration graph, the concentration of carbon dioxide is found from the optical density of the solution.

The main sources of indoor air pollution can be conditionally divided into four groups:

1. Substances entering the room with polluted air. Household dust is the main source of indoor air pollution. It is the smallest particles of various substances that can float in the air. Dust also adsorbs many chemical compounds. The degree of penetration of atmospheric pollution into the building for different chemicals is different. When comparing the concentrations of nitrogen dioxide, nitrogen oxide, carbon monoxide and dust in residential buildings and in the atmospheric air, it was found that these substances are at or below their concentrations in the outdoor air. Concentrations of sulfur dioxide, ozone and lead are usually lower inside than outside. The concentrations of acetaldehyde, acetone, benzene, toluene, xylene, phenol, a number of saturated hydrocarbons in the indoor air exceeded the concentrations in the atmospheric air by more than 10 times.

2. Destruction products polymer materials.

3. Anthropotoxins .

4. Combustion products of household gas and household activities.

One of the most common sources of indoor air pollution is smoking. Cigarette smoke in the home is a direct threat to health. It contains heavy metals, carbon monoxide, nitric oxide, sulfur dioxide, styrene, xylene, benzene, ethylbenzene, nicotine, formaldehyde, phenol, about 16 carcinogens.

Another possible source of air pollution in an apartment is septic tanks in the water supply and sewerage network. The garbage chute also poses a health hazard, especially if the receiving hatches are installed in the kitchen or in the hallway.

Indicators of the sanitary condition of indoor air:

Oxidability (the amount of O2 required for oxidation organic compounds air)

Criteria for assessing the sanitary condition of indoor air.

1. TOTAL MICROBIAL POLLUTION. in 1m3 of air.

2. NUMBER OF SANITARY INDICATIVE AIR MICROBES. IN 250 LITERS OF AIR.

Sanitary-indicative microbes of indoor air are:

1) Staphylococcus aureus

2) a-green streptococcus

3) b-hemolytic streptococcus

These bacteria are indicators of oral droplet contamination. They share a common route of release into the environment with airborne pathogens. The terms of their survival in the environment do not differ from the terms characteristic of most pathogens of airborne infections.

Methods are divided into sedimentation and aspiration.

Carbon dioxide is an indirect indicator of pollution because:

Anthropotoxins in indoor air. Sanitary and hygienic value of carbon dioxide content.

In the course of his life, a person releases about 400 chemical compounds. The air environment of unventilated premises deteriorates in proportion to the number of persons and the time of their stay in the premises. Chemical analysis indoor air made it possible to identify a number of toxic substances in them, the distribution of which according to hazard classes is as follows:

the second class of danger - highly dangerous substances (dimethylamine, hydrogen sulfide, nitrogen dioxide, ethylene oxide, benzene, etc.);

the third hazard class is low-hazard substances (acetic acid, phenol, methylstyrene, toluene, methanol, vinyl acetate, etc.).

Even a two-hour stay in these conditions adversely affects mental performance. With a large crowd of people in the room (classes, audiences), the air becomes heavy.

CO2 value: indirect indicator of indoor air pollution, where the main source is a person.

Carbon dioxide is an indirect indicator of pollution because:

1. CO2 best characterizes a person as a source of indoor air pollution.

2. There is a correlation between the accumulation of CO2 and the denaturation of the air environment (changes in the physical, chemical and microbial composition)

3. There are express methods for determining CO2 (available, reliable, cheap).

Polymeric materials and household gas as sources of air pollution in residential and public buildings. Features of the action of air pollutants on the body. Prevention measures.

Currently, about 100 types of polymeric materials are used only in construction. Almost all polymeric materials emit certain toxic substances into the air. chemical substances that have a detrimental effect on human health.

Fiberglass based on various mixtures used in construction, sound and heat insulation release significant amounts of acetone, methacrylic acid, toluene, butanol, formaldehyde, phenol and styrene into the air. Paints and adhesives are also sources of indoor air pollution.

Many types of beautiful synthetic finishing materials - films, oilcloths, laminates, etc. - distinguish a set harmful substances, for example, methanol, dibutyl phthalate, etc. Carpet products made from chemical fibers emit styrene, isophenol, and sulfur dioxide in significant concentrations. Facilities household chemicals- detergents, cleaners, insecticides, rodents, pesticides, various adhesives, car cosmetics, polishes, varnishes, paints and many others - can cause various diseases in humans, especially if stocks of such substances are stored in a poorly ventilated area.

atmospheric pollution can cause non-communicable diseases in humans, in addition, they can worsen sanitary conditions human lives and cause economic damage.

Biological effect of atmospheric pollution

Atmospheric pollution can have acute and chronic effects .

Measures for the sanitary protection of atmospheric air

1. Legislative

Exists a large number of normative documents regulating the protection of atmospheric air. The Federal Law "On Environmental Protection" states that every citizen has the right to a favorable environment, to its protection from negative impact caused by economic and other activities. The Law "On the Protection of Atmospheric Air" regulates the development and implementation of measures to eliminate and prevent air pollution - the construction of gas cleaning and dust collection devices at industrial enterprises and thermal power plants.

2. Technological

Technological measures are the main measures for the protection of atmospheric air, since only they can reduce or completely eliminate the release of harmful substances into the atmosphere at the place of their formation. These activities are directly directed at the source of emissions.

3. Sanitary.. The purpose of sanitary measures is to extract or neutralize the components of emissions that are in gaseous, liquid or solid form from organized stationary sources. For this, various gas and dust trapping installations are used.

4. Architectural planning

This group of activities includes:

Functional zoning of the city, that is, the allocation functional areas– industrial, external transport zone, suburban, municipal

Rational planning of the territory

Prohibition of the construction of air polluting enterprises in the residential area locality and their placement in the industrial area, taking into account the prevailing wind direction in the area;

Creation of sanitary protection zones. The SPZ is the area around an industrial enterprise or other facility that is a source of environmental pollution, the size of which ensures that the levels of exposure to industrial hazards in a residential area are reduced to the maximum permissible values.

Rational building of streets, arrangement of transport interchanges on the main highways with the construction of tunnels;

Landscaping of the city. Green spaces play the role of a kind of filters, affect the dispersion of industrial emissions in the atmosphere, changing the wind regime and the circulation of air masses.

Selection of a land plot for the construction of an enterprise, taking into account the terrain, aeroclimatic conditions and other factors.

5. Administrative

Rational distribution of traffic flows according to their intensity, composition, time and direction of movement;

Restriction of movement within the residential area of ​​the city of heavy vehicles;

Monitoring the condition of road surfaces and the timeliness of their repair and cleaning;

System for monitoring the technical condition of vehicles.

52. Features of the composition and properties of atm. Air, industrial, residential and public buildings.atmospheric air It has chemical, physical and mechanical properties which have both beneficial and detrimental effects on the human body.

· Chemical properties due to the normal gas composition of the air and harmful gaseous impurities;

· TO physical properties air include:

Atmosphere pressure,

Temperature,

Humidity,

Mobility,

electrical condition,

Solar radiation,

Electromagnetic waves

depends on the physical properties of air climate And weather;

· Mechanical properties air depend on the content of impurities in it of solid particles in the form

And the presence of microorganisms.

The air environment is heterogeneous in physical terms and harmful impurities , which is related to the conditions formation And pollution.

It should be distinguished:

1. Clean atmospheric air;

2. Atmospheric air of industrial regions;

3. indoor air of residential and public buildings;

4. indoor air of industrial enterprises.

These types of air differ from each other in composition and properties, and hence in their effect on the human body.

I.atmospheric air

Physical properties of atmospheric air:

Temperature,

Humidity

Mobility,

Atmosphere pressure,

electrical condition

Physical properties of atmospheric air unstable and associated with climatic features of the geographical region. The presence of gaseous solid impurities in the air ( dust And soot) depends on the nature of air emissions, dilution conditions and self-cleaning processes.

On concentration of harmful substances in the atmosphere are affected by:

1. speed and direction of prevailing winds,

2. temperature, air humidity,

3. precipitation, solar radiation,

4. quantity, quality and height of emissions into the atmosphere.

Air properties of residential and public buildings more stable - in these buildings is supported optimal microclimate through ventilation and heating. Gaseous impurities are associated with the release of human waste products into the air, the release of toxic substances from materials and household items made of polymeric materials, combustion products of household gas, etc. On the properties of air industrial premises features have a significant impact technological process. In some cases, the physical properties of air acquire an independent value of harmful professional factor and air pollution with toxic substances can lead to occupational diseases.

53. Solar radiation is the integral radiation flux emitted by the sun. From a hygienic point of view, of particular interest is the optical part of sunlight, which occupies the range from 280-2800 nm. Longer waves -- radio waves, shorter - gamma rays. AND Onizing radiation does not reach the Earth's surface, because it is retained in the upper layers of the atmosphere, in the ozone layer.

The intensity of solar radiation depends primarily on the height of the sun above the horizon. If the sun is at its zenith, then the path that the sun's rays travel will be much shorter than their path if the sun is near the horizon. By increasing the path, the intensity of solar radiation changes. The intensity of solar radiation also depends on the angle at which the sun's rays fall, and the illuminated area also depends on this (with an increase in the angle of incidence, the area of ​​illumination increases). Thus, the same solar radiation falls on a large surface, so the intensity decreases. The intensity of solar radiation depends on the mass of air through which the sun's rays pass. The intensity of solar radiation in the mountains will be higher than above sea level, because the layer of air through which the sun's rays pass will be less than above sea level. Of particular importance is the impact on the intensity of solar radiation the state of the atmosphere, its pollution. If the atmosphere is polluted, then the intensity of solar radiation decreases (in the city, the intensity of solar radiation is on average 12% less than in rural areas). The voltage of solar radiation has a daily and annual background, that is, the voltage of solar radiation changes during the day, and also depends on the time of year. The greatest intensity of solar radiation is observed in summer, the smallest - in winter. According to its biological effect, solar radiation is heterogeneous: it turns out that each wavelength has a different effect on the human body. In this regard, the solar spectrum is conditionally divided into 3 sections:

1. ultraviolet rays, from 280 to 400 nm

2. visible spectrum from 400 to 760 nm

3. infrared rays from 760 to 2800 nm.

With daily and annual solar radiation, the composition and intensity of individual spectra undergo changes. The greatest changes are exposed to the rays of the UV spectrum.

Solar radiation is a powerful healing and preventive factor.

54. Quantitative and qualitative characteristics of solar radiation. Due to the absorption, reflection and scattering of radiant energy in world space on the surface of the Earth, the solar spectrum is limited, especially in its short-wavelength part. If at the boundary of the earth's atmosphere the UV part is 5%, the visible part is 52%, the infrared part is 43%, then at the Earth's surface the composition of solar radiation is different: the UV part is 1%, the visible part is 40%, the infrared part is 59%. This is due to varying degrees of purity of atmospheric air, a wide variety of weather conditions, the presence of clouds, and so on. On high altitude the thickness of the atmosphere traversed by the sun's rays decreases, the degree of their absorption by the atmosphere decreases, the intensity of solar radiation increases. Depending on the height of the Sun above the horizon, the ratio of direct solar radiation and diffused radiation changes, which is essential in assessing the effect of its biological action.

55.Hygienic characteristic ultraviolet part of solar radiation. This is the most biologically active part of the solar spectrum. She is also heterogeneous. In this regard, a distinction is made between long-wave and short-wave UV. UV promotes tanning. When UV enters the skin, 2 groups of substances are formed in it: 1) specific substances, these include vitamin D, 2) non-specific substances - histamine, acetylcholine, adenosine, that is, these are protein breakdown products. Tanning or erythemal action is reduced to a photochemical effect - histamine and other biologically active substances contribute to vasodilation. The peculiarity of this erythema is that it does not occur immediately. Erythema has clearly defined boundaries. UV erythema always results in a more or less pronounced tan, depending on the amount of pigment in the skin. The mechanism of tanning action is still not well understood. It is believed that erythema first occurs, nonspecific substances such as histamine are released, the body converts the products of tissue decay into melanin, as a result of which the skin acquires a peculiar shade. Sunburn, therefore, is a test of the protective properties of the body (a sick person does not tan, tans slowly).

The most favorable tan occurs under the influence of UV light with a wavelength of approximately 320 nm, that is, when exposed to the long-wave part of the UV spectrum. In the south, short-wave UFL prevails, and in the north, long-wave UFL. Shortwave rays are the most susceptible to scattering. And dispersion is best in a clean atmosphere and in the northern region. Thus, the most useful tan in the north is longer, darker. UVB is a very powerful factor in the prevention of rickets. With a lack of UV radiation, rickets develops in children, and osteoporosis or osteomalacia in adults. Usually encountered in the Far North or groups of workers working underground. IN Leningrad region from mid-November to mid-February, the UV part of the spectrum is practically absent, which contributes to the development of solar starvation. To prevent sun starvation, artificial tanning is used. Under the action of UV in the air, ozone is formed, the concentration of which must be controlled.

UV light has a bactericidal effect. It is used to disinfect large wards, food products, water.

The intensity of UV radiation is determined by the photochemical method by the amount decomposed under the action of UV oxalic acid in quartz tubes(ordinary glass does not pass UFL). The intensity of UV radiation is also determined by an ultravioletmeter. IN medical purposes ultraviolet is measured in biodoses.

56. Physiological and hygienic significance of ultraviolet radiation. Measures for the prevention of UV weeks.See 55.

Prevention of UV deficiency

1. Architectural and planning activities.

In the design and construction of residential buildings, children's, medical and other institutions, it is necessary to take into account the insolation regime.

2. Heliotherapy (sunbathing). Can be organized on the beaches, in solariums. Sunbathing can be total (general and local), weakened, training. Total baths are used for healthy, hardened children. General sunbathing can be weakened through the use of lattice awnings, gauze.

3. Use of artificial sources.

57. Biological action ultraviolet rays (UFL) is very, very diverse. It can be both positive and destructive. The most dangerous are the effects of exposure to short-wave UV radiation (10-200 nm), the vast majority of which is retained in the upper layers of the atmosphere, in particular, in its ozone layer. However, the danger of UV damage occurs when a person stays in the sun for a long time, as well as in production conditions when working with artificial sources of UV radiation (electric welding), performing physiotherapy (therapeutic, preventive ultraviolet irradiation). Increasing the dose of UFL leads to protein denaturation, which, in the first place, is due to the development of cataracts, which requires protection of the visual analyzer when working with UFL. The destructive effect of UV light is used in practical activities person. In particular, their detrimental effect on microbial cells (bactericidal effect at a wavelength of 180–280 nm, maximum at 254 nm) is widely used for sanitizing the air, maintaining an antimicrobial regime in the premises of medical institutions, and disinfecting water. The ability of various media to luminesce under UV light is used in analytical chemistry. For example, the luminescent method is used to determine vitamins in food raw materials and foodstuffs.

The positive aspects of the action of the UFL are as follows:

UV light stimulates the production of antibodies, phagocytosis, accumulation of agglutinins in the blood, increasing natural immunity, the body's resistance to adverse environmental factors

UV light causes pigmentation (wavelengths around 340 nm) and erythema

UFL play a significant role in providing the body with vitamin D3

In climatology, according to the UFL level, a “deficit zone” (latitude above 57.5 °), a “comfort zone” (42.5–57.5 °), and an “excess zone” (less than 42.5 °) are distinguished, which must be taken into account when hygienic education of the population, carrying out preventive measures.

The UFL deficiency is primarily associated with the development of light starvation syndrome, which can be observed in people living in the "deficiency zone", in cities with a polluted atmosphere, working underground, rarely going outdoors.

For UV protection collective and individual methods and means are used: shielding of radiation sources and workplaces; removal service personnel from sources of ultraviolet radiation (protection by distance - remote control); rational placement of jobs; special coloring of premises; PPE and protective equipment (pastes, ointments). Screens, shields or special cabins are used to shield workplaces. Walls and screens are painted in light colors (gray, yellow, blue), zinc and titanium white are used to absorb ultraviolet radiation. Personal protective equipment against ultraviolet radiation includes: thermal protective overalls; mittens; footwear; protective helmets; goggles and shields with light filters, depending on the work performed. To protect the skin from ultraviolet radiation, ointments containing substances that serve as light filters for these radiations (salol, salicylic methyl ether, etc.) are used.

3.4 Lighting. Rational illumination is necessary first of all for the optimal function of the visual analyzer. Light also has a psychophysiological effect. Rational lighting has a positive effect on the functional state of the cortex big brain, improves the function of other analyzers. In general, light comfort, improving the functional state of the central nervous system and increasing the efficiency of the eye, leads to an increase in productivity and quality of work, delays fatigue, and helps to reduce occupational injuries. The above applies to both natural and artificial lighting. But natural lighting, in addition, has a pronounced general biological action is synchronizer of biological rhythms, has thermal and bactericidal action (see chapter III). Therefore, residential, industrial and public buildings should be provided with rational daylight.

On the other hand, using artificial lighting it is possible to create a predetermined and stable illumination throughout the day in any place of the room. The role of artificial lighting is currently high: second shifts, night work, underground work, evening homework, cultural leisure, etc.

TO main indicators characterizing lighting include: 1) the spectral composition of light (from the source and reflected), 2) illumination, 3) brightness (light source, reflective surfaces), 4) uniformity of illumination.

Spectral composition of light. The highest labor productivity and the least eye fatigue occurs with standard lighting. daylight. The standard of daylight in lighting engineering is the spectrum of scattered light from the blue sky, i.e., entering the room, the windows of which are oriented to the north. The best color differentiation is observed in daylight. If the dimensions of the parts under consideration are one millimeter or more, then for visual work about the same lighting sources that generate white daylight and yellowish.

The spectral composition of light is also important in the psychophysiological aspect. So, red, orange and yellow colors by association with the flame, the sun cause a feeling of warmth. Red excites, yellow - tones, improves mood and performance. Light blue, blue and purple seem cold. So, painting the walls of a hot shop in blue creates a feeling of coolness. Blue color - soothes, blue and purple - oppress. Green color - neutral - pleasant by association with green vegetation, it tires the eyesight less than others. Painting walls, cars, desk covers in green tones favorably affects the well-being, performance and visual function of the eye.

Painting walls and ceilings in white has long been considered hygienic, as it provides the best illumination of the room due to the high reflection coefficient of 0.8-0.85. Surfaces painted in other colors have a lower reflectance: light yellow - 0.5-0.6, green, gray - 0.3, dark red - 0.15, dark blue - 0.1, black - - 0.01. But the white color (due to its association with snow) evokes a feeling of cold, it seems to increase the size of the room, making it uncomfortable. Therefore, the walls are often painted in light green, light yellow and colors close to them.

The next indicator characterizing lighting is illumination. Illumination is called surface density luminous flux. The unit of illumination is 1 lux - the illumination of a surface of 1 m 2, on which a luminous flux of one lumen falls and is evenly distributed. Lumen- the luminous flux emitted by a complete emitter (absolutely black body) at the temperature of platinum solidification from an area of ​​0.53 mm 2 . Illuminance is inversely proportional to the square of the distance between the light source and the illuminated surface. Therefore, to economically create high illumination, bring the source closer to the illuminated surface (local illumination). Illumination is measured with a luxmeter.

Hygienic regulation of illumination is difficult, as it affects the function of the central nervous system and the function of the eye. Experiments have shown that with an increase in illumination to 600 lux, the functional state of the central nervous system improves significantly; a further increase in illumination to 1200 lux to a lesser extent, but also improves its function, illumination above 1200 lux has almost no effect. Thus, wherever people work, illumination of the order of 1200 lux is desirable, at least 600 lux.

Illumination affects the visual function of the eye when different sizes the items under consideration. If the parts under consideration have a size of less than 0.1 mm, when illuminated with incandescent lamps, an illumination of 400-1500 lux is required, 0.1-0.3 mm -300-1000 lux, 0.3-1 mm -200-500 lux, 1 - 10 mm - 100-150 lux, more than 10 mm - 50-100 lux. With these standards, the illumination is sufficient for the function of vision, but in some cases it is less than 600 lux, i.e. insufficient from a psychophysiological point of view. Therefore, when illuminated with fluorescent lamps (since they are more economical), all of the listed norms are increased by 2 times and then the illumination approaches the optimal one in psychophysiological terms.

When writing and reading (schools, libraries, classrooms), the illumination in the workplace should be at least 300 (150) lux, in living rooms 100 (50), kitchens 100 (30).

For the characteristics of lighting is of great importance brightness. Brightness- the intensity of light emitted from a unit surface. In fact, when we look at an object, we see not illumination, but brightness. The unit of brightness is candela per square meter (cd / m 2) - the brightness of a uniformly luminous flat surface that radiates in a perpendicular direction from each square meter a light intensity equal to one candela. Brightness is determined by a luminance meter.

At rational lighting there should be no bright light sources or reflective surfaces in the field of view of a person. If the surface under consideration is excessively bright, then this will negatively affect the work of the eye: a feeling of visual discomfort appears (from 2000 cd / m 2), the performance of visual work decreases (from 5000 cd / m 2), causes glare (from 32,000 cd / m 2 ) and even pain sensation (from 160,000 cd/m2). Optimum brightness of working surfaces is several hundred cd/m 2 . The permissible brightness of light sources that are in the field of view of a person is desirable no more than 1000-2000 cd / m 2, and the brightness of sources that rarely fall into the field of view of a person is not more than 3000-5000 cd / m 2

Lighting should be uniform and do not create shadows. If the brightness often changes in the field of view of a person, then fatigue occurs in the muscles of the eye that take part in adaptation (constriction and expansion of the pupil) and accommodation synchronously with it (change in the curvature of the lens). Illumination should be uniform throughout the room and at the workplace. At a distance of 5 m from the floor of the room, the ratio of the highest illumination to the smallest should not exceed 3:1, at a distance of 0.75 m of the workplace - no more than 2:1. The brightness of two adjacent surfaces (for example, a notebook - a desk, a school board - a wall, a wound - surgical linen) should not differ more than 2: 1-3: 1.

The illumination created general lighting, should be at least 10% of the value normalized for combined, but not less than 50 lux for incandescent lamps and 150 lux for fluorescent lamps.

Daylight. The sun creates illumination outdoors, typically in the order of tens of thousands of lux. Natural lighting of the premises depends on the light climate of the area, the orientation of the windows of buildings, the presence of shading objects (buildings, trees), the arrangement and size of windows, the width of the interwindow walls, the reflectivity of the walls, ceiling, floor, glass cleanliness, etc.

For good daylight, the area of ​​​​windows should correspond to the area of ​​\u200b\u200bthe rooms. Therefore, a common way to evaluate natural light premises is geometric, in which the so-called light factor, i.e. the ratio of the glazed window area to the floor area. The larger the value of the light coefficient, the better lighting. For residential premises, the luminous coefficient should be at least 1/8-1/10, for classrooms and hospital wards 1/5-1/6, for operating rooms 1/4-1/5, for utility rooms 1/10-1/12 .

Evaluation of natural light only by the light coefficient may be inaccurate, since the illumination is affected by the inclination of the light rays to the illuminated surface ( angle of incidence rays). In the event that, due to an opposing building or trees, not direct sunlight, but only reflected rays enter the room, their spectrum is devoid of the short-wavelength, biologically most effective part - ultraviolet rays. The angle within which direct rays from the sky hit a certain point in the room is called hole angle.

Angle of incidence formed by two lines, one of which goes from the top edge of the window to the point where the lighting conditions are determined, the second is a line on horizontal plane, connecting the measurement point to the wall on which the window is located.

Hole Angle formed by two lines going from the workplace: one - to the upper edge of the window, the other - to the highest point of the opposing building or some kind of fence (fence, trees, etc.). The angle of incidence must be at least 27º and the opening angle at least 5º. Illumination inner wall the room also depends on the depth of the room, and therefore, to assess the conditions of daylight, they also determine penetration factor- the ratio of the distance from the upper edge of the window to the floor to the depth of the room. The penetration ratio must be at least 1:2.

None of the geometric indicators reflects the completeness of the influence of all factors on natural lighting. The influence of all factors is taken into account chiaroscuro indicator-coefficient natural light(KEO). KEO\u003d E p: E 0 * 100%, where E p - illumination (in lux) of a point located indoors 1 m from the wall opposite the window, : E 0 - illumination (in lux) of a point located outside the premises, provided its illumination by scattered light (overcast) of the entire sky. Thus, KEO is defined as the ratio of indoor illumination to simultaneous outdoor illumination, expressed as a percentage.

For residential premises, KEO should be at least 0.5%, for hospital wards - at least 1%, for school classes - at least 1.5%, for operating rooms - at least 2.5%.

artificial lighting must meet the following requirements: be sufficiently intense, uniform; ensure proper shadow formation; do not dazzle or distort colors: do not heat; in terms of spectral composition approach daytime.

There are two artificial lighting systems: general And combined when the general is supplemented with local, concentrating light directly on the workplace ..

The main sources of artificial lighting are incandescent and fluorescent lamps. Incandescent lamp -- convenient and trouble-free light source. One of its disadvantages is a small light output, the predominance of yellow and red rays in the spectrum and a lower content of blue and violet. Although in psychophysiological terms, such a spectral composition makes the radiation pleasant, warm. With regard to visual work, the light of an incandescent lamp is inferior to daylight only when it is necessary to examine very small parts. It is not suitable for applications where good color discrimination is required. Since the surface area of ​​the filament is negligible, quality incandescent lamps significantly exceeds that which blinds. To combat brightness, lighting fittings that protect against the blinding effect of direct rays of light are used and lamps are suspended out of the field of view of people.

Distinguish lighting fittings direct light, reflected, semi-reflected and diffused. fittings direct Light directs over 90% of the light of the lamp to the illuminated place, providing its high illumination. At the same time, a significant contrast is created between the illuminated and unlit areas of the room. Sharp shadows are formed, and a dazzling effect is not excluded. This armature is used for lighting auxiliary premises and sanitary facilities. fittings reflected light characterized by the fact that the rays from the lamp are directed to the ceiling and to upper part walls. From here they are reflected and evenly, without the formation of shadows, distributed throughout the room, illuminating it with soft diffused light. This type of fixture creates the most hygienically acceptable lighting, but it is not economical, since over 50% of the light is lost. Therefore, more economical fixtures of semi-reflected and diffused light are often used to illuminate dwellings, classrooms, and wards. At the same time, part of the rays illuminates the room, passing through milky or frosted glass, and part - after reflection from the ceiling and walls. Such reinforcement creates satisfactory lighting conditions, it does not blind the eyes and does not form sharp shadows.

Fluorescent lamps meet most of the requirements above. Fluorescent Lamp is a tube of ordinary glass, the inner surface of which is coated with a phosphor. The tube is filled with mercury vapor, electrodes are soldered on both ends. When you turn on the lamp in the electrical network between the electrodes occurs electricity("gas discharge"), generating ultraviolet radiation. Under the influence of ultraviolet rays, the phosphor begins to glow. By selecting phosphors, fluorescent lamps are made with a different spectrum of visible radiation. The most commonly used fluorescent lamps (LD), white light lamps (LB) and warm white light (LTB). The emission spectrum of the LD lamp is approaching the spectrum of natural lighting in rooms with a northern orientation. With it, the eyes get tired the least even when looking at small details. The LD lamp is indispensable in rooms where correct color differentiation is required. The disadvantage of the lamp is that the skin of people's faces in this light, rich in blue rays, looks unhealthy, cyanotic, which is why these lamps are not used in hospitals, school classes and a number of similar premises. Compared to LD lamps, the spectrum of LB lamps is richer in yellow rays. When illuminated by these lamps, the high working capacity of the eye is maintained and the skin color of the face looks better. Therefore, LB lamps are used in schools, classrooms, dwellings, hospital wards, etc. The spectrum of LTB lamps is richer in yellow and pink rays, which somewhat reduces the performance of the eye, but significantly revitalizes the skin color of the face. These lamps are used to illuminate train stations, cinema lobbies, metro rooms, etc.

Spectrum diversity is one of hygienic items advantages of these lamps. The light output of fluorescent lamps is 3-4 times that of incandescent lamps (with 1W 30-80lm), so they more economical. The brightness of fluorescent lamps is 4000-8000 cd / m 2, i.e. above the permissible. Therefore, they are used with protective fittings. In numerous comparative tests with incandescent lamps in production, in schools, and classrooms, objective indicators characterizing the state of the nervous system, eye fatigue, and performance almost always testified to the hygienic advantage of fluorescent lamps. However, this requires skilled application. Required right choice lamps according to the spectrum, depending on the purpose of the room. Since the sensitivity of vision to the light of fluorescent lamps, as well as to daylight, is lower than to the light of incandescent lamps, the illumination standards for them are set 2-3 times higher than for incandescent lamps (Table 7.6.).

If, with fluorescent lamps, the illumination is below 75-150 lux, then a “twilight effect” is observed, i.e. illumination is perceived as insufficient even when considering large details. Therefore, with fluorescent lamps, the illumination should not be lower than 75-150 lux.