Carbon dioxide is an invisible danger. The effect of carbon dioxide concentration on the human body

Main components atmospheric air are oxygen (about 21%), nitrogen (78%), carbon dioxide (0.03-0.04%), water vapor, inert gases, ozone, hydrogen peroxide (about 1%).

Oxygen is the most component air. With its direct participation, all oxidative processes in the human and animal body proceed. At rest, a person consumes about 350 ml of oxygen per minute, and during heavy physical work, the amount of oxygen consumed increases several times.

The inhaled air contains 20.7-20.9% oxygen, and the exhaled air contains about 15-16%. Thus, the tissues of the body absorb about 1/4 of the oxygen present in the composition of the inhaled air.

In the atmosphere, the oxygen content does not change significantly. Plants absorb carbon dioxide and break it down to absorb carbon, while the released oxygen is released into the atmosphere. The source of oxygen formation is also the photochemical decomposition of water vapor in upper layers atmosphere under the influence ultraviolet radiation sun. Mixing is also important in ensuring a constant composition of atmospheric air. air currents in the lower layers of the atmosphere. The exception is hermetically sealed rooms, where, due to the long stay of people, the oxygen content can significantly decrease (submarines, shelters, pressurized aircraft cabins, etc.).

For the body importance has a partial pressure * of oxygen, and not its absolute content in the inhaled air. This is due to the fact that the transition of oxygen from the alveolar air to the blood and from the blood to the tissue fluid occurs under the influence of a difference in partial pressure. The partial pressure of oxygen decreases with increasing elevation above sea level (Table 1).

Table 1. Partial pressure of oxygen on different heights

Great importance has the use of oxygen for the treatment of diseases accompanied by oxygen starvation (oxygen tents, inhalers).

Carbon dioxide. The content of carbon dioxide in the atmosphere is fairly constant. This constancy is explained by its circulation in nature. Despite the fact that the processes of decay and the vital activity of the organism are accompanied by the release of carbon dioxide, a significant increase in its content in the atmosphere does not occur, since carbon dioxide is absorbed by plants. At the same time, carbon goes to the construction of organic substances, and oxygen enters the atmosphere. Exhaled air contains up to 4.4% carbon dioxide.

Carbon dioxide is a physiological causative agent of the respiratory center, therefore, during artificial respiration, it is added in small quantities to the air. AT large quantities it can have a narcotic effect and cause death.

Carbon dioxide also has hygienic significance. According to its content, the purity of the air in residential and public premises (i.e., premises where people are located) is judged. When people accumulate in poorly ventilated rooms, in parallel with the accumulation of carbon dioxide in the air, the content of other human waste products increases, the air temperature rises and its humidity increases.

It has been established that if the content of carbon dioxide in the indoor air exceeds 0.07-0.1%, then the air acquires bad smell and can disrupt the functional state of the body.

The parallelism of changes in the listed properties of air in residential premises and an increase in the concentration of carbon dioxide, as well as the simplicity of determining its content, make it possible to use this indicator for hygienic assessment of air quality and the efficiency of ventilation in public premises.

nitrogen and other gases. Nitrogen is the main integral part atmospheric air. In the body, it is in a dissolved state in the blood and tissue fluids, but does not take part in chemical reactions.

At present, it has been experimentally established that, under conditions of high pressure, air nitrogen causes in animals a disorder of neuromuscular coordination, subsequent excitation and a narcotic state. Researchers observed similar phenomena in divers. The use of a helium-oxygen mixture for divers' breathing makes it possible to increase the depth of descent to 200 m without pronounced symptoms of intoxication.

During electrical lightning discharges and under the influence ultraviolet rays the sun in the air produces a small amount of other gases. Their hygienic value is relatively small.

* The partial pressure of a gas in a mixture of gases is the pressure that a given gas would produce if it occupied the entire volume of the mixture.

Loss of strength, weakness, headache, depression - is this condition familiar? Most often this happens in autumn and winter, and poor health is attributed to a lack of sunlight. But it's not about him, but about the excess carbon dioxide in the air you breathe. The situation with the level of CO₂ in residential premises and transport in our country is truly catastrophic. stuffiness, high humidity and mold are also the result of a lack of ventilation. Sealed plastic windows And the air conditioners only make matters worse. Do you know that with a twofold excess (relative to the street background) of the level of carbon dioxide in the air, brain activity decreases by 2 times? By the way, yawning students at lectures are an indicator of high CO₂ content in the classroom. And very often there is no ventilation in office buildings. What productivity can we talk about if a person simply does not have brains?

So let's start with the basics. A person breathes in oxygen and releases carbon dioxide. Carbon dioxide is also released when hydrocarbons are burned. Middle level CO₂ on our planet is currently about 400 PPM (Parts per million - parts per million, or 0.04%) and is constantly growing due to the constant increase in the consumption of petroleum products. At the same time, it is worth knowing that trees absorb carbon dioxide and this is precisely their main function (and not, as it is mistakenly believed that they only produce oxygen).

As long as a person is outdoors, there are no problems, but they begin when he is indoors. If a person is locked in a sealed room without fresh air, then he will die not from a lack of oxygen, as most people mistakenly believe, but from a multiple excess of carbon dioxide, which this person himself developed in his lungs. Let's set aside the problems of ventilation of public transport (I will write about this separately) and turn our attention to city apartments / country houses, in which there is a massive lack of ventilation.

At the same time, a person spends at least a third of his life in his house / apartment, but in reality, half - you cannot save on your own health!

2. The problem of high CO₂ content in the air is especially relevant in the cold season, because In the summer, almost all windows are constantly open. And with the onset of cold weather, the windows are opened less and less, ultimately reducing to episodic ventilation. And, what a coincidence, it is in the cold season that depression, drowsiness and loss of strength appear.

3. Previously, there was even such a tradition - to seal the cracks on the windows before the cold weather. Often, together with window vents, they completely excluded the flow of fresh air into the house. I once again emphasize that fresh air is needed not because it contains the oxygen necessary for breathing, but in order to reduce the excess carbon dioxide content by replacing the air in the room.

4. Many people think that they also have a hood (in apartments, at least in the kitchen and in the bathroom), and the room will be ventilated through it. Yeah, in addition, installing plastic windows that are completely airtight. But how will the air go into the exhaust if you do not have an inflow in the form of either slots in the frames or an open window? And with good traction, it usually pulls air from the entrance.

5. It’s worse just to put the air conditioner in the form of a split system and use it when closed windows. Remember, when the air conditioner is running, DO NOT close the windows! Here is a modern hermetic country house, which has no gaps in the building envelope. And do not be led by stories that wood or aerated concrete "breathe" and therefore you can not give a damn about ventilation. Remember, this term refers to the high vapor permeability of the material, and not the ability to supply fresh outdoor air into the house.

6. Most are limited to a fan on the hood from the bathroom and kitchen. Okay, turn on the fan, all windows and doors are closed in the house. What will be the result? That's right, there will be a rarefaction in the house, because the new air has nowhere to come from. To natural ventilation work, fresh air must enter the house.

7. For measuring the level of carbon dioxide in the air, relatively affordable sensors with an NDIR sensor have now appeared. The non-dispersive infrared method (NDIR) is based on the change in the intensity of infrared radiation before and after absorption in an infrared detector with selective sensitivity. Initially, I was going to buy such a sensor on aliexpress last year (then it cost about $ 100), but the increased price due to the growth of the dollar made me think and look alternatives. Unexpectedly, this sensor was found in Russia under the Russian brand for the same $ 100 at last year's exchange rate. In total, on Yandex.Market I found the most profitable proposition and purchased a sensor at a price of 3500 rubles. The model is called MT8057. Of course, the sensor has an error, but it is not important when it comes to the fact that measurements with carbon dioxide concentrations exceeding several times the norm are important to us.

8. Closed plastic windows, air conditioners - all this is nonsense compared to the gas stove in the apartment (for the photo I lit gas burner, because to shoot the plate, it had to be washed).

9. So, all attention is on the chart. Kitchen 9 square meters, ceilings 3 meters high, opened door to the kitchen (!), a closed window, there is a hood with a natural impulse (draft is weak in summer), one person. The sensor is placed at a height of 1 meter from the floor, on dining table. The "normal" level of CO₂ in a room without people is about 600 PPM. One person comes - the level of CO₂ instantly rises. Leaves - falls. Comes again - rises again. And after that includes one (!) gas burner. The level of CO₂ almost instantly rises above 2000 PPM. Anxiety! We open the porthole. We observe how the concentration of carbon dioxide in the air slowly decreases. And add 1-2 more people here. Even if you do not turn on the gas stove, then 3 adults without doing hard physical work raise the CO₂ level in the room to a critical level in 30 minutes.

Cook for gas stove? Be sure to open the window and turn on the hood (do both at the same time).

Did you turn on the air conditioner? Be sure to open the window.

Are you just in the room? Be sure to open the hatch. And if there are a lot of people in the room, open the window.

And at night, during sleep, the window must be kept open.

In short, you either need to have an inlet ventilation duct, or a permanently open window.

10. As for trees and how they can be useful. Their most important function during growth is the absorption of carbon dioxide. Few people think about why firewood burns and where there is so much energy in them. So this energy in the form of carbon accumulates in the trunk of a tree as a result of the absorption of carbon dioxide. Trees produce oxygen as a byproduct of photosynthesis.

11. Opening a window in the warm season is not difficult and in general the problem is not so urgent in summer (except when using air conditioners with closed windows). Problems begin in winter, because no one keeps the window open all the time, this is a huge uncontrolled loss of heat and it will be corny cold. It is precisely at this moment that it is worth raising the alarm. Health is priceless.

The problem is very serious and has a global character. For example, until the fall of last year, I didn’t think at all about the importance of ventilation for health: what’s in the apartment, what’s in country house. If you look into the past, then it is regular autumn depressions, drowsiness and Bad mood during the cold season in a city apartment, they made me think in the direction of leaving the city and building, so to speak. in autumn-winter I had a headache and there was a general weakness of the body when I was in the city. But as soon as I went out into nature, the problem disappeared. I didn't write it off as a lack of sunlight, but that wasn't the point. In winter, I stopped keeping the window open (it’s cold) and I got a multiple excess of CO₂ in the apartment.

The simplest and affordable solution problems - constantly keep the window open, or ventilate, focusing on the indicators from the CO₂ sensor. A normal level of CO₂ in a room can be considered a concentration of up to 1000 PPM, if it is higher, it is urgent to ventilate. Humidity can be considered an indirect indicator of the high concentration of carbon dioxide in the air. If without objective reasons As the room temperature drops, the humidity starts to rise, which means that the CO₂ level also rises.

The danger of high concentrations of carbon dioxide in the air is that human body reacts with a very long delay. By the time you felt that it was stuffy in the room and you needed to ventilate it, you had already been in a room with a high content of CO₂ in the air for at least half an hour.

In the next post I will talk about what problems there are with ventilation in public transport(buses, trains, planes). I will also show you how to properly organize ventilation in a country house, which for some reason everyone forgets about.

To be continued.

Articles on the topic, for self-study.

ANNOTATION

In this paper, the influence of carbon dioxide concentration on the human body is considered. This topic is relevant due to the frequent violation of the level of comfortable concentration of CO 2 in enclosed spaces, as well as due to the lack of standards for carbon dioxide content in Russia.

ABSTRACT

In this paper, the effect of the concentration of carbon dioxide on the human body is considered. The actual topic is topical in connection with the frequent violation of the level of comfort of CO 2 concentration in enclosed premises, as well as in concentration with the absence in Russia of standards for the content of carbon dioxide.

Respiration is a physiological process that guarantees the course of metabolism. For a comfortable existence, a person must breathe air, consisting of 21.5% oxygen and 0.03 - 0.04% carbon dioxide. The rest is filled with a diatomic gas without color, taste and smell, one of the most common elements on Earth - nitrogen.

Table 1.

Parameters of oxygen and carbon dioxide content in various environments

At a concentration of carbon dioxide above 0.1% (1000 ppm), there is a feeling of stuffiness: general discomfort, weakness, headache, decreased concentration of attention. The frequency and depth of breathing also increase, bronchial constriction occurs, and at a concentration above 15%, a spasm of the glottis occurs. With a long stay in rooms with an excess amount of carbon dioxide, changes occur in the circulatory, central nervous, and respiratory systems; during mental activity, perception, working memory, and distribution of attention are disturbed.

Exist misconception that these are manifestations of lack of oxygen. In fact, these are signs advanced level carbon dioxide in the environment.

At the same time, carbon dioxide is essential for the body. The partial pressure of carbon dioxide affects the cerebral cortex, respiratory and vasomotor centers, carbon dioxide is also responsible for the tone of blood vessels, bronchi, metabolism, secretion of hormones, electrolyte composition of blood and tissues. This means that it indirectly affects the activity of enzymes and the rate of almost all biochemical reactions of the body.

Reducing the oxygen content to 15% or increasing it to 80% does not significantly affect the body. While a change in the concentration of carbon dioxide by 0.1% has a significant negative impact. From this we can conclude that carbon dioxide is about 60-80 times more important than oxygen.

Table 2.

Depending on the amount of carbon dioxide emitted by the type of human activity

CO 2 l/h	Activity
18	A state of calm wakefulness
24	Computer work
30	Walking
36
32-43	Household chores

Modern man spends a lot of time indoors. In harsh climates, people spend only 10% of their time outdoors.

Indoors, the concentration of carbon dioxide rises faster than the concentration of oxygen decreases. This pattern can be traced from the graphs obtained empirically in one of the school classes

Figure 1. Time dependence of carbon dioxide and oxygen levels.

The level of carbon dioxide in the classroom during lesson (a) is constantly rising. (The first 10 minutes is instrument adjustment, so the readings jump.) For 15 minutes, changes at open window the CO2 concentration falls and then rises again. The oxygen level (b) remains virtually unchanged.

When indoor carbon dioxide concentrations are above 800 - 1000 ppm, people working there experience sick building syndrome (SBS), and buildings are labeled "sick". The level of impurities that could cause irritation of the mucous membranes, dry cough and headache increases much more slowly than the level of carbon dioxide. And when in the office its concentration fell below 800 ppm (0.08%), then the symptoms of SBS became weaker. The problem of SBZ became relevant after the advent of sealed double-glazed windows and low efficiency forced ventilation due to energy savings. Undoubtedly, the reasons for the SBZ may be the allocation of construction and finishing materials, mold spores, etc. with inadequate ventilation, the concentration of these substances will increase, but not as fast as the concentration of carbon dioxide.

Table 3

How different amounts of carbon dioxide in the air affect a person

CO 2 level, ppm	Physiological manifestations
380-400	Ideal for human health and wellness.
400-600	Normal air quality. Recommended for children's rooms, bedrooms, schools and kindergartens.
600-1000	There are complaints about air quality. People with asthma may have more frequent attacks.
Above 1000	General discomfort, weakness, headache. The concentration of attention falls by a third. The number of errors in the work is growing. Can lead to negative changes in the blood. May cause problems with the respiratory and circulatory systems.
Above 2000	The number of errors in the work is greatly increased. 70% of employees can't focus on work.

The problem of elevated levels of carbon dioxide in the room exists in all countries. It is actively pursued in Europe by the USA and Canada. In Russia, there are no strict standards for the content of carbon dioxide in the premises. Let's turn to the legal literature. In Russia, the air exchange rate is at least 30 m 3 / h. In Europe - 72 m 3 / h.

Consider how these numbers were obtained:

The main criterion is the amount of carbon dioxide emitted by a person. It, as discussed earlier, depends on the type of human activity, as well as on age, gender, etc. Most sources consider 1000 ppm as the maximum allowable concentration of carbon dioxide in a room for a long stay.

For calculations, we will use the notation:

• V - volume (air, carbon dioxide, etc.), m 3;
• V k - the volume of the room, m 3;
• V CO2 - the volume of CO 2 in the room, m 3;
• v - gas exchange rate, m 3 /h;
• v in - "ventilation rate", the volume of air supplied to the room (and removed from it) per unit of time, m 3 / h;
• v d - "breathing rate", the volume of oxygen replaced by carbon dioxide per unit time. Respiration coefficient (unequal volume of consumed oxygen and exhaled carbon dioxide) is not taken into account, m 3 / h;
• v CO2 - the rate of change in the volume of CO 2, m 3 /h;
• k—concentration, ppm;
• k(t) - CO 2 concentration versus time, ppm;
• k in - concentration of CO 2 in the supplied air, ppm;
• k max - the maximum allowable concentration of CO 2 in the room, ppm;
• t – time, h.

Find the change in the volume of CO 2 in the room. It depends on the intake of CO 2 with supply air from the ventilation system, the intake of CO 2 from breathing and the removal of polluted air from the room. We will assume that CO 2 is evenly distributed throughout the room. This is a significant simplification of the model, but allows a quick estimate of the order of magnitude.

dV CO2 (t) = dV in * k in + v d * dt - dV in * k(t)

Hence the rate of change in the volume of CO 2:

v CO2 (t) = v in * k in + v d - v in * k(t)

If a person enters the room, then the concentration of CO 2 will increase until it reaches an equilibrium state, i.e. it will be removed from the room exactly as much as it did with breathing. That is, the rate of change of concentration will be zero:

v in * k in + v d - v in * k = 0

The established concentration will be equal to:

k = k in + v d / v in

From here it is easy to find out the required ventilation rate at an acceptable concentration:

v in \u003d v d / (k max - k in)

For one person with v d \u003d 20l / h (= 0.02 m 3 / h), k max \u003d 1000ppm (=0.001) and clean air outside the window with v v \u003d 400ppm (=0.0004) we get:

v in \u003d 0.02 / (0.001 - 0.0004) \u003d 33 m 3 / h.

We have received the figure given in the joint venture. This is the minimum amount of ventilation per person. It does not depend on the area and volume of the room, only on the "breathing rate" and the volume of ventilation. Thus, in a state of calm wakefulness, the concentration of CO 2 will increase to 1000 ppm, and when physical activity there will be excess.

For other values ​​of k max, the volume of ventilation should be:

Table 4.

Required air exchange to maintain a given concentration of CO 2

CO 2 concentration, ppm	Required air exchange, m 3 / h
1000	33
900	40
800	50
700	67
600	100
500	200

From this table, you can find the required ventilation volume for a given air quality.

Thus, the air exchange of 30 m 3 /h, adopted by the normative in Russia, does not allow you to feel comfortable in the room. The European air exchange standard of 72 m 3 /h allows you to maintain a concentration of carbon dioxide that does not affect a person's well-being.

Bibliography:

1. I. V. Gurina. “Who will be responsible for stuffiness in the room” [Electronic resource]. Access mode: http://swegon.by/publications/0000396/ (Date of access: 06/25/2017)
2. Oxygen and carbon dioxide in human blood. [Electronic resource]. Access mode: http://www.grandars.ru/college/medicina/kislorod-v-krovi.html (Date of access: 06/23/2017)
3. SP 60.13330.2012 "Heating, ventilation and air conditioning" p. 60 (Appendix K).
4. What is carbon dioxide? [Electronic resource]. Access mode: http://zenslim.ru/content/%D0%A3%D0%B3%D0%BB%D0%B5%D0%BA%D0%B8%D1%81%D0%BB%D1%8B% D0%B9-%D0%B3%D0%B0%D0%B7-%D0%B2%D0%B0%D0%B6%D0%BD%D0%B5%D0%B5-%D0%BA%D0%B8 %D1%81%D0%BB%D0%BE%D1%80%D0%BE%D0%B4%D0%B0-%D0%B4%D0%BB%D1%8F-%D0%B6%D0%B8 %D0%B7%D0%BD%D0%B8 (Accessed: 06/13/2017)
5. EN 13779 Ventilation for non-residential buildings - p.57 (Table A/11)

Research and indoor carbon dioxide levels.

AT last years Precise infrared sensors appeared to measure the level of carbon dioxide in the premises. They are part of gas analyzers and show the concentration of carbon dioxide in real time, so it is convenient to install them in residential and public buildings, schools and kindergartens. However, in order for these measurements to be useful, clear standards for the level of carbon dioxide in the premises are needed. And we don't have them yet. In Europe, the USA and Canada, as a rule, 1000 ppm (0.1%) is considered the norm. Yes, in the near future we will measure the level of carbon dioxide in Minsk apartments and streets.

Apartments.

The craze for plastic windows, completely armless or non-working ventilation systems aggravate the situation. I measured in my apartment: with tightly closed windows and doors, a room of 16 square meters. meters, the level of carbon dioxide in the room reaches 1500 ppm in an hour and a half. Often people do not pay attention to the exhaust vents in the kitchen and toilet. Some even wall them up during repairs. Sometimes the mesh on the vents is so clogged that it practically stops the ventilation from working. These factors contribute to the deterioration of the air quality in the apartment. Imagine that you and several other people are in one small enclosed space, actively moving, preparing to eat, etc. After some time, if the air is not renewed, it becomes very difficult to be in this space, many pollutants are concentrated in the air, including carbon dioxide

Bedroom.

For good sleep quality and human health, it is necessary that the level of CO2 in bedrooms and children's rooms is no higher than 0.08%. Scientists at the Delft University of Technology, the Netherlands, believe that sleep is more important quality air in the bedroom than sleep duration. High level CO2 in bedrooms can also increase snoring.

Carbon dioxide in an air-conditioned room.

The air conditioner gives a stream of cold air, a temperature difference when going outside, bacteria living comfortably in the cool. But, besides this, to save electricity, when the air conditioner is running, all windows are closed. At the same time, the concentration of carbon dioxide quickly reaches a significant value and cool air, but containing an excess of carbon dioxide, is obtained.

Schools.

Even more disturbing data came from a large-scale international study initiated by the European Respiratory Society in schools in France, Italy, Denmark, Sweden and Norway. It showed that in educational institutions where the concentration of CO2 in the classrooms exceeded 1000 ppm, the susceptibility of students to diseases of the respiratory organs increased by 2-3.5 times. True, a clarification needs to be made here. Nevertheless, the researchers of the problem came to the conclusion that the safe level of CO2 in the room should not exceed 1000 ppm.

And in schools, the US Department of Health recommends keeping carbon dioxide levels below 600 ppm. In addition, there is another rule: indoor air in terms of CO2 content should not differ from outdoor air by more than 350 ppm. Theoretically, ventilation and air conditioning systems should provide such a ratio.

Many schools monitor air quality for carbon dioxide levels. Of course, this level does not always and everywhere correspond to the norm. But in this case, the school administration is obliged to take measures to improve the situation. In Finland, for example, a school whose classrooms are found to have elevated levels of carbon dioxide may even be closed until ventilation is established.

Offices.

In 2007, Doctor of Medical Sciences Yu. D. Gubernsky (Institute of Human Ecology and Hygiene environment them. A. N. Sytina of the Russian Academy of Medical Sciences) and Candidate of Technical Sciences E. O. Shilkrot (TsNIIPromzdaniy OJSC) conducted a study of the air environment in Moscow offices and on the streets of Moscow. Despite the fact that the measurements were carried out on far from the most unfavorable days in terms of meteorological conditions, the level of carbon dioxide on the streets was 1000 ppm. And in offices, the concentration of CO2 reached 2000 ppm and even higher.

Often converted into an office premises without properly functioning ventilation, in this case, problems are guaranteed. This is especially true of small conference rooms, in which 20 people are packed. If 20 people sit in a meeting room for 20 squares, then in an hour the concentration of carbon dioxide will increase to 10 "000 ppm of carbon dioxide in the room - and this is already the level at which the brains stop working. Therefore, in small meeting rooms without constantly blowing ventilation, fresh air(not air conditioning!) the allowable time spent by 5-10 people without a decrease in cognitive abilities is no more than 10-20 minutes.

For ventilation at large facilities, it is fashionable to implement power control by measuring the concentration of CO2 in the exhaust air so that the air is not automatically driven in vain when everyone has left the office (huge amounts of power are spent on heating / cooling).

Fitness rooms.

Doing fitness or gyms you can also face the problem of high carbon dioxide levels, and instead of benefiting, harm your body. This is especially true because during physical exertion, the level of carbon dioxide concentration in the blood already rises, and in a poorly ventilated room a person will feel signs of hypercapnia (excess of carbon dioxide).

Perspiration, headache, dizziness and shortness of breath caused by hypercapnia are attributed to physical fatigue and are perceived almost as evidence of their physical activity. In fact, this may indicate an excess of carbon dioxide in the arterial blood. Prolonged hypercapnia is characterized by vasodilation of the myocardium and brain, which can lead to an increase in blood acidity, secondary spasm of blood vessels, and a slowdown in heart rate.

What to do? I will write about this in the next article.

Air is a mixture of gases:

Nitrogen 78%,

Oxygen 20%,

Argon 1%,

Carbon dioxide CO2 0.03%,

Neon, methane, helium, krypton, hydrogen and xenon less than 1%.

Human beings are the main source of indoor carbon dioxide. We breathe out 18 to 25 L/hour of CO2. Elevated levels of carbon dioxide are observed in all rooms where people are.

The fact that we do not have enough oxygen in a stuffy room is a myth!

We are stuffy because of the high concentration of carbon dioxide

400 ppm = 0.04% outside the city

600 ppm= 0.06% in the bedroom

1000 ppm = 0.1% in the office

1 ppm - ppm or ppm corresponds to 0.0001% CO2

Calculations show that headache, weakness, and other symptoms occur in a person in a room not from a lack of oxygen, but from an excess of carbon dioxide!

More recently in European countries and the United States, the level of carbon dioxide in the room was measured only in order to check the quality of the ventilation, and it was believed that CO2 was dangerous to humans only in high concentrations.

Studies on the effect of carbon dioxide on the human body at a concentration of approximately 1000ppm appeared quite recently.

Few people know that clean air outside the city contains about 400ppm carbon dioxide, and the closer the CO2 content in the room to this figure, the better the person feels.

Residents of a large metropolitan area are exposed to negative influence elevated levels of carbon dioxide around the clock. First, in crowded public transport and in their own cars, which are stuck in traffic jams for a long time. Then at work, where it is often stuffy and there is nothing to breathe.

It is also very important to support good quality air and in own house especially in the bedroom, where we spend a third of our lives. To get a good night's sleep, clean air is much more important than sleep duration, and CO2 levels in bedrooms and children's rooms should be lower. 600ppm. High levels of CO2 in these rooms can cause symptoms such as nasal congestion, throat and eye irritation, headaches and insomnia.

Scientists have found a way to solve this problem, based on the axiom that if in nature the level of carbon dioxide is 350-400ppm, then in the premises it should be close to this level.

*All levels shown in the table are quite normal and are acceptable from time to time.

carbon dioxide in office space reduces the productivity of employees, worsens their health, leads to the Sick Building Syndrome (SBS). Measurements carried out in offices showed that the concentration of carbon dioxide CO2 reached 2000ppm and above.

Studies have shown that at concentrations of carbon dioxide above 800-1000ppm employees office buildings begin to experience symptoms of RBS: irritation of the mucous membranes, dry cough, headache, decreased performance, inflammation of the eyes, nasal congestion, inflammation of the nasopharynx, problems associated with the respiratory system, dry cough, headache, fatigue and difficulty concentrating. Moreover, carbon dioxide is one of the main reasons for the development of SBZ.

In order to understand the limits of CO2 concentration, we made the following measurements with a gas analyzer (a device that measures the content of carbon dioxide in the air):

The content of carbon dioxide CO2 in the office, measured in ppm:

The content of carbon dioxide CO2 in the apartment with and without ventilation, measured in ppm:

In fact - in the morning in a room with closed plastic windows and a closed supply valve- 2000 ppm (ppm).

Please note that when airing the room, the humidity of the air decreases!

Help! Installed plastic windows, it became stuffy and smells bad.

Cause of stuffiness - does not work exhaust ventilation in the kitchen and bathroom.

Let's do an experiment. Bring a lit candle or match to ventilation grille, the flame should deviate towards the grate. If the flame remains motionless or deviates from the grate, ventilation does not work. Now open the window in the room and bring a match, the flame deviated more towards the grate or went out.
Conclusion. An apartment is like communicating vessels, how much air enters, the same amount is removed. If there is an air supply from the street, exhaust ventilation in the kitchen and bathroom removes dirty, humid air with odors. Modern hermetic windows allow little air to pass through, which means that exhaust ventilation does not remove air enough.
If you constantly keep the windows ajar, the point of buying new windows is reduced to nothing: cold, dust and the roar of trams are back in the house. Micro-ventilation systems on windows are not much more efficient - they ventilate well, but they quickly cool the room and do not save from drafts, street noise and dust.

In the air of the apartment, the content of carbon dioxide CO2 increases. The main reason for poor health, lack of sleep and chronic fatigue syndrome is an excess of carbon dioxide CO2 in the air.