Increased humidity in the atmospheric air as a percentage. Why does a change in weather affect a person’s well-being? The effect of solar radiation on immunity

Air humidity- content in the air, characterized by a number of values. Water that evaporates from the surface when they are heated enters and concentrates in the lower layers of the troposphere. The temperature at which the air reaches saturation with moisture for a given water vapor content and constant is called the dew point.

Humidity is characterized by the following indicators:

Absolute humidity(Latin absolutus - complete). It is expressed by the mass of water vapor in 1 m of air. Calculated in grams of water vapor per 1 m3 of air. The higher the temperature, the greater the absolute humidity, since more water changes from liquid to vapor when heated. During the day, absolute humidity is higher than at night. The indicator of absolute humidity depends on: in polar latitudes, for example, it is equal to up to 1 g per 1 m2 of water vapor, at the equator up to 30 grams per 1 m2 in Batumi (, coast) absolute humidity is 6 g per 1 m, and in Verkhoyansk ( , ) - 0.1 grams per 1 m The vegetation cover of the area largely depends on the absolute humidity of the air;

Relative humidity. This is the ratio of the amount of moisture in the air to the amount it can contain at the same temperature. Relative humidity is calculated as a percentage. For example, relative humidity is 70%. This means that the air contains 70% of the amount of steam that it can hold at a given temperature. If the daily variation of absolute humidity is directly proportional to the variation of temperatures, then relative humidity is inversely proportional to this variation. A person feels good at 40-75%. Deviation from the norm causes a painful state of the body.

Air in nature is rarely saturated with water vapor, but always contains some amount of it. Nowhere on Earth has a relative humidity of 0% been recorded. At meteorological stations, humidity is measured using a hygrometer; in addition, recorders - hygrographs - are used;

The air is saturated and unsaturated. When water evaporates from the surface of the ocean or land, the air cannot hold water vapor indefinitely. This limit depends on. Air that can no longer hold moisture is called saturated air. From this air, at the slightest cooling, droplets of water begin to be released in the form of dew. This happens because water, when cooled, changes from a state (steam) to liquid. Air above a dry, warm surface usually contains less water vapor than it would at a given temperature. Such air is called unsaturated. When it cools, water does not always release. The warmer the air, the greater its ability to absorb moisture. For example, at a temperature of -20°C, air contains no more than 1 g/m of water; at a temperature of + 10°C - about 9 g/m3, and at +20°C - about 17 g/m3 Therefore, with seemingly high air humidity in

Atmospheric air- this is the environment that surrounds a person constantly, through which his basic life 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 the physical or chemical properties of air easily affect a person’s well-being, disturbing the harmonious balance of our body, i.e. health.

The ecological role of the air environment for humans is as follows:

air delivers oxygen to the body;

accepts carbon dioxide and gaseous metabolic products;

affects thermoregulation;

Sun rays act on the body through the air;

air is a reservoir of harmful gases, suspended substances and microbes that affect humans.

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

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

Air temperature depends on the time of year, climate zone, time of day, intensity of solar glow and the underlying surface of the earth. The sun's rays passing through the atmosphere do not heat it. The air is heated by heat transfer from the soil, which absorbs the sun's rays. Heated air rises up, giving way to cold air - this movement is called convection- it promotes the movement of air masses and uniform heating of the surface layers of the atmosphere. The hygienic significance of air temperature lies in its effect on the heat exchange of the body. Moreover, not only the absolute values ​​of air temperature, but also the amplitude of its fluctuations are of hygienic importance. In humans, heat is formed as a result of oxidative processes in cells and tissues and its normal existence is possible at a constant body temperature. Thanks to the complex mechanism of thermoregulation with the environment (in children under 7-8 years old it is imperfect), the body maintains thermal balance. The most favorable temperature for human well-being is 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 to 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 in 1 m 3 of air at a given temperature. Maximum humidity - the maximum amount of water vapor that can be contained in the air at a given temperature, measured in g per m3. Relative Humidity is the ratio of absolute humidity to maximum humidity, measured in %. Optimal parameters for health relative humidity are 30-60%. The hygienic importance of humidity lies in its effect on human sweating, which, by influencing body temperature, maintains its constancy. With increasing humidity, a person becomes hot in the warmth, and cold and chilly in the cold.

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 Hg. The hygienic importance of atmospheric pressure is to maintain blood pressure (BP). An increase or decrease in pressure affects human physiology. For a healthy person, these changes are invisible, but for a patient they are sensitive: changes in pressure are signaled by the state of health. At increased pressure the partial pressure of oxygen increases (% of it remains the same): the pulse and respiratory rate decrease, the maximum blood pressure decreases and the minimum blood pressure increases, the vital capacity of the lungs increases, skin sensitivity and hearing decrease, a feeling of dry mucous membranes (in the mouth) appears, intestinal motility increases and the release of gases; blood and tissues absorb oxygen better, which improves performance and well-being. With an artificial increase in pressure (for divers), the dissolution of atmospheric nitrogen increases, which dissolves well in fats, nervous tissue and subcutaneous tissue, from where it is slowly released during decompression. When a diver quickly rises from the depths, nitrogen boils and clogs the small vessels of the brain, causing the death of the diver, which requires slow extraction from the depths. But even under normal operating conditions, divers cannot avoid nitrogen embolism of blood vessels - their joints hurt and hemorrhages are frequent.

Decreased pressure causes a decrease in the partial pressure of oxygen, and when climbing mountains, a decrease in its concentration. Symptoms of “altitude sickness” occur: drowsiness, increased maximum blood pressure and decreased minimum blood pressure, heaviness in the head, headaches, apathy, depression; Dissolved nitrogen released into the blood acts in the form of joint pain and itching. 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 those moving to the city from a dacha or from the countryside: shortness of breath, palpitations, dizziness, nausea, and nosebleeds.

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

where it moves from and is called rumbo m. A graphic 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 predominant NE wind. Architects must take the wind rose into account when constructing residential areas and industrial enterprises: residential areas should be located on the windward side in relation to industrial enterprises.

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

Air ionization is formed under the influence of electrical discharges, radioactive elements, UV and cosmic rays. Light negative ions predominate in clean air, while heavy positive ions predominate in polluted air. The polluted air of cities is less ionized than in rural areas and resort areas. Negative ions enter the home from the street, and already in the window opening they account for only 20% of the street concentration. In multi-storey buildings they are actively absorbed by concrete walls, dust, CO 2, moisture, and higher air temperatures. In this case, instead of negative ions, the number of positive ones increases. A person feels stuffy, it seems like there is “not enough air”, but in reality there are not enough negative ions. Therefore, the level of ionization of a home is an indicator of air cleanliness. The hygienic role of negative ions - they negatively charge red blood cells, they absorb and release oxygen better, metabolic processes in tissues go better, acidosis decreases - mental work improves, efficiency increases, old age recedes. Mice in a 5-liter jar, into which ambient air is supplied, passed through electrodes, die after 2 hours, while controls with normal air live. Therefore, air ionizers such as Chizhevsky lamps are used in homes. For medicinal purposes, air ionization is used to treat hypertension and bronchial asthma. Therefore, for a healthy lifestyle, it is advisable for people to spend more time in the fresh air, and not sit in the 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 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 parts of visible light act differently: red rays excite; yellow, green - calm; purple ones are depressing. With a lack of light, vision becomes strained and worsens (sharpness and speed of discrimination). High brightness is blinding and tiring, 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-wave radiation is absorbed by the surface layer of the skin and causes it to warm up and a burning sensation is felt. Short-wave radiation is not felt and penetrates into the deep 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, including cataracts. At noon, short-wave radiation predominates, so sunbathing at this time is dangerous. UFL have the greatest biological activity. In the spring, under their influence, metabolism, immunity, and performance increase. They have an antirachitic effect, because under their influence, vitamin D is synthesized in the skin, which improves calcium metabolism and hematopoiesis, and the resistance of capillaries. Without UFL, rickets occurs in children, and osteoporosis occurs in adults: depletion of bones in calcium, leading to their fragility, teeth destruction (caries). This condition is called “light starvation” - it is often of professional origin: in miners, in people sent to the North, as well as in people who spend little time in 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 using UV lamps. Window glass weakens UV radiation, so they need to be washed more often to remove dust. UV rays have a harmful effect on the eyes, causing inflammation (photophthalmia) - an occupational disease of welders, as well as climbers, residents of mountain and arctic regions. Prevention: use of protective shields, black glasses, etc.

Why does a change in weather affect a person’s well-being?

If you are a person whose well-being can be used to predict the weather, then this article is just for you.

In my article, I want to talk about how changes in temperature, air humidity and atmospheric pressure affect human health and how you can avoid the negative impact of weather conditions on your body.

Man is a child of nature and is an integral part of it!

Everything in this world has its own balance and clear relationship; in this case, we will talk about the connection between weather conditions and human well-being.

Some people, often moving across time and climate zones (frequent flights), constantly change the climate and feel very comfortable.

Others, on the contrary, “lying on the couch” feel the slightest fluctuations in temperature and atmospheric pressure, which in turn negatively affects their well-being - it is this sensitivity to changes in weather conditions that is called weather dependence.

Weather-dependent people or people - “barometers” - are most often patients suffering from diseases of the cardiovascular system, who often work long hours, are constantly overtired and do not get enough rest.

Weather-dependent people include people with diseases of atherosclerosis of the vessels of the heart, brain and lower extremities, patients with diseases of the respiratory system, musculoskeletal system, allergy sufferers and patients with neurasthenia.

How do changes in atmospheric pressure affect on a person's well-being?

In order for a person to be comfortable, the atmospheric pressure must be equal to 750 mm. Hg pillar

If the atmospheric pressure deviates even by 10 mm in one direction or another, a person feels uncomfortable and this can affect his health.

What happens when atmospheric pressure decreases?

As atmospheric pressure decreases, air humidity increases, precipitation and an increase in air temperature are possible.

The first to feel a decrease in atmospheric pressure are people with low blood pressure (hypotonics), “heart patients”, as well as people with respiratory diseases.

Most often, there is general weakness, difficulty breathing, a feeling of lack of air, and shortness of breath occurs.

A decrease in atmospheric pressure is especially acutely and painfully felt by people with high intracranial pressure. Their migraine attacks worsen. In the digestive tract, not everything is in order either - discomfort appears in the intestines due to increased gas formation.

How to help yourself?

• An important point is to normalize your blood pressure and maintain it at the usual (normal) level.
• Drink more fluids (green tea, with honey)
• Don't skip your morning coffee these days.
• These days you shouldn't give up your morning coffee.
• Take tinctures of ginseng, lemongrass, and eleutherococcus
• After a working day, take a contrast shower
• Go to bed earlier than usual

What happens when atmospheric pressure increases?

When atmospheric pressure rises, the weather becomes clear and does not have sudden changes in humidity and temperature.

With an increase in atmospheric pressure, the health of hypertensive patients, patients suffering from bronchial asthma and allergy sufferers worsens.

When the weather becomes calm, the concentration of harmful industrial impurities in the city air increases, which are an irritating factor for people with respiratory diseases.

Frequent complaints are headaches, malaise, heart pain and decreased general ability to work. An increase in atmospheric pressure negatively affects the emotional background and is often the main cause of sexual disorders.

Another negative characteristic of high atmospheric pressure is decreased immunity. This is explained by the fact that an increase in atmospheric pressure lowers the number of leukocytes in the blood, and the body becomes more vulnerable to various infections.

How to help yourself?

• Do some light morning exercise
• Take a contrast shower
• Morning breakfast should contain more potassium (cottage cheese, raisins, dried apricots, bananas)
• Don't overeat during the day
• If you have increased intracranial pressure, take the medications prescribed by your neuropathologist in advance
• Take care of your nervous and immune system - do not start important things on this day
• Try to spend this day with minimal expenditure of physical strength and emotions, because your mood will leave much to be desired
• When you get home, rest for about 40 minutes, go about your daily activities and try to go to bed early.

How do changes in air humidity affect on a person's well-being?

Low air humidity is considered to be 30 - 40%, which means that the air becomes dry and can be irritating to the nasal mucosa.

Allergy sufferers and asthmatics suffer when the air is dry.

What to do?

• In order to moisturize the mucous membrane of the nasopharynx, rinse through the nose with a slightly salted solution or ordinary non-carbonated water.
• Now there are many nasal sprays that contain mineral salts, help moisturize the nasal passages and nasopharynx, relieve swelling and help improve nasal breathing.

What happens to the body when air humidity rises?

High air humidity is 70 - 90% when the climate is characterized by frequent precipitation. An example of weather with high air humidity can be Russia and Sochi.

High air humidity negatively affects people with respiratory diseases, because at this time the risk of developing hypothermia and colds increases.

Increased air humidity contributes to the exacerbation of chronic diseases of the kidneys, joints and inflammatory diseases of the female genital organs (appendages).

How to help yourself?

• If possible, change the climate to dry
• Reduce exposure to damp and wet weather
• Warm yourself when leaving home
• Take your vitamins
• Treat and prevent chronic diseases in a timely manner

How do changes in air temperature affect a person’s well-being?

For the human body, the optimal ambient temperature is 18 degrees; this is the temperature recommended to maintain in the room where you sleep.

Sudden temperature changes are accompanied by changes in the oxygen content in the atmospheric air, and this significantly depresses a person’s well-being.

A person is a living creature that needs oxygen in order to live and naturally feel good.

When the ambient temperature decreases, the air becomes saturated with oxygen, and when it warms, on the contrary, there is less oxygen in the air and therefore it is difficult for us to breathe in hot weather.

When air temperature rises and atmospheric pressure decreases, people with cardiovascular and respiratory diseases are the first to suffer.

When, on the contrary, the temperature decreases and the atmospheric pressure increases, it is especially difficult for hypertensive patients, asthmatics, people with diseases of the digestive tract and those who suffer from urolithiasis.

With a sharp and significant fluctuation in ambient temperature, by about 10 degrees during the day, a large amount of histamine is produced in the body.

Histamine is a substance that provokes the development of allergic reactions in the body in healthy people, not to mention allergy sufferers.

How to help yourself?

• In this regard, before a sharp cold snap, limit the consumption of foods that can cause allergies (citrus fruits, chocolate, coffee, tomatoes)
• During extreme heat, the body loses a large amount of fluid, and therefore, in the summer, drink more purified water - this will help preserve your heart, blood vessels and kidneys.
• Always listen to weather forecasts. Having information about temperature changes will help you reduce the likelihood of exacerbations of chronic diseases, and maybe protect you from the emergence of new health problems?!

What are magnetic storms And How do they affect a person’s well-being?

Solar flares, eclipses and other geophysical and cosmic factors affect human health.

Have you probably noticed that over the past 15 - 25 years, along with the weather forecast, they talk about magnetic storms and warn about possible exacerbations of diseases in certain categories of people?

Each of us reacts to magnetic storms, but not everyone notices it, much less associates it with a magnetic storm.

According to statistics, it is on the days of magnetic storms that the largest number of ambulance calls occur for hypertensive crises, heart attacks and strokes.

These days, not only the number of hospitalizations in cardiology and neurology departments is increasing, but also the number of deaths due to heart attacks and strokes is growing.

Why do magnetic storms prevent us from living?

During magnetic storms, the work of the pituitary gland is inhibited.

The pituitary gland is a gland that is located in the brain and produces melatonin.

Melatonin is a substance that, in turn, controls the functioning of the gonads and the adrenal cortex, and the metabolism and adaptation of our body to unfavorable environmental conditions depend on the adrenal cortex.

Once upon a time, studies were even conducted in which it was proven that during magnetic storms the production of melatonin is suppressed, and more cortisol, the stress hormone, is released in the adrenal cortex.

Prolonged or frequent exposure to magnetic storms on the body can lead to disruption of biorhythms, which are also controlled by the pituitary gland. The result of this can be not only a deterioration in well-being, but also serious health problems (for example: neuroses, chronic fatigue syndrome, hormonal imbalances).

In conclusion, I would like to say that people who spend little time outdoors suffer more often from weather changes, and therefore even minor weather fluctuations can cause poor health.

“11 ways to get rid of weather dependence”

1. Hardening

2. Swimming

3. Walking, running

4. Frequent walks in the fresh air

5. Healthy and nutritious diet

6. Get enough sleep

7. Correction of the emotional sphere (autogenic training, relaxation, yoga, massage, conversation with a psychologist)

8. Taking vitamins

9. Eating seasonal foods

10. Giving up bad habits

11. Weight normalization

Tips in case of sudden weather changes

• Limit physical activity.
• Avoid additional emotional and physical stress.
• Monitor your blood pressure and do not forget to take the medications prescribed to you by your cardiologist. Neurologist, pulmonologist or allergist.
• Don't overeat or overuse salt.
• Walk outdoors for at least 1 hour before going to bed.
• If your blood pressure rises, massage your neck and thoracic spine.
• Take anti-anxiety medications.
• Don't forget about vitamins C and B.

If you have read the article to the end, then you are really worried about the state of your health and you clearly feel the weather fluctuations.

But what if not the mood deteriorates when environmental changes interfere with our lives? And if this happens often, we are exposed to constant negativity, of which there is already a lot around us, and then there’s the weather….

LECTURE 6

WATER VAPOR IN THE ATMOSPHERE

Humidity is the content of water vapor in the atmosphere. Water vapor is one of the most important components of the earth's atmosphere.

Water vapor continuously enters the atmosphere due to the evaporation of water from the surface of reservoirs, soil, snow, ice and vegetation, which consumes an average of 23% of solar radiation arriving at the earth's surface.

The atmosphere contains an average of 1.29 10 13 t of moisture (water vapor and liquid water), which is equivalent to a layer of water of 25.5 mm.

Air humidity is characterized by the following values:

absolute humidity, partial pressure of water vapor, saturated vapor pressure, relative humidity, saturation water vapor deficit, dew point temperature and specific humidity.

Absolute humidity a (g/m³) is the amount of water vapor, expressed in grams, contained in 1 m³ of air.

Partial pressure (elasticity) of water vapor e - the actual pressure of water vapor in the air, measured in millimeters of mercury (mmHg), millibars (mb) and hectopascals (hPa). Water vapor pressure is often called absolute humidity. However, these different concepts cannot be mixed, since they reflect different physical quantities of atmospheric air.

Saturated water vapor pressure, or saturation elasticity, E - the maximum possible value of partial pressure at a given temperature; measured in the same units as e. Saturation elasticity increases with increasing temperature. This means that at a higher temperature, air is able to hold more water vapor than at a lower temperature.

Relative humidity f is the ratio of the partial pressure of water vapor contained in the air to the pressure of saturated water vapor at a given temperature. It is usually expressed as a percentage accurate to whole numbers:

f =(e/E)*100%.

Relative humidity expresses the degree of saturation of air with water vapor.

Saturation deficit of water vapor (lack of saturation) d - the difference between the saturation elasticity and the actual elasticity of water vapor:

d = E - e

The saturation deficit is expressed in the same units and with the same accuracy as the values ​​of e and E. With increasing relative humidity, the saturation deficit decreases and at f = 100% becomes equal to zero.

Since E depends on the air temperature, and e - on the water vapor content in it, the saturation deficit is a complex value that reflects the heat and moisture content of the air. This allows the saturation deficit to be used more widely than other moisture characteristics to assess the growing conditions of agricultural plants.

Dew point td (°C) is the temperature at which water vapor contained in the air at a given pressure reaches a state of saturation relative to a chemically pure flat surface of water. At f = 100%, the actual air temperature coincides with the dew point. At temperatures below the dew point, condensation of water vapor begins with the formation of fogs, clouds, and dew, frost, and frost form on the surface of the earth and objects.

Specific humidity q (g/kg) - the amount of water vapor in grams contained in 1 kg of humid air:

q = 622 e/P,

where e is the water vapor pressure, hPa; P - atmospheric pressure, hPa.

Specific humidity is taken into account in zoometeorological calculations, for example, when determining evaporation from the surface of the respiratory organs of farm animals and when determining the corresponding energy costs.

Changes in the characteristics of air humidity in the atmosphere with altitude

The greatest amount of water vapor is contained in the lower layers of air directly adjacent to the evaporating surface. Water vapor penetrates into the overlying layers as a result of turbulent diffusion.

The penetration of water vapor into the overlying layers is facilitated by the fact that it is 1.6 times lighter than air (the density of water vapor relative to dry air at 00C is 0.622), therefore air enriched with water vapor, being less dense, tends to rise upward.

The vertical distribution of water vapor pressure depends on changes in pressure and temperature with height, on the processes of condensation and cloud formation. Therefore, it is difficult to theoretically establish the exact pattern of changes in the elasticity of water vapor with height.

The partial pressure of water vapor decreases with height 4...5 times faster than atmospheric pressure. Already at an altitude of 6 km, the partial pressure of water vapor is 9...10 times less than at sea level. This is explained by the fact that water vapor continuously enters the surface layer of the atmosphere as a result of evaporation from the active surface and its diffusion due to turbulence. In addition, the air temperature decreases with height, and the possible content of water vapor is limited by temperature, since its decrease promotes saturation of the vapor and its condensation.

A decrease in vapor pressure with height can alternate with its increase. For example, in an inversion layer, vapor pressure usually increases with height.

Relative humidity is distributed unevenly vertically, but on average it decreases with height. In the surface layer of the atmosphere on summer days it increases slightly with height due to a rapid decrease in air temperature, then begins to decrease due to a decrease in the supply of water vapor and again increases to 100% in the cloud formation layer. In inversion layers it sharply decreases with height as a result of increasing temperature. Relative humidity changes especially unevenly up to a height of 2...3 km.

Daily and annual variation of air humidity

In the surface layer of the atmosphere there is a well-defined daily and annual variation in moisture content associated with corresponding periodic changes in temperature.

The daily variation of water vapor pressure and absolute humidity over the oceans, seas and coastal areas of land is similar to the daily variation of water and air temperature: minimum before sunrise and maximum at 14...15 hours. The minimum is due to very weak evaporation (or its absence at all) at this time of day. During the day, as the temperature increases and, accordingly, evaporation, the moisture content in the air increases. The diurnal variation of water vapor pressure over the continents in winter is the same.

The annual variation of water vapor pressure and absolute humidity coincides with the annual variation of air temperature both over the ocean and over land. In the Northern Hemisphere, the maximum air moisture content is observed in July, the minimum in January. For example, in St. Petersburg, the average monthly vapor pressure in July is 14.3 hPa, and in January - 3.3 hPa.

The daily variation of relative humidity depends on vapor pressure and saturation pressure. With increasing temperature of the evaporating surface, the rate of evaporation increases and, therefore, e increases. But E increases much faster than e, therefore, with increasing surface temperature, and with it the air temperature, relative humidity decreases. As a result, its course near the earth's surface turns out to be the opposite of the course of surface and air temperature: the maximum relative humidity occurs before sunrise, and the minimum at 15...16 hours (Fig. 5.2). Its daily decrease is especially pronounced over the continents in the summer, when, as a result of turbulent diffusion of vapor upward, E at the surface decreases, and due to an increase in air temperature, E increases. Therefore, the amplitude of daily fluctuations in relative humidity on continents is much greater than over water surfaces.

In the annual cycle, relative air humidity, as a rule, also changes inversely to the temperature trend. For example, in St. Petersburg, relative humidity in May averages 65%, and in December - 88% (Fig. 5.3). In areas with a monsoon climate, the minimum relative humidity occurs in winter, and the maximum in summer due to the summer transfer of moist sea air masses to land: for example, in Vladivostok in summer f = 89%, in winter f = 68%.

The course of the saturation deficit of water vapor is parallel to the course of air temperature. During the day, the deficit is greatest at 14...15 hours, and the smallest - before sunrise. During the year, the saturation deficit of water vapor has a maximum in the hottest month and a minimum in the coldest month. In the arid steppe regions of Russia in the summer at 13:00, a saturation deficit exceeding 40 hPa is observed annually. In St. Petersburg, the saturation deficit of water vapor in June averages 6.7 hPa, and in January it is only 0.5 hPa.

Air humidity in vegetation cover

Vegetation cover has a great influence on air humidity. Plants evaporate a large amount of water and thereby enrich the ground layer of the atmosphere with water vapor; there is an increased moisture content in the air compared to the bare surface. This is also facilitated by the reduction of wind speed by the vegetation cover, and, consequently, the turbulent diffusion of vapor. This is especially pronounced during the daytime. The vapor pressure inside tree crowns on clear summer days can be 2...4 hPa greater than in an open area, in some cases even 6...8 hPa. Inside agrophytocenoses, it is possible to increase the vapor pressure by 6...11 hPa compared to the steam field. In the evening and night hours, the influence of vegetation on moisture content is less.

Vegetation cover also has a great influence on relative humidity. Thus, on clear summer days, inside the crops of rye and wheat, the relative humidity is 15...30% higher than above the open area, and in the crops of tall crops (corn, sunflower, hemp) - 20...30% higher than over bare soil. In crops, the highest relative humidity is observed at the soil surface, shaded by plants, and the lowest in the upper tier of leaves.

Accordingly, the saturation deficit of water vapor in crops is significantly less than over bare soil. Its distribution is characterized by a decrease from the upper tier of leaves to the lower.

It was previously noted that vegetation cover significantly affects the radiation regime, soil and air temperature, significantly changing them compared to an open place, i.e. In the plant community, its own special meteorological regime is formed - phytoclimate. How strongly it is expressed depends on the type, habit and age of the plants, the density of the planting, and the method of sowing (planting).

Weather conditions also influence the phytoclimate - in partly cloudy and clear weather, phytoclimatic features are more pronounced.

Methods and instruments for measuring air humidity

Air humidity can be measured by several methods: absolute (weight), psychrometric and hygrometric (sorption).

The essence of the absolute method consists in passing a certain volume of air through glass tubes filled with some hygroscopic substance (for example, calcium chloride, strong sulfuric acid). The tubes are weighed before and after passing moist air through them, and the amount of water vapor absorbed is determined by the addition of their mass. By dividing the added mass by the volume of air passed through the tubes, its absolute humidity is determined in g/m3.

This method of determining air humidity is laborious and time-consuming, and therefore it is used only in laboratories.

The most widely used are psychrometric and hygrometric (sorption) methods.

Psychrometric method The measurement is based on the cooling of one of the two psychrometric thermometers due to evaporation, since its reservoir is wrapped in a piece of cambric and is moistened with distilled water before measurement. Station and aspiration psychrometers operate on this principle.

Station psychrometer installed in a psychrometric booth (Fig. 5.4) at the weather site.

Aspiration psychrometer MV-4M (Fig. 5.5) does not differ in operating principle from a station psychrometer. The main design feature of this device is the presence of an aspiration device that ensures air is blown into the thermometer tanks. It is widely used for field observations as it is convenient to carry.

When measuring temperature and air humidity in crops, an aspiration psychrometer is installed horizontally (or vertically) at the required level. The openings of the protective tubes should be oriented in the direction opposite to the Sun and towards the wind.

Using a psychrometer, air humidity is determined only up to an air temperature of -10 "C. At lower temperatures, the psychrometer readings are unreliable, so they switch to the sorption method.

Hygrometric (sorption) method air humidity measurements are based on the property of hygroscopic bodies that respond to changes in air humidity.

Hair hygrometer MV-1 serves to measure relative air humidity (Fig. 5.6). The operation of the device is based on the property of defatted human hair to change its length depending on the relative humidity of the air.

Hair hygrograph M-21A used for continuous recording of relative air humidity (Fig. 5.7). The moisture receiver is a bundle of defatted human hair. Depending on the rotation speed of the drum, there are two types of hygrographs: daily and weekly.

Devices operating on the hygrometric principle are relative. Therefore, their readings must be adjusted in a certain way with the readings of the psychrometer.

The value of air humidity for agricultural production

Water vapor contained in the atmosphere, as noted in Chapter 2, is of great importance in maintaining heat on the earth's surface, since it absorbs the heat emitted by it. Air humidity is one of the weather elements that is also significant for agricultural production.

Air humidity has a great influence on the plant. It largely determines the intensity of transpiration. At high temperatures and low humidity, transpiration increases sharply and plants experience a great lack of water, which affects their growth and development. For example, there is underdevelopment of generative organs and flowering is delayed.

Low humidity during the flowering period causes pollen to dry out and, consequently, incomplete fertilization, which, for example, causes crossgrain in cereals. During the period of grain filling, excessive dryness of the air leads to the fact that the grain turns out puny and the yield is reduced.

Low moisture content in the air leads to small-fruited fruit, berry crops, grapes, poor bud formation for next year's harvest and, consequently, a decrease in yield.

Air humidity also affects the quality of the crop. It has been noted that low humidity reduces the quality of flax fiber, but increases the baking qualities of wheat, the technical properties of linseed oil, the sugar content in fruits, etc.

A decrease in relative air humidity with a lack of soil moisture is especially unfavorable. If hot and dry weather lasts for a long time, the plants may dry out.

A long-term increase in moisture content (f > 80%) also has a negative effect on the growth and development of plants. Excessively high air humidity causes the large-cell structure of plant tissue, which subsequently leads to lodging of grain crops. During the flowering period, such air humidity interferes with normal pollination of plants and reduces the yield, since the anthers open less and insect life decreases.

Increased air humidity delays the onset of full grain ripeness, increases the moisture content in the grain and straw, which, firstly, adversely affects the operation of harvesting machines, and secondly, requires additional costs for drying the grain.

A decrease in the saturation deficit to 3 hPa or more leads to virtually the cessation of harvesting work due to poor conditions.

In the warm season, increased air humidity contributes to the development and spread of a number of fungal diseases of agricultural crops (late blight of potatoes and tomatoes, mildew of grapes, white rot of sunflower, various types of rust of grain crops, etc.). The influence of this factor especially increases with increasing temperature.

The timing of a number of agricultural works also depends on air humidity: weed control, putting feed into silage, ventilating warehouses, drying grain, etc.

In the thermal balance of farm animals and humans, heat exchange is associated with air humidity. At air temperatures below 10 °C, increased humidity increases heat transfer from organisms, and at high temperatures it slows it down.

How weather conditions affect the body depends on its adaptive abilities: some react to them, others don’t notice them at all, and there are also those who can predict the weather based on how they feel. It is believed that people with an unbalanced nervous system - melancholic and choleric people - are especially susceptible to dependence on weather conditions. In sanguine and phlegmatic people, it most often manifests itself either against the background of weakened immunity or with a chronic disease. However, meteosensitivity as a diagnosis is typical specifically 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, and rheumatoid arthritis.

What weather factors affect our well-being? The head of the neurology department of the 122nd Clinical Hospital, Professor Alexander Elchaninov, considers the most significant meteorological factors to be: 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 considered to be a combination of temperature 18-20C° and humidity 40-60%. At the same time, fluctuations in air temperature within the range of 1-10°C are considered favorable, 10-15°C - unfavorable, and above 15°C - very unfavorable. - explains Professor Elchaninov. - Comfortable temperature for sleeping - from 16°C to 18°C.

The oxygen content in the air directly depends on the air temperature. When it gets colder, it becomes saturated with oxygen, and when it gets warmer, on the contrary, it becomes rarefied. As a rule, in hot weather the atmospheric pressure also decreases, and as a result, those suffering from diseases of the respiratory and cardiovascular systems feel unwell.

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

Extreme temperatures

According to Sergei Boytsov, director of the State Research Center for Preventive Medicine, during abnormal heat people feel best with a normal thermoregulation mechanism, in which the cardiovascular system is actively involved, increasing blood circulation directly under the skin. But if the air temperature exceeds 38 degrees, it no longer helps: the external temperature becomes higher than the internal one, and the risk of thrombosis arises against the background of centralization of blood flow and blood thickening. Therefore, in the heat there is a high risk of stroke. Doctors advise that during abnormal heat, stay indoors as much as possible with air conditioning or at least a fan, and avoid the sun and unnecessary physical activity. Other recommendations depend on the person’s health status.

An anticyclone is an increased atmospheric pressure that brings with it windless, 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 increased air temperature.

In extremely cold weather, the body can become hypothermic due to increased heat transfer. The combination of low temperature with high humidity and high air speed is especially dangerous. Moreover, due to reflex mechanisms, the feeling of cold arises not only in the area of ​​its influence, but also in parts of the body that seem to be far from it. So, if your feet are frozen, your nose will inevitably freeze, and a feeling of cold will appear in your throat, as a result of which ARVI and diseases of the ENT organs develop. In addition, if you are cold, say, while waiting for public transport, another reflex mechanism is activated, in which spasm of the kidney vessels occurs, circulatory disorders and decreased 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, bathhouse, contrast shower.

Air humidity

At high temperatures, air humidity (saturation of air 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 the home air, and not the increased humidity outside, that becomes the cause of the tendency to colds: the mucous membranes of the nasopharynx dry out, reducing its protective functions, which makes it easy for respiratory viruses to “take root.” To avoid increased dryness in the nasopharynx, allergy sufferers and those who frequently suffer from ENT diseases are recommended to rinse with a solution of slightly salted or still mineral water.

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

Fluctuations in humidity levels 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 calm and light wind (1-4 m/s) a person feels good. However, as soon as the temperature rises, he will experience similar sensations if the air movement becomes faster. Conversely, at low temperatures, high wind speed increases the feeling of cold. Both the mountain-valley wind and other wind regimes (breeze, foehn) have a daily periodicity. Day-to-day fluctuations in the wind regime are important: a 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 reaction to the weather. This is both true and not true. Because it mainly affects our body in combination with other natural phenomena. It is generally accepted that a meteorological 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 sharply decreases, humidity and temperature increase, a person’s blood pressure drops and the speed of blood flow decreases, as a result, breathing becomes difficult, heaviness appears in the head, and the functioning of the cardiovascular system is disrupted. When atmospheric pressure drops, hypotensive people feel the worst, which is manifested by severe pastiness (swelling) of tissues, tachycardia, tachypnea (frequent breathing), that is, symptoms characterizing the deepening of hypoxia (oxygen starvation) caused by low atmospheric pressure. For hypertensive patients, such weather improves their well-being: blood pressure decreases, and only with increasing hypoxia do drowsiness, fatigue, shortness of breath, and ischemic heart pain appear, that is, the same symptoms that hypotensive patients immediately experience in such weather. When the temperature decreases with an increase in atmospheric pressure, the oxygen content in the air increases, hypertensive patients feel unwell because their blood pressure rises and the speed of blood flow increases. Hypotonic people live well in such weather, they feel a surge of strength.

Solar Activity

We are the children of the sun; if it were not 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 functioning 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. It is not without reason that with short winter daylight hours, almost everyone suffers from hyposolar syndrome: increased drowsiness, fatigue, depression, apathy, decreased performance and attention. We can say that the number of sunny days per year is much more important for the body than changes in, say, atmospheric pressure. Therefore, residents of coastal, for example, Mediterranean countries, or high mountains, live more comfortably than residents of St. Petersburg or polar explorers.

Weather in the house

We cannot influence weather conditions. But we can reduce the health risks associated with the influence of the external environment. The main thing to remember is that weather sensitivity does not manifest itself as an independent problem; it, like a carriage behind a locomotive, follows a certain disease, most often chronic. Therefore, first of all, it is necessary to identify and treat it. In case of exacerbation of the disease due to bad weather, you should take medications prescribed by a doctor for the underlying pathology (migraine, vegetative-vascular dystonia, panic attacks, neuroses and neurasthenia). And besides, in accordance with the weather forecast, you need to develop certain rules of conduct for yourself. For example, “heart patients” react sharply to high air humidity and the approach of a thunderstorm, which means that on such days it is necessary to avoid physical activity and be sure to take medications prescribed by a doctor.

• It is important for everyone whose health changes due to changing climatic conditions to take more care of their health on such days: do not overwork, get enough sleep, avoid drinking alcoholic beverages, as well as physical activity. Put off, for example, your morning jog, otherwise, say, in hot weather you can run away from a heart attack and run into a stroke. Any emotional and physical stress in bad weather conditions is stress that can lead to disruptions in autonomic regulation, heart rhythm disturbances, surges in blood pressure, and exacerbation of chronic diseases.
• Monitor your barometric pressure to understand how to control your blood pressure. For example, with low atmospheric pressure, hypertensive patients need to reduce their intake of medications that lower blood pressure, and hypotensive patients should take adaptogens (ginseng, eleutherococcus, lemongrass) and drink coffee. In general, it should be remembered that in summer, in warm and hot weather, there is a redistribution of blood from 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 external environment is disturbed, and its adaptive capabilities are reduced. We should increase the body's resistance to adverse weather changes. Therefore, if there are no contraindications, train the autonomic nervous and cardiovascular systems. A contrast or cold shower, Russian bath, sauna, walking, preferably before bed will help you with this.
• Organize yourself physical activity - it increases blood pressure, decreases the level of oxygen in tissues, increases metabolism, heat generation and heat transfer. The cardiovascular and respiratory systems are well trained by brisk walking for 1 hour, light jogging, and swimming. Trained people easily tolerate weather changes, which have a similar effect on the body.
• It is recommended to sleep with the window open. Moreover, the sleep should be sufficient - when you wake up, you should feel that you have had enough sleep.
• Monitor the level of humidity and artificial light in the apartment.
• Dress “for the weather” so that your 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.” Failure of seasonal adaptation is dangerous even for practically healthy people.

Irina Dontsova

Doctor Peter