Physical factors of air, their hygienic value

To the factors of environment having constant influence on the person, physical factors of air - temperature, humidity, movement, atmospheric pressure, an ionising radiation concern.

The Sun, sending on the earth the beams, heats up it. Air heating occurs for the account teplootdachi the soil absorbing and transforming solar radiation. The temperature of atmospheric air changes depending on a climatic zone, a season, time of days; the big impact on a thermal exchange between the person and environment makes. Fluctuations of temperature of air are essentially reflected in change of conditions teplootdachi; the heat limits possibility of return of heat to a body, low - raises it.

Normal ability to live of an organism and high working capacity are possible only in the event that in it thermal balance without considerable pressure of mechanisms of thermoregulation remains, i.e. If conformity between production of heat and its return in an environment remains.

Teplootdacha occurs different ways: the basic way - through a skin. Through a skin the organism can give heat carrying out, radiation and evaporation.

By carrying out, or konvektsii, the organism loses heat.na environment heating, namely - air. Heat loss konvenktsiej is directly proportional to a difference between temperature of a skin of the person and air temperature. The more low air temperature, the is more teplootdacha konvektsiej. If air temperature increases, heat loss konvektsiej decreases, and at the temperature equal 35-36 В°s, absolutely stops.

Loss of heat by radiation is connected with temperature of associates of the person of subjects. The quantity of radiated heat increases with rise in temperature of a body of the person. Therefore the person radiates more than radiant heat, than receives from subjects surrounding it if their temperature more low 35 В°s, and as a result loses heat. Thus, return of heat by radiation raises with difference increase between a body temperature of the person and temperature being on distance from it surrounding subjects. In the conditions of open atmosphere loss of heat by radiation depends on intensity of solar radiation, temperature of soil, walls of buildings.

Teplootdacha evaporation depends on quantity of the moisture (sweat) evaporating from a surface of a body. At a room temperature from a surface of a skin of the person evaporates about 0,2 l of a moisture a day. With rise in temperature of air and walls loss of heat by radiation and konvektsiej goes down and increases teplopoterja evaporation. If temperature of an environment above a body temperature of the person, a unique way of return of heat - evaporation.

Thus, according to an ambient temperature comes into effect both the mechanism of development of heat, and the mechanism regulating its loss.

Deterioration of conditions of return of heat conducts to its accumulation in an organism and to an overheat, and sometimes and to a heatstroke. Superfluous loss of heat causes cooling, sharp respiratory diseases and otmorozhenie. The person adapts to thermal conditions of an environment actively, using clothes, dwelling, heating, and is passive - by means of the mechanisms of thermoregulation balancing teploproduktsiju and teplootdachu. Thus, thanks to presence of the difficult mechanism of thermoregulation even at considerable fluctuations of temperature of the air environment it is supported by a body temperature constancy.

However limits of mechanisms of thermoregulation are completely not boundless, and their excess causes infringement of thermal balance of an organism that can do essential harm to health.

In a rest condition thermal balance remains at temperature 20-25 В°s, at physical work of average weight - at temperature 10-15 В°s, and at heavy work - at temperature 5-10 В°s. Teploproduktsija an organism increases at strengthening of muscular movements. Hence, at performance of physical work in conditions with air heat probably overheating of an organism. Air heat thus is considerable loading on cardiovascular system and breath bodies that leads big potootdeleniju. Thus there is a condensation of blood and fall of level of chlorides in it, that, in turn, leads to development of the convulsive illness which are taking place at work in hot shops. Spasms of muscles of the top and bottom finitenesses, and in some cases of muscles of a stomach and a diaphragm are thus observed.

Long stay of the person in the conditions of a heat causes pulse acceleration, decrease in functions of nervous system, such as attention, coordination of movements, speed of reactions, i.e. Impellent and mental block. In such conditions faster fatigue and fall of intellectual and physical working capacity is marked.

Owing to plentiful potootdelenija in organism fabrics the quantity of water that leads to a blood condensation, deterioration of function of heart and infringement of blood supply of bodies and fabrics decreases. Thus together with mineral elements (sweat of the person contains about 0,5% of the chlorides dissolved in it) owing to what it is broken vodno-elektrolitnoe balance are then allocated.

At overheating there is a headache, weakness, sometimes a nausea and vomiting, the body temperature raises, breath and pulse become frequent. In heavy cases sudden loss of consciousness, pallor of the skin, the pulse speeded up weak filling, sometimes convulsive reductions of muscles are observed. This condition name a heatstroke.

At direct influence of solar heat on a head vessels of a brain overheat and there is a sunstroke, the body temperature thus can remain normal.

The Low temperature of air, increasing teplootdachu, creates danger of overcooling. Thus raises teplootdacha by direct carrying out and heat radiation in environment. Short-term cooling, thanks to protective action of thermoregulation, can be transferred by an organism without harmful consequences. Long cooling often causes infringement of thermoregulation and decrease in resistibility of an organism to infectious activators. At overcooling the radiculitis, a pneumonia are possible an aggravation of chronic diseases, miozit, rheumatism, nevrit.

Local action on a fabric of low temperature is shown in the form of a fever and otmorozhenija.

Fast fall of temperature of air as the organism thus not always has time to adapt is especially unhealthy. As a result sharp respiratory diseases in which basis lays nejroreflektornyj the mechanism consisting in dystrophic changes in fabrics, caused by infringement of regulation of exchange processes can be observed. And. P.Pavlov, explaining essence of cold, specified, that prostudnyj an element, lowering ability to live of an organism, its separate bodies, promotes infection development, causing this or that disease (a nephrite, a pneumonia, etc.).

Fluctuations of temperature of air are especially dangerous to the persons, suffering heart diseases, a sclerosis of vessels, illnesses of kidneys. Change of temperatures the people badly eating and retired difficultly transfer.

To support thermal balance at constant level, despite considerable fluctuations of an ambient temperature, it is possible to raise Ability of an organism zakalivaniem, observance of rational diets, work, rest, etc.

Optimum temperature of air in premises for the person being in a condition of rest and dressed in usual house clothes, is the temperature 18-20 В°s at the relative humidity equal of 60%, and speed of movement of air - 0,1-0,2 km/s.