Atmospheric air is an environment that constantly surrounds a person, through which his primary vital needs are satisfied. The role of air in the occurrence and treatment of diseases was emphasized by Hippocrates. F.F. Erisman noted that any changes in physical or chemical properties air easily affect the well-being of a person, disrupting the harmonic balance of our body, i.e. health.

Ecological role air environment for humans is as follows:

1. air delivers oxygen to the body;

2. accepts carbon dioxide and gaseous metabolic products;

3. affects thermoregulation;

4. through the air, the sun's rays act on the body;

5. air is a reservoir of harmful gases, suspended solids and microbes that affect a person.

In this topic, we will consider the impact on human health of the physical factors of air: temperature (T), humidity, atmospheric pressure, air velocity, ionization and solar radiation. It should be immediately noted that physical factors, unlike chemical factors, act on the body only complex.

Physical properties atmospheric air- temperature (T), humidity, atmospheric pressure and speed of movement are meteorological factors of the air. The measurement of their physical parameters is carried out with special devices: temperature - with a thermometer, humidity - with a psychrometer and hygrometer, air velocity - with an anemometer (in the atmosphere) and catathermometer - in a dwelling, atmospheric pressure - with a barometer. Hygiene assessment meteorological factors is carried out according to the degree of their impact on the body, for which integral indicators are used: temperature reaction - changes in T of the skin of the forehead (normal - 33-34 ° C) and hands (30-31 ° C), the amount of sweat evaporation (weight change) , pulse rate, respiration, blood pressure and subjective sensations of a person, for example, on temperature changes - on a 5-point scale: cold, cool, good, warm, hot; to the light - brightness, brilliance.

Air temperature depends on the time of year climate zone, time of day, intensity of solar radiation and the underlying surface of the earth. The sun's rays passing through the atmosphere do not heat it. The heating of the air comes from the heat transfer of the soil, which absorbs the sun's rays. Warm air rises to give way to cold air - this movement is called convection- it promotes movement air masses and uniform heating of the surface layers of the atmosphere. The hygienic significance of air temperature lies in its effect on the body's heat exchange. Moreover, not only the absolute values ​​of air temperature, but also the amplitudes of its fluctuations are of hygienic importance. In humans, heat is generated as a result of oxidative processes in cells and tissues, and its normal existence is possible at a constant body temperature. Due to the complex mechanism of thermoregulation with the environment (in children under 7-8 years old it is imperfect), the body maintains a thermal balance. The most favorable for the well-being of a person is T-18-22 o C (for men - 20 o C, for women - 22 o C) and the amplitude of its fluctuations is 2-4 o C during the day.

Air humidity is the amount of water vapor in the air. Depends on the climate zone, season of the year and proximity water basins: in a maritime climate, there is more moisture than in a continental or desert climate. The degree of air humidity is determined by three indicators: absolute, maximum and relative humidity. Absolute humidity - the amount of water vapor in grams per 1 m 3 of air at a given temperature. Maximum humidity - how much water vapor can be contained in the air at a given temperature, measured in g per m 3. Relative humidity is the ratio absolute humidity to the maximum, measured in%. Optimal parameters for health relative humidity- 30-60%. The hygienic value of humidity is in its effect on human perspiration, which, by affecting body temperature, maintains its constancy. With an increase in humidity - in warmth a person becomes hot, in the cold - cold, chilly.

Atmosphere pressure is the pressure of the atmospheric column of air as a result of gravity. At sea level, the pressure is constant: per 1 cm 2 - 1.033 kg or 760 mm of mercury. The hygienic value of atmospheric pressure is in maintaining blood pressure (BP). An increase or decrease in pressure affects human physiology. For healthy person these changes are imperceptible, but for the patient they are sensitive: changes in pressure are signaled by well-being. At increase in pressure the partial pressure of oxygen increases (% of it remains the same): the pulse and respiratory rate slow down, the maximum blood pressure decreases and the minimum blood pressure rises, the vital capacity of the lungs increases, skin sensitivity and hearing decrease, there is a feeling of dryness of the mucous membranes (in the mouth), intestinal motility increases and gas outlet; blood and tissues absorb oxygen better, which improves performance and well-being. With an artificial increase in pressure (in divers), the dissolution of atmospheric nitrogen increases, which dissolves well in fats, nervous tissue and subcutaneous tissue, from where it slowly exits during decompression. When a diver quickly rises from a depth, nitrogen boils and clogs the small vessels of the brain, which causes the death of the diver, which requires him to be slowly removed from the depths. But even under normal operating conditions, divers cannot avoid vascular nitrogen embolism - their joints hurt and hemorrhages are frequent.

pressure drop causes a decrease in the partial pressure of oxygen, and when climbing mountains and a decrease in its concentration. There are symptoms of "altitude sickness": drowsiness, an increase in maximum blood pressure and a decrease in minimum blood pressure, heaviness in the head, headaches, apathy, depression; the dissolved nitrogen released into the blood in the form of pain in the joints and itching acts. In the city, the atmospheric pressure is lower than outside the city or on the plain, and the partial pressure of oxygen is lower. This determines the manifestation of symptoms of "altitude sickness" in people moving to the city from their summer cottage or from the countryside: shortness of breath, palpitations, dizziness, nausea, and nosebleeds occur.

air movement- is determined by the speed of its movement and the direction of the wind. Wind speed is measured in m/s. Good health is maintained when air moves at a speed of 0.1-0.3 m / s - this is the norm for residential premises. The lower limit of air movement from the hygienic side is determined by the need to blow off the enveloping person

SW FROM

from where it moves, and is called rumbo m. A graphical representation of the frequency of wind in a given area in the direction of parts of the world is called wind rose. For example, in fig. No. 1 shows a wind rose with a prevailing NE wind. The wind rose must be taken into account by architects when building residential areas and industrial enterprises: residential areas should be located on the windward side in relation to industrial enterprises.

In addition to meteorological factors, the quality of the air environment is characterized by air ionization and solar radiation.

Air ionization It is formed under the influence of electric discharges, radioactive elements, UV and cosmic rays. AT clean air light negative ions predominate, while heavy positive ions predominate in polluted water. Polluted air in cities is less ionized than in rural areas and resort areas. Negative ions enter the dwelling from the street, and already in the window opening they make up only 20% of the street concentration. In multi-storey buildings, they are actively absorbed by concrete walls, dust, CO2, moisture, higher air temperature. In this case, instead of negative ions, the number of positive ions increases. It is stuffy for a person, it seems that there is “little air”, but in reality there are few negative ions. Therefore, the level of ionization of the dwelling is an indicator of the purity of the air. The hygienic role of negative ions - they negatively charge red blood cells, they absorb and give off oxygen better, metabolic processes in tissues go better, acidosis decreases - mental work improves, efficiency increases, old age recedes. Mice in a 5-liter jar, which is served ambient air, passed through the electrodes, die after 2 hours, while the controls with ordinary air live. Therefore, air ionizers such as Chizhevsky's lamps are used in dwellings. For medicinal purposes, air ionization is used to treat hypertension and bronchial asthma. Therefore, for a healthy lifestyle, it is advisable for people to be in the fresh air more often, and not sit out in an apartment.

Solar radiation. We owe life to the sun - it is a source of heat and light. Sunlight is a stream of electromagnetic vibrations, which, passing through the Earth's atmosphere, is partially absorbed, scattered, and only 43% reaches the soil. Sunlight affects the body with all parts of its spectrum. Visible part It has a general biological effect on the body, on the organ of vision, the central nervous system and through it on all organs. But different areas of visible light act differently: red rays excite; yellow, green - soothe; purple - oppressive. With a lack of light, vision strains and deteriorates (sharpness and speed of discrimination). High brightness - blinds and tires, and with prolonged exposure (snow) causes inflammation of the retina. Invisible part of the world: infrared and ultraviolet - very biologically active. infrared radiation is divided into 1) long-wave and 2) short-wave. Long-wavelength is absorbed by the surface layer of the skin and causes it to warm up, a burning sensation is felt. Shortwave is not felt and penetrates into the deeper layers of the skin, causing burns and general overheating of the body. In production, short-wave radiation causes changes in the cornea of ​​​​the eye, up to cataracts. At noon, short-wave radiation prevails, so sunbathing at this time is dangerous. UFL have the highest biological activity. In the spring, under their influence, metabolism, immunity, and working capacity increase. They have an anti-rachitic effect, tk. under their influence, vitamin D is synthesized in the skin, which improves calcium metabolism and blood formation, and the resistance of capillaries. Without UV radiation, rickets occurs in children, and osteoporosis in adults: calcium depletion of bones, leading to their fragility, teeth decay (caries). This condition is called “light starvation” - it is often of professional origin: among miners, among people sent to the North, and also among people who rarely go out into the fresh air. Prevention of hypovitaminosis D: exposure to the sun, irradiation with UV lamps, taking calciferol. UV lamps also have a bactericidal effect - they kill microbes, which is used in medicine to destroy them with the help of UV lamps. Window glasses weaken UV radiation, so they need to be cleaned more often from dust. UV radiation has a harmful effect on the eyes, causing their inflammation (photophthalmia) - an occupational disease of welders, as well as climbers, residents of mountainous and arctic regions. Prevention: use of protective shields, black glasses, etc.

How weather conditions affect the body depends on its adaptive abilities: someone reacts to them, someone does not notice at all, and there are those who, by their well-being, can predict the weather. It is believed that people with an unbalanced nervous system - melancholic and choleric people - are especially clearly susceptible to weather conditions. In sanguine and phlegmatic people, it most often manifests itself either against the background of a weakened immune system, or in a chronic disease. However, meteosensitivity as a diagnosis is typical just for those who already suffer from some kind of illness. As a rule, these are pathologies of the respiratory and cardiovascular systems, diseases of the nervous system, rheumatoid arthritis.

What weather factors affect our well-being? Head of the Department of Neurology of the 122nd Clinical Hospital, Professor Alexander Elchaninov refers to the most significant meteorological factors: air temperature, humidity, wind speed and barometric (atmospheric) pressure. Heliophysical factors also affect the human body - magnetic fields.

Air temperature

It has the most noticeable effect on a person's well-being in combination with air humidity. The most comfortable is the combination of temperature 18-20C° and humidity 40-60%. At the same time, fluctuations in air temperature within 1-10°C are considered favorable, 10-15°C - unfavorable, and above 15°C - very unfavorable. - explains Professor Elchaninov. - Comfortable temperature for sleep - from 16°С to 18°С.

The oxygen content in the air directly depends on the air temperature. When cold, it is saturated with oxygen, and when it warms, on the contrary, it is rarefied. As a rule, in hot weather, atmospheric pressure also decreases, and as a result, those suffering from diseases of the respiratory and cardiovascular systems do not feel well.

If in the background high pressure the air temperature drops and is accompanied by cold rains, it is especially difficult for hypertensive patients, asthmatics, people with kidney and gallstone diseases. Sudden changes in temperature (8-10 ° C per day) are dangerous for allergy sufferers and asthmatics.

extreme temperatures

According to Sergey Boytsov, director of the State Research Center for Preventive Medicine, people with a normal thermoregulation mechanism, which actively participates in the cardiovascular system, which increases blood circulation directly under the skin, feel best in abnormal heat. But if the air temperature exceeds 38 degrees, it no longer saves: the external temperature becomes higher than the internal one, there is a risk of thrombosis against the background of centralization of blood flow and blood clotting. Therefore, in the heat, the risk of stroke is high. Doctors advise in abnormal heat to be in a room with air conditioning or at least a fan as much as possible, to avoid the sun, unnecessary physical exertion. The rest of the recommendations depend on the state of health of the person.

An anticyclone is an increased atmospheric pressure that brings with it calm, clear weather, without sudden changes in temperature and humidity.

A cyclone is a decrease in atmospheric pressure, which is accompanied by cloudiness, high humidity, precipitation and an increase in air temperature.

In extremely frosty weather, the body can supercool due to increased heat transfer. Especially dangerous is the combination of low temperature with high humidity and high speed air movement. Moreover, due to reflex mechanisms, a feeling of cold occurs not only in the area of ​​its influence, but also in seemingly distant parts of the body. So, if your legs are frozen, your nose will inevitably freeze, a feeling of cold will also appear in your throat, as a result of which SARS, diseases of the ENT organs develop. Also, if you're cold, let's say waiting public transport, another reflex mechanism is activated, in which a spasm of the vessels of the kidneys occurs, circulatory disorders and a decrease in immunity are also possible. As a rule, extremely low temperatures cause spastic-type reactions. Any procedures and actions that increase blood circulation help to cope with them: gymnastics, hot foot baths, sauna, bath, contrast shower.

Air humidity

At high temperature air humidity (air saturation with water vapor) decreases, and in rainy weather it can reach 80-90%. During the heating season, the air humidity in our apartments drops to 15-20% (for comparison: in the Sahara Desert, the humidity is 25%). Often it is the dryness of home air, and not the high humidity on the street, that causes a tendency to colds: the mucous membranes of the nasopharynx are dried, reducing its protective functions, which makes it easy for respiratory viruses to "take root". To avoid increased dryness in the nasopharynx, it is recommended for allergy sufferers and those who often suffer from ENT diseases to wash with a solution of lightly salted or non-carbonated mineral water.

With high humidity, those suffering from diseases are more at risk of getting sick respiratory tract, joints and kidneys, especially if the humidity is accompanied by a cold snap.

Humidity fluctuations from 5 to 20% are assessed as more or less favorable for the body, and from 20 to 30% as unfavorable.

Wind

The speed of air movement - the wind is perceived by us as comfortable or uncomfortable, depending on the humidity and temperature of the air. So, in the thermal comfort zone (17-27C°) with a quiet and light wind (1-4 m/s), a person feels good. However, as soon as the temperature rises, he will experience a similar sensation if the air movement becomes faster. Conversely, at low temperatures, high wind speeds increase the sensation of cold. The daily periodicity has both the mountain-valley wind and other wind regimes (breeze, hair dryer). Importance have day to day fluctuations wind regime: the difference in air speed within 0.7 m/s is favorable, and 8-17 m/s is unfavorable.

Atmosphere pressure

Weather-sensitive people are sure that leading role in their response to the weather exerts atmospheric pressure. This is both so and not so. Because basically it affects our body in combination with other natural phenomena. It is generally accepted that a meteorologically stable state is observed at an atmospheric pressure of about 1013 mbar, that is, 760 mm Hg. Art., - says Professor Alexander Elchaninov.

If, with a decrease in atmospheric pressure, the oxygen content in the atmosphere decreases sharply, humidity and temperature increase, a person’s arterial pressure and the speed of blood flow decreases, as a result, breathing becomes difficult, heaviness appears in the head, and the work of the cardiovascular system is disrupted. When atmospheric pressure drops, hypotension feels worst of all, which is manifested by severe pastosity (swelling) of tissues, tachycardia, tachypnea (frequent breathing), that is, symptoms that characterize the deepening of hypoxia (oxygen starvation) caused by low atmospheric pressure. In hypertensive patients, this weather improves well-being: blood pressure decreases and only with increasing hypoxia does drowsiness, fatigue, shortness of breath, ischemic heart pains appear, that is, the same symptoms that hypotensive patients immediately experience in such weather. When the temperature drops with an increase in atmospheric pressure, the oxygen content in the air increases, hypertensive patients feel bad, because their blood pressure rises and the blood flow speed increases. Hypotonic patients live well in such weather, they feel a surge of strength.

Solar Activity

We are the children of the sun, if it weren't there, there would be no life. Thanks to the notorious solar wind and changes in solar activity, the Earth's magnetic field, the permeability of the ozone layer, and the standards of meteorological conditions change. It is the sun that influences the cyclical work of the human body, which works in accordance with the seasons. We have an innate need for a certain amount of sunlight, sunlight and warmth. No wonder during the short winter light day almost everyone suffers from hyposolar syndrome: increased drowsiness, fatigue, depression, apathy, decreased performance and attention. We can say that the number sunny days per year for the organism is much more important than a change in, say, atmospheric pressure. Therefore, residents of coastal, for example, Mediterranean countries, or highlands, live more comfortably than Petersburgers or polar explorers.

Weather in the house

To impact on weather we can not. But we can reduce the health risks associated with the influence of the external environment. The main thing to remember is that meteorological sensitivity does not manifest itself as an independent problem, it is like a carriage behind a steam locomotive, it follows a certain disease, most often chronic. Therefore, first of all, it must be identified and treated. In case of exacerbation of the disease on the background bad weather, you should take medications prescribed by a doctor for the main pathology (migraine, vegetovascular dystonia, panic attacks, neurosis and neurasthenia). And besides, in accordance with the weather forecast, you need to work out certain rules of behavior for yourself. For example, "cores" react sharply to high humidity air and the approach of a thunderstorm, which means that on such days it is necessary to avoid physical exertion and be sure to take the medicines prescribed by the doctor.

• Everyone who, when changing climatic conditions well-being changes, it is important to treat your health more carefully on such days: do not overwork, get enough sleep, avoid drinking alcohol, as well as physical exertion. Postpone, for example, every morning jog, otherwise, say, in hot weather, you can run away from a heart attack, resorting to a stroke. Any emotional and physical exercise in bad weather, this is stress that can lead to failures in autonomic regulation, heart rhythm disturbances, jumps in blood pressure, and exacerbation of chronic diseases.
• Keep track of atmospheric pressure to understand how to control blood pressure. For example, with low atmospheric hypertension, it is necessary to reduce the intake of drugs that reduce blood pressure, and hypotensive patients should take adaptogens (ginseng, eleutherococcus, magnolia vine), drink coffee. And in general, it should be remembered that in summer, in warm and hot weather, blood is redistributed from the internal organs to the skin, so blood pressure in summer is lower than in winter.
• Residents of St. Petersburg, like any other metropolis, spend most of their lives indoors. And the more time we “hide” in comfort from external climatic factors, the more the balance between the human body and the environment is disturbed, its adaptive capabilities decrease. We should increase the body's resistance to adverse weather changes. Therefore, if there are no contraindications, train the autonomic nervous and cardiovascular system. A contrast or cold shower, Russian bath, sauna, walking tours will help you with this, preferably before going to bed.
• Organize physical activity for yourself - with them, blood pressure rises, the level of oxygen in the tissues decreases, metabolism, heat generation and heat transfer increase. Good cardiovascular training respiratory system brisk walking for 1 hour, light running, swimming. Trained people easily endure changes in the weather, which have a similar effect on the body.
• It is recommended to sleep with the window open. Moreover, sleep should be sufficient - when you wake up, you should feel that you have had enough sleep.
• Monitor the level of humidity and artificial lighting in the apartment.
• Dress "for the weather" so that the body is comfortable in all weather conditions.
• If you notice that you feel dependent on the weather, forget about traveling to distant countries “from winter to summer” or “from summer to winter”. Disruption of seasonal adaptation is dangerous even for healthy people.

Irina Dontsova

Dr. Peter

The main factor in creating an optimal microclimate is the air temperature (the degree of its heating, expressed in degrees), which to the greatest extent determines the influence of the environment on a person.

AT vivo On the surface of the Earth, the temperature of atmospheric air varies from -88 to + 60 °C, while the temperature of the internal organs of a person, due to the thermoregulation of his body, remains comfortable, close to 37 °C. When performing heavy work and at high ambient temperatures, the human body temperature can rise by several degrees. The highest temperature of the internal organs that a person can withstand is 43 ° C, the minimum is 25 ° C.

Humidity also has a significant impact on the microclimate.

Air humidity is characterized by the following concepts:

absolute humidity (BUT), which is expressed by the partial pressure of water vapor (Pa), or in weight units in a certain volume of air (g / m 3);

maximum humidity (F)- the amount of moisture at full saturation of air at a given temperature (g / m 3);

relative humidity (R) expressed in %, P \u003d A / Fx \ 00%.

High relative humidity (the ratio of water vapor content in 1 m 3 of air to their maximum possible content in this volume) at high air temperature contributes to overheating of the body, while at low temperature it increases heat transfer from the skin surface, which leads to hypothermia of the body. Low humidity leads to intense evaporation of moisture from the mucous membranes, their drying and cracking, and then to contamination with pathogenic microbes.

The optimal microclimate for a particular person is determined only on the basis of his subjective assessments. It is well known that the subjective sensation of heat or cold depends not only on climatic conditions, but also on factors such as body constitution, age, gender, severity of work, clothing, etc. Therefore, in practice we are talking, usually about ranges optimal temperatures and air humidity.

Normal thermal well-being takes place when the heat release of a person is completely perceived by the environment. If the body's heat production cannot be fully transferred to the environment, the temperature of the internal organs rises, and such a thermal well-being is characterized by the concept of "hot". Otherwise - "cold".

Thus, the thermal well-being of a person, or the heat balance in the “human-environment” system, depends on the temperature of the environment, mobility and relative humidity of the air, atmospheric pressure, temperature of surrounding objects and the intensity of physical activity.

For example, a decrease in temperature and an increase in the speed of air movement contribute to an increase in convective heat transfer and the process of heat transfer during the evaporation of sweat, which can lead to hypothermia of the body. An increase in the speed of air movement worsens health, as it contributes to an increase in convective heat transfer and the process of heat transfer during sweat evaporation.

The parameters of the microclimate of the air environment, which determine the optimal metabolism in the body and in which there are no unpleasant sensations and tension in the thermoregulation system, are called comfortable or optimal. The zone in which environment completely removes the heat generated by the body, and there is no tension in the thermoregulation system, called the comfort zone. Conditions under which the normal thermal state of a person is violated are called uncomfortable. With a slight tension in the thermoregulation system and slight discomfort, acceptable meteorological conditions are established. Permissible values ​​of microclimate indicators are established in cases where, according to technological requirements, technical and economic principles, optimal standards are not provided.

Atmospheric pressure refers to the pressure of atmospheric air on the surface of the Earth and objects located on it. The degree of pressure corresponds to the weight of atmospheric air with a base of a certain area and configuration.

The basic unit for measuring atmospheric pressure in the SI system is the Pascal (Pa). In addition to Pascals, other units of measurement are also used:

• Bar (1 Ba=100000 Pa);
• millimeter of mercury (1 mm Hg = 133.3 Pa);
• kilogram of force per square centimeter (1 kgf / cm 2 \u003d 98066 Pa);
• technical atmosphere (1 at = 98066 Pa).

The above units of measurement are used for technical purposes, with the exception of millimeters of mercury, which is used for weather forecasts.

The barometer is the main instrument for measuring atmospheric pressure. Devices are divided into two types - liquid and mechanical. The design of the first is based on a flask filled with mercury and immersed with an open end in a vessel with water. The water in the vessel transmits the pressure of the column of atmospheric air to mercury. Its height acts as an indicator of pressure.

Mechanical barometers are more compact. The principle of their operation lies in the deformation of a metal plate under the influence of atmospheric pressure. The deformable plate presses on the spring, and that, in turn, sets in motion the arrow of the device.

Effect of atmospheric pressure on the weather

Atmospheric pressure and its effect on the state of the weather varies depending on the place and time. It varies depending on the altitude above sea level. Moreover, there are dynamic changes associated with the movement of areas of high pressure (anticyclones) and low pressure (cyclones).

Changes in weather associated with atmospheric pressure occur due to the movement of air masses between areas of different pressure. The movement of air masses form a wind, the speed of which depends on the pressure difference in local areas, their scale and distance from each other. In addition, the movement of air masses leads to a change in temperature.

Standard atmospheric pressure is 101325 Pa, 760 mm Hg. Art. or 1.01325 bar. However, a person can easily endure wide range pressure. For example, in the city of Mexico City, the capital of Mexico with a population of almost 9 million people, the average atmospheric pressure is 570 mm Hg. Art.

Thus, the value of the standard pressure is determined exactly. A comfortable pressure has a significant range. This value is quite individual and completely depends on the conditions in which a particular person was born and lived. Thus, a sudden movement from an area with relatively high pressure to an area of ​​lower pressure can affect the work circulatory system. However, with prolonged acclimatization Negative influence comes to naught.

High and low atmospheric pressure

In high pressure zones, the weather is calm, the sky is cloudless, and the wind is moderate. High atmospheric pressure in summer leads to heat and droughts. In low pressure zones, the weather is predominantly cloudy with wind and precipitation. Thanks to such zones, cool weather sets in in summer. cloudy weather with rain, and in winter there are snowfalls. The high pressure difference in the two areas is one of the factors leading to the formation of hurricanes and storm winds.

2.1. Structure earth's atmosphere. The impact of atmospheric air on human health

The atmosphere has a multilayer structure. The troposphere is adjacent to the earth's surface - the densest layer of air ranging in size from 8 to 18 km in different latitudes. Above the troposphere is stratosphere- a layer of air up to 40-60 km in size, in which ozone molecules are formed that make up the ozone layer of the atmosphere. An even more rarefied layer of air extends over the stratosphere up to 80 km in size - mesosphere, the above follows thermosphere- a layer of the atmosphere up to 300 km high, the temperature in which reaches 1500°C. Behind her is ionosphere- a layer of ionized air, the size of which, depending on the time of year and day, is 500-1000 km. Still higher are sequentially placed exosphere(up to 3000 km), the density of which almost does not differ from the density of airless outer space, and the upper boundary of the Earth's atmosphere - magnetosphere(from 3000 to 50000 km), which includes radiation belts.

The air environment - the atmosphere - the gaseous shell of the Earth significantly affects the energy and hydrological processes, the quantity and quality of solar radiation. The meteorological and microclimatic component of the air environment consists of air temperature, its humidity and mobility, non-ionizing solar radiation, and barometric pressure. Physical factors as components of the environment and enclosed spaces ensure human life and health. Solar radiation and air temperature determine the thermal state of a person, his vital functions: growth, development, resistance, metabolic processes, health.

2.2. Physical factors of the atmosphere, their hygienic characteristics and influence on the body (temperature, humidity, air mobility, barometric pressure, electrical state of the air, thermal radiation, air ionization)

The physical parameters of the air environment include: temperature, humidity, speed of movement (mobility) of air; Atmosphere pressure; solar radiation; electrical state (lightning discharges, air ionization, electric field of the atmosphere); radioactivity.

Air temperature. One of the conditions for the implementation of the normal course of life processes is the constancy of temperature, in violation of which the development of severe, sometimes irreversible changes is possible.

When exposed to the body low temperatures air, there is a violation of tissue trophism with the further development of neuritis, myositis; a decrease in the body's resistance due to the reflex factor, which contributes to the development of pathological conditions of both infectious and non-infectious nature. Local cooling (especially of the legs) can lead to colds: tonsillitis, acute respiratory viral infection, pneumonia. This is due to a reflex decrease in the temperature of the mucous membrane of the upper respiratory tract (nasopharynx).

With prolonged exposure high temperature air disturbed water-salt and vitamin metabolism, especially when performing physical work. Increased sweating leads to loss of fluid, salts and water-soluble vitamins. At high air temperature, the activity of the gastrointestinal tract changes. The release of chlorine ion from the body, the intake of large amounts of water lead to inhibition of gastric secretion and a decrease in the bactericidal action of gastric juice, which creates favorable conditions for the development of inflammatory processes in gastrointestinal tract. The influence of high air temperature also negatively affects the functional state of the central nervous system (CNS), which is manifested by a weakening of attention, a violation of the accuracy and coordination of movements, and a slowdown in reactions. This contributes to a decrease in the quality of work and an increase in industrial injuries.

The most common complication is overheating or thermal hyperthermia (Table 2.1).

Table 2.1 - The main signs of overheating of the body

In severe cases, overheating occurs in the form of heat stroke. There is a rapid increase in temperature to 41 ° C and above, a decrease in blood pressure, loss of consciousness, impaired blood composition, convulsions. Breathing becomes frequent (up to 50-60 per minute), superficial. As a result of a violation of the water-salt balance at high temperatures, convulsive illness may develop. When providing first aid, it is necessary to take measures to cool the body (cool shower, bath, etc.).

A comfortable thermal state of the environment and a person is considered at an air temperature of 17-22 ° C, the maximum permissible - at an upper limit of 25 ° C and a lower limit of 14 ° C; extremely tolerable - respectively at 35°C and 10°C; extreme - at 40°C and 40-50°C. In the latter case, ordinary winter clothes cannot maintain the body's thermal equilibrium.

Air humidity. Atmospheric air humidity is determined by the evaporation of water from the surface of the oceans, seas and, to a lesser extent, lakes, rivers, moist soil and vegetation cover. In enclosed spaces, household (washing clothes, cooking, etc.) and production factors, as well as moisture evaporation from the surface of the skin.

The degree of air humidity is determined by the concepts of absolute, maximum and relative humidity. When conducting field studies, absolute, maximum, relative humidity, saturation deficit, physiological humidity deficit, dew point are found.

Absolute humidity is determined by the amount of water vapor in grams, which is contained in 1 m 3 of air in this moment(or the elasticity of water vapor in the air in millimeters of mercury).

Maximum humidity characterized by the limiting amount of water vapor (in grams per 1 m 3 of air) saturating the air at a given temperature; it can also be expressed in millimeters of mercury.

relative humidity called the ratio of absolute humidity to the maximum, expressed as a percentage, or, otherwise, the percentage of air saturation with water vapor at the time of observation. This last value is used mainly in sanitary practice.

saturation deficit is the difference between maximum and absolute humidity.

Physiological moisture deficiency - the ratio of the amount of water vapor actually contained in the air to their maximum amount that can be contained in the air at the temperature of the surface of the human body and lungs, i.e. respectively at 34 and 37°C. Physiological moisture deficit shows how many grams of water each cubic meter of inhaled air can extract from the body.

Dew point - the temperature at which water vapor in the air saturates the space of 1 m 3 of air.

Relative humidity and saturation deficiency are of the greatest hygienic importance, since they determine the degree of air saturation with water vapor and allow one to judge the intensity and rate of sweat evaporation from the body surface at a given temperature. The lower the relative humidity, the faster the evaporation of water will occur, therefore, the more intense will be the heat transfer by evaporation of sweat.

The optimal value of relative humidity is in the range of 40-60%, acceptable lower - 30%, acceptable upper - 70%, extreme lower - 10-20% and extreme upper 80-100%.

Air movement. The main factor that determines the movement of air (wind) is the difference in pressure and temperature. The hygienic value of air mobility is determined by the effect of heat transfer. The influence of air mobility directly on a person leads to an increase in heat transfer from the body surface. At low ambient temperatures, this causes cooling of the body, at high air temperatures, increasing heat transfer by convection and evaporation, protects the body from overheating

Atmosphere pressure. The atmosphere, subject to the force of gravity, exerts pressure on the surface of the Earth and on all objects located on it. At sea level at 15°C, this value is 760 mm Hg. Art. Due to the fact that the external pressure is completely balanced by the internal one, our body practically does not feel the heaviness of the atmosphere. A significant increase and decrease in atmospheric pressure are possible, which can lead to adverse changes in the body.

Reduced atmospheric pressure contributes to the development of a symptom complex in people, known as high-altitude (mountain) sickness. It can occur when climbing to a height and, as a rule, occurs in pilots and climbers in the absence of measures (devices) that protect against the influence of low atmospheric pressure. In the lung tissue there is an exchange of blood gases and alveolar air. Diffusing through membranes, gases tend to a state of equilibrium, moving from a region of high pressure to a region of low pressure.

Altitude sickness occurs as a result of a decrease in the partial pressure of oxygen in the inhaled air, which leads to oxygen starvation of tissues.

As the partial pressure of oxygen decreases, the oxygen saturation of hemoglobin decreases, followed by a disruption in the supply of oxygen to cells. The first symptoms of oxygen deficiency are determined when climbing to a height of 3000 m without an oxygen device.

Acclimatization measures for oxygen deficiency include training in pressure chambers, staying in high altitude conditions, hardening, etc. Taking an increased amount of vitamins C, P, B1, B2, B6, PP, folic acid has a positive effect.

Increased atmospheric pressure is the main production factor in the construction of underwater tunnels, subways, diving operations, etc. Persons are subjected to short-term (instantaneous) exposure to high pressure when bombs, mines, shells, shots and rocket launches explode. Most often, work in conditions of high atmospheric pressure is carried out in special chambers-caissons or spacesuits. When working in caissons, three periods are distinguished: compression, stay in conditions of high pressure and decompression.

Compression is characterized by minor functional disorders: tinnitus, congestion, pain due to mechanical air pressure on the eardrum. Trained people endure this stage easily, without discomfort.

Staying under conditions of high blood pressure is usually accompanied by mild functional disorders: a decrease in heart rate and respiratory rate, a decrease in maximum and an increase in minimum blood pressure, a decrease in skin sensitivity and hearing.

In the zone of increased atmospheric pressure, the blood and tissues of the body are saturated with air gases (saturation), mainly nitrogen. This saturation continues until the partial pressure of nitrogen in the ambient air equalizes with the partial pressure of nitrogen in the tissues.

Blood is saturated the fastest, adipose tissue is the slowest. At the same time, adipose tissue is saturated with nitrogen 5 times more than blood or other tissues. The total amount of nitrogen dissolved in the body with increased atmospheric pressure, can reach 4-6 liters against 1 liter of nitrogen dissolved at normal pressure.

During the period of decompression, the reverse process is observed in the body - the removal of gases from the tissues (desaturation). With properly organized decompression, dissolved nitrogen in the form of a gas is released through the lungs (150 ml of nitrogen in 1 minute). However, with rapid decompression, nitrogen does not have time to be released and remains in the blood and tissues in the form of bubbles, with the largest amount of them accumulating in the nervous tissue and subcutaneous tissue. From here and from other organs, nitrogen enters the bloodstream and causes a gas embolism (caisson disease). The danger of gas embolism occurs when the partial pressure of nitrogen in the tissues is more than 2 times higher than the partial pressure of nitrogen in the alveolar air. A characteristic symptom of this disease are pulling pains in the joints and muscles. With embolism of the blood vessels of the central nervous system, dizziness is observed, headache, disorder of gait, speech, convulsions. In severe cases, paresis of the limbs, urinary disorder occur, the lungs, heart, eyes, etc. are affected. To prevent the possible development of decompression sickness, the correct organization of decompression and compliance with the operating regime are important.

Barometric pressure for Belarus is determined at 740-745 mm Hg. Art. Daily fluctuations in atmospheric pressure of 3-5 mm Hg. Art. do not have a significant effect on the body of a healthy person. With a decrease in the functionality of the body, sensitivity to changes in barometric pressure increases.

Electrical state of the air. The term "atmospheric electricity" is usually understood as a whole complex of phenomena, including air ionization, electric and magnetic fields of the atmosphere.

Air ionization. The physical essence of air ionization consists in the action of various ionizing factors on air molecules: radioactive elements, cosmic, UV radiation, electrical, lightning discharges, balloelectric effect, the use of air ionizers.

Air ionization is understood as the disintegration of molecules and atoms with the formation of air ions. As a result, an electron is detached from the molecule and it becomes positively charged, and the detached free electron, having joined one of the neutral molecules, gives it a negative charge. Therefore, a pair of oppositely charged particles is formed in the atmosphere - negative and positive ions.

Molecular complexes (10-15 molecules) with one elementary charge are called normal, or light, ions. They have a size of 10-8 cm and have a relatively high mobility. Colliding with larger particles constantly present in the atmosphere, light ions settle on them and impart their charge to them. Secondary ions appear, including medium (10-6 cm) and heavy (10-5 cm) air ions.

The ionic composition of the air is an important hygienic indicator. Human exposure to light negative air ions is a favorable biological factor. On the contrary, excessively high concentrations of positive ions, especially heavy ones, indicate a low hygienic air quality.

The ratio of the number of heavy ions to the number of light ions determines the ionization regime of the air. To characterize the ionization of air, the unipolarity coefficient (q) is used, showing the ratio of the number of positive ions to the number of negative ones. The more polluted the air, the higher this coefficient.

The amount of light ions depends on geographical, geological conditions, weather, the level of environmental radioactivity, and air pollution. With an increase in air humidity, the number of heavy ions increases due to the recombination of ions with moisture drops. A decrease in atmospheric pressure promotes the release of radium emanation from the soil, which leads to an increase in the amount of light ions. The ionizing effect of sprayed water is manifested in increased air ionization, which is especially noticeable near fountains, along the banks of turbulent rivers, near reservoirs.

Electric field. The earth as a whole has the properties of a negative charged conductor, and the atmosphere - a positively charged one. As a result, the ions of both signs move and a vertical electric current arises. With an increase in atmospheric pressure, a decrease in air transparency and the formation of fogs, the electric field can increase by 2-5 times. Naturally, such large changes can have a negative impact on the well-being of sick, weakened people.

A magnetic field. A rapid change in the magnetic field (magnetic disturbances and storms) arises due to an increase in the influx of charged particles from the surface of the Sun during a period of increased activity. It has been established that these changes can affect the functional state of the CNS, causing an increase in the processes of inhibition. During the period of magnetic storms, the frequency of exacerbations of neuropsychiatric diseases sharply increases.

Solar radiation is the most important factor for the existence of life on Earth. From a physical point of view, solar energy is a stream of electromagnetic radiation with different wavelengths. The spectral composition of solar radiation varies in a wide range from long to ultrashort waves. From a hygienic point of view, the optical part of the solar spectrum is of particular interest, which is divided into three ranges: infrared rays with a wavelength of 28,000 to 760 nm, the visible part of the spectrum - from 760 to 400 nm and the UV part - from 400 to 10 nm.

It has been established that solar radiation has a powerful biological effect: it stimulates physiological processes in the body, changes metabolism, improves a person's well-being, and increases his working capacity.

Air radioactivity. The natural radioactivity of the atmosphere depends on the presence in it of gases such as radon, actinon and thoron, which are the decay product of radium, actinium and thorium. The air contains carbon-14, argon-41, fluorine-18, sulfur-32 and a number of other isotopes formed as a result of the bombardment of nitrogen, hydrogen and oxygen atoms by streams of cosmic radiation particles.

Artificial radioactive contamination of the biosphere is due to the tests of atomic weapons, accidents at a nuclear power plant, and the widespread use of sources of ionizing radiation in industry, agriculture, medicine, and other branches of science and technology.