Chemical indicators of indoor air pollution. Natural and artificial ventilation, types, hygienic characteristics. Indicators of indoor air purity. Impact of human activity on nature

The capital of Russia is one of the largest cities on the planet. Of course, it contains all the problems of megacities. The main one is air pollution, which appeared more than a decade ago and is only getting worse every year. This could cause a real man-made

Clean air standard

Natural atmospheric air is a mixture of gases, the main ones of which are nitrogen and oxygen. Their volume is 97-99% depending on the terrain and atmospheric pressure. The air also contains hydrogen, inert gases, and water vapor in small quantities. This composition is considered optimal for life. As a result of this, a constant cycle of gases occurs in nature.

But human activity makes significant changes to it. For example, just in a closed room without plants, one person can change percentage oxygen, carbon dioxide and water vapor only due to the fact that he will breathe there. Just imagine what the air pollution could be like in Moscow today, where millions of people live, thousands of cars drive and huge industrial enterprises operate?

Main harmful impurities

According to research, the highest concentrations in the atmosphere over the city are phenol, carbon dioxide and benzopyrene, formaldehyde, and nitrogen dioxides. Consequently, an increase in the percentage of these gases entails a decrease in oxygen concentration. Today we can state that the level of air pollution in Moscow has exceeded acceptable standards by 1.5-2 times, which becomes extremely dangerous for people living in this territory. After all, not only do they not receive enough oxygen, but they also poison the body with dangerous toxic and carcinogenic gases, which have a huge concentration in the Moscow air, even in enclosed spaces.

Sources of air pollution in Moscow

Why is it becoming increasingly difficult to breathe in the capital of Russia every year? According to recent studies, main reason Air pollution in Moscow comes from cars. They filled the capital on every major highway and small street, on avenues and in courtyards. 83% enters the atmosphere precisely as a result of the operation of internal combustion engines.

There are several large industrial enterprises, which also act as sources causing air pollution in Moscow. Although most of them have modern cleaning systems, life-threatening gases still enter the atmosphere.

The third largest source of pollution is large thermal power plants and boiler houses that run on coal and fuel oil. They enrich the air of the metropolis with a large number of combustion products, such as carbon monoxide and carbon dioxide s.

Factors that increase the concentration of harmful substances

It is noteworthy that the amount of harmful gases in the air of the Russian capital is not always and not the same everywhere. There are several factors that contribute to its purification or greater contamination.

According to statistics, per person in Moscow there are approximately 7 square meters green spaces. This is very little compared to others big cities. In those regions where there is a greater concentration of parks, the air is much cleaner than in the rest of the city. During cloudy weather, the air cannot purify itself and collects near the ground. a large number of gases that cause complaints from the local population about poor health. High humidity also retains gases near the ground, causing air pollution in Moscow. But frosty weather, on the contrary, can temporarily clear it.

Most polluted regions

In the capital, the industrial Southern and South-Eastern districts are considered the dirtiest regions. The air is especially bad in Kapotnya, Lyublino, Maryino, Biryulyovo. Large industrial plants are located here.

The level of air pollution is high in Moscow and directly in the center. There are no huge enterprises here, but the largest concentration of cars. In addition, everyone remembers the famous Moscow traffic jams. It is in them that cars produce the most harmful gases, since the engines do not operate at full power, and petroleum products do not have time to burn completely, forming carbon monoxide.

The largest number of thermal power plants is also in the central part of Moscow. They burn coal and fuel oil, enriching the air with the same carbon dioxide and carbon dioxide. In addition, they also produce dangerous carcinogens that significantly affect the health of Muscovites.

Clean air in Moscow

There are also relatively clean regions in the capital in which the level of harmful gases is close to normal. Of course, cars and small industry leave their negative mark here, but compared to industrial regions it is quite clean and fresh. Geographically, these are western regions, especially those located beyond the Moscow Ring Road. In Yasenevo, Teply Stan and Severny Butovo you can breathe deeply without fear. In the northern part of the city there are also several areas that are relatively favorable for normal life - these are Mitino, Strogino and Krylatskoye. In all other respects, air pollution in Moscow today can be called close to critical. This is especially alarming because the situation is only getting worse every year. There are fears that soon there will be no areas left in the city where the air will be more or less clean.

Diseases

The inability to breathe normally causes a number of discomforts and chronic diseases. Children and older people are especially sensitive to this.

Scientists state that air pollution in Moscow has now caused every fifth person to have asthma or an asthmatic factor. Children are five times more likely to suffer from pneumonia, bronchitis, adenoids and polyps of the upper respiratory tract.

Lack of oxygen causes oxygen starvation of the brain. As a result, frequent headaches, migraines, and low levels of dangerous carbon monoxide develop and cause drowsiness and general fatigue. Against the background of all this, cardiovascular diseases, diabetes, and neuroses develop.

The presence of a large amount of dust in the air does not allow the natural filters in the nose to retain it all. It enters the lungs, settles in them and reduces their volume. In addition, dust may contain very hazardous substances, which accumulate and cause cancer.

When Muscovites find themselves outside the city or in the forest, they begin to experience dizziness and migraines. This is how the body reacts to an unusually large amount of oxygen that enters the blood. This abnormal phenomenon shows the real impact of air pollution in Moscow on human health.

The fight to clean the air

Every year, scientists carefully study the causes, factors and rates of air pollution in Moscow. 2014 showed that there is a worsening trend, although measures are constantly being taken to reduce harmful impurities in the air.

Factories and thermal power plants install filters that retain the most dangerous products their activities. To relieve traffic flow, new interchanges, bridges and tunnels are being built. To make the air much cleaner, the area of ​​green spaces is constantly increasing. After all, nothing cleanses the atmosphere like trees. Administrative penalties are also taken. Both private car owners and large enterprises are fined for violating the gas exchange regime and emitting more harmful gases.

But the forecast results are still disappointing. Clean air may soon become scarce in Moscow, as has already happened in the most To prevent this from happening tomorrow, you need to think today about whether it’s worth leaving your car with the engine on. long time, while you are waiting for someone at the entrance.

PRACTICAL SIGNIFICANCE OF THE TOPIC:

The air in poorly ventilated wards and other enclosed areas of hospitals, due to changes in the chemical and bacterial composition, physical and other properties, can cause bad influence on the state of health, causing or worsening the course of diseases of the lungs, heart, kidneys, etc. All this indicates the great hygienic importance of the state of the air environment, since clean air, according to F.F. Erisman, one of the first aesthetic needs of the human body.

OBJECTIVE OF THE LESSON:

To consolidate theoretical knowledge about the hygienic importance of air purity (CO 2 . anthropotoxins, bacterial contamination).

To teach students methods for determining carbon dioxide and bacteria in the air and assessing the degree of air pollution in accordance with hygienic standards.

Study the hygienic requirements for ventilation of various hospital rooms.

Teach students methods for assessing the ventilation regime (calculating the air exchange rate during natural ventilation).

THEORY QUESTIONS:

Indicators of air pollution (organoleptic, physical, chemical, bacteriological).

Physiological and hygienic significance of carbon dioxide.

Methods for determining carbon dioxide in enclosed spaces.

Calculation and assessment of the air exchange rate based on carbon dioxide.

Methods for determining bacterial air pollution in hospital premises and their hygienic assessment.

PRACTICAL SKILLS:

Students must:

Master the technique of determining carbon dioxide using the express method.

Study the structure and rules of working with Krotov’s device.

Learn to assess the state of the air environment and justify ventilation modes (using the example of solving situational problems).

Literature:

A) main:

1.Hygiene with the basics of human ecology [Text]: textbook for students of higher professional education studying in specialties 060101.65 “General Medicine”, 0601040.65 “Medical and Preventive Care” in the discipline “Hygiene with the basics of human ecology. VG” / [P. I. Melnichenko and others] ; edited by P. I. Melnichenko.- M.: GEOTAR-Media, 2011.- 751 p.

2. Pivovarov, Yuri Petrovich. Hygiene and fundamentals of human ecology [Text]: textbook for students of medical universities studying in the specialty 040100 "General Medicine", 040200 "Pediatrics" / Yu. P. Pivovarov, V. V. Korolik, L. S. Zinevich; edited by Yu. P. Pivovarova. - 4th ed., revised. and additional - M.: Academy, 2008.- 526 p.

3. Kicha, Dmitry Ivanovich. General hygiene [Text]: manual for laboratory exercises: tutorial/ D. I. Kicha, N. A. Drozhzhina, A. V. Fomina. - M.: GEOTAR-Media, 2010. - 276 p.

B) additional literature:

1. Mazaev, V.T. Communal hygiene [[Text]]: textbook for universities: [At 2 hours] / V. T. Mazaev, A. A. Korolev, T. G. Shlepnina; edited by V. T. Mazaeva. - M.: GEOTAR-Media, 2005.

2. Shcherbo, A.P. Hospital hygiene / A.P. Shcherbo. - St. Petersburg. : Publishing house SPbMAPO, 2000 .- 482 p.

TRAINING MATERIAL FOR INDEPENDENT PREPARATION

Sanitary assessment of air purity

The presence of people or animals in enclosed spaces leads to air pollution with metabolic products (anthropotoxins and other chemicals). It is known that a person in the process of life emits more than 400 different compounds - ammonia, ammonium compounds hydrogen sulfide, volatile fatty acids, indole, mercaptan, acrolein, acetone, phenol, butane, ethylene oxide, etc. Exhaled air contains only 15-16% oxygen and 3.4-4.7% carbon dioxide, is saturated with water vapor and has a temperature of about 37. Pathogenic microorganisms (staphylococci, streptococci) enter the air etc.), the number of light ions decreases and heavy ones accumulate. In addition, during the operation of medical institutions, unpleasant odors may enter the air of ward, reception, treatment and diagnostic departments due to an increase in the content of under-oxidized substances, the use of building materials (wood, polymer materials), and the use of various medications (ether, oxygen, gaseous anesthetic substances , evaporation of drugs). All this has an adverse effect on both staff and, in particular, patients. Therefore, control over the chemical composition of the air and its bacterial contamination is of great hygienic importance.

A number of indicators are used to assess air cleanliness:

1. Organoleptic.

The organoleptic properties of the air in the main rooms of a healthcare facility (using a 6-point Wright scale) must correspond to the following parameters: rating 0 (no odor), air in utility rooms - rating 1 (barely noticeable odor).

2. Chemical.

Oxygen concentration - 20-21%.

Carbon dioxide concentration is up to 0.05% (very clean air), up to 0.07% (air of good cleanliness), up to 0.17c (air of satisfactory cleanliness).

Concentrations chemical substances correspond to maximum permissible concentrations for atmospheric air.

Air oxidability (the amount of oxygen in mg required for the oxidation of organic substances in 1 m 3 of air): clean air - up to 6 mg/m 3, moderately polluted - up to 10 mg/m 3; air in poorly ventilated rooms - more than 12 mg/m3.

3.Physical

Changes in air temperature and relative humidity.

Unipolarity coefficient is the ratio of the concentration of heavy ions. Clean atmospheric air has a unipolarity coefficient of 1.1-1.3. When air is polluted, the unipolarity coefficient increases.

An indicator of the electrical state of air is the concentration of light ions (the sum of negative and positive) of the order of 1000-3000 ions per 1 cm 3 of air (±500).

Bacteriological ("Guidelines for microbiological control over the sanitary and hygienic condition of hospitals and maternity hospitals" number 132-11):

1. Surgical operating rooms: the total air contamination before the operation should not exceed 500 microbes per 1 m 3, after the operation - 1000; pathogenic staphylococci and streptococci should not be detected in 250 liters of air.

   Preoperative and dressing: the total air contamination before work should not exceed 750 microbes per 1 m 3, after work - 1500; pathogenic staphylococci and streptococci should not be detected in 250 liters of air.

   Maternity rooms: total air contamination is less than 2000 microbes per 1 m3, the number of hemolytic staphylococci and streptococci is no more than 24 per 1 m3.

   Manipulation rooms: total air contamination - less than 2500 microbes per 1 m 3 .; the number of hemolytic staphylococci and streptococci is no more than 32 per 1 m 3 of air.

   Wards for patients with scarlet fever: total contamination - less than 3500 microbes per 1 m 3; the number of hemolytic staphylococci and streptococci is up to 72-100 per 1 m 3 of air.

   Ward for newborns: total air contamination - less than 3000 microbes per 1 m 3; the number of hemolytic staphylococci and streptococci is less than 44 per 1 m 3 of air.

In other hospital premises there is clean air for the summer regime of microorganisms in 1 m 3 - 3500,

hemolytic staphylococcus - 24, viridans and hemolytic streptococcus - 16; for winter mode these figures are 5000, 52 and 36, respectively.

Assessment of indoor air pollution by metabolic products based on carbon dioxide content.

Detection of all numerous metabolic products in the air is associated with great difficulties, therefore it is customary to evaluate the quality of the indoor air environment indirectly by an integral indicator - the carbon dioxide content. An express method for determining CO2 in the air is based on the reaction of carbon dioxide with a soda solution. The principle of the method is that a pink solution of soda with the indicator phenolphthalein becomes discolored when all the sodium carbonate reacts with air CO2 and turns into bicarbonate of soda. A 100 ml syringe is filled with 20 ml of a 0.005%) solution of soda with phenolphthalein, then sucked in 80 ml of air and shaken for 1 minute. If the solution has not discolored, carefully squeeze out the air from the syringe, leaving the solution in it, draw in a portion of air again and shake for another 1 minute. This operation is repeated 3-4 times, after which air is added in small portions, 10-20 ml, each time shaking the syringe for 1 minute until the solution becomes discolored. By calculating the total volume of air passed through the syringe, determine the concentration of CO2 in the air according to the table

Dependence of CO 2 content in the air on the volume of air providing 20 ml of 0.005% soda solution

Sanitary and bacteriological study of air

The following methods are distinguished:

sedimentation - based on the principle of spontaneous sedimentation of microorganisms;

filtration methods - involve sucking a certain volume of air through a sterile medium, after which the filter material is used to grow bacteria on nutrient media (meat peptone agar - to determine the microbial number and blood agar - to count the number of hemolytic streptococci);

based on the principle of air impact.

The latter is considered one of the most advanced, since it provides better capture of highly dispersed phases of microbial aerosol. The most common in sanitary practice is sedimentation-aspiration air intake using a Krotov device. Krotov’s device is a cylinder with a removable lid, which contains a motor with centrifugal fans. The air being tested is sucked in at a speed of 20-25 l/min through a wedge-shaped slot in the lid of the device and hits the surface of a dense nutrient medium. To ensure uniform seeding of microbes, the Petri dish with the nutrient medium rotates at a speed of 1 revolution per 1 second. The total volume of air with significant air pollution should be 40-50 liters, with minor air pollution - more than 100 liters. The Petri dish is covered with a lid, labeled and placed in a thermostat for 2 days at a temperature of 37° C, after which the number of grown colonies is counted. Considering the volume of air sample taken, calculate the number of microbes in 1 m3

Calculation example: 60 liters of air were passed through the device for 2 minutes (30 l/min). The number of grown colonies is 510. The number of microorganisms in 1 m 3 of air is equal to: 510/60 x 1000 = 8500 in 1 m 3.

Hygienic requirements for hospital ventilation

In modern standard design of medical institutions, there is a tendency to increase the number of floors and beds of hospitals, as well as the number of diagnostic departments and services. This makes it possible to reduce the building area, the length of communications, get rid of duplication of support services, and allows the creation of more powerful treatment and diagnostic departments. At the same time, greater compaction of ward sections and their vertical location increases the possibility of air flow over ward sections and floors. These features of modern hospital construction place increased demands on the organization of air exchange in order to prevent outbreaks of nosocomial infections and postoperative complications. This especially applies to operating rooms, surgical hospitals, maternity care facilities, children's and infectious diseases departments of hospitals. Thus, when carrying out operations in operating rooms with ventilation units providing 5-6 times air exchange and 100 % purification of air from microorganisms, the number of purulent-inflammatory complications does not exceed 0.7-1.0%, and in operating rooms - in the absence of air supply. exhaust ventilation increases to 20-30% or more. Ventilation requirements are set out in SNiP-2.04.05-80 “Heating, ventilation and air conditioning”. For the operation of heating and ventilation systems, two modes are established: the mode of the cold and transition periods of the year (air temperature below +10 ° C), the mode of the thermal period of the year (temperature above 10 C). To create an isolated air regime in the wards, they should be designed with an airlock connected to the bathroom. Exhaust ventilation of rooms should be carried out through individual ducts, which prevents vertical air flow. In infectious diseases departments, exhaust ventilation is provided in all boxes and semi-boxes separately by gravity (due to thermal pressure), by installing independent channels and shafts, as well as by installing deflectors for each of the listed rooms. The flow of air into boxes, half-boxes, filter boxes should be carried out due to infiltration from the corridor, through leaks building structures. To ensure rational exchange of air in the operating unit, it is necessary to ensure the movement of air flows from the operating rooms to the adjacent rooms (preoperative, anesthesia), as well as from these rooms to the corridor. Exhaust ventilation is installed in the corridor of the operating units. The most widely used scheme in operating rooms is the supply of air through supply devices located under the ceiling at an angle of 15.C to the vertical plane and its removal from two zones of the room (upper and lower). This scheme ensures laminar air flow and improves the hygienic conditions of the premises. Another scheme is to supply air into the operating room through the ceiling, through a perforated panel and side inlet slits, which create a sterile area and an air curtain. The air exchange rate in the central part of the operating room reaches up to 60-80 per hour. In all premises of medical institutions, except operating rooms, in addition to an organized ventilation system, folding transoms must be installed in the windows. The outside air supplied by air supply units to operating rooms, anesthesia rooms, maternity rooms, resuscitation rooms, postoperative wards, intensive care wards, 1-2-bed wards for patients with skin burns, wards for newborns, premature and injured children is additionally purified in bacteriological filters. To reduce microbial contamination of air in small rooms, mobile, recirculating air purifiers are recommended, providing fast and highly effective air purification. Dust and bacterial contamination after 15 minutes of continuous operation are reduced by 7-10 times. Air purifiers work based on continuous circulation of air through a filter made of ultra-fine fibers. They operate in both full recirculation mode and with air intake from adjacent rooms or from the street. Air purifiers are used to clean the air during surgery. They do not cause discomfort and do not affect others.

Air conditioning is a set of measures for creating and automatically maintaining an optimal artificial microclimate and air environment in the premises of medical institutions in operating rooms, anesthesia, delivery rooms, postoperative wards, resuscitation rooms, intensive care wards, cardiology and endocrinology departments, in 1-2-bed patient wards with Skin burns, for 50% of beds in departments for infants and newborns, as well as in all wards of departments for premature and injured children. An automatic microclimate control system must provide the parameters it requires: air temperature - 17-25 C 0, relative humidity - 40-70%, mobility - 0.1-0.5 m/sec.

Sanitary assessment of ventilation efficiency is carried out on the basis of:

sanitary inspection of the ventilation system and its operating mode;

calculating the actual ventilation volume and air exchange rate based on instrumental measurements;

objective study of the air environment and microclimate of ventilated premises.

Having assessed the mode of natural ventilation (infiltration of outside air through various cracks and leaks in windows, doors and partly through the pores of building materials into rooms), as well as their ventilation using open windows, vents and other openings arranged to enhance natural air exchange, consider the installation of aeration devices (transoms, vents, aeration channels) and ventilation mode. If artificial ventilation is available (mechanical ventilation, which does not depend on outside temperature and wind pressure and, under certain conditions, provides heating, cooling and purification of outside air), the time of its operation during the day, the conditions of maintenance of the air intake and air purification chambers are specified. Next, it is necessary to determine the effectiveness of ventilation, finding it from the actual volume and frequency of air exchange. It is necessary to distinguish between the necessary and actual values ​​of the volume and frequency of air exchange.

The required volume of ventilation is the amount of fresh air that should be supplied to the room per 1 person per hour so that the CO 2 content does not exceed the permissible level (0.07% or 0.1%).

The required ventilation rate is a number indicating how many times within 1 hour the indoor air must be replaced by outside air so that the CO 2 content does not exceed the permissible level.

Ventilation can be natural or artificial

Natural ventilation means the exchange of indoor air with outside air through various cracks and leaks present in window openings, etc., and partly through the pores of building materials (the so-called infiltration), as well as through vents and other openings arranged to enhance natural air exchange. In both cases, air exchange occurs mainly due to the difference in temperature between outside and indoor air and wind pressure.

The best device for ventilating a room are transoms placed at the top of the windows; they reduce the pressure of the wind and the currents of cold air passing through them enter the area where people are already moved with the warm air of the room. The minimum ratio of the window area to the floor area required to ensure sufficient ventilation is 1: 50, i.e. with a room area of ​​50 m2. THE AREA OF THE WINDOWS MUST be at least 1m2.

In public buildings with large crowds of people, as well as in rooms with increased air pollution, natural ventilation alone is not enough and, moreover, in the cold season it cannot always be widely used due to the danger of the formation of cold air currents. Therefore, in a number of rooms, artificial mechanical ventilation is installed, which does not depend on temperature fluctuations in the outside air and wind pressure, providing the possibility of heating the outside air. It can be local - for one room and central - for the entire building. With local ventilation, harmful impurities are removed directly from the place of their formation, and with general ventilation, the air of the entire room is exchanged.

The air entering the room is called supply air, and the air removed is called exhaust air. A ventilation system that only supplies clean air is called supply air, and one that only removes polluted air is called exhaust.

Supply and exhaust ventilation simultaneously supplies clean air and removes polluted air. Typically, air supply is indicated by a (+) sign, and exhaust air by a (-) sign.

Inflow and exhaust can be balanced: either with a predominance of inflow or exhaust.

To combat steam formation, ventilation is arranged with a predominance of exhaust over inflow. In operating rooms and maternity rooms, inflow prevails over exhaust. This achieves a greater guarantee of keeping the air in operating rooms and maternity rooms clean, since with such an organization the air from them flows into adjacent rooms, and not vice versa,

The following hygienic requirements apply to ventilation systems and installations:

Ensure the necessary air purity;

Do not create high and unpleasant air speeds;

Maintain, together with heating systems, the physical parameters of the air - the required temperature and humidity;

Be trouble-free and easy to use;

Work smoothly;

Be silent and safe.

The criteria that determine the required air exchange vary depending on the purpose of the room. For example, to calculate the ventilation of baths, showers, and laundries, permissible temperature values ​​and moisture content in the air are used. To calculate the ventilation of dwellings, they use the values ​​of carbon dioxide in the air, as well as anthropotoxins, but they have not been widely used due to the difficulty of their determination.

M. Pettenkofer proposed to consider the hygienic standard for CO 2 content to be 0.07%, K. Flugge - -0.1%, O.B. Elisova - 0.05%. The CO 2 value in residential air of 0.1% is still generally accepted for assessing the degree of air pollution from the presence of people. Carbon dioxide accumulates indoors as a result of the vital activity of the body in quantities that are directly dependent on the degree of air pollution by other indicators of human metabolism (decomposition products of dental plaque, water vapor, etc., which make the air “stale, residential” and adversely affect people on their well-being).

It is noted that air acquires such qualities at a CO 2 concentration of more than 0.1%, although these CO 2 concentrations in themselves do not have a harmful effect on the body.

Since the concentration of CO 2 in the air is much easier to determine than the presence of volatile compounds (anthropotoxins), therefore, in sanitary practice it is customary to assess the degree of air pollution in residential and public buildings by the concentration of CO 2.

Particular attention is paid to the organization of ventilation in kitchens and sanitary facilities. Insufficient air exchange or improperly functioning exhaust ventilation often leads to deterioration of the air composition not only in these rooms, but also in living rooms.

When checking the effectiveness of ventilation, it is first necessary to evaluate:

Air condition: temperature, humidity, presence of harmful fumes, microorganisms, accumulation of carbon dioxide in the inspected premises;

Ventilation volume - i.e. the amount of air supplied or removed by ventilation devices in m 3 per hour. This indicator is assessed taking into account the number of people in the premises, its volume, the source of air pollution and depends on the speed of air movement and the cross-sectional area of ​​the channel.

3. Ventilation rate - an indicator indicating how many times the air in the examined premises is exchanged within an hour. For residential premises, the multiplicity factor should be 2-3, because Less than 2 times will not meet the need for an air cube per person, and more than 3 times will create excess air speed.

TYPES OF VENTILATION

ARTIFICIAL

1.Local - a) Supply (+)

b) Exhaust(-)

2. General exchange - a) Exhaust (-)

b) Supply and exhaust (+ -)

c) Supply (+)

3. Air conditioning - a) Central

b) Local

NATURAL

1. Unorganized (infiltration)

2. Organized (aeration)

Air exchange rate in hospital premises (SNiP-69-78)

To determine the rate of air exchange in a room with natural ventilation, it is necessary to take into account the cubic capacity of the room, the number of occupants V it people and the nature of the conducted V no work. Using the above data, the natural air exchange rate can be calculated using the following three methods:

1. In residential and public buildings, where changes in air quality occur depending on the number of people present and household processes associated with them, the calculation of the required air exchange is usually made based on the carbon dioxide emitted by one person. The volume of ventilation based on carbon dioxide is calculated using the formula:

L = K x n / (P - Ps) (m 3 / h)

L is the required volume of ventilation, m3; K is the volume of carbon dioxide released by 1 person per hour (22.6 l); n - number of people in the room; P - maximum permissible carbon dioxide content in indoor air in ppm (1% or 1.0 l/m3 of cubic air); Ps - carbon dioxide content in atmospheric air (0.4 ppm or 0.4 l/m3)

The volume of required ventilation air per person is 37.7 m3 per hour. Based on the ventilation air standard, the dimensions of the air cube are determined, which in ordinary residential premises should be at least 25 m 3 when calculated per adult. The necessary ventilation is achieved with a 1.5-fold air exchange per hour (37.7:25 = 1.5).

Purpose of the lesson:studying methods for determining the content of certain chemical pollutants in indoor air and assessing the degree of air pollution in accordance with hygienic standards.

In preparation for the lesson, students must work through the following: theoretical issues.

1. Chemical composition clean atmospheric air and the physiological and hygienic significance of its components.

2. The main sources of atmospheric air pollution, the composition of atmospheric pollution in cities. The influence of atmospheric pollution on sanitary living conditions and public health.

3. Hygienic regulation of atmospheric air pollution.

4. Anthropogenic indoor air pollution. Sanitary indicators of indoor air pollution. Maximum concentrations of CO2 in non-production premises.

5. Preventive measures to reduce air pollution levels.

After mastering the topic the student must know:

Methodology for air sampling, analysis, determination of the degree of pollution harmful substances air in pharmacy premises and production premises of chemical and pharmaceutical enterprises;

be able to:

Assess research results for compliance with hygienic standards;

Assess the working conditions of pharmacy staff when exposed to chemical factors based on the results of a sanitary and hygienic examination and laboratory tests;

Use basic regulatory documents and reference information sources to organize control over the content of harmful substances in the air of pharmaceutical

new premises and the development of preventive measures to reduce the level of air pollution in pharmacy premises and production premises of chemical and pharmaceutical enterprises.

Training material for completing the assignment

One of the main human habitats is the atmosphere. Clean atmospheric air at the Earth’s surface is a physical mixture various gases: 78.1% nitrogen, 20.93% oxygen, 0.03-0.04% carbon dioxide and up to 1% other inert gases (argon, neon, helium, krypton, xenon, radon, actinon, thoron). The main reasons for changes in the gas composition of the atmosphere is the entry into the air of so-called small impurities, the content of which in the atmosphere is many times less than the main gases (nitrogen and oxygen). In the conditions of a modern large city, pollution is concentrated mainly in the ground layer up to 1-2 km high, and in medium-sized cities - in a layer hundreds of meters thick. Sources of air pollution can be natural or natural (dust storms, volcanic eruptions, forest fires, weathering) and anthropogenic or artificial (industrial enterprises, transport, thermal power plants, agriculture), the flow of pollution from which is often continuous and increasing. Pollution in atmospheric air are present in various states of aggregation: in the form of solid suspended particles (aerosols), in the form of vapor, liquid droplets and gases. Most often, atmospheric air is polluted with carbon monoxide and dioxide, nitrogen oxides, sulfur oxides and other sulfur compounds (hydrogen sulfide, carbon disulfide), hydrocarbons, aldehydes, ozone, ash, soot. Highly toxic substances are found in the air that actively interact with components of the atmosphere and biosphere: lead, arsenic, mercury, cadmium, phenol, formaldehyde. In recent decades, biotechnology enterprises have begun to occupy a significant role in air pollution, the air emissions of which contain organic dust consisting of viable microorganisms, final and intermediate products of microbiological synthesis (including antibiotics, amino acids, proteins). In addition, there is soil and household dust in the air, the amount of which is determined by the nature of the soil, the degree of improvement of the city territory and the weather. Dust resistance in

air and the effectiveness of methods for its collection and removal are determined by such physical properties of dust as dispersion, flowability, hygroscopicity, electrical charge, etc.

The formation of charged particles in the air occurs as a result of the natural process of splitting gas molecules and atoms under the influence of cosmic rays, radionuclides from soil, water, air, as well as short-wave ultraviolet radiation from the Sun. Light positive or negative air ions are formed when gas molecules attach to charged particles. By settling on mechanical particles (dust particles) and microbes contained in the air, light air ions become medium, heavy and super-heavy. The ionization regime of the air environment is determined by the ratio of the number of heavy air ions to the number of light ones (N/n) and the unipolarity coefficient (n+/n -) - the ratio of the number of positive air ions to the number of negative ones. The higher this coefficient, the more polluted the air. The range of the permissible level of the unipolarity coefficient is in the range of 0.4-1.0. Charged dust particles remain in the air longer and are retained in the respiratory tract 2 times more intensely than neutral ones. The concentration of air ions of both polarities is defined as the number of air ions in 1 cm 3 of air (e/cm 3) and in unpolluted air should be at least 400-600 e/cm 3. Phytoncides released by some plants (geranium, buckwheat, white acacia, red oak, willow) help increase the concentration of light air ions in the air.

Increasing atmospheric pollution (dynamic anthropogenic denaturation of nature) leads to adverse consequences in the environment: toxic photochemical fogs; ozone holes, i.e. a decrease in the amount of ozone over limited areas of the Earth; the so-called greenhouse effect, i.e. global warming climate due to an increase in the concentration of greenhouse gases in the atmosphere (carbon dioxide, methane, nitrogen oxides, ozone, freons), which prevent thermal radiation from the surface layers of the atmosphere; acid rain.

A hygienic assessment of the degree of air pollution is given based on a comparison of the results of air analyzes with maximum permissible concentrations (MPC) of chemicals in the atmospheric air. There are maximum one-time MPC (MPCmr) and average daily MPC (MPCss) of chemicals, including aerosols for atmospheric air and non-industrial air.

premises [Hygienic standards “Maximum permissible concentrations (MAC) of pollutants in the atmospheric air of populated areas” GN 2.1.6.1338-03] (Table 4). The maximum one-time MPC is used to assess atmospheric pollution during periods of short-term increases in concentrations; the average daily MPC is used as a hygienic standard for long-term intake of atmospheric pollution into the body.

Table 4.Maximum permissible concentrations of chemicals in atmospheric air (extracts from GN 2.1.6.695-98)

In operation regulatory document 3 dust standards are given depending on the level of silicon dioxide content in it. MPC of inorganic dusts in atmospheric air with a SiO 2 content of more than 70% - 0.05 mg/m 3, from 70 to 20% - 0.1 mg/m 3, less than 20% - 0.15 mg/m 3. The maximum permissible concentrations of dust in the atmospheric air of settlements are differentiated taking into account the harmfulness and danger of dust to human health, depending on the content of a specific component in it.

IN pharmacies and at enterprises of the chemical and pharmaceutical industry, the air of production premises and atmospheric air can be polluted by vapors and aerosols of drugs, intermediate and by-products of synthesis, as well as auxiliary substances (fillers, sweeteners, leavening agents, emulsifiers, etc.) used in the production and processing process medicinal products, when weighing, transporting, loading and unloading equipment, packaging and dosing of medicinal substances.

Medicines and waste from chemical and pharmaceutical enterprises are a specific factor in industrial and environmental pollution, which has a number of features, such as high stability, increasing their level of danger, large differences in production volume and amount of emissions into the atmosphere (from several kg to tens of tons per year ), predominant state of aggregation in the form of fine aerosols in the air working area and atmospheric air of populated areas. Medicines often represent a complex of several ingredients, which requires special methodological approaches when assessing their danger.

Changes in chemical composition and physical properties atmospheric air lead to disruption of human health and various negative consequences in environmental objects. Depending on the characteristics of the release into the atmospheric air and the biological effect of its components, atmospheric pollutants can have acute and chronic resorptive impact on human health, as well as reflexive and irritating action. Acute exposure to atmospheric air pollution manifests itself only in special situations (for example, during accidents at industrial enterprises or in the case of toxic fogs) and is a provoking factor in the exacerbation of chronic cardiovascular, pulmonary, allergic (bronchial asthma) diseases and an increase in overall morbidity and mortality from chronic diseases. diseases. The chronic resorptive effect of urban air pollution on public health is the most common and unfavorable. It can be specific when the pollution component is an etiological factor for health problems (for example, when air is polluted with beryllium compounds, cases of specific berylliosis are observed in the population

Specific pulmonary granulomatosis, in which the diffusion capacity of the lungs is impaired and hypoxia develops secondarily). Some impurities in atmospheric air can have carcinogenic and sensitizing effects. Chronic nonspecific exposure to atmospheric air pollution causes a weakening of the body’s immunoprotective properties and disorders physical development children, increases the incidence of infectious and non-infectious diseases, contributes to the exacerbation of various chronic diseases: bronchitis, emphysema, dermatitis, conjunctivitis, acute respiratory diseases.

The reflex and irritating effects of atmospheric air pollution are manifested by various reflex reactions (cough, nausea, headache). In addition, atmospheric pollution reduces the general sanitary living conditions of the population, worsens the microclimate and light climate, contributes to the death of plants and animals, destroys concrete and metal structures, and causes great economic damage.

It must be taken into account that several different chemical substances can be present in the air at the same time, which have a joint effect on the body. If the same body system is exposed to the combined action of chemical factors, then an interdependent action takes place, which can manifest itself as synergy(increased influence in case of unidirectional action) or how antagonism(reduced effect with multidirectional action). With independent simultaneous action of chemicals, it appears additive Effect (summation effect). Finally, with the combined action of factors of different nature, a new effect may appear (coalitional), not inherent in any of the factors when they are influenced separately.

To assess the level of atmospheric air pollution with the simultaneous presence of several substances in the atmospheric air in the case of not exceeding the MPC level, the sum of the ratios of the concentrations of each substance to its MPC should not exceed one:

C1/MPC1 + C2/MPC2 +...-+ Cn/MPCn<1,

Where: C\, C 2, S p- actual concentrations of substances in the atmospheric air;

MAC1, MAC2, MACn - MAC of the same substances in atmospheric air.

In conditions of the same degree of exceeding the MPC level, taking into account the fact that the severity of biological effects when exposed to substances of different hazard classes is different, to assess the real degree of danger of multi-component air pollution, it is necessary to use the coefficients of the excess of the MPC for substances of the 3rd class: 1.7, 1 .3, 1.0, 0.9, respectively, for substances of 1, 2, 3, 4 hazard classes. From here, the calculation of the complex indicator of air pollution (K) is calculated using the formula:

The “K” indicator is used in methodological documents of the sanitary-epidemiological service, and in the documents of the Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet) a similar indicator is used as a criterion for the level of air pollution in settlements - comprehensive air pollution index (CIPA). KIZA is used for ongoing observation (monitoring) and analysis of the dynamics of atmospheric air composition over time. The level of air pollution is considered low when the CIZA is below 5, elevated from 5 to 6, high from 7 to 13, and extremely high when the CIZA is equal to or above 14. The annual reports of Roshydromet note the cities with the highest levels of air pollution (CIZA >14) . Usually these are cities that host large enterprises of non-ferrous and ferrous metallurgy, oil refining, petrochemical and chemical industries, and large energy facilities.

A person can exist without air for no more than 5 minutes. A person's daily need for air is 12 m 3 (about 15 kg). But a person is forced to breathe only with the atmospheric air that is available at the place of his stay, and at the same time there is a constant, round-the-clock flow of air pollutants into the air.

organism, a person is not free to interrupt this process. Therefore, protecting the atmospheric air of settlements from adverse technogenic influences and preventing its possible pollution in order to protect both public health and the environment in the broad sense of the word is an acute socially determined problem.

Atmospheric air protection is a system of measures aimed at reducing the anthropogenic impact on atmospheric air, ensuring the preservation of health and a favorable living environment, and also taking into account economic aspects. This system is divided into technological, aimed at maximizing the reduction of harmful emissions into the atmosphere, sanitary, used to reduce the harmfulness of emissions or purify them, planning, implementing spatial removal of the emission source from the human environment, and administrative actions that contribute to the timely implementation of all the above activities. TO technological measures include replacing energy sources with less harmful ones, raw materials with less toxic ones, Preliminary processing fuel or raw materials in order to reduce harmful emissions, improve technological process to reduce the volume of emissions or their harmfulness (use of wet technological processes instead of dry ones), sealing of technological equipment and equipment. Sanitary activities include physical methods collecting dust (aerosol), smoke, fog droplets or splashes using special structures: cyclones, multicyclones, wet scrubbers, fabric filters, electric precipitators, as well as chemical methods purification of atmospheric air due to adsorption by liquid or solids or the use of catalytic converters. Planning measures include functional zoning of the territory of settlements taking into account the wind rose, their improvement (landscaping, watering, asphalt paving of streets), rational planning of residential areas, organization of traffic lightless traffic intersections through the construction of underground tunnels, overhead overpasses, construction of bypass or ring roads to exclude transit traffic flows through urban areas, organization of sanitary protection zones.

The system of monitoring and monitoring of atmospheric air is carried out in our country by Roshydromet based on the requirements of GOST 17.2.3.01-86 “Nature conservation. Atmosphere. Rules for monitoring air quality in populated areas" and RD 52.04 186-89 "Guidelines for the control of air pollution." Basic requirements for the protection of atmospheric air, i.e. ensuring that atmospheric air quality standards are not exceeded in accordance with sanitary and hygienic standards and rules are set out in the Federal Laws: “On the Protection of Atmospheric Air” and “On the Sanitary and Epidemiological Welfare of the Population.” The executive authority in the field of atmospheric air protection is the Federal Service for Ecology and Natural Resources Management (Rosprirodnadzor), which records facilities that have a harmful effect on the atmospheric air, organizes and conducts state environmental assessment of industrial facility projects, subject to the availability of a sanitary and epidemiological conclusion on the project. Providing sanitary and epidemiological supervision over the protection of atmospheric air in populated areas is the main task of the State Sanitary Epidemiological Supervision, which is part of the Federal Service for Surveillance in the Sphere of Consumer Rights Protection and Human Welfare, which builds its work on the basis of SanPiN 2.1.6.1032-01 “Hygienic requirements for quality assurance atmospheric air of populated areas." The main provision of SanPiN is the prohibition of the placement, design, construction and commissioning of facilities whose emissions contain substances that do not have approved hygienic standards (MPC or OBUV). Important stages sanitary and epidemiological supervision are: participation in the selection of a site for the construction of an object, participation in the development of the project of the object and its examination and the project for the organization and improvement of the sanitary protection zone, supervision of compliance with hygienic requirements for the protection of atmospheric air at the stage of construction of the object and its commissioning . SanPiN includes issues related to the organization of industrial control of air pollution, the results of which must be submitted to the sanitary-epidemiological service within the established time frame.

Air sampling for analysis

The methods for taking air samples are varied, which is determined by the specifics chemical analysis analyte. They are divided into two groups: dynamic and instantaneous.

Analysis of atmospheric air and indoor air can be carried out in samples that are taken once to detect maximum concentrations, for example, at the time of the greatest emission of pollutants, on the leeward side of the source of pollution, as well as in average daily samples, when air is taken continuously for a day or at least 4 times a day at equal intervals with averaging of the data obtained. The duration of sampling (no more than 15-20 minutes) depends on the sensitivity of the method and the content of harmful substances in the air. It is customary to take air samples for analysis in the breathing zone of an adult, i.e. at a height of 1.5 m from the floor. If a relatively small volume of air is required for analysis, samples are taken into gas pipettes, calibrated bottles, rubber chambers or plastic bags. When selecting large quantities of air, it is passed using an aspiration device (water or electric aspirator) through special absorbers or filters that retain the gas or aerosol being tested. The rate of air intake in the electric aspirator is determined on a rheometer scale, calibrated in liters per minute (l/min): two rheometers (from 0 to 3 l/min) are used to take air samples to determine the gas content in it, two more rheometers ( from 0 to 20 l/min) - for taking air samples to determine the dust content in it. Depending on the method of chemical analysis, solid sorbents ( Activated carbon, silica gel, graphite, kaolin), polymer sorbents (porapak, polysorb, chromosorb, tenax), absorption solutions; various filters (AFA) are used to determine highly dispersed aerosols (smoke, mists, dust) in the air.

Air samples are taken in various temperature conditions, therefore, to obtain comparable research results, its volume must be brought to normal conditions, i.e. to a temperature of 0? C and a barometric pressure of 760 mm Hg. The calculation is carried out according to the formula:

V 0= / [(273 + t?) 760],

where: V) is the volume of air at t?= 0?С and IN= 760 mmHg; V 1- volume of air taken for analysis; B- Atmosphere pressure, mmHg.;

t?- air temperature at the time of air sampling, ? C; 273 - gas expansion coefficient.

Hygienic characteristics of air in residential and public buildings

The main sources of indoor air pollution are atmospheric air entering the room through window openings and leaks in 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 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 air ducts, heaters and filters of supply ventilation systems or air conditioners, as a result of the absorption of light air ions during the breathing process of people, adsorption by their skin and clothing, as well as conversion account

light air ions into heavy ones due to their deposition on particles of dust floating in the air. Air ionization is of hygienic importance, since a change in the ionization regime, i.e. The ratio of light and heavy air ions can serve as a sensitive indicator of the sanitary state of indoor air (Table 5).

Table 5.Standard values ​​for indoor air ionization in public buildings

A high degree of ionization due to an increase in the amount of light negative air ions has a beneficial effect on people’s well-being and increases their performance. The predominance of heavy positive air ions over light negative ions, which is typical for stuffy, dusty rooms, causes drowsiness, headaches, and decreased mental performance.

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 in indoor air varies in chemical composition and origin. The sorption capacity of dust particles contributes to an increase in the entry into the respiratory tract of chemicals migrating into the air from construction and finishing materials. Dust is a factor in the transmission of infectious diseases through aerosol propagation and bacterial infections (for example, tuberculosis). Dust containing mold fungi of genera Penicillium And Mukor, causes allergic diseases.

Impact various factors on a person indoors can cause problems with his health, i.e. “building-related diseases” 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 organs, dry cough, dry and itchy skin, weakness, nausea, increased fatigue, sensitivity to odors), occurring in specific rooms and almost completely disappearing 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. Chemical and biological air pollution contributes to the development chronic fatigue syndrome (immune dysfunction syndrome), those. a feeling of severe fatigue, observed for at least 6 months and combined with impaired short-term memory, disorientation, speech impairment and difficulty performing counting operations. Multiple chemical sensitivity syndrome, characterized by disruption of the body’s adaptation to the action of various factors against the background of hereditary or acquired sensitivity to chemicals, most often develops in people who have had acute poisoning with chemicals in the past (organic solvents, pesticides and irritants).

Changes in the physical and chemical properties of air adversely affect a person’s well-being and performance. The presence in the air of residential and public premises of a huge number of biologically active chemical substances in a variety of concentrations and constantly changing combinations that worsen the properties of air makes it impossible to determine each of them separately and forces the use of an integral indicator of air pollution. Air quality is usually assessed indirectly by the integral sanitary indicator air purity - carbon dioxide content (Pettenkofer index), and use its concentration in the premises as the maximum permissible standard (MAC) - 1,0 %Withor 0.1%(1000 cm 3 in 1 m 3). Carbon dioxide is constantly released into the air of closed rooms

tion 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 accumulated in the air along 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.

Laboratory work “Assessment of the content of dust and certain chemicals in indoor air”

Student assignments

1. Familiarize yourself with the samples of absorption devices, filters available in the training room, the design and principles of operation of devices used for taking air samples for gases and dust (electric aspirator with rheometers).

2. Calculate the dust content of the air in the room using the gravimetric aspiration method, using the data of the situational problem, and give a conclusion about the degree of dust content in the air, comparing the obtained calculated data with the relevant standards.

3. Conduct an air analysis to determine the content of carbon monoxide, sulfur dioxide, and ammonia. Give a hygienic conclusion on the degree of air pollution by comparing the concentrations of these substances with the corresponding hygienic standards.

4. Determine the concentration of carbon dioxide in the air of the classroom using the express method. Give a hygienic conclusion about the cleanliness of indoor air according to the integral sanitary indicator (CO 2) by comparing the concentration of CO 2 with the corresponding hygienic standard. Develop measures to reduce the level of air pollution in the room under study.

Working method

1. Determination and assessment of air dust content Methods for determining air dust levels are divided into two groups:

based on the separation of the dispersed phase (dust particles) from the dispersion medium (air): sedimentation (weight and counting), aspiration (weight and counting);

Without separation of the dispersed phase: optical, photometric, electrometric.

Determination of dust content in the air is most often carried out using the aspiration weight (gravimetric) method. The method is based on collecting dust from the air sucked through the filter at an aspiration rate of 10-20 l/min.

Progress.A non-hygroscopic aerosol filter (AFA), made of special fabric FPP-15, is weighed together with a paper ring on an analytical balance with an accuracy of 0.0001 g and secured in a metal or plastic allonge (cartridge) using a screw-on ring. Pass the air through the filter for 5-10 minutes using an aspirator equipped with a rheometer that allows you to regulate the aspiration rate. In educational research conditions, it is enough to take a sample for 2-5 minutes at a speed of 10-20 l/min. Carefully remove the filter from the cartridge and reweigh it on an analytical balance. The original weight of the filter is subtracted from the weight of the filter after sampling. The volume of air drawn in is calculated by multiplying the aspiration rate (in l/min) by the sampling time in minutes.

The amount of dust is calculated using the formula:

X= [(L 2 -L 1) 1000] / V

Where: X- air dust content, mg/m3;

A2 - weight of the filter with dust after sampling, mg;

A 1- weight of the filter before sampling, mg; V- volume of drawn air, l.

2. Methods for determining the content of certain chemicals in indoor air

To analyze selected air samples in sanitary laboratories of industrial enterprises, various methods are used: optical, electrochemical, chromatographic. To quickly determine the degree of air pollution with harmful substances, express methods are used. Express studies are carried out by colorimetry of solutions using standard scales or using reagent paper and indicator tubes. These methods are almost always based on color reactions.

*Express method for determining the concentration of sulfur dioxide (sulfur dioxide)

Sulfur dioxide (SO2) is a colorless gas with a pungent, irritating odor. It is the most common air pollutant. The main sources of SO2 pollution are thermal power plants (CHPs, state district power plants, boiler houses) and vehicle emissions. As a result of the reaction of SO 2 with water vapor present in the atmospheric air, sulfuric acid is formed, which under certain conditions falls in the form of an aerosol as part of “acid rain”. SO 2 increases the overall prevalence of respiratory diseases of non-infectious and infectious nature, causes the development of chronic rhinitis, pharyngitis, chronic bronchitis, often with asthmatic components, inflammation of the auditory canal and eustachian tube.

Principle of the method - reduction of iodine with sulfur dioxide to HI. Progress. Pour 1 ml of an absorption solution consisting of a mixture of 0.0001 N into the Polezhaev absorber. iodine solution with starch. Using an electric aspirator, draw air from the bottle through the absorber at a speed of 10 ml/min (at this speed you can easily count the air bubbles passing through the absorption solution) until the color of the absorption solution disappears. Determine the volume of air passing through the absorber by multiplying 10 ml/min by the aspiration time in minutes. The concentration of SO 2 in the air is determined from the table. 6.

Table 6.Dependence of sulfur dioxide concentrations on the volume of air decolorizing the absorption solution

Determination of ammonia concentration in air Ammonia (NH3) is a colorless gas with a pungent odor. Anthropotoxin from residential and public premises enters the air with emissions from industrial enterprises, livestock farms. Ammonia has an irritating effect on the mucous membranes of the upper respiratory tract and eyes, causing coughing attacks, lacrimation and pain in the eyes, dizziness and vomiting.

Progress.Add 5 ml of 0.01 N into an absorption vessel with a porous plate. H2SO4 solution and connect to the bottle with the air being analyzed. Then take a sample using an electric aspirator for 5 minutes at a speed of 1 l/min. Add 5 ml of the solution from the absorption vessel into a test tube and add 0.5 ml of Nessler’s reagent, shake and after 5-10 minutes photometer in cuvettes with a layer thickness of 10-20 mm with a blue filter, comparing with the control, which is prepared simultaneously and similarly try. When ammonia reacts with Nessler's reagent, a compound colored yellow-brown is formed. The color intensity is proportional to the amount of ammonium ions. The ammonia content in the analyzed volume is determined using a previously constructed calibration graph. To construct a calibration graph, prepare a scale of standards according to table. 7.

Table 7.Standard scale for determination of ammonia

Process all scale tubes in the same way as samples, measure optical density and plot a graph. The standard scale can also be used for visual determination; it is prepared in colorimetric tubes simultaneously with the samples.

WITH= A/ V,

Where: A- amount of ammonia in the analyzed sample volume, µg; V- volume of air selected for analysis, l.

Express method for determining the concentration of sulfur dioxide (carbon dioxide) in indoor air

Carbon dioxide (CO 2) is a colorless, odorless gas, 1.5 times heavier than air. Carbon dioxide is released into the air as a result of the natural processes of respiration of people and animals, the oxidation of organic substances during combustion, fermentation, and decay. In addition, significant amounts of carbon dioxide are formed as a result of the operation of industrial enterprises and vehicles that burn huge amounts of fuel. Along with the processes of formation in nature, there are processes of assimilation of carbon dioxide - active absorption by plants during photosynthesis and leaching of CO 2 by precipitation. An increase in carbon dioxide content to 3% causes shortness of breath, headache, and decreased performance. Death can occur at CO2 levels of 8-10%. CO 2 content - sanitary indicator, which evaluates the degree of cleanliness of indoor air. Express method of determination

the concentration of CO 2 in the air is based on the reaction of carbon dioxide with a soda solution.

Progress.In a glass syringe graduated to 100 ml, add 20 ml of a 0.005% solution of soda with pink phenolphthalein, and then draw 80 ml of air into the same syringe (up to the 100 ml mark) and shake for 1 minute.

Table 8.Dependence of CO content 2 in the air from the volume of air decolorizing 20 ml of 0.005% soda solution

If the solution has not become discolored, carefully squeeze out the air from the syringe, leaving the solution in it, draw in the same portion of air again and shake it for another 1 minute. If after shaking the solution does not become discolored, this operation should be repeated several more times until the solution is completely discolored, adding air in small portions, 10-20 ml, each time shaking the syringe for 1 minute. Having calculated the total volume of air that passed through the syringe and discolored the soda solution, determine the concentration of CO 2 in the room air according to the table. 8.

Sample protocol for completing the laboratory task “Assessing the content of dust and certain chemicals in indoor air”

1. Determination and assessment of dust content in indoor air (situational task).

Filter weight before sampling, mg (A1) ...

Weight of the filter with dust after sampling, mg (A 2). Calculation of the amount of dust using the formula: ...

Hygienic assessment of the degree of dust content in the air based on comparison of the results of air analyzes with the maximum permissible concentration of aerosol in the air.

Conclusion(sample).

1. The analysis showed that the air in the room contains: mg/m 3 of dust, which is below or exceeds the maximum permissible concentration of dust (maximum one-time or average daily). It is necessary to indicate measures to reduce dust in the air in the room (for example, carry out regular wet cleaning of the room, etc.).

2. Determination of carbon dioxide concentration in a room using the express method:

Volume of air decolorizing 20 ml of 0.005% soda solution.

The amount of CO 2 in the room air (Table 8).

Hygienic assessment of the degree of indoor air pollution based on comparison of CO 2 concentration with the maximum permissible concentration of CO 2 in indoor air.