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 the 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 the content of water vapor in 1 m 3 of air to their maximum possible content in this volume) at high air temperatures contributes to overheating of the body, while at low temperatures it enhances 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 factors such as body constitution, age, gender, severity of work, clothing, etc. Therefore, in practice, we are usually talking 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, air mobility and relative humidity, 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.

ATMOSPHERE OF THE EARTH(Greek atmos steam + sphaira ball) - gaseous shell, surrounding the earth. The mass of the atmosphere is about 5.15·10 15 The biological significance of the atmosphere is enormous. In the atmosphere, there is a mass-energy exchange between living and inanimate nature, between flora and fauna. Atmospheric nitrogen is assimilated by microorganisms; plants synthesize organic substances from carbon dioxide and water due to the energy of the sun and release oxygen. The presence of the atmosphere ensures the preservation of water on Earth, which is also an important condition for the existence of living organisms.

Studies carried out with the help of high-altitude geophysical rockets, artificial earth satellites and interplanetary automatic stations have established that the earth's atmosphere extends for thousands of kilometers. The boundaries of the atmosphere are unstable, they are influenced by the gravitational field of the moon and the pressure of the flow of sunlight. Above the equator in the region of the earth's shadow, the atmosphere reaches heights of about 10,000 km, and above the poles, its boundaries are 3,000 km from the earth's surface. The main mass of the atmosphere (80-90%) is within altitudes up to 12-16 km, which is explained by the exponential (nonlinear) nature of the decrease in density (rarefaction) of its gas environment as altitude increases.

The existence of most living organisms in natural conditions is possible in even narrower boundaries of the atmosphere, up to 7-8 km, where a combination of such atmospheric factors as gas composition, temperature, pressure, and humidity, necessary for the active course of biological processes, takes place. The movement and ionization of air are also of hygienic importance, precipitation, the electrical state of the atmosphere.

Gas composition

The atmosphere is a physical mixture of gases (Table 1), mainly nitrogen and oxygen (78.08 and 20.95 vol. %). The ratio of atmospheric gases is almost the same up to altitudes of 80-100 km. The constancy of the main part of the gas composition of the atmosphere is due to the relative balancing of the processes of gas exchange between animate and inanimate nature and the continuous mixing of air masses in the horizontal and vertical directions.

Table 1. CHARACTERISTICS OF THE CHEMICAL COMPOSITION OF DRY ATMOSPHERIC AIR NEAR THE EARTH'S SURFACE

At altitudes above 100 km, the percentage of individual gases changes due to their diffuse stratification under the influence of gravity and temperature. In addition, under the action of the short-wavelength part of ultraviolet and X-rays at an altitude of 100 km or more, oxygen, nitrogen and carbon dioxide molecules dissociate into atoms. At high altitudes, these gases are in the form of highly ionized atoms.

The content of carbon dioxide in the atmosphere of different regions of the Earth is less constant, which is partly due to the uneven distribution of large industrial enterprises that pollute the air, as well as the uneven distribution of vegetation on the Earth, water basins absorbing carbon dioxide. Also variable in the atmosphere is the content of aerosols (see) - particles suspended in the air ranging in size from several millimicrons to several tens of microns - formed as a result of volcanic eruptions, powerful artificial explosions, pollution by industrial enterprises. The concentration of aerosols decreases rapidly with height.

The most unstable and important of the variable components of the atmosphere is water vapor, the concentration of which at the earth's surface can vary from 3% (in the tropics) to 2 × 10 -10% (in Antarctica). The higher the air temperature, the more moisture, ceteris paribus, can be in the atmosphere and vice versa. The bulk of water vapor is concentrated in the atmosphere up to altitudes of 8-10 km. The content of water vapor in the atmosphere depends on the combined influence of the processes of evaporation, condensation and horizontal transport. At high altitudes, due to a decrease in temperature and condensation of vapors, the air is practically dry.

The Earth's atmosphere, in addition to molecular and atomic oxygen, contains a small amount of ozone (see), the concentration of which is very variable and varies depending on the height and season. Most of the ozone is contained in the region of the poles by the end of the polar night at an altitude of 15-30 km with a sharp decrease up and down. Ozone arises as a result of the photochemical action of ultraviolet solar radiation on oxygen, mainly at altitudes of 20-50 km. In this case, diatomic oxygen molecules partially decompose into atoms and, joining undecomposed molecules, form triatomic ozone molecules (polymeric, allotropic form of oxygen).

The presence in the atmosphere of a group of so-called inert gases (helium, neon, argon, krypton, xenon) is associated with the continuous flow of natural radioactive decay processes.

The biological significance of gases the atmosphere is very large. For most multicellular organisms, a certain content of molecular oxygen in a gas or aquatic environment is an indispensable factor in their existence, causing the release of energy during respiration from organic substances created initially in the course of photosynthesis. It is no coincidence that the upper boundaries of the biosphere (part of the surface the globe and the lower part of the atmosphere where life exists) are determined by the presence of sufficient oxygen. In the process of evolution, organisms have adapted to a certain level of oxygen in the atmosphere; changing the oxygen content in the direction of decreasing or increasing has an adverse effect (see Altitude sickness, Hyperoxia, Hypoxia).

The ozone-allotropic form of oxygen also has a pronounced biological effect. At concentrations not exceeding 0.0001 mg / l, which is typical for resort areas and sea coasts, ozone has a healing effect - it stimulates respiration and cardiovascular activity, improves sleep. With an increase in the concentration of ozone, its toxic effect is manifested: eye irritation, necrotic inflammation of the mucous membranes of the respiratory tract, exacerbation of pulmonary diseases, autonomic neuroses. Entering into combination with hemoglobin, ozone forms methemoglobin, which leads to a violation of the respiratory function of the blood; the transfer of oxygen from the lungs to the tissues becomes difficult, the phenomena of suffocation develop. Atomic oxygen has a similar adverse effect on the body. Ozone plays a significant role in creating the thermal regimes of various layers of the atmosphere due to the extremely strong absorption of solar radiation and terrestrial radiation. Ozone absorbs ultraviolet and infrared rays most intensively. Solar rays with a wavelength of less than 300 nm are almost completely absorbed by atmospheric ozone. Thus, the Earth is surrounded by a kind of "ozone screen" that protects many organisms from the harmful effects of ultraviolet radiation from the Sun, Nitrogen atmospheric air is of great biological importance primarily as a source of the so-called. fixed nitrogen - a resource of plant (and ultimately animal) food. The physiological significance of nitrogen is determined by its participation in creating the level of atmospheric pressure necessary for life processes. Under certain conditions of pressure changes, nitrogen plays a major role in the development of a number of disorders in the body (see Decompression sickness). Assumptions that nitrogen weakens the toxic effect of oxygen on the body and is absorbed from the atmosphere not only by microorganisms, but also by higher animals, are controversial.

The inert gases of the atmosphere (xenon, krypton, argon, neon, helium) at the partial pressure they create under normal conditions can be classified as biologically indifferent gases. With a significant increase in partial pressure, these gases have a narcotic effect.

The presence of carbon dioxide in the atmosphere ensures the accumulation of solar energy in the biosphere due to the photosynthesis of complex carbon compounds, which continuously arise, change and decompose in the course of life. This dynamic system is maintained by the activities of algae and land plants that capture energy sunlight and using it to convert carbon dioxide (see) and water into a variety of organic compounds with the release of oxygen. The upward extension of the biosphere is partially limited by the fact that at altitudes of more than 6-7 km, chlorophyll-containing plants cannot live due to the low partial pressure of carbon dioxide. Carbon dioxide is also very active in physiological terms, as it plays an important role in the regulation of metabolic processes, the activity of the central nervous system, respiration, blood circulation, oxygen regime of the body. However, this regulation is mediated by the influence of carbon dioxide produced by the body itself, and not from the atmosphere. In the tissues and blood of animals and humans, the partial pressure of carbon dioxide is approximately 200 times higher than its pressure in the atmosphere. And only with a significant increase in the content of carbon dioxide in the atmosphere (more than 0.6-1%), there are violations in the body, denoted by the term hypercapnia (see). The complete elimination of carbon dioxide from the inhaled air cannot directly have an adverse effect on the human and animal organisms.

Carbon dioxide plays a role in absorbing long-wavelength radiation and maintaining the "greenhouse effect" that raises the temperature near the Earth's surface. The problem of the influence on thermal and other regimes of the atmosphere of carbon dioxide, which enters the air in huge quantities as a waste product of industry, is also being studied.

Atmospheric water vapor (air humidity) also affects the human body, in particular, heat exchange with the environment.

As a result of the condensation of water vapor in the atmosphere, clouds form and precipitation (rain, hail, snow) falls. Water vapor, scattering solar radiation, participate in the creation of the thermal regime of the Earth and the lower layers of the atmosphere, in the formation of meteorological conditions.

Atmosphere pressure

Atmospheric pressure (barometric) is the pressure exerted by the atmosphere under the influence of gravity on the surface of the Earth. The value of this pressure at each point in the atmosphere is equal to the weight of the overlying column of air with a unit base, extending above the place of measurement to the boundaries of the atmosphere. Atmospheric pressure is measured with a barometer (see) and expressed in millibars, in newtons per square meter or the height of the mercury column in the barometer in millimeters, reduced to 0 ° and the normal value of the acceleration of gravity. In table. 2 shows the most commonly used units of atmospheric pressure.

The change in pressure occurs due to uneven heating of air masses located above land and water at different geographical latitudes. As the temperature rises, the density of air and the pressure it creates decrease. A huge accumulation of fast-moving air with reduced pressure (with a decrease in pressure from the periphery to the center of the vortex) is called a cyclone, with increased pressure (with an increase in pressure towards the center of the vortex) - an anticyclone. For weather forecasting, non-periodic changes in atmospheric pressure are important, which occur in moving vast masses and are associated with the emergence, development and destruction of anticyclones and cyclones. Especially large changes in atmospheric pressure are associated with the rapid movement of tropical cyclones. At the same time, atmospheric pressure can vary by 30-40 mbar per day.

The drop in atmospheric pressure in millibars over a distance of 100 km is called the horizontal barometric gradient. Typically, the horizontal barometric gradient is 1–3 mbar, but in tropical cyclones it sometimes rises to tens of millibars per 100 km.

As the altitude rises, atmospheric pressure decreases in a logarithmic relationship: at first very sharply, and then less and less noticeably (Fig. 1). Therefore, the barometric pressure curve is exponential.

The decrease in pressure per unit vertical distance is called the vertical barometric gradient. Often they use the reciprocal of it - the barometric step.

Since the barometric pressure is the sum of the partial pressures of the gases that form the air, it is obvious that with the rise to a height, along with a decrease in the total pressure of the atmosphere, the partial pressure of the gases that make up the air also decreases. The value of the partial pressure of any gas in the atmosphere is calculated by the formula

where P x ​​is the partial pressure of the gas, P z is the atmospheric pressure at altitude Z, X% is the percentage of gas whose partial pressure is to be determined.

Rice. 1. Change in barometric pressure depending on the height above sea level.

Rice. 2. Change in the partial pressure of oxygen in the alveolar air and saturation of arterial blood with oxygen depending on the change in altitude when breathing air and oxygen. Oxygen breathing starts from a height of 8.5 km (experiment in a pressure chamber).

Rice. 3. Comparative curves of the average values ​​of active consciousness in a person in minutes at different heights after a rapid rise while breathing air (I) and oxygen (II). At altitudes above 15 km, active consciousness is equally disturbed when breathing oxygen and air. At altitudes up to 15 km, oxygen breathing significantly prolongs the period of active consciousness (experiment in a pressure chamber).

Since the percentage composition of atmospheric gases is relatively constant, to determine the partial pressure of any gas, it is only necessary to know the total barometric pressure at a given height (Fig. 1 and Table 3).

Table 3. TABLE OF STANDARD ATMOSPHERE (GOST 4401-64) 1

1 Given in abbreviated form and supplemented by the column "Partial pressure of oxygen".

When determining the partial pressure of a gas in humid air you need to subtract the pressure (elasticity) of saturated vapors from the barometric pressure.

The formula for determining the partial pressure of a gas in moist air will be slightly different than for dry air:

where pH 2 O is the elasticity of water vapor. At t° 37°, the elasticity of saturated water vapor is 47 mm Hg. Art. This value is used in calculating the partial pressures of gases in alveolar air in ground and high-altitude conditions.

The effect on the body of increased and reduced pressure. Changes in barometric pressure upwards or downwards have a variety of effects on the organism of animals and humans. The influence of increased pressure is associated with the mechanical and penetrating physical and chemical action of the gaseous medium (the so-called compression and penetrating effects).

The compression effect is manifested by: general volumetric compression, due to a uniform increase in the forces of mechanical pressure on organs and tissues; mechanonarcosis due to uniform volumetric compression at very high barometric pressure; local uneven pressure on tissues that limit gas-containing cavities when there is a broken connection between the outside air and the air in the cavity, for example, the middle ear, the accessory cavities of the nose (see Barotrauma); increase in gas density in the system external respiration, which causes an increase in resistance to respiratory movements, especially with forced breathing (exercise, hypercapnia).

The penetrating effect can lead to the toxic effect of oxygen and indifferent gases, an increase in the content of which in the blood and tissues causes a narcotic reaction, the first signs of a cut when using a nitrogen-oxygen mixture in humans occur at a pressure of 4-8 atm. An increase in the partial pressure of oxygen initially reduces the level of functioning of the cardiovascular and respiratory systems due to the shutdown of the regulatory effect of physiological hypoxemia. With an increase in the partial pressure of oxygen in the lungs more than 0.8-1 ata, its toxic effect is manifested (damage to the lung tissue, convulsions, collapse).

The penetrating and compressive effects of the increased pressure of the gaseous medium are used in clinical medicine in the treatment of various diseases with general and local impairment of oxygen supply (see Barotherapy, Oxygen therapy).

Lowering the pressure has an even more pronounced effect on the body. Under conditions of an extremely rarefied atmosphere, the main pathogenetic factor leading to loss of consciousness in a few seconds, and to death in 4-5 minutes, is a decrease in the partial pressure of oxygen in the inhaled air, and then in the alveolar air, blood and tissues (Fig. 2 and 3). Moderate hypoxia causes the development of adaptive reactions of the respiratory system and hemodynamics, aimed at maintaining oxygen supply primarily to vital organs (brain, heart). With a pronounced lack of oxygen, oxidative processes are inhibited (due to respiratory enzymes), and aerobic processes of energy production in mitochondria are disrupted. This leads first to a breakdown in the functions of vital organs, and then to irreversible structural damage and death of the body. The development of adaptive and pathological reactions, a change in the functional state of the body and human performance with a decrease in atmospheric pressure is determined by the degree and rate of decrease in the partial pressure of oxygen in the inhaled air, the duration of stay at a height, the intensity of the work performed, the initial state of the body (see Altitude sickness).

A decrease in pressure at altitudes (even with the exclusion of lack of oxygen) causes serious disorders in the body, united by the concept of "decompression disorders", which include: high-altitude flatulence, barotitis and barosinusitis, high-altitude decompression sickness and high-altitude tissue emphysema.

High-altitude flatulence develops due to the expansion of gases in gastrointestinal tract with a decrease in barometric pressure on the abdominal wall when ascending to altitudes of 7-12 km or more. Of certain importance is the release of gases dissolved in the intestinal contents.

Expansion of gases leads to stretching of the stomach and intestines, raising the diaphragm, changing the position of the heart, irritating the receptor apparatus of these organs and causing pathological reflexes that disrupt breathing and blood circulation. Often there are sharp pains in the abdomen. Similar phenomena sometimes occur in divers when ascending from depth to the surface.

The mechanism of development of barotitis and barosinusitis, manifested by a feeling of congestion and pain, respectively, in the middle ear or accessory cavities of the nose, is similar to the development of high-altitude flatulence.

The decrease in pressure, in addition to expanding the gases contained in the body cavities, also causes the release of gases from liquids and tissues in which they were dissolved under pressure at sea level or at depth, and the formation of gas bubbles in the body.

This process of an exit of the dissolved gases (first of all nitrogen) causes development of a decompression sickness (see).

Rice. 4. Dependence of the boiling point of water on altitude and barometric pressure. The pressure numbers are located below the corresponding altitude numbers.

With a decrease in atmospheric pressure, the boiling point of liquids decreases (Fig. 4). At an altitude of more than 19 km, where the barometric pressure is equal (or less) than the elasticity of saturated vapors at body temperature (37 °), “boiling” of the interstitial and intercellular fluid of the body can occur, resulting in large veins, in the cavity of the pleura, stomach, pericardium , in loose adipose tissue, that is, in areas with low hydrostatic and interstitial pressure, water vapor bubbles form, high-altitude tissue emphysema develops. Altitude "boiling" does not affect cellular structures, being localized only in the intercellular fluid and blood.

Massive steam bubbles can block the work of the heart and blood circulation and disrupt the functioning of vital systems and organs. This is a serious complication of acute oxygen starvation that develops at high altitudes. Prevention of high-altitude tissue emphysema can be achieved by creating external counterpressure on the body with high-altitude equipment.

The very process of lowering barometric pressure (decompression) under certain parameters can become a damaging factor. Depending on the speed, decompression is divided into smooth (slow) and explosive. The latter proceeds in less than 1 second and is accompanied by a strong bang (as in a shot), the formation of fog (condensation of water vapor due to cooling of expanding air). Typically, explosive decompression occurs at altitudes when the glazing of a pressurized cockpit or pressure suit breaks.

In explosive decompression, the lungs are the first to suffer. A rapid increase in intrapulmonary excess pressure (more than 80 mm Hg) leads to a significant stretching of the lung tissue, which can cause rupture of the lungs (with their expansion by 2.3 times). Explosive decompression can also cause damage to the gastrointestinal tract. The amount of overpressure that occurs in the lungs will largely depend on the rate of air outflow from them during decompression and the volume of air in the lungs. It is especially dangerous if the upper airways at the time of decompression turn out to be closed (when swallowing, holding the breath) or decompression coincides with the phase of deep inspiration, when the lungs are filled with a large amount of air.

Atmospheric temperature

The temperature of the atmosphere initially decreases with increasing altitude (on average, from 15° near the ground to -56.5° at an altitude of 11-18 km). The vertical temperature gradient in this zone of the atmosphere is about 0.6° for every 100 m; it changes during the day and year (Table 4).

Table 4. CHANGES IN THE VERTICAL TEMPERATURE GRADIENT OVER THE MIDDLE STRIP OF THE USSR TERRITORY

Rice. 5. Change in the temperature of the atmosphere at different heights. The boundaries of the spheres are indicated by a dotted line.

At altitudes of 11 - 25 km, the temperature becomes constant and amounts to -56.5 °; then the temperature begins to rise, reaching 30–40° at an altitude of 40 km, and 70° at an altitude of 50–60 km (Fig. 5), which is associated with intense absorption of solar radiation by ozone. From a height of 60-80 km, the air temperature again decreases slightly (up to 60°C), and then progressively increases and reaches 270°C at an altitude of 120 km, 800°C at an altitude of 220 km, 1500°C at an altitude of 300 km, and

on the border with outer space - more than 3000 °. It should be noted that due to the high rarefaction and low density of gases at these heights, their heat capacity and ability to heat colder bodies is very small. Under these conditions, the transfer of heat from one body to another occurs only through radiation. All considered changes in temperature in the atmosphere are associated with the absorption by air masses of the thermal energy of the Sun - direct and reflected.

In the lower part of the atmosphere near the Earth's surface, the temperature distribution depends on the influx of solar radiation and therefore has a mainly latitudinal character, that is, lines of equal temperature - isotherms - are parallel to latitudes. Since the atmosphere in the lower layers is heated from the earth's surface, the horizontal temperature change is strongly influenced by the distribution of continents and oceans, the thermal properties of which are different. Usually, reference books indicate the temperature measured during network meteorological observations with a thermometer installed at a height of 2 m above the soil surface. The highest temperatures (up to 58°C) are observed in the deserts of Iran, and in the USSR - in the south of Turkmenistan (up to 50°), the lowest (up to -87°) in Antarctica, and in the USSR - in the regions of Verkhoyansk and Oymyakon (up to -68° ). In winter, the vertical temperature gradient in some cases, instead of 0.6 °, can exceed 1 ° per 100 m or even take a negative value. During the day in the warm season, it can be equal to many tens of degrees per 100 m. There is also a horizontal temperature gradient, which is usually referred to as a distance of 100 km along the normal to the isotherm. The magnitude of the horizontal temperature gradient is tenths of a degree per 100 km, and in frontal zones it can exceed 10° at 100 m.

The human body is able to maintain thermal homeostasis (see) within a fairly narrow range of outdoor temperature fluctuations - from 15 to 45 °. Significant differences in the temperature of the atmosphere near the Earth and at heights require the use of special protective technical means to ensure the thermal balance between the human body and the environment in high-altitude and space flights.

Characteristic changes in the parameters of the atmosphere (temperature, pressure, chemical composition, electrical state) make it possible to conditionally divide the atmosphere into zones, or layers. Troposphere- the closest layer to the Earth, the upper boundary of which extends at the equator up to 17-18 km, at the poles - up to 7-8 km, in middle latitudes - up to 12-16 km. The troposphere is characterized by an exponential pressure drop, the presence of a constant vertical temperature gradient, horizontal and vertical movements of air masses, and significant changes in air humidity. The troposphere contains the bulk of the atmosphere, as well as a significant part of the biosphere; here all the main types of clouds arise, air masses and fronts are formed, cyclones and anticyclones develop. In the troposphere, due to the reflection of the sun's rays by the snow cover of the Earth and the cooling of the surface layers of air, the so-called inversion takes place, that is, an increase in temperature in the atmosphere from the bottom up instead of the usual decrease.

In the warm season in the troposphere there is a constant turbulent (random, chaotic) mixing of air masses and heat transfer by air flows (convection). Convection destroys fogs and reduces the dust content of the lower atmosphere.

The second layer of the atmosphere is stratosphere.

It starts from the troposphere as a narrow zone (1-3 km) with a constant temperature (tropopause) and extends to heights of about 80 km. A feature of the stratosphere is the progressive rarefaction of the air, the exceptionally high intensity of ultraviolet radiation, the absence of water vapor, the presence of a large amount of ozone and the gradual increase in temperature. The high content of ozone causes a number of optical phenomena (mirages), causes the reflection of sounds and has a significant effect on the intensity and spectral composition of electromagnetic radiation. In the stratosphere there is a constant mixing of air, so its composition is similar to the air of the troposphere, although its density at the upper boundaries of the stratosphere is extremely low. The prevailing winds in the stratosphere are westerly, and in the upper zone there is a transition to easterly winds.

The third layer of the atmosphere is ionosphere, which starts from the stratosphere and extends to altitudes of 600-800 km.

Distinctive features of the ionosphere are the extreme rarefaction of the gaseous medium, a high concentration of molecular and atomic ions and free electrons, as well as high temperature. The ionosphere affects the propagation of radio waves, causing their refraction, reflection and absorption.

The main source of ionization in the high layers of the atmosphere is the ultraviolet radiation of the Sun. In this case, electrons are knocked out of the gas atoms, the atoms turn into positive ions, and the knocked-out electrons remain free or are captured by neutral molecules with the formation of negative ions. The ionization of the ionosphere is influenced by meteors, corpuscular, X-ray and gamma radiation of the Sun, as well as the seismic processes of the Earth (earthquakes, volcanic eruptions, powerful explosions), which generate acoustic waves in the ionosphere, which increase the amplitude and speed of oscillations of atmospheric particles and contribute to the ionization of gas molecules and atoms (see Aeroionization).

The electrical conductivity in the ionosphere, associated with a high concentration of ions and electrons, is very high. The increased electrical conductivity of the ionosphere plays an important role in the reflection of radio waves and the occurrence of auroras.

The ionosphere is the area of ​​flights of artificial earth satellites and intercontinental ballistic missiles. Currently, space medicine is studying the possible effects on the human body of flight conditions in this part of the atmosphere.

Fourth, outer layer of the atmosphere - exosphere. From here, atmospheric gases are scattered into the world space due to dissipation (overcoming the forces of gravity by molecules). Then there is a gradual transition from the atmosphere to the interplanetary outer space. The exosphere differs from the latter by the presence of a large number of free electrons that form the 2nd and 3rd radiation belts of the Earth.

The division of the atmosphere into 4 layers is very arbitrary. So, according to electrical parameters, the entire thickness of the atmosphere is divided into 2 layers: the neutrosphere, in which neutral particles predominate, and the ionosphere. The temperature distinguishes the troposphere, stratosphere, mesosphere and thermosphere, separated respectively by tropo-, strato- and mesopauses. The layer of the atmosphere located between 15 and 70 km and characterized by a high content of ozone is called the ozonosphere.

For practical purposes, it is convenient to use the International Standard Atmosphere (MCA), for which the following conditions are accepted: the pressure at sea level at t ° 15 ° is 1013 mbar (1.013 X 10 5 nm 2, or 760 mm Hg); the temperature decreases by 6.5° per 1 km to a level of 11 km (conditional stratosphere), and then remains constant. In the USSR, the standard atmosphere GOST 4401 - 64 was adopted (Table 3).

Precipitation. Since the bulk of the atmospheric water vapor is concentrated in the troposphere, the processes of phase transitions of water, which cause precipitation, proceed mainly in the troposphere. Tropospheric clouds usually cover about 50% of the entire earth's surface, while clouds in the stratosphere (at altitudes of 20-30 km) and near the mesopause, called mother-of-pearl and noctilucent clouds, respectively, are observed relatively rarely. As a result of the condensation of water vapor in the troposphere, clouds form and precipitation occurs.

According to the nature of precipitation, precipitation is divided into 3 types: continuous, torrential, drizzling. The amount of precipitation is determined by the thickness of the layer of fallen water in millimeters; precipitation is measured by rain gauges and precipitation gauges. Precipitation intensity is expressed in millimeters per minute.

The distribution of precipitation in certain seasons and days, as well as over the territory, is extremely uneven, due to the circulation of the atmosphere and the influence of the Earth's surface. Yes, on Hawaiian Islands on average, 12,000 mm falls per year, and in the driest regions of Peru and the Sahara, precipitation does not exceed 250 mm, and sometimes does not fall for several years. In the annual dynamics of precipitation, the following types are distinguished: equatorial - with a maximum of precipitation after spring and autumn equinox; tropical - with a maximum of precipitation in summer; monsoon - with a very pronounced peak in summer and dry winter; subtropical - with maximum precipitation in winter and dry summer; continental temperate latitudes- with a maximum of precipitation in summer; marine temperate latitudes - with a maximum of precipitation in winter.

The entire atmospheric-physical complex of climatic and meteorological factors that make up the weather is widely used to promote health, hardening, and for medicinal purposes (see Climatotherapy). Along with this, it has been established that sharp fluctuations in these atmospheric factors can adversely affect the physiological processes in the body, causing the development of various pathological conditions and the exacerbation of diseases, which are called meteotropic reactions (see Climatopathology). Of particular importance in this regard are frequent, long-term disturbances of the atmosphere and abrupt fluctuations in meteorological factors.

Meteotropic reactions are observed more often in people suffering from diseases of the cardiovascular system, polyarthritis, bronchial asthma, peptic ulcer, skin diseases.

Bibliography: Belinsky V. A. and Pobiyaho V. A. Aerology, L., 1962, bibliogr.; Biosphere and its resources, ed. V. A. Kovdy. Moscow, 1971. Danilov A. D. Chemistry of the ionosphere, L., 1967; Kolobkov N. V. Atmosphere and its life, M., 1968; Kalitin H.H. Fundamentals of atmospheric physics as applied to medicine, L., 1935; Matveev L. T. Fundamentals of general meteorology, Physics of the atmosphere, L., 1965, bibliogr.; Minkh A. A. Air ionization and its hygienic value, M., 1963, bibliogr.; it, Methods of hygienic researches, M., 1971, bibliogr.; Tverskoy P. N. Course of meteorology, L., 1962; Umansky S.P. Man in space, M., 1970; Khvostikov I. A. High layers of the atmosphere, L., 1964; X r g and a N A. X. Physics of the atmosphere, L., 1969, bibliogr.; Khromov S.P. Meteorology and climatology for geographical faculties, L., 1968.

Effects of high and low blood pressure on the body- Armstrong G. Aviation medicine, trans. from English, M., 1954, bibliogr.; Saltsman G.L. Physiological bases of a person's stay in conditions of high pressure of the gases of the environment, L., 1961, bibliogr.; Ivanov D. I. and Khromushkin A. I. Human life support systems during high-altitude and space flights, M., 1968, bibliogr.; Isakov P. K., etc. Theory and practice of aviation medicine, M., 1971, bibliogr.; Kovalenko E. A. and Chernyakov I. N. Oxygen of fabrics at extreme factors of flight, M., 1972, bibliogr.; Miles S. Underwater medicine, trans. from English, M., 1971, bibliography; Busby D. E. Space clinical medicine, Dordrecht, 1968.

I. H. Chernyakov, M. T. Dmitriev, S. I. Nepomnyashchy.

2.1. The structure of the 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 activity of gastric juice, which creates favorable conditions for the development of inflammatory processes in the 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 at a given moment (or by 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 (instruments) 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 space suits. 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 at elevated 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, during 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, headache, gait, speech, and convulsions are observed. 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 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 lies in the action of various ionizing factors on air molecules: radioactive elements, cosmic, UV radiation, electric, 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 ionizing radiation sources in industry, agriculture, medicine, and other branches of science and technology.

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. The human body is also influenced by heliophysical factors - 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, against the background of high pressure, the air temperature drops and is accompanied by cold rains, then hypertensive patients, asthmatics, people with kidney stone and cholelithiasis suffer it especially hard. 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 as much as possible to be in a room with air conditioning or at least a fan, 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. The combination of low temperature with high humidity and high air velocity is especially dangerous. 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 temperatures, 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.

At high humidity more than others, those suffering from diseases of the respiratory tract, joints and kidneys are at risk of getting sick, 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 believe that atmospheric pressure plays a major role in their response to the weather. 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 their 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 hypotension sufferers 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 body 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

We cannot influence the weather conditions. 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 car 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.

• For everyone who, when climatic conditions change, their well-being changes, it is important to treat their 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 disruptions 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 is lower in summer 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 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

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 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. So, a sharp movement from a zone with a relatively high pressure to a lower one can affect the work of the 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.