Criteria and indicators of air pollution: physical and chemical. Microclimate in the house: parameters, requirements and control. The fight to clean the air
Composition of atmospheric air: nitrogen - 78.08%, oxygen - 20.95%, carbon dioxide - 0.03-0.04, gas impurities (argon, neon, helium, radon, krypton, ozone, hydrogen, xenon, nitrous oxide, methane) in minimal concentrations. The latter are indicators of ongoing processes in living organisms.
Nitrogen In terms of quantitative content, it is the most significant component of atmospheric air. It belongs to the indifferent gases and plays the role of an oxygen diluent. At excess pressure (4 atm), nitrogen can have a narcotic effect.
In nature, there is a continuous nitrogen cycle, as a result of which atmospheric nitrogen, under the influence of electrical discharges, is converted into nitrogen oxides, which, washed out of the atmosphere by precipitation, enrich the soil with salts of nitrous and nitric acids. Under the influence of soil bacteria, nitrous acid salts are converted into nitric acid salts, which, in turn, are absorbed by plants and serve for protein synthesis. When organic matter decomposes, nitrogen is restored and again enters the atmosphere, from which it is again bound by biological objects.
Air nitrogen is absorbed by blue-green algae and some types of soil bacteria (nodule and nitrogen-fixing).
Oxygen. A constant oxygen content is maintained by continuous processes of its exchange in nature. Oxygen is consumed through human and animal respiration and is necessary for combustion and oxidation. Oxygen enters the atmosphere as a result of plant photosynthesis. Terrestrial plants and phytoplankton annually supply about 1.5×1015 tons of oxygen to the atmosphere, which approximately corresponds to its consumption. In recent years, it has been found that under the influence of sunlight, water molecules disintegrate to form oxygen molecules. This is the second source of oxygen formation in nature.
The human body is very sensitive to lack of oxygen. A decrease in its content in the air to 17% leads to increased heart rate and breathing. At an oxygen concentration of 11-13%, severe oxygen deficiency is observed, leading to a sharp decrease in performance. A content of 7-8% oxygen in the air is incompatible with life.
Carbon dioxide in nature it is found in a free and bound state. Carbon dioxide is 1.5 times heavier than air. Continuous processes of release and absorption of carbon dioxide occur in the environment. It is released into the atmosphere as a result of human and animal respiration, as well as combustion, rotting, and fermentation.
Carbon dioxide is a physiological stimulant of the respiratory center. His partial pressure in the blood is ensured by the regulation of acid-base balance. In the body, it is in a bound state in the form of sodium bicarbonate salts in plasma and red blood cells. When large concentrations of carbon dioxide are inhaled, redox processes are disrupted. The more carbon dioxide in the air we breathe, the less of it the body can release. The accumulation of carbon dioxide in the blood and tissues leads to the development of tissue anoxia. An increase in the content of carbon dioxide in the inhaled air up to 3% leads to respiratory dysfunction (shortness of breath), headaches and decreased performance; at 4%, increased headaches, tinnitus, palpitations, and agitation are noted; at 8% or more, severe poisoning and death occurs. The content of carbon dioxide is used to judge the cleanliness of the air in residential and public buildings; a significant accumulation of this compound in the air of enclosed spaces indicates sanitary problems in the premises (overcrowding, poor ventilation).
It is believed that the feeling of discomfort is usually associated not only with an increase in the carbon dioxide content above 0.1%, but also with a change in the physical properties of the air when people crowd indoors: humidity and temperature increase, the ionic composition of the air changes mainly due to an increase in positive ions and etc.
Of all the indicators associated with the deterioration of air properties, carbon dioxide is the most easily determined. Therefore, the concentration (0.1%) has long been accepted in hygienic practice as the maximum permissible value, which integrally reflects the chemical composition and physical properties of air in residential and public spaces. Thus, carbon dioxide is an indirect hygienic indicator by which the degree of air cleanliness is assessed. Ventilation in residential and public buildings is calculated based on the carbon dioxide content.
IZA is a complex index of air pollution, taking into account several impurities, representing the sum of the concentrations of selected pollutants in fractions of the maximum permissible concentration (in accordance with RD 52.04.186-89 Guidelines for the control of air pollution).
Depending on the IPA value, the level of air pollution is determined as follows:
Level of atmospheric air pollution ISA values
Low is less than or equal to 5
Elevated 5-7
High 7-14
Very high greater than or equal to 14
7. Indicators of indoor air pollution. Carbon dioxide as an indicator of air pollution in hospital premises. Standardization and determination methods.
The air stagnates in the room, where the concentration of substances harmful to health is constantly increasing due to the use of various building and finishing materials, structural and upholstery materials furniture, polymers, household chemicals, plastics, as well as many different electronic devices. But do not forget that this results in diseases of varying severity, such as asthma, allergies, constant headaches, stress, fatigue, brain disorders, and oncological pathology can also develop.
The main indirect indicator of residential air pollution is carbon dioxide (more precisely, its concentration in the air).
When people are in the room, concentration carbon dioxide gradually increases, since the exhaled air contains an increased amount of it.
Carbon dioxide concentration is expressed as percentage (%) and ppm (P°). 1 ppm (1 L") is the amount of ml of gas in 1 liter of air.
As is known, the concentration of carbon dioxide in atmospheric air is approximately 0.04%
MPC (maximum permissible concentration) of carbon dioxide in the air of residential premises is equal to:
0.7% - for “clean” rooms (hospitals) - operating rooms, wards, dressing rooms, etc.
0.1% - for ordinary residential premises.
The regulation of carbon dioxide content in the air is due to the fact that when its concentration increases, it has an adverse effect on humans. Thus, when the concentration of carbon dioxide in the inhaled air increases to 2% or more, it has toxic effect, at a concentration of 3-4% there is a strong toxic effect, and a concentration of 7-8% is lethal.
When people stay indoors, the amount of carbon dioxide increases. One person emits approximately 22.6 liters of carbon dioxide per hour.
Each liter of air supplied to the room contains 0.4%° carbon dioxide, that is, each liter of this air contains 0.4 ml of carbon dioxide and thus can still “accept” 0.3 ml (0.7 - 0.4) for clean rooms(up to 0.7 ml per liter or 0.7 /~) and 0.6 ml (1 - 0.4) for ordinary rooms (up to 1 ml per liter or 1 /~).
Since every hour 1 person emits 22.6 liters (22600 ml) of carbon dioxide, and each liter of supplied air can “accept” the above number of ml of carbon dioxide, the number of liters of air that must be supplied to the room for 1 person per hour is (rooms , operating rooms) - 22600 / 0.3 = 75000 l = 75 m3. That is, 75 m3 of air per person per hour must enter the room so that the concentration of carbon dioxide in it does not exceed 0.7%
The main sources of indoor air pollution can be divided into four groups:
1. Substances entering the room with polluted air. The main source of indoor air pollution is household dust. It is the smallest particles of various substances that can float in the air. Dust also adsorbs many chemical compounds. The degree of penetration of atmospheric pollution into the building for different chemical substances different. When comparing the concentrations of nitrogen dioxide, nitrogen oxide, carbon monoxide and dust in residential buildings and in the atmospheric air, it was found that these substances are at or below their concentrations in the outdoor air. Concentrations of sulfur dioxide, ozone and lead are usually lower inside than outside. The concentrations of acetaldehyde, acetone, benzene, toluene, xylene, phenol, and a number of saturated hydrocarbons in the indoor air exceeded the concentrations in the atmospheric air by more than 10 times.
2. Products of destruction of polymeric materials.
3. Anthropotoxins .
4. Combustion products domestic gas and household activities.
One of the most common sources of indoor air pollution is smoking. Cigarette smoke in the home is a direct threat to health. It contains heavy metals, carbon monoxide, nitrogen oxide, sulfur dioxide, styrene, xylene, benzene, ethylbenzene, nicotine, formaldehyde, phenol, about 16 carcinogens.
Another possible source of air pollution in an apartment is settling tanks in the water supply and sewerage network. Garbage chutes also pose health hazards, especially if the chutes are located in the kitchen or hallway.
Indicators of the sanitary condition of indoor air:
Oxidability (the amount of O2 required for oxidation organic compounds air)
Criteria for assessing the sanitary condition of indoor air.
1. GENERAL MICROBIAL POLLUTION in 1 m3 of air.
2. NUMBER OF SANITARY INDICATORY MICROBES IN THE AIR. IN 250 LITERS OF AIR.
Sanitary indicator microbes in indoor air are:
1) Staphylococcus aureus
2) a-viridans streptococcus
3) b-hemolytic streptococcus
These bacteria are indicators of oral droplet contamination. They share a common route of release into the environment with pathogenic microorganisms transmitted by airborne droplets. Their survival times in the environment do not differ from those characteristic of most pathogens of airborne infections.
Methods are divided into sedimentation and aspiration.
Carbon dioxide is an indirect indicator of pollution because:
Anthropotoxins in indoor air. Sanitary and hygienic value of carbon dioxide content.
In the course of his life, a person releases about 400 chemical compounds. The air environment of unventilated rooms deteriorates in proportion to the number of people and the time they spend in the room. Chemical analysis indoor air allowed us to identify a number of toxic substances in them, the distribution of which according to hazard classes is as follows:
second hazard class - high hazardous substances(dimethylamine, hydrogen sulfide, nitrogen dioxide, ethylene oxide, benzene, etc.);
third hazard class - low-hazard substances (acetic acid, phenol, methylstyrene, toluene, methanol, vinyl acetate, etc.).
Even a two-hour stay in these conditions negatively affects mental performance. When there are large crowds of people in a room (classes, auditoriums), the air becomes heavy.
CO2 value: an indirect indicator of indoor air pollution, where the main source is humans.
Carbon dioxide is an indirect indicator of pollution because:
1. CO2 the best way characterizes a person as a source of indoor air pollution.
2. There is a correlation between the accumulation of CO2 and denaturation of the air environment (changes in physical, chemical and microbial composition)
3. There are express methods for determining CO2 (available, reliable, cheap).
Polymer materials and household gas as sources of air pollution in residential and public buildings. Features of the effect of air pollutants on the body. Prevention measures.
Currently, about 100 types of polymer materials are used in construction alone. Almost all polymer materials release certain toxic chemicals into the air that have a harmful effect on human health.
Fiberglass plastics based on various mixtures used in construction, sound and thermal insulation emit significant amounts of acetone, methacrylic acid, toluene, butanol, formaldehyde, phenol and styrene into the air. Paint and varnish coatings and adhesive-containing substances are also sources of indoor air pollution.
Many types of beautiful synthetic finishing materials - films, oilcloths, laminates, etc. - emit a set of harmful substances, for example, methanol, dibutyl phthalate, etc. Carpet products made from chemical fibers emit styrene, isophenol, and sulfur dioxide in significant concentrations. Household chemicals - detergents, cleaners, pesticides for fighting insects, rodents, pesticides, various types of adhesives, car cosmetics, polishes, varnishes, paints and many others - can cause various diseases in people, especially if stocks of such substances are stored in a poorly ventilated area.
Atmospheric pollution can cause non-infectious diseases in humans; in addition, they can worsen the sanitary living conditions of people and cause economic damage.
Biological effects of atmospheric pollution
Atmospheric pollution can have acute and chronic effects .
Measures for sanitary protection of atmospheric air
1. Legislative
There are a large number of regulatory documents regulating the protection of atmospheric air. The Federal Law “On Environmental Protection” states that every citizen has the right to a favorable environment, to its protection from negative impact caused by economic and other activities. The Law “On the Protection of Atmospheric Air” regulates the development and implementation of measures to eliminate and prevent air pollution - the construction of gas cleaning and dust collection devices at industrial enterprises and thermal power plants.
2. Technological
Technological measures are the main measures for the protection of atmospheric air, since only they can reduce or completely eliminate the emission of harmful substances into the atmosphere at the place of their formation. These measures are directly aimed at the source of emissions.
3. Sanitary... The purpose of sanitation measures is to remove or neutralize emission components in gaseous, liquid or solid form from organized stationary sources. For this purpose, various gas and dust collection systems are used.
4. Architectural and planning
This group of events includes:
Functional zoning of the city territory, that is, the allocation functional zones– industrial, external transport zone, suburban, communal
Rational planning of the territory
Prohibition of the construction of air polluting enterprises in residential areas settlement and their placement in an industrial zone, taking into account the prevailing wind direction in this area;
Creation of sanitary protection zones. A sanitary protection zone is an area around an industrial enterprise or other facility that is a source of environmental pollution, the size of which ensures that the levels of exposure to industrial hazards in a residential area are reduced to the maximum permissible values.
Rational development of streets, construction of transport interchanges on main highways with the construction of tunnels;
Greening the city area. Green spaces play the role of unique filters, affecting the dispersion of industrial emissions in the atmosphere, changing the wind regime and the circulation of air masses.
Choice for enterprise construction land plot taking into account the terrain, aeroclimatic conditions and other factors.
5. Administrative
Rational distribution of traffic flows according to their intensity, composition, time and direction of movement;
Restriction of movement of heavy vehicles within the residential area of the city;
Monitoring the condition of road surfaces and the timeliness of their repair and cleaning;
System for monitoring the technical condition of vehicles.
52. Features of the composition and properties of atm. Air, industrial, residential and public buildings.Atmospheric air It has chemical, physical and mechanical properties, which have both beneficial and unfavorable effects on the human body.
· Chemical properties caused by the normal gas composition of the air and harmful gaseous impurities;
· TO physical properties air include:
Temperature,
Humidity,
Mobility,
electrical condition,
Solar radiation,
Electromagnetic waves
depend on the physical properties of air climate And weather;
· Mechanical properties air depend on the content of solid impurities in it in the form
And the presence of microorganisms.
The air environment is heterogeneous By physical parameters and harmful impurities, which is related to the conditions of its formation And pollution.
It is necessary to distinguish:
1. Clean atmospheric air;
2. Atmospheric air of industrial regions;
3. indoor air in residential and public buildings;
4. indoor air of industrial enterprises.
These types of air differ from each other in composition and properties, and therefore in their effect on the human body.
I.atmospheric air
Physical properties of atmospheric air:
Temperature,
Humidity,
Mobility,
Atmosphere pressure,
Electrical condition
Physical properties of atmospheric air unstable and related to climatic features of the geographical region.· The presence of gaseous solid impurities in the air ( dust And soot) depends on the nature of emissions into the atmosphere, dilution conditions and self-purification processes.
On concentration of harmful substances in the atmosphere influence:
1. speed and direction of prevailing winds,
2. temperature, air humidity,
3. precipitation, solar radiation,
4. quantity, quality and height of emissions into the atmosphere.
Air properties of residential and public buildings more stable - these buildings maintain an optimal microclimate due to ventilation and heating. Gaseous impurities are associated with the release of human waste products into the air, the release of toxic substances from materials and household items made of polymer materials, combustion products of household gas, etc. On the properties of air industrial premises features have a significant impact technological process. In some cases, the physical properties of air acquire independent significance as a harmful occupational factor, and air pollution with toxic substances can lead to occupational diseases.
53. Solar radiation- integrated flux of radiation emitted by the sun. From a hygienic point of view, the optical part of sunlight, which occupies the range from 280-2800 nm, is of particular interest. Longer waves -- radio waves, shorter - gamma rays. AND ionizing radiation does not reach the Earth's surface because it is retained in the upper layers of the atmosphere, in the ozone layer.
The intensity of solar radiation depends primarily on the height of the sun above the horizon. If the sun is at its zenith, then the path taken by the sun's rays will be much shorter than their path if the sun is at the horizon. By increasing the path, the intensity of solar radiation changes. The intensity of solar radiation also depends on the angle at which the sun's rays fall, and the illuminated area also depends on this (as the angle of incidence increases, the area of illumination increases). Thus, the same solar radiation falls on a larger surface, so the intensity decreases. The intensity of solar radiation depends on the mass of air through which the sun's rays pass. The intensity of solar radiation in the mountains will be higher than above sea level, because the layer of air through which the sun's rays pass will be less than above sea level. Of particular importance is the influence on the intensity of solar radiation by the state of the atmosphere and its pollution. If the atmosphere is polluted, then the intensity of solar radiation decreases (in the city the intensity of solar radiation is on average 12% less than in rural areas). The voltage of solar radiation has a daily and annual background, that is, the voltage of solar radiation changes throughout the day, and also depends on the time of year. The highest intensity of solar radiation is observed in summer, the lowest in winter. In terms of its biological effect, solar radiation is heterogeneous: it turns out that each wavelength has a different effect on the human body. In this regard, the solar spectrum is conventionally divided into 3 sections:
1. ultraviolet rays, from 280 to 400 nm
2. visible spectrum from 400 to 760 nm
3. infrared rays from 760 to 2800 nm.
With daily and annual solar radiation, the composition and intensity of individual spectra undergo changes. The rays of the UV spectrum undergo the greatest changes.
Solar radiation is a powerful healing and preventive factor.
54. Quantitative and qualitative characteristics of solar radiation. Due to the absorption, reflection and scattering of radiant energy in space on the Earth's surface, the solar spectrum is limited, especially in its short-wavelength part. If at the boundary of the earth’s atmosphere the UV part is 5%, visible is 52%, infrared is 43%, then at the surface of the Earth the composition of solar radiation is different: UV part is 1%, visible is 40%, infrared is 59%. This is due to varying degrees of atmospheric air purity, a wide variety of weather conditions, the presence of clouds, etc. At high altitudes, the thickness of the atmosphere traversed by solar rays decreases, the degree of their absorption by the atmosphere decreases, and the intensity of solar radiation increases. Depending on the height of the Sun above the horizon, the ratio of direct solar radiation to scattered radiation changes, which is essential in assessing the effect of its biological action.
55. Hygienic characteristics of the ultraviolet part of solar radiation. This is the most biologically active part of the solar spectrum. It is also heterogeneous. In this regard, a distinction is made between long-wave and short-wave UV. UV promotes tanning. When UV enters the skin, 2 groups of substances are formed in it: 1) specific substances, these include vitamin D, 2) non-specific substances - histamine, acetylcholine, adenosine, that is, these are products of protein breakdown. The tanning or erythema effect comes down to a photochemical effect - histamine and other biologically active substances promote vasodilation. The peculiarity of this erythema is that it does not appear immediately. Erythema has clearly defined boundaries. Ultraviolet erythema always leads to a more or less pronounced tan, depending on the amount of pigment in the skin. The mechanism of tanning action has not yet been sufficiently studied. It is believed that first erythema occurs, nonspecific substances such as histamine are released, the body converts the products of tissue breakdown into melanin, as a result of which the skin acquires a peculiar shade. Tanning is thus a test protective properties body (a sick person does not sunbathe, tans slowly).
The most favorable tan occurs under the influence of UV light with a wavelength of approximately 320 nm, that is, when exposed to the long-wave part of the UV spectrum. In the south, short-wave UFLs predominate, and in the north, long-wave UFLs predominate. Short-wavelength rays are most susceptible to scattering. And dispersion occurs best in a clean atmosphere and in the northern region. Thus, the most useful tan in the north is longer, darker. UFL are a very powerful factor in the prevention of rickets. With a lack of UVB, rickets develops in children, and osteoporosis or osteomalacia in adults. This is usually encountered in the Far North or among groups of workers working underground. IN Leningrad region from mid-November to mid-February there is practically no UV part of the spectrum, which contributes to the development of solar starvation. To prevent sunburn, artificial tanning is used. When exposed to UV in the air, ozone is formed, the concentration of which must be controlled.
UFLs have a bactericidal effect. It is used to disinfect large wards, food products, water.
The intensity of UV radiation is determined by the photochemical method by the amount decomposed under the influence of UV oxalic acid in quartz tubes(ordinary glass does not transmit UV light). The intensity of UV radiation is also determined by an ultraviolet meter. For medical purposes, ultraviolet radiation is measured in biodoses.
56. Physiological and hygienic significance of ultraviolet radiation. Measures to prevent UV rays.See 55.
Prevention of UV deficiency
1. Architectural and planning activities.
When designing and constructing residential buildings, children's, treatment-and-prophylactic and other institutions, it is necessary to take into account the insolation regime.
2. Heliotherapy (sunbathing). Can be organized on beaches, in solariums. Sunbathing can be total (general and local), weakened, or training. Summary baths are used for healthy, hardened children. General sunbathing can be weakened by the use of lattice awnings and gauze.
3. Use of artificial sources.
57. Biological effect of ultraviolet rays(UFL) is very, very diverse. It can be both positive and destructive. The most dangerous are the effects of short-wave UV rays (10-200 nm), the vast majority of which are retained in the upper layers of the atmosphere, in particular in the ozone layer. However, the danger of damage from UV rays occurs when a person spends a long time in the Sun, as well as in production conditions when working with artificial sources of UV rays (electric welding), performing physical procedures (therapeutic, preventive ultraviolet irradiation). Increasing the dose of UV rays leads to protein denaturation, which is primarily responsible for the development of cataracts, which requires protection of the visual analyzer when working with UV rays. The destructive effect of UV rays is used in practical activities person. In particular, their destructive effect on microbial cells (bactericidal effect at a wavelength of 180–280 nm, maximum at 254 nm) is widely used for air sanitation, maintaining an antimicrobial regime in the premises of medical institutions, and water disinfection. The ability of various media to luminesce under the influence of UV rays is used in analytical chemistry. For example, the luminescent method is used to determine vitamins in food raw materials and foodstuffs.
The positive aspects of the UFL are as follows:
· UV rays stimulate the production of antibodies, phagocytosis, accumulation of agglutinins in the blood, increasing natural immunity and the body’s resistance to adverse environmental factors
· UV rays cause pigment formation (wavelengths around 340 nm) and erythema formation
UFL play a significant role in providing the body with vitamin D3
In climatology, according to the level of ultraviolet radiation, there is a “deficit zone” (latitude above 57.5°), a “comfort zone” (42.5–57.5°), and an “excess zone” (less than 42.5°), which must be taken into account when hygienic education of the population, carrying out preventive measures.
UVL deficiency is primarily associated with the development of light starvation syndrome, which can be observed in people living in the “deficiency zone”, in cities with a polluted atmosphere, working underground, and spending little time in the open air.
For UV protection Collective and individual methods and means are used: shielding of radiation sources and workplaces; deletion service personnel from sources of ultraviolet radiation (protection distance – remote control); rational placement of workplaces; special painting of premises; PPE and protective equipment (pastes, ointments). Screens, shields or special booths are used to shield workplaces. Walls and screens are painted in bright hues(gray, yellow, blue), zinc and titanium white are used to absorb ultraviolet radiation. Personal protective equipment against ultraviolet radiation includes: thermal protective clothing; mittens; safety shoes; safety helmets; safety glasses and shields with light filters, depending on the work being performed. To protect the skin from ultraviolet radiation, ointments containing substances that serve as light filters for these radiations (salol, salicylic methyl ether, etc.) are used.
Modern man spends time in residential and public buildings, depending on his lifestyle and conditions. labor activity from 52 to 85% of the daily time. Therefore internal environment premises even at relatively low concentrations large quantity toxic substances is not indifferent to a person and can affect his well-being, performance and health.
In addition, in buildings, toxic substances do not act in isolation, but in combination with factors such as temperature and humidity, ionic conditions, radioactive background, etc.
Chemical pollution of indoor air. The main sources of indoor air pollution are atmospheric air, construction and finishing polymer materials, the vital activity of the human body and household activities.
The quality of the indoor air in terms of chemical composition largely depends on the quality of the surrounding atmospheric air, since buildings have a constant exchange and do not protect residents from polluted atmospheric air. The migration of dust and toxic substances contained in the atmosphere is due to their natural and artificial ventilation, and therefore substances present in the outdoor air are also found in rooms, even in those that are supplied with conditioned air.
The degree to which various chemical air pollutants penetrate indoors varies: concentrations of sulfur dioxide, ozone and lead are usually lower than outside; concentrations of nitrogen oxides, carbon and dust are similar inside and outside; concentrations of acetaldehyde, acetone, benzene, ethyl alcohol, toluene, ethylbenzene, xylene and other organic compounds in indoor air exceed their concentrations in the atmosphere by more than 10 times, which is apparently due to internal sources of pollution.
One of the most powerful internal sources of indoor air pollution are polymer building and finishing materials. The range of polymer materials includes about 100 items. They are used for covering floors, finishing walls, thermal insulation of external roofs and walls, waterproofing, sealing and cladding panels, manufacturing window blocks and doors, etc.
The scale and feasibility of using polymers in the construction of residential and public buildings are determined by the presence of a number of positive properties that facilitate their use, improve the quality of construction and reduce its cost. However, it has been established that all polymer materials emit a variety of substances toxic to the human body: polyvinyl chloride materials emit benzene, toluene, ethylbenzene, cyclohexane, xylene, butyl alcohol into the air; particle boards on phenol-formaldehyde and urea-formaldehyde bases - phenol, formaldehyde and ammonia; fiberglass - acetone, methacrylic acid, toluene, butanol, formaldehyde, phenol, styrene; paint coatings and maple-containing substances - toluene, butyl methacrylate, butyl acetate, xylene, styrene, acetone, butanol, ethylene glycol; carpet products made from chemical fibers - styrene, isophenol, sulfur dioxide.
The intensity of the release of volatile substances depends on the operating conditions of polymer materials - temperature, humidity, air exchange rate, operating time. Even in small concentrations, these chemicals can cause sensitization to the body. It has been established that in rooms saturated with polymer materials, there is a greater susceptibility of the population to allergic and colds, hypertension, neurasthenia, and vegetative-vascular dystonia. The most sensitive organisms are children and sick people.
The next internal source of indoor air pollution is waste products of the human body - anthropotoxins. It has been established that a person, in the course of his life, releases about 400 chemical compounds called anthropotoxins, and a fifth of them are considered highly dangerous substances (hazard class 2), these are dimethylamine, hydrogen sulfide, nitrogen dioxide, ethylene oxide, benzene.
Concentrations of dimethylamine and hydrogen sulfide exceeded the maximum permissible concentration for atmospheric air; concentrations of carbon dioxide, carbon monoxide and ammonia exceeded the maximum permissible concentration or were at their level.
Class 3 - low-hazard substances - includes acetic acid, phenol, methylstyrene, toluene, methanol, vinyl acetate.
The remaining substances constituted tenths or smaller fractions of the maximum permissible concentration, but taken together they indicated an unfavorable air environment, since even a 2-4-hour stay in these conditions negatively affected the mental performance of the subjects. The air environment of unventilated rooms deteriorates in proportion to the number of people and the time they spend in the room.
Household processes are also a source of air pollution. Gasification of apartments increases the level of their improvement, but the results of numerous studies have shown that open burning of gas worsens the condition of the air environment of gasified dwellings in terms of pollution with various chemicals and deterioration of the microclimate of the premises.
It was found that when the gas burned for an hour in the indoor air, the concentrations of substances were (mg/m3): carbon monoxide - 15; formaldehyde - 0.037; nitric oxide - 0.62; carbon dioxide - 0.44; benzene - 0.07, and high concentrations of these substances were found not only in the kitchen, but also in living quarters.
The air temperature in the room during gas combustion increased by 3-6 "C, humidity - by 10-15%. After turning off the gas, the concentrations of chemical substances decreased, but sometimes did not return to their original values even after 1.5-2.5 hours.
Smoking is also a source of household air pollution. When smoking, the air is polluted, according to gas chromatography-mass spectrometric analysis, with 186 chemical compounds, including oxides of carbon and nitrogen, sulfur, styrene, xylene, limonene, benzene, ethylbenzene, nicotine, formaldehyde, hydrogen sulfide, phenol, acrolein, acetylene, benzene ( a) pyrene, and in fairly high concentrations.
In passive smokers (non-smoking people close to smokers), components tobacco smoke caused irritation of the mucous membranes of the eyes, an increase in the level of carboxyhemoglobin in the blood, an increase in heart rate, and an increase in blood pressure levels. The development of cancer of the bronchopulmonary system is directly associated with smoking. It is estimated that 40 cigarettes smoked per day deliver about 150 mg of benzo(a)pyrene to the lungs in addition to the benzo(a)pyrene of atmospheric air.
Microbial indoor air pollution. Various microorganisms are found in the air, of which bacteria and viruses are of greatest hygienic interest. Atmospheric air is not a favorable environment for the life of microorganisms, and therefore, once in it, they die relatively quickly due to drying out, lack of nutrient material and the bactericidal effect of ultraviolet radiation from the Sun. Bacteria contained in the atmosphere are saprophytes, which are more stable in the environment than pathogenic microbes.
The air of closed, poorly ventilated and overcrowded rooms contains a significant number of microbes, among which may be pathogenic (causative agents of viral diseases - influenza, measles, chickenpox, etc., bacterial - whooping cough, diphtheria, scarlet fever, tuberculosis and other infections, which may even have a massive, epidemic nature of distribution).
P.N. Lashchenkov established that there are two ways of transmitting infection through the air, airborne droplets and airborne dust.
With airborne transmission, infection occurs as a result of inhalation of tiny droplets of saliva, sputum, mucus secreted by a patient or a carrier of germs during coughing, sneezing and even talking. It is known that the smallest droplets can be sprayed over a distance of 1 to 1.5 m, moving further with air currents for several meters, remaining in suspension for up to 1 hour. In this case, transmission routes into the air, and then into the body of a susceptible person, are virulent pathogens. In addition, they are better protected from drying out, easily and quickly entering the human body through Airways. All this makes airborne transmission of infections more dangerous epidemiologically. Indeed, all epidemic infections spread this way.
In the airborne dust transmission route, infection occurs through dust suspended in the air containing pathogenic microorganisms, the virulence of which is weakened due to the drying of infected droplets of the patient's secretions. Dust particles with microbes settled on them can remain in the form of a bacterial aerosol from several minutes to 2-4 hours. There is a direct relationship between the content of dust in the indoor air and the number of microbes: the more dust, the more abundant the microflora. Therefore, the fight against dust in enclosed spaces is also the fight against bacterial air pollution.
Measures to prevent the transmission of infections by air include basic rules of behavior when coughing and sneezing (covering your nose and mouth with a handkerchief, turning away from nearby people; wearing gauze masks by all people during epidemics is very effective); maintaining cleanliness of the premises through regular wet cleaning, compliance with established standards for the area and cubic capacity of residential and public buildings; sanitization of air and premises of health care facilities using disinfectants and bactericidal lamps.
Air exchange standards in residential buildings
To assess the degree of air purity, the concentration of carbon dioxide in the air, air oxidation, general content microorganisms and the content of streptococci and staphylococci (Table 7.5).
Table 7.5.
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 cerebral cortex and 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 greatest productivity and the least eye fatigue occurs when illuminated with standard 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 under consideration are one millimeter or more, then for visual work the 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 white has long been considered hygienic, as it provides the best illumination of the room due to the high reflection coefficient of 0.8-0.85. Surfaces painted in other colors have a lower reflectance: light yellow - 0.5-0.6, green, gray - 0.3, dark red - 0.15, dark blue - 0.1, black - - 0.01. But 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 the characteristics of lighting is of great importance 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 lamps, 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 daylight, 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 light 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 to the top of the 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, some of the rays illuminate the room after passing through milky or frosted glass, and some - 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, the inner surface of which is coated with phosphor. The tube is filled with mercury vapor, and electrodes are soldered at both ends. When the lamp is connected to the electrical network, an electric current (“gas discharge”) arises between the electrodes, 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.
The main sources of indoor air pollution are atmospheric air penetrating into the room through window openings and leaks in building structures, construction and finishing polymer materials that emit various substances toxic to humans into the air, many of which are highly hazardous (benzene, toluene, cyclohexane, xylene , acetone, butanol, phenol, formaldehyde, acetaldehyde, ethylene glycol, chloroform), human waste products and 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 at the same time, even in small quantities, they indicate an unfavorable air environment, which has a negative impact on the state of 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 is deionized during its passage through the supply ventilation systems 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 of premises, construction and finishing polymer materials that release various substances toxic to humans into the air, and 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 indoor spaces during 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 property indoor air, 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 cleanliness in residential and public areas. 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.
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