home · electrical safety · An indicator of indoor air quality. Sources of indoor air pollution. Indicators of the sanitary condition of the air in residential and public buildings. Most polluted regions

An indicator of indoor air quality. Sources of indoor air pollution. Indicators of the sanitary condition of the air in residential and public buildings. Most polluted regions

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

On the other hand, with the help of artificial lighting, you can create a specified and stable illumination throughout the day anywhere in the room. The role of artificial lighting is currently high: second shifts, night work, underground work, evening home activities, cultural leisure, etc.

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

Spectral composition of light. The highest labor productivity and the least eye fatigue occurs with standard lighting daylight. The spectrum of diffused light from the blue sky, i.e., entering a room whose windows are oriented to the north, is taken as the standard for daylight in lighting engineering. The best color discrimination is observed in daylight. If the dimensions of the parts in question are one millimeter or more, then for visual work Illumination from sources generating white daylight and yellowish light is approximately the same.

The spectral composition of light is also important in the psychophysiological aspect. So, red, orange and yellow colors by association with flame, the sun evokes a feeling of warmth. Red color excites, yellow tones, improves mood and performance. Blue, indigo and violet appear cold. Thus, painting the walls of a hot shop in Blue colour creates a feeling of coolness. Blue color is calming, blue and violet are depressing. Green color- neutral - pleasant in association with green vegetation, it tires the eyes less than others. Painting walls, cars, and desk tops in green tones has a beneficial effect on well-being, performance, and visual function of the eye.

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

The next indicator characterizing lighting is illumination Illuminance is the surface density luminous flux. The unit of illumination is 1 lux - the illumination of a surface of 1 m2 on which a luminous flux of one lumen falls and is evenly distributed. Lumen- luminous flux that is emitted by a complete emitter (absolute black body) at the solidification temperature of platinum from an area of ​​0.53 mm 2. Illumination is inversely proportional to the square of the distance between the light source and the illuminated surface. Therefore, in order to economically create high illumination, the source is brought closer to the illuminated surface (local lighting). Illumination is determined with a lux meter.

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

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

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

For lighting characteristics great importance It has brightness. Brightness- the intensity of light emitted from a unit surface. In fact, when examining an object, we see not illumination, but brightness. The unit of brightness is candela per square meter (cd/m2) - the brightness of a uniformly luminous flat surface emitting in a perpendicular direction from each square meter luminous intensity equal to one candela. Brightness is determined with a brightness meter.

At rational lighting There should be no bright light sources or reflective surfaces in a person’s field of vision. If the surface in question is excessively bright, then this will negatively affect the functioning of the eye: a feeling of visual discomfort appears (from 2000 cd/m2), visual performance decreases (from 5000 cd/m2), causes glare (from 32,000 cd/m2 ) and even painful sensation(with 160,000 cd/m2). The optimal brightness of working surfaces is several hundred cd/m2. The permissible brightness of light sources located in a person’s field of vision is desirable no more than 1000-2000 cd/m2, and the brightness of sources that rarely fall into a person’s field of vision is no more than 3000-5000 cd/m2

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

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

Daylight. The sun produces outdoor illumination usually on the order of tens of thousands of lux. Natural lighting of premises depends on the light climate of the area, the orientation of building windows, the presence of shading objects (buildings, trees), the design and size of windows, the width of the inter-window partitions, the reflectivity of walls, ceilings, floors, the cleanliness of glass, etc.

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

Estimation of natural light only by light coefficient may be inaccurate, since illumination is influenced by the inclination of light rays to the illuminated surface ( angle of incidence rays). In the event that, due to an opposing building or trees, a non-direct line enters the room sunlight, but only reflected rays, their spectrum is devoid of the short-wave, most biologically effective part - ultraviolet rays. The angle within which direct rays from the sky fall at a certain point in the room is called hole angle.

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

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

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

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

Artificial lighting must answer following requirements: be sufficiently intense, uniform; ensure proper shadow formation; do not dazzle or distort colors: do not heat; the spectral composition approaches daytime.

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

The main sources of artificial lighting are incandescent and fluorescent lamps. Incandescent lamp-- convenient and trouble-free light source. Some of its disadvantages are low light output, a predominance of yellow and red rays in the spectrum and a lower content of blue and violet. Although, from a psychophysiological point of view, such a spectral composition makes the radiation pleasant and warm. In terms of visual work, incandescent light is inferior to daylight only when it is necessary to examine very small details. It is unsuitable in cases where good color discrimination is required. Since the surface of the filament is negligible, rage incandescent lamps significantly exceeds that which blinds. To combat brightness, they use lighting fixtures that protect from the glare of direct rays of light and hang the lamps out of people’s field of vision.

There are lighting fixtures direct light, reflected, semi-reflected and diffused. Armature direct The light directs over 90% of the lamp light to the illuminated area, providing it with high illumination. At the same time, a significant contrast is created between the illuminated and unlit areas of the room. Sharp shadows are formed and blinding effects are possible. This fixture is used for lighting auxiliary rooms and sanitary facilities. Armature reflected light characterized by the fact that the rays from the lamp are directed to the ceiling and top part walls From here they are reflected and evenly, without the formation of shadows, distributed throughout the room, illuminating it with soft diffused light. This type of fixture creates the most acceptable lighting from a hygienic point of view, but it is not economical, since over 50% of the light is lost. Therefore, to illuminate homes, classrooms, and wards, more economical fittings of semi-reflected and diffused light are often used. In this case, part of the rays illuminates the room, passing through the dairy or frosted glass, and part - after reflection from the ceiling and walls. Such fittings create satisfactory lighting conditions; they do not dazzle the eyes and do not create sharp shadows.

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

Spectrum diversity is one of hygienic items advantages of these lamps. The light output of fluorescent lamps is 3-4 times greater than incandescent lamps (with 1 W 30-80 lm), so they more economical. The brightness of fluorescent lamps is 4000-8000 cd/m2, i.e. higher than permissible. Therefore, they are also used with protective fittings. In numerous comparative tests with incandescent lamps in production, in schools, and classrooms, objective indicators characterizing the state of the nervous system, eye fatigue, and performance almost always indicated the hygienic advantage of fluorescent lamps. However, this requires qualified use of them. It is necessary to select the correct lamps according to the spectrum depending on the purpose of the room. Since the sensitivity of vision to the light of fluorescent lamps is the same as to daylight, lower than the light of incandescent lamps, illumination standards for them are set 2-3 times higher than for incandescent lamps (Table 7.6.).

If with fluorescent lamps the illumination is below 75-150 lux, then a “twilight effect” is observed, i.e. illumination is perceived as insufficient even when viewing large details. Therefore, with fluorescent lamps, the illumination should be at least 75-150 lux.

Main sources of air pollution closed premises are atmospheric air entering the room through window openings and leaks building structures, construction and finishing polymer materials, releasing into the air a variety of substances toxic to humans, many of which are highly hazardous (benzene, toluene, cyclohexane, xylene, acetone, butanol, phenol, formaldehyde, acetaldehyde, ethylene glycol, chloroform), waste products of humans and their household activities (anthropotoxins: carbon monoxide, ammonia, acetone, hydrocarbons, hydrogen sulfide, aldehydes, organic acids, diethylamine, methyl acetate, cresol, phenol, etc.), accumulating in the air of unventilated rooms with a large number of people. Many substances are highly hazardous, classified as hazard class 2. These are dimethylamine, hydrogen sulfide, nitrogen dioxide, ethylene oxide, indole, skatole, mercaptan. Benzene, chloroform, and formaldehyde have the greatest overall risk. Present simultaneously even in small quantities, they indicate trouble air environment, which has a negative impact on the mental performance of people in these premises.

In addition, the air exhaled by people, compared to atmospheric air, contains less oxygen (up to 15.1-16%), 100 times more carbon dioxide (up to 3.4-4.7%), is saturated with water vapor, heated to human body temperature and deionized during its passage through the system supply ventilation due to the retention of light positive and negative air ions in the air ducts.

A significant number of microbes enter the air, some of which may be pathogenic. The more dust there is in the indoor air, the more microbial contamination there is. Dust is a factor in the transmission of infectious diseases through aerosol propagation and bacterial infections (for example, tuberculosis). Dust containing mold fungi of the genera Penicillium and Mukor causes allergic diseases.

Impact various factors on a person indoors can cause problems with his health, i.e. diseases associated with the building,” for example, formaldehyde vapors released from polymer and wood-based materials.

Symptoms of the disease persist for a long time, even after eliminating the source harmful effects. “Sick building syndrome” manifests itself in the form of acute health problems and discomfort (headache, irritation of the eyes, nose and respiratory system, dry cough, dry and itchy skin, weakness, nausea, increased fatigue, sensitivity to odors) occurring in specific premises and almost completely disappear when leaving it. The development of this syndrome is associated with the combined and combined actions of chemical, physical (temperature, humidity) and biological (bacteria, unknown viruses, etc.) factors. Its causes are most often insufficient natural and artificial ventilation premises, construction and finishing polymer materials that release various substances toxic to humans into the air, irregular cleaning of premises.

The quality of the air environment is usually assessed indirectly by the integral sanitary indicator of air purity - carbon dioxide content (Pettenkofer index), and as a maximum permissible standard (MAC) its concentration in premises is used - 1.0%c or 0.1% (1000 cm3 in 1 m3). Carbon dioxide is constantly released into the air of enclosed spaces when breathing, is most accessible to simple determination and has a reliable direct correlation with total air pollution. The Pettenkofer index is not the maximum permissible concentration of carbon dioxide itself, but an indicator of the harmfulness of the concentrations of numerous human metabolites that have accumulated in the air in parallel with carbon dioxide. More high content CO2 (>1.0% o) is accompanied by a total change in the chemical composition and physical properties of the air in the room, which adversely affect the condition of the people in it, although carbon dioxide itself does not exhibit toxic properties for humans even in much higher concentrations. When assessing air quality and designing ventilation systems for rooms with a large number of people, the carbon dioxide content is the main design value.

Measures to prevent indoor air pollution are their ventilation, if possible, maintaining cleanliness through regular wet cleaning of premises, compliance with established standards for the area and cubic capacity of premises, air sanitation using disinfectants and bactericidal lamps.

As a result, the concentration of carbon dioxide in the air increases, ammonia, aldehydes, ketones and other foul-smelling gases appear, humidity, dust and microbial pollution of the air increases, which is generally characterized as stuffy (living) air, which affects the well-being, performance and health of people. The concentration of carbon dioxide in such air can determine the degree of its overall pollution. Therefore, carbon dioxide serves as a sanitary indicator of air purity in residential and public spaces. The air is considered fresh if the concentration of carbon dioxide in it does not exceed 0.1%. This value is considered the maximum permissible for air in residential and public premises.

In addition, one should take into account the fact that carbon dioxide is heavier than air and can accumulate in lower parts confined spaces that are not subject to intensive ventilation. This is most important for those places where enhanced oxidative processes occur (fermentation tanks, abandoned mines or wells, at the bottom of which there is rotting or fermenting waste, etc.). In such places, the concentration of carbon dioxide can reach large values ​​and pose a danger to human health and existence. If the concentration of carbon dioxide in the inhaled air exceeds 3%, then living in such an atmosphere becomes hazardous to health. A CO2 concentration of about 10% is considered life-threatening (loss of consciousness occurs after a few minutes of breathing such air). At a concentration of 20%, paralysis of the respiratory center occurs within a few seconds.

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

The composition of clean dry atmospheric air in volume percent is shown in Fig. 1,2,

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

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

Rice. 1.2. Chemical composition atmospheric air under normal conditions.

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

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

Green plants produce oxygen in very large quantities, and due to the constant mixing of layers of atmospheric air, its content in atmospheric air remains practically constant everywhere - about 21%. Low concentrations of oxygen, essential for the life of the human body, are observed when ascending to a height and when people stay in hermetically sealed rooms in the event of emergency situations when the technical means of maintaining life are disrupted. Increased oxygen content is observed under conditions of high atmospheric pressure (in caissons). At partial pressure above 600 mm Hg. it behaves as a toxic substance, causing pulmonary edema and pneumonia.

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

Ozone plays a vital role in protecting the planet’s biological objects from the harmful effects of hard ultraviolet radiation, trapping it in the stratosphere at an altitude of 20-30 km.

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

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

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

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

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

Significant amounts of CO2 are formed as a result of work industrial enterprises and vehicles that burn huge amounts of fuel, resulting in last years Data has emerged that the carbon dioxide content in the air of large modern cities is approaching 0.04%, which raises concerns among environmentalists about the formation of the “greenhouse effect,” which will be discussed in more detail later.

Carbon dioxide participates in the body's metabolic processes, being a physiological stimulant of the respiratory center.

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

And yet, the content of CO2 in the air of enclosed spaces has sanitary significance, being indirect indicator air purity. The fact is that in parallel with the accumulation of CO2, usually not higher than 0.2%, other properties of the air deteriorate: temperature and humidity, dust content, the content of microorganisms, the number of heavy ions increase, and anthropotoxins appear. This complex of changed physical properties of air along with chemical pollution and causes deterioration in people's well-being. This change in air properties corresponds to a carbon dioxide content equal to OD%, and therefore this concentration is considered the maximum permissible for indoor air.

In recent years, it has been found that this indicator is not enough to assess the sanitary state of indoor air, since it requires determination of the content of some toxic substances. chemical substances, released into the air from polymer building materials, widely used for interior decoration (phenol, ammonia, formaldehyde, etc.).

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

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

More than 200 different compounds, mainly organic metabolic products, were found in exhaled air (Table 5.1). An integral quantitative indicator of the content of these compounds in the air can be the so-called air oxidability , those. the number of milligrams of 02, which is necessary for the oxidation of under-oxidized airborne HIV substances (g/m3). Exhaled breath oxidation healthy person, normally is 15-20 mg/l. The air in residential premises is considered clean if the oxidability does not exceed 5 mg/l, moderately polluted - if the oxidability is 6-9 mg/l, polluted - if the oxidability is 10 mg/l or more.

Table 5.1

Special studies (IL Nikberg, 1987) have shown that the amount of individual ingredients (carbon dioxide, ammonia), as well as the total amount of under-oxidized substances in exhaled air (that is, its oxidability) significantly depend on the state of human health, the nature of the disease and its severity , tobacco smoking, features of metabolic processes, etc.

Among the chemical components of indoor air, a large number hygienic value It has carbon dioxide (CO 2 ). This gas belongs to physiologically active compounds, is a stimulant of the respiratory center and an O2 antagonist, is odorless and colorless, poorly soluble in water, and twice as heavy as air. Normal in blood partial pressure CO2 is 10 mm, which is 8-10 mmHg higher than in inhaled air, in which its concentration is 3.5-4.5%.

Depending on the concentration of CO in exhaled air, the reaction of the human body may be different. If the CO2 concentration is less than 0.1%, the person feels normal, there are no subjective or objective disorders. Exactly this concentration (0.1%) set as maximum permissible for residential air. MPC of carbon dioxide in air medical institutions equal to 0.07%.

If the CO2 concentration fluctuates within 0,1-0,5%. Conditioned reflex activity worsens (the latent period of reaction to a visual or auditory stimulus increases), a feeling of discomfort appears, and some changes may be detected on the ECG.

When inhaling air containing CO concentrations, more than 0.5% (0.5-1%), the first manifestations of acidosis and changes in the electrolyte properties of the blood appear (the Na content increases, the K content in red blood cells decreases). However, physical and mental activity does not deteriorate significantly, so people are sometimes allowed to stay at such concentrations (on submarines, etc.).

If the CO2 concentration increases up to 2% - Acidosis increases, performance decreases, and signs of hypoxia appear. Under such conditions, it is possible to work in production only for a limited time - up to 3-4 hours.

If the CO2 concentration more than 2% (2-7%), clear subjective and objective manifestations of the toxic effects of CO2 are observed in the form of narcotic effects, inadequate mental arousal, tachypnea, headaches, dizziness, and shortness of breath occur. Under such conditions, a long stay in the premises is unacceptable (it can only be forced in case of emergency situations, last up to 60 minutes and be accompanied by strict medical supervision).

Staying in a room with CO2 concentration in the air more than 7% quickly leads to loss of consciousness and death.

The dominant toxic component among the main sources of residential air pollution is carbon monoxide (CO).

Carbon monoxide CO It is a product of incomplete combustion of fuel and is part of all combustible mixtures. Carbon monoxide, penetrating through the pulmonary alveoli into the blood, forms carboxyhemoglobin with hemoglobin. And this causes profound quantitative and qualitative changes in the processes of oxygen transport to tissues, enhances hypoxic conditions, negatively affects the biochemical processes of the body, and can lead to chronic and acute poisoning. Acute carbon monoxide poisoning is not usually observed in the free atmosphere and in residential areas. Chronic poisoning is possible at concentrations exceeding 20-30 mg/m3. They are characterized by headaches, memory loss, increased fatigue, sleep disturbances, etc. Maximum permissible average daily concentration of carbon monoxide in the atmosphere is 1 mg/m 3, a maximum single dose - 3 mg/m 3.

Carbon monoxide can appear in residential air when stove heating, especially when closed prematurely chimney. In modern gasified kitchens and bathrooms as a result of gas leakage from the network or its incomplete combustion during operation. In production, carbon monoxide can form and accumulate in work areas as a result of technological processes. Tobacco contains about 0.5-1.0% carbon monoxide. According to IL. Datsenko and R.D. Gabovich (1999), In gasified apartments, the CO content in the air not only in kitchens, but also in living rooms may exceed the maximum permissible for atmospheric air (10 mg/m3).

The source of CO pollution in the atmosphere are emissions from industrial enterprises, exhaust gases from vehicles, etc. An ordinary woman contains about 3% carbon monoxide in the exhaust gases during normal engine operation - 7.7%. On city streets with heavy traffic and in houses located on these streets, when open windows the concentration of carbon monoxide increases to 10-20 mg/m3.

Due to the widespread introduction of internal combustion engines into the national economy, the development of automobile traffic, aviation, the use of agriculture various kinds self-propelled vehicles Much attention is paid to the fight against carbon monoxide air pollution.

Classification of chemical factors of the production environment:

A) By state of aggregation: gases, vapors, aerosols and mixtures;

b) by origin (chemical classes): organic, inorganic, organoelement, etc.;

V) by the nature of the effect on the human body: general toxic, irritant, sensitizing, carcinogenic, mutagenic, affecting reproductive function, embryotoxic and teratogenic;

G) depending on the damage to organs and systems: polytropic, neurotropic, nephrotoxic and cardiotoxic poisons, as well as blood poisons

d) by degree of toxicity: extremely toxic, highly toxic, moderately toxic and low toxic;

e) according to the degree of impact on the body as a whole: extremely dangerous (class 1), highly dangerous (class 2), moderately dangerous (class 3) and low-hazard (class 4).

> Carbon dioxide

Scientists have discovered that excess carbon dioxide indoors is very harmful to health. Carbon dioxide is almost the main thing today actor many catastrophic scenarios that many scientists scare us with. He is blamed for global warming and all the future cataclysms associated with this.

But, as it turned out, this gas has been doing his “dirty deed” for a long time. And not at all on a planetary scale, but in any stuffy room. There is not enough oxygen, we say in this case. Especially if your head starts to hurt, your eyes turn red, your attention sharply decreases, and you feel tired. However, as recent studies by foreign scientists have shown, the reason is not at all a lack of oxygen. The excess carbon dioxide that each of us exhales is to blame. By the way, from 18 to 25 liters of this gas per hour.

Why is carbon dioxide dangerous? Indian scientists have come to completely unexpected conclusions. Even in relatively low concentrations, this gas is toxic and is close in its “toxicity” to nitrogen dioxide, which can lead to cardiovascular disease, hypertension, fatigue, etc.

Clean air outside the city contains about 0.04 percent carbon dioxide. Until recently, in Europe and the USA it was believed that the gas was dangerous to humans only in high concentrations. However, in Lately began to study how it affects humans at concentrations higher than 0.1 percent. It turned out that if the content exceeds this level, then, for example, many students’ attention decreases, their academic performance deteriorates, they miss lessons due to diseases of the lungs, bronchi, nasopharynx, etc. This is especially true for children with asthma. Therefore, air requirements in many countries are very high. In Russia, such studies of air pollution sources have never been carried out. However, a comprehensive examination of Moscow children and adolescents showed that respiratory diseases predominated among the detected diseases.

It is important to maintain high air quality levels in the bedroom, where people spend a third of their lives. To get a good night's sleep, bedroom air quality is much more important than sleep duration, and carbon dioxide levels in bedrooms and children's rooms should be below 0.08 percent.

Finnish scientists have found a way to solve the problem. They created a device that removes excess carbon dioxide from indoor air. As a result, the gas content is no more than outside the city. The principle is based on the absorption (absorption) of carbon dioxide by a special substance. In Russia about the existence of a problem negative impact higher level Only a few know about carbon dioxide in the room so far.

Irina Mednis

19.03.2008 | Russian newspaper

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