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Chemical composition of air
| a |
| CO2 |
| N2 (nitrogen) || Inert gases and impurities |
| 20.94% || 0.03-0.04% || 78.1% || 1% |
The biological significance of oxygen lies in participation in respiration; it is necessary for oxidative processes in the body.
A person absorbs 12 liters of oxygen per hour or 6-7 liters of air per minute, athletes - up to 120 liters per hour.
It is given: - atmosphere
- green (chlorophyll) plants.
Indoors, its fluctuations should be within 1%, but 17-18% is acceptable (increased heart rate and respiration), 11% (decreased performance), 7-8% (death).
Ozone is a chemically unstable oxygen isomer, a powerful oxidizing agent (removes bad odors, neutralizes water).
It is formed when: - electric charges;
- upon evaporation of water;
- under the influence of UV radiation.
The nitrogen content in the lower atmosphere is negligible.
Ozone is an indicator of air purity. During a thunderstorm, in the mountains, coniferous forests (tarry discharge).
Carbon dioxide is an indirect indicator of air pollution. It is formed by breathing, burning fuel, decay, decomposition.
In the city, the critical value is up to 0.05% due to gas emissions.
In residential and public buildings can be up to 0.1%.
In medical institutions - 0.07%.
The content in the air of 8-10% is fatal to humans.
The biological significance of carbon dioxide - excites the respiratory center.
Nitrogen - is an indifferent gas for humans. For plants, it can be a source of nutrition. Up to 93% nitrogen in the air is the lethal composition of the gas mixture for humans.
The biological significance of nitrogen is to dilute oxygen and other gases. Inert gases (argon, helium, krypton) have no physiological significance.
Smelling gases (hydrogen, methane, ammonia, hydrogen sulfide, nitrous oxide): sweat decomposition products; skin discharge; oral cavity; dirty shoes and clothes.
The self-cleaning ability of air is very high.
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Chemical composition of air
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