The properties of air are its temperature, atmospheric pressure, humidity, mobility, solar radiation, and the state of the electric field. All these factors affect the human body.
The complex of physical factors determines the climate. These are such basic properties of air as its temperature, relative humidity and mobility, which affect the regulation of human heat transfer.
Temperature
The thermophysical properties of air are determined by its temperature. This factor characterizes the thermal state of the human body and the external environment, i.e. heat transfer, which consists of heat production and heat transfer.
Heat production is the result of oxidation of food and the release of heat during contractions of muscles, solar heat, heated objects, hot food and warm air.
Heat transfer occurs due to conduction or convection, radiation or radiation, evaporation.
When exposed to high temperatures on the body, immunity decreases and the overall incidence increases. According to the laws of heat radiation (Stefan-Boltzmann, Kirchhoff, Wien), the heat radiation of heated objects occurs more intensively than their temperature rises, and the radiation spectrum shifts toward short waves, which contributes to a deeper, penetrating effect of heat on the body.
Low air temperature causes an increase in heat loss due to radiation and convection, which leads to cooling of the body due to heat deficiency. There is a decrease in skin temperature, loss of pain sensitivity, weakening of muscle activity, muscle weakness and drowsiness appear.
Humidity
The properties of air are characterized by its humidity, which is determined by the content of water vapor in the air.
Absolute humidity is a content of 1 cubic meter. meter of water vapor in grams. In hygienic practice, relative humidity is usually taken into account .
Relative humidity is the degree of saturation with water vapor (%). This is the ratio of absolute humidity to the amount of moisture that saturates the air. Saturation deficit is the difference between maximum and absolute humidity.
Air mobility
The mobility of air characterizes the speed of its movement. It is determined by the number of meters that air travels in a second. With moderate air mobility and high temperature, cooling of the skin occurs, and with high air mobility and low temperature - overcooling. Frosty, calm weather is easier tolerated than during strong winds.
The most favorable is the speed of movement of air masses, equal to 1-5 m / s, and in the premises - 0.1-0.3 m per second.
Atmosphere pressure
The properties of air are determined by its atmospheric pressure, i.e. its pressure on the surface of the earth. The higher the surface of the earth, the lower the pressure and density of air.
Significant increases and decreases in atmospheric pressure adversely affect the human body.
Lowering atmospheric pressure causes hypoxia (oxygen starvation), to which the brain is sensitive, because it consumes oxygen 30 times more than other cells.
Air ionization
This is the decay of molecules and gas atoms under the action of ionizers, i.e. radioactive radiation, ultraviolet and light radiation of the sun, cosmic rays, heating surfaces, spraying water, etc.
In the atmosphere, the processes of ion destruction and ion formation occur constantly, as a result of which, some ionization equilibrium is established.
Pure air contains more light ions, in polluted - heavy ions. At waterfalls and on the banks of rivers, the content of light ions reaches 40 thousand per 1 cubic meter. cm of air, in villages - 2-3 thousand, in cities this number is reduced to 4 thousand in 1 cubic meter. cm.
The ionization mode is determined by the pollution coefficient, i.e. the ratio of the number of heavy ions to the number of light ions and the unipolarity coefficient.
The properties of air also determine the electric field of the earth, the radioactivity of the air and the magnetic field.