Theme: Methods of determination of the ultraviolet radiation intensity as such as preventive dose of it’s irradiation and use it for diseases prevention and air disinfection in premises icon

Theme: Methods of determination of the ultraviolet radiation intensity as such as preventive dose of it’s irradiation and use it for diseases prevention and air disinfection in premises




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НазваTheme: Methods of determination of the ultraviolet radiation intensity as such as preventive dose of it’s irradiation and use it for diseases prevention and air disinfection in premises
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Theme: Methods of determination of the ultraviolet radiation intensity as such as preventive dose of it’s irradiation and use it for diseases prevention and air disinfection in premises



Theme: Methods of determination of the ultraviolet radiation intensity as such as preventive dose of it’s irradiation and use it for diseases prevention and air disinfection in premises.


Topicality of the theme. Ultraviolet part of sun spectrum has considerable physiological importance. Natural ultraviolet irradiation is especially important for child's organism. The artificial sources of ultraviolet radiation (UVR) are widely used for indemnification of ultraviolet deficiency. Biological effect of ultraviolet rays has both biogenic and abiogenous constituents that depends on spectral structure of radiation and its intensity. And that in turn determines the necessity of strict dosage of irradiation taking into account the individual features of an organism and presence of contraindication for use of UV-irradiation (UVI) in prophylactic and medical purposes and also keeping of hygienic requirements at the use of sources of short-wave UVI for disinfection of objects of environment and on enterprises for the prophylaxis of possible unfavorable influence of radiation on the human’s organism.

Purpose (general): To know how to assess of ultraviolet radiation and to work out recommendations for the prophylaxis of UV-deficiency and superfluous influence on the human organism and also to evaluate deficiency of disinfection of environmental objects.


Goals:

  1. To analyse structure of sun radiation and character of their biological effects.

  2. To interpret the possibility of adverse effect origin due to insufficient and superfluous influence of UV-radiation on the human organism.

  3. To know how to determine biodose, prophylactic and physiological doses of UV-irradiation using the photochemistry method.

  4. To substantiate possibility and necessity of the use of the artificial sources of UV-radiation in prophylactic, medical purposes and for disinfection of environmental objects.

  5. To recommend the measures of the UV-insufficiency prophylaxis and superfluous influence of ultraviolet rays on the organism of man.

  6. To calculate efficiency of bactericidal effect of short-wave UV-radiation.


Theoretical questions underlining the implementation of purpose full activities.

  1. Structure of sun radiation. Ultraviolet part of sun spectrum.

  2. Biological effect of ultraviolet radiation.

  3. Methods of investigation of intensity of ultraviolet radiation. Units. Notion about biodose, prophylactic and physiological doses.

  4. Health disorders and diseases mediated related by ultraviolet insufficiency.

  5. Prophylaxis of ultraviolet insufficiency.

  6. Application of the artificial sources of UV-irradiation with prophylactic and medical purposes.

  7. Application of artificial sources of short-wave UV-irradiation for disinfection of environmental objects.

  8. Unfavorable effects of the superfluous influence of UV-radiation on the organism. Their prophylaxis.


Structure of sun radiation. Ultraviolet part of sun spectrum.

A sun is an energy, heat and light source on our planet. All organic life on Earth is obliged to the sun radiation by the existence. Under a sun radiation the integral stream of radiation which spreads rectilinearly at a speed of 300000 cm/s emitted by a Sun is understood. From the physical point of view sun energy is the electromagnetic and corpuscular radiation. The electromagnetic radiation engulfs the range of lengths of waves from the shortest, gamma- and x-ray photography, with a wave-length to 10 nm, ultraviolet (from 10 to 400 nm), visible part of spectrum (from 400 to 760 nm), infra-red radiation (from 760 to 100000 nm) and most long range of radio frequencies. Its power maximum is on visible part of spectrum. The corpuscular constituent of sun radiation consists mainly of electrons, protons, α-particles and other.

Energy of a Sun on the border of atmosphere, falling on a 1 sm2 of surface perpendicular to the direction of rays, during 1 minute and shown in calories is named as solar constant. On the border of atmosphere the tension of radiation on the average is equal to 1,98 calories sm2/min, or 7,86 joule/min, thus this size, in spite of the fact that is called solar constant, considerably hesitates depending on the row of astronomic reasons, in particular activity of a Sun.

Because of absorption, reflection and dispersion of radiant energy it is exposed to both quantitative and qualitative changes at passing through the air cover of Earth. As a result no more than 43 % of primary power of sun radiation achieves a terrene. The amount of the radiant energy reflected from Earth, and which is expressed in percents from energy falling on it, is called albedo. Falling out snow, water surface, sand, maximally reflects radiant energy, and moist soil, black earth possess minimum reflecting ability. A direct sun radiation is basic component part of radiation balance, intensity of which increases during a year from the north to the south.

Balance of sun energy is formed thus: the annual amount of sun energy on the border of atmosphere is adopted as 100 %. From Earth is reflected and is gone back into the space 42 % energies, thus 38 % it is reflected by an atmosphere and only 4 % - by surface. Other 58 % are taken in by an atmosphere (14 %) and soil (44 %). The heated surface returns all absorbed energy backwards. Thus the radiation of energy by surface is 20 %, and about 24% are going on warming of air and evaporation of moisture.

The amount of sun radiation in the separate districts of Earth depends on the sun rays angle. Than more is height of a Sun above horizon, the more is amount of sun energy falling on the unit of area. When a Sun is at the line of horizon, sun rays pass a way in an atmosphere almost in 35 times longer, than in that case, when a Sun is in a zenith.

The annual regimen of insolation changes depending on a latitude of the area and height above sea level. With getting up on first 3000 m the radiation is multiplied on 10 % on every kilometer of height.

The maximum of sun radiation for a day long is observed at 12 o'clock of day, when a Sun maximally approaches a zenith. Maximal tension of sun radiation in south latitudes is observed in March-April, and in north - in April-May. The other, the less expressed, maximum is observed in August-September. The minimum midday value is typical for December. The decrease is also observed in July-August. Such distribution of radiation is determined by height of Sun and degree of transparency of atmosphere.

Thus, during a year the highest values of direct sun radiation are observed not in summer, when a sun arrives at the highest point at midday, but in spring, that is explained by decreasing of transparency of air in summer time due to large pollution of atmosphere and heightened humidity. At a serene a maximum radiations fall on short UV-rays, at gloomy sky a maximum radiations is displaced in more long-wave region of spectrum. When the weather is cloudy the UV-radiation intensity at a surface can go down on 80 %, due to pollution of atmospheric air this loss is about from 11 to 50 %. Spectral structure of radiant energy swings in a very wide range.

Optical part of sun spectrum, including infra-red rays with a wave-length 2800 - 760 nm, visible (760 - 400 nm) and ultraviolet (400 - 290 nm) has its maximum at the surface. Thus, if on the border of atmosphere ultraviolet part of sun spectrum is 5 %, visible - 52 % and infra-red - 43 %, then at the surface they are 1, 40 and 59 % agreeably. As a sun radiation is one of kinds of electromagnetic radiations, its biological effect depends on energy of quantum, depth of penetration in tissues of body, intensity of irradiation (amount of energy on unit of area in time unit), its mode that determines, in particular, dose of irradiation, area of irradiation, terms, which the irradiation is at, and state of organism.


Table 1.

Spectral structure and biological effects of sun radiation


Type of radiation

Wave-length , nm

Energy of quantum, eV

Permeability of the skin, mm

Primary effect

Biological effect

Note

Infrared


Visible


Ultraviolet:


region A (long)


region B (middle)


region C (short)

4000 -760


760 - 400


400 - 290


400 - 315


315 - 280


280 - 180

0,01- 1,6


1,6 - 3,2


3,2 -6,0

1 - 25


25- 2


Fractions of mm

deep thermal


deep thermal, weak photochemical


photochemical


photochemical


photochemical

increase of metabolism in the skin, intensify-

cation of UV-irradiation effects


feeling of light, restorative action


chromogenic (sunburn), a weak stimulatory

strong stimulatory, sunburn, synthesis of cholecalciferol (vitamin genereting), weak bactericidal

strong bactericidal



The UVR range that achieves the troposphere


The most valuable biologically


less than 290 nm are stopped by layer of ozone on height of a 20-30 km


Ultraviolet part of spectrum of sun radiation possesses the biggest biological effect, the shortest ( less than 290 nm) rays of which (destructive for all living) are detained by the layer of oxygen and ozone in the top layers of earthly atmosphere and do not come to the surface. However contamination of atmosphere by the industrial emissions, especially by Freon contributes to destruction of ozone layer of atmosphere and origin of the so-called «ozone holes» through which these destructive for all living the shortest UV-rays can penetrate.

UV-rays occupy intermediate position between a thermal and penetrating radiation and that is why unifying in itself their lines. UV-radiation is subdivided into long-wave part - 315 - 400 nm (region A); middle wave - 280 - 315 nm (region B) and short-wave, with a wave-length shorter than280 nm (region C) - in the artificial sources of UVR.


Biological effect of ultraviolet radiation.


Ultraviolet part of sun spectrum exerts both biogenic and abiogenous influence on living organisms.

General stimulating biogenic effect includes vitamin generating and chromogenic effects.

The general stimulating (erythemous) effect of UVR is peculiar to the range 250 - 320 nm, with a maximum at 250 and 297 nm (double peak) and minimum at 280 nm. This effect shows up in photolysis of proteins of skin (UV-rays penetrate the skin on a depth of 3-4 mm) accompanied by formation of products of photolysis - histamine, choline, adenosine, pyrimidine compounds and others that getting into blood stimulate the metabolism in the organism reticuloendothelial system, marrow, influence on the system of hematosis, activity of respiratory enzymes, functions of liver, central nervous system etc. The general stimulating effect of UVR increases due to an erytemous effect especially if the intensive infra-red radiation influence simultaneously.

D- vitamin generating (antirachitic) effect – is peculiar to a range 315 - 280 nm (region B) with a maximum in a range 280-297 nm. Vitamin D2 (ergocalciferol), vitamin D3 (cholecalciferol) are produced from ergosterin (7,8-dehydrocholesterol) in skinning fat (in oil-glands) because of breaking up of benzene ring under the influence of UVR and from the provitamin of 2,2-dehydroergosterin - is the vitamin D4.


Chromogenic (sunburn) effect is peculiar for the ranges of regions A and B with a wave-length 280 - 340 nm. It is conditioned by transformation of amino acid of tyrosine, dihydroxyphenylalanine, products of disintegration of adrenalin, under the UVR influencing and enzyme of tyrosinase in a black pigment melanin. Melanin protects a skin and whole organism from superfluous action of UVR, visible and infra-red radiation.

Abiogenous effect of UVR includes:

Bactericidal effect that is peculiar to the regions C and B embraces the range of lengths of waves from 300 to 180 nm with a maximum at a wave-length 254 nm. Under influence of ultraviolet rays at first there is the irritation of bacteria with activation of their vital functions, replaced with the increase of dose by an UVI bacteriostatic effect and then photodestruction, melting of proteins and at the end death of microorganisms.

The photo ophthalmologic effect of UVR (inflammation of mucous membrane of eyes) shows up highly in mountains (alpinists have snow illness) and as occupational hazard of electric welders, physiotherapeutists working with the artificial sources UV-irradiation without the observance of safety regulations.

The carcinogenic effect of UVR shows up in the conditions of hot tropical climate and in industry with high levels and long action of the technical sources of UVR (electric welding etc.).

Ultraviolet rays possess the wide spectrum of biological influence on the organism of man and the functional changes are originated because of this mainly positively reflecting on the common state of health and physical and mental capacity for work. So, under the UV-rays influencing strengthening of activity of adrenal glands, thyroid and other endocrine glands is marked, trophism is intensified, the regeneration of tissues is accelerated, the metabolism (albuminous, fatty, carbohydrate, mineral) rises, thus due to activation of the proper enzymatic systems there is the effect of disintegration of superfluous fatty deposits. The tissue breathing of cutaneous epithelium changes, activity of reticuloendothelial system and hematosis systems increases. UV-irradiation causes the changes in the immunobiological state of organism, contributes to strengthening of reaction of phagocytosis that results in the increase of protective forces of organism, increase of immunity. It is proved in the experiment, that the designed diseases (blood pressure high, and atherosclerosis, cancer, nephrite and other) under influencing of UV-radiation develop more slowly compared to the unirradiated animals.

The processes of wound repair when agents destroying a cellular substance gain in importance are going better under the UV-rays that is connected with making of histamine-like substances which change the active reaction of tissues in a sour side and because of that raise of permeability of capillary wall and cellular membranes. Histamine plays part of protective mechanism. Thus, bactericidal effect of UV-rays on wounds, their ability to accelerate the selection of pus, to stimulate the keratoplastical functions of organism and calm pain contribute to acceleration of wounds repair also.

The mechanism of the biological effect of UV-rays on an organism is difficult and to the present is not studied fully. Numerous theories explain general biological effect of ultraviolet radiations from different positions: by increased making of histamine-like substances, by activation of sulfhydric groups of protein molecules, by stimulation of the hypophysial–and-adrenal system etc.

As it was already marked higher that biological effect of any electromagnetic radiation depends on energy of quantum, depth of penetration in tissues of body, intensity of irradiation (amounts of energy on unit of area in time unit), its mode (determining, in particular, the dose of irradiation), area of irradiation, terms, which the irradiation is at, and state of organism.

In diagram form the process of influence on an organism can be represented as successive stages. The first stage is primary, cleanly physical, power, co-operation between the quanta of electromagnetic radiation and molecules of the irradiated tissues and as a result of it depending on energy of quantum there is a thermal effect, excitation or ionization of atoms and molecules. After it a next stage is the series of biochemical reactions and physiological processes accompanied by them (for example dilatation of capillaries). Further, the generalized reaction of holistic organism (third stage) develops because of neuroreflectory and humoral communications, in which determining part is played by the neuroendocrine regulation. By these features it is explained that the ultraviolet radiation of a Sun, penetrable on portions of the millimeter in a skin, is able to cause the expressed local inflammatory process (erythema) and general reaction of organism.

Thus, the biophysical scheme of the physiological effect of UV-radiation can be represented that way: absorption of quantum - primary power co-operation - the chain of biochemical reactions - physiological acts in the irradiated tissues - physiological reaction of holistic organism.

The ultraviolet radiation, especially the B- region, possesses strong photochemistry effect. It is enough of energy of quantum in order to stimulate remains of amino acid (tyrosine, tryptophan, phenylalanine and other), pyrimidine and purine bases that are parts of molecules of proteins and nucleic compounds (thymine, cytosine and other). As a result there is disintegration of protein molecules (photolysis of proteins) with formation of row of physiological active compounds (histamine-like, choline, acetylcholine and other), activating of the hypophysial–and-adrenal system metabolic and trophic processes.

Distinctions of dermal erytemous reaction arising up at action of short-wave and long-wave UV-rays are experimentally proved. So, UV-rays of regions A cause the increase of temperature of the skin and intensification of blood supply of the irradiated areas of the skin is caused due to dilatation of vessels, and action of short-wave UV-radiation results in the decrease of skin temperature and its turn red. The sun-burn effect for the separate regions of UV-spectrum also has the differences. So, at a wave-length of 300 nm relative unit is 1,7, and at a wave-length 370 nm - 0,17, I.e. in 10 times less. A reflex act lies in basis of this reaction, in which CNS takes direct part. Erythema has, as a rule, sharp scopes and develops only in a area of UV-irradiation. Characteristic feature of erythema is its appearance after a latent period and then it turns into the sunburn. The cells of epidermis swell on the place of erythema, infiltrate appears, afterwards there is the cornification, the thickness of epithelium multiplies and a process is completed by pigmentation of the irradiated area of the skin, I.e. sunburn.

A pigment - melanin that gives to the skin the effect of sunburn is located in the cells of basal layer of epidermis and is formed of colourless propigments - melanogenes as a result of action of oxidative enzymes. The process of formation of pigment changes optical properties of skin and it results in the increase of absorption of sunbeams by skin. The sensitiveness of skin in spring rises as compared to an autumn period. Optical properties of skin can sharply change depending on the degree of humidity of skin. A swarthy skin very quickly gets accustomed to UV-rays and less sensible to them compared to unpigmented. The photochemistry reactions arising up under influence of UV-rays contribute to the synthesis of the D (calciferol) vitamins, in particular cholecalciferol (vitamin D3) in the superficial layers of skin from the provitamin - 7,8-dehydrocholesterol being in dermal fat. It determines the antirachitic effect of UVR.

Abiogenous effect of UV-radiation is related to the phototoxic, photoallergenic and carcinogenic effects, which shows up at people and bactericidal effect - on microorganisms.

The bactericidal effect of UV-rays is widely used in practice, is well-known, in particular for sanation and disinfection of different objects of environment - air, water, food products, surgical instruments, etc.

An ultraviolet radiation disinfects water from typhoid bacillus, colon bacillus and blue pus bacillus comma bacillus and other microorganisms. This feature of radiation plays important part in natural purification of rivers and seas. The mechanism of this effect is that in the body of bacteria there are photochemistry processes which cause the colloid-chemical changes of protein molecules which result in death of bacteria. The vegetative forms of microbes and viruses perish under direct sunbeams during 10-15 minutes, spore forms - 40-60 minutes. The most strong bactericidal effect possesses region C of ultraviolet radiation, which is generated by bactericidal and mercury-quartz lamps. Except for it, short-wave UV-rays change gas structure of atmosphere, and serve as ionizators of air, and cause photo-electric effect in surrounding objects. UV-rays are absorbed by oxygen, nitrogen and hydrogen. It results in photodissociation of molecules of oxygen. The releasing atomic oxygen combines with the molecule of oxygen and forms ozone - О3. Ozone also possesses ability to absorb UV-rays.

Thus, an ultraviolet radiation has not only generalbiological influence but also has specific effect peculiar to the certain range of lengths of waves. Waves in a range from 400 to 320 nm have generalstimulating erythemous and sun-burn effects, from 320 to 280 nm have antirachitic and weak bactericidal effects, short-wave UV-radiation in the range of waves from 280 to 180 nm has damaging effect on biological tissues. On the earthly surface biological objects are not exposed to destructive influences of most short-wave UV-radiation because waves long less than 290 nm are spread and absorbed in the top layers of atmosphere. UV-radiation that causes erythemous effect has the highest specific gravity of all spectrum of UV-radiation at the earthly surface.

Taking into account the high biological activity of UVR it becomes obvious that for the organism of man both deficiency and superfluity of the UV-radiation lead to the unfavorable consequences.

Methods of investigation of intensity of ultraviolet radiation


The biological importance of sun radiation and radiant energy of artificial sources conditions the significance and necessity of hygienic assessment of quantitative and qualitative descriptions of radiation.

Qualitative descriptions of radiation are received by spectroscopy methods, quantitative – by devices of type of spectroradiometers. Quantitative description is intensity of radiant energy (tension of radiation, I.e. amount of energy in joules (system units) or calories (miscellaneous units), which falls during time unit on a 1m2 (sm2) of surface located perpendicular to the radiant) and superficial flux density of energy in watt, which falls on unit of the irradiated surface.

Intensity of infra-red (thermal) radiation is measured by pyranometer or solar radiation instrument action of which is based on principle of absorption of energy by a black body and transformation of radiant energy in the thermal one.

Pyranometer the universal is intended for measuring of total, diffused and reflected radiation of the Sun with a wave-length 300 - 2400 nm (calorie/sm2 ×min).

Pyranometer of Yanyshevskiy is intended for measuring of total and diffused radiation.


Intensity of ultra-violet radiation is determined by biological, photochemical and photo-electric (physical) methods.

Biological method. It is widely used in medical practice. It is based on definition of a biodose - minimal erythemous dozes of irradiation (MED) which corresponds to minimal time of an irradiation after which through 8 - 20 hours arise reddening (erythema) not sunburnt skin. This threshold erythemous doze is changeable. It depends on a sex, age, a state of health and other specific features of an organism.

The biodose should be established experimentally at everyone or selectively at the most weakened persons of an irradiated contingent. Definition of a biodose is carried out by the same source artificial UVR which will be applied for a preventive irradiation.

Definition of a biodose is made by means of the special device - Dalfed-Gorbachev's biodosimeter which represents busk with six apertures in the size 1,5 х 1,0 sm which are closed by a mobile plate. A biodosimeter fix on not sunburnt part of a body, more often on an internal part of a forearm, or on epigastric areas or a back. On a skin a ball pen mark an arrangement and number windows.

The patient of 0, 5 m from source UVI (after preliminary warming up of a lamp within 10-15 minutes) have on distance, closing consistently apertures of a biodosimeter every other minute, since 6-th window.

Thus, under window № 1 surface of a body is irradiated within 6 minutes;

under № 2 - 5 minutes;

3 - 4 minutes;

4 - 3 minutes;

5 - 2 minutes;

6 - 1 minute.

The control of occurrence of erythema spend through 18 - 20 hours after an irradiation.

Biodose express in minutes by the number of window under which erythema will be hardly appreciable, that there correspond 600-800 mcWt/sm2.

It is experimentally established, that for preventive maintenance of ultra-violet insufficiency (hypo-and avitaminosis D, disturbance of phosphoritic-calcic exchange, etc. adverse consequences) it is necessary to receive daily 1/8 - 1/10 biodoses (the minimal daily preventive doze) (75-100 mcWt/sm2).

Optimum, or physiological doze from the point of view of it adaptogenic actions makes 1/2 - 1/4 biodoses (200-400 mcWt/sm2).

Example: hardly appreciable erythema is revealed on a skin under a window № 3 of biodosimeter at duration of an irradiation of 4 minutes. Thus, the biodose corresponds to duration of an irradiation - 4 minutes, accordingly the preventive doze will make - 0,5 minutes, and physiological - 1-2 minutes.

Time of reception of a biodose depends on distance up to source UVR.

Х = А х ( В/С) 2

Where X - a biodose, minutes; A - a biodose on standard distance of 0,5 m, minutes;

B - distance on which there is a patient, m; C - standard distance on which determined a biodose, m.

Thus, at increase in distance up to a source in 2, 3, 4 times from standard (0,5 м) time of an irradiation necessary for occurrence hardly appreciable erythema should increase accordingly in 4, 9, 16 times, i.e. in a geometrical progression.

In medical practice preventive dozes UVI from the Sun and a firmament during reception of solar and air baths define a settlement method by means of tab. 2.

Photochemical (oxalate) the method developed by Z.N.Kulichkovoj, is based on decomposition of a solution oxalic acids at the presence of nitrate uranyl proportionally of intensity and duration of ultra-violet its irradiation titrated solution.

Technique of research:

In the quartz test tube covered black it is delicious, with window for penetration of UV-beams and with an aperture for output СО2

pour 0,1 н solution oxalic acids with uranyl and irradiate with an artificial source of UV-radiation.

After end of an exposition 25 ml of this solution with the help of the measured cylinder transfer in heat-resistant conic cone, add of 2,5 ml in a solution of 25 % of a solution of a sulfuric acid, heat up a mix on the closed electric plate up to 90-95о With and in a hot kind titrated by 0,1 н a solution of permanganate potassium (КМпО4) to the weak - pink coloring which are not disappearing within 1 minute.


1. In control test pour 25 ml 0,1 n the oxalic acids, not exposed to an irradiation, add 2,5 ml of 25 % of a solution of a sulfuric acid, also heat up on an electric stove up to 90-95о С and titrate by permanganate of potassium.

2. Difference in ml of permanganate of potassium, which were titrated in control and skilled tests, multiply on correction factor (C), (it corresponds to amount 0,1 n of oxalic acids (in ml), spread out under action UVI), and on 6,3 (1 ml 0,1 n a solution contains 6,3 g of oxalic acids) – reducing in mg spread out oxalic acids.

3. The further calculation of intensity of ultra-violet radiation is made in view of duration of an irradiation and the area of the window through which the irradiation of a solution was made.

Thus, intensity UVR pays off under the formula:


А = (Х к - Х оп) х К х 6,3

S x t

Where Xk - amount in ml 0,1 н of sol. КМпО4, used on titration of skilled test;

X op - amount in ml 0,1 н of sol.КМпО4, used on titration of control test;

K - correction factor (a credit sol.КМпО4) –0, 95 ;

S - the window's area for an irradiation -5 cm 2 ;

T - time of an exposition, hour-3 hour


Violations of health and diseases, caused

by ultraviolet insufficiency.


The insufficient irradiation of the organism by UV-radiation was named by В.В Pashutyn (1902) as «sun starvation». Terms for complete sun starvation up to 6 months in a year are presented in north latitudes, especially in Polarity. However and in middle latitudes there is ultraviolet insufficiency in winter months, plenty of gloomy days, short stay on air, warm clothes contribute to it. For rural areas this period proceeds 2 months and for cities in connection with large contamination of the air it can stretch up to 4 months.

As it was marked higher UV-radiation of antirachitic spectrum belongs to the short-wave radiation and because of that is very easily absorbed and dispersed in the conditions of intensive contamination of atmospheric air by a dust and other industrial emissions. Therefore the inhabitants of large industrial centers, regardless of latitude of locality have «ultraviolet starvation». Ultraviolet insufficiency is characteristic for the people limited because of one or another reason in possibility of stay outdoors and receipts of the necessary dose of UV-radiation. Considerable part of population resident in the middle and north latitudes is in the conditions of «ultraviolet starvation» in winter time. Work in the conditions of absence of natural illumination is characteristic for miners, workers of underground passages, of unilluminated workshops etc. and contributes to the development of ultraviolet insufficiency

Ultraviolet insufficiency is negatively reflected on a health. Numerous experimental researches and supervisions in model terms showed the decrease of adaptation possibilities of organism, development of anaemia, worsening of regeneration of tissues, lowering of resistance of organism to the toxic, carcinogenic, mutagenic and infectious agents, increase of fatigability.

At insufficient influence of the UV-radiation of antirachitic spectrum phosphoric-calcium exchange, the nervous system, parenchymal organs and system of hematosis are suffering, activity of oxidizing-restoration processes is going down, firmness of capillaries is violated, the capacity for work and resistance to the cold diseases is decreased. Children have a rachitis with the certain clinical displays. Thus additional administration of the D vitamin can only partly compensate insufficient influence of radiation factor. As a result children that receive a lot of fats and vitamins with food but have short time of walks under the sun light are more incurred to the rachitis and the increased level of phosphatase is registered in their blood. At adults violation of phosphoric-calcium exchange because of D hypovitaminosis results in osteoporosis, osteomalacia, bad fracture bones healing, weakening of ligamentous apparatus of joints, destruction of enamel of teeth and increase of morbidity of caries.


Prophylaxis of ultraviolet insufficiency


The prophylaxis of ultraviolet starvation consists in proper development of land building from hygienic positions and protection of atmospheric air, from contamination, sufficient stay outdoors in daily time ( especially this is important for children), maximal use of week ends for these aims, cleanness of glazing, application of uveolic (allowing to UV-radiation to pass through) glass, placing of patients being on the long-term care on beds near the windows oriented to the south rhumbs, organization in children’s establishments and in the hospitals of verandahs with glazing from uveolic or organic glass and others. For children it is recommended to arrange grounds for the games and athletic exercise and also to stay during vacations in summer camps.

For the prophylaxis of ultraviolet insufficiency it is necessary to recommend the maximal use of the natural sun radiation. In table.2 it is brought a scheme of air- and sun-bathes taking for different contingents of population (children, adult) depending on time of the day and month of the year.

However often for this purpose it is necessary to resort to the irradiation by the artificial sources of ultraviolet radiation. Last years the use of solariums became contribution of fashion especially among young people.


Application of the artificial sources of UV-radiation

in prophylactic and medical purposes.


A sun radiation and artificial sources of UVR are used for the primary and secondary prophylaxis of chronic cardio-vascular diseases and their treatment. By practical medicine and special scientific researches of the Ukrainian scientists under the direction of В.Г. Бардова (1990) material testifying to the positive influencing of natural (sun) and artificial UV-irradiation was accumulated and applied on certain schemes in prophylactic doses when development and clinical course of cardio-vascular diseases. At this contingent of patients tone of cortex was risen after the prophylactic course of UVI, normalization of processes of excitation and inhibition was marked, the state of the vegetative nervous system got better, activity of number of enzymes was risen, maintenance of hemoglobin in a blood was multiplied, a lipid, mineral (special phosphoric-calcium) exchange, permeability of cellular membranes, the anticoagulative function of blood were normalized, the decline of arterial pressure at hypertension was marked, frequency and weight of hypertensic crisis, attacks of stenocardia, cases of heart attack of myocardium, strokes were decreased, majority of indexes of the functional state of the cardio-vascular system got better on the whole.

Aerosolariums (air-baths) and medical beaches are organized for the primary and secondary helioprophylaxis of diseases and functional states, where conditions both for overheating and for undercooling of organism (protection from wind) should be eliminated. Duration of sun- and air-baths and is to be determined according to the special tables that are made taking into account the sun climate of area (Application 1).

The artificial sources of UVI are widely used in medical aims - at rheumatism, neuralgias, skinning tuberculosis and, especially, in surgical practice with the purpose of acceleration of repair of surgical, traumatic, battle, festering wounds and their complications. The UVR action on wounds consists in the bactericidal action of UV-rays, ability to accelerate tearing away of festering excretions, stimulation of keratoplastic functions of skin, common anaesthetic effect. Therefore the artificial sources of the UVR of wide range such as direct mercury-quartz lamps (DMQ) are used for that purpose.

The prophylactic irradiation with the use of artificial sources of the UVI of contingent of expectant and nursing mothers, children, miners, workers of industrial enterprises in the special premises named as photaries gives a very good result.

Two types of irradiating plants are used for that purpose: of long-term and short action. In the plants of the long-term action the ordinary artificial lighting of premises luminescent lamps is saturated by ultraviolet rays by the sources of UV-radiation. Thus people being in the room are exposed to the irradiation during all time of stay in it by the stream of ultraviolet rays of small intensity (photoradiating plant). Plants of short-term action are equipped in photaries.

The 3 types of artificial sources of ultraviolet radiation are widely used:

Erytemous luminescent lamps LE (EUV) are sources of ultraviolet radiation in regions A and В. Maximum of radiations of such lamp is region B (313 nm). It is used for the prophylactic and medical irradiation of people. It is made from the special uveolic glass that passing through UV-rays. The EUV lamps are produced with power 15 watt (EUV-15), 30 watt (EUV-30; LE-30; LER-30), 40 watt (LER-40).

Direct mercury-quartz lamps DMQ. The AMQ - arc mercury-quartz lamps are powerful radiants in regions A, B, C and visible part of spectrum. A maximum of the radiations of the DMQ lamps is in UV-parts of spectrum B (25 % of all radiation) and C (15 % of radiations). In this connection the DMQ lamps are used both for the irradiation of people by prophylactic and medical doses and for disinfection of objects of external environment ( air, water, instruments and other). Application of the DMQ-lamps for the irradiation of people is necessary to be with the special carefulness, because under influencing of short-wave part of spectrum (region C) there can be the burns of mucous membrane of eyes (photoelectric ophthalmia), the changes in structure a blood and other undesirable consequences. Time of irradiation and distance to the lamp is very strictly measured out, eye of the irradiated persons and personnel are protected by dark glasses. According to the power of the DMQ lamps they are divided on a few types: DMQ-2 (375 watt); DMQ-4 (220 watt); DMQ-7 (1000 watt).

Bactericidal lamps from the uveolic glass BUV (DB) are the sources of ultraviolet radiation in C region. Maximum radiation is 254 nm. Lamps are applied only for disinfection of objects of external environment: air, water, different objects. The irradiation of people by direct rays from these lamps is not allowed. In the case of irradiation there can be the same unfavorable consequences as at irradiation by the DMQ lamps. Lamps are produced with power of 15 watt (BUV-15); 30 watt (BUV-30; DB-30-1); 60 watt (BUV-60; DB-60) and 30 watt with the increased current strength (BUV-30-II). For these lamps the special screening armature that sends rays so that they can not get into the eyes of the standing man is developed.

When using erythemous photoradiating plants (long-term action) radiator is to be disposed on ceiling or on walls on a height about 2,5 м above the floor. People that are in the apartment stay in ordinary clothes but with opened face, neck and hands. Duration of irradiation is determined by time of staying in this apartment ( in the classes of schools - 4-6 hours; in kindergartens - 6-8 hours). The amount of lamps that give necessary erythemous stream is set on this data (a calculation is made according to the special formulas).

Plants of short-term action are set in the specially equipped apartments - photaries. The dosage is produced in biodoses.

When using of irradiating plants of short-term action (photaries) people are exposed to the rays by the intensive stream of UV-irradiation during a few minutes. Photaries can be of cabin, communicating and lighthouse type. The EUV-30, DMQ-2, DMQ-4, DMQ-7 lamps are used. Duration of session depends on power of source of radiation and distance to the source. Distance must be that long that duration of irradiation would be no less than 4-5 and no more than 10-15 minutes.

It is necessary to mean that the intensive ultraviolet irradiation is contra-indicated at the active form of tuberculosis, full-blown atherosclerosis, diseases of liver, kidneys, thyroid gland, malignant tumors.


Application of artificial sources of short-wave

ultraviolet radiation.


For the purposes of disinfection of objects of external environment the BUV lamps are most suitable in application.

Most practical value has the application of bactericidal lamps for disinfection of air of the closed crowded premises : waiting rooms of out - patient clinic, group rooms in kindergartens and etc. Air disinfection of premises by the BUV lamps is carried out either in presence of people or in absence of them.

Conducting of disinfection of air in presence people is most effective because people are the basic source of contamination of air by microorganisms. The upper zone of premises is irradiated by the BUV lamps screened from below with that purpose. The screened lamps are to be fixed on a height about 2, 5 м above the floor in the places of the most intensive convection of streams (above an entrance door, above heating devices etc.).

Time of irradiation of air in the closed premises must not exceed 8 hours per day. It is preferable to conduct disinfection of air 3-4 times per day with interruptions for ventilation of premises, because ozone and oxides of nitrogen appear during the work of UV-irradiators.

Power of radiation of lamp is proportional to the power consumed by a lamp from a network system. Specific power of lamps (amount of watt/ m3 volume of a room ) that is necessary for effective disinfection of air environment depends on the features of the applied lamps (bactericidal uveolic lamps (BUV) or direct mercury-quartz lamps (DMQ) and terms of their application ( in presence of people, or in their absence).

At the calculation of efficiency of disinfection by lamps BUV it is necessary that on a 1 m3 volume of the room in presence of people there should be no less than 0,75-1 watt / m 3 of power that lamp consumes from a network system.. The BUV lamps have power accordingly: BUV-15 - 15 watt, BUV-30 - 30 watt.

Disinfection of air of the room in absence people is conducted usually in the apartments of operating room, dressing room, bacteriological laboratories after the moist cleaning up. In such cases the opened lamps are placed either evenly on all premises or primary above desktops. As a rule lamp is also placed above the door in order to create a «curtain» from bactericidal rays.

The number of lamps for effective disinfection in absence of people must be such that on a 1 m 3 volume of the room there were no less than 1,5 watt/ m 3 of consumable powers. Minimum time of irradiation is 15 - 20 minutes. Disinfection of air of premises by the DMQ lamps also can be conducted both in the presence and in the absence of people. At a necessity of disinfection of air in presence of people a lamp is to be set on the height of 1,7 m above the floor with the reflector turned upwards. The irradiation is there conducted for 30 minutes once or twice in a day with intervals for ventilation of apartment. Time of irradiation of air in absence of people must be maximum increased. Power of lamps is: DMQ-4 - 220 watt; DMQ-2 - 375 watt; DMQ-7 - 1000 watt. On a 1 m 3 of volume of the room in presence of people there must be no less than 2 (2-3) watt/ m 3 of consumable power of lamps; in absence of people - no less than 5 (5- 10) watt/m 3 of power.

At the use for disinfection of sources of UV-radiation of direct action the stream of radiation from which is directed from ceiling on the floor in the apartment it is possible to be only to the personnel in protective clothes and glasses. At the use of irradiators of the mediated action with direction on ceiling the surface density of stream of energy of the reflected radiation at the 8-hours stay in the apartment must not exceed 0,5 mkwatt/m 2, and at the round-the-clock stay - 0,1 mkwatt/cm 2.

Bactericidal effect is achieved at the UV-radiation flux density 1,5 - 6 mkwatt/cm2with a wave-length 250 - 270 nm on condition of placing of the irradiated object in the distance no more than 2 m from the source.

For assessment of efficiency of bactericidal irradiation the inoculation of microorganisms from the air is held before and after irradiation and the degree of efficiency (on how many % the amount of microorganisms in a 1m3 of air after the irradiation was diminished) or coefficient of efficiency (in how many times the amount of microorganisms in a 1 m3 of air was diminished) are to be determined. These sizes must accordingly consist 80 % and 5 times.

For assessment of disinfection efficiency of air it is necessary to conduct sowing of microorganisms on the Petry’s cups with beef-extract or the special nutrient medium by the Krotov’s device before and after irradiation of the room by bactericidal lamps. After growing of microbes in a thermostat during 24 hours the calculation of colonies is to be done.

Estimation of microbial contamination of air is conducted by determination of microbial number (general number of microorganisms in 1 m 3 of air) and hemolytic streptococcus.


A microbial number is calculated on a formula:


М. n. = (A х 1000)/(Т х V), where


М.n. it is microbial number is amount of microbes in 1 m3 of air;

A is amount of colonies on the Petry’s cup;

Т is duration of selection of test of air, minutes;

V is speed of passng of air through the Krotov’s device, l/minutes.

Table 3.

Reference indices for assessmen6t of microbial contamination

(degree of cleanness) of air of some premises


Apartments

Microbial number on m3

Assessment of the air purity of air




Common microbial number

Including hemolytic streptococcus




Living quarters

Public

Children’s intitutions

To 2000

To 10

Very clean




2000 - 4000

11 - 40

Clean enough




4000 -7000

40 - 120

Moderately polluted




More than 7000

More than 120

Strongly polluted

Operating-room:

a) before operations

To 500

It must not be

Clean

б) at the end of work

To 1000

No more than 3

Clean

Dressing room:

a) before work

To 500

It must not be

Clean

б) at the end of work

To 2000

No more than 3

Clean

Manipulation room

To 1000

To 16

Very clean




To 2500

To 16

Clean enough

Wards

To 3500

To 100

Clean



Bactericidal action of ultraviolet radiation is characterized by the degree of efficiency of disinfection (DED) (relation of difference between the quantity of colonies before and after desinfection to the quantity of colonies before disinfection) and coefficient of efficiency of disinfection (CED) that shows in how many times the quantity of colonies of microorganisms were reduced as a result of disinfection).

Disinfection is considered effective if DED is 80 % and more and CED is no less than 5.

Indices after disinfection (microbial number) are compared to the information of possible bacterial contamination of air of the closed premises (look at the table 3).

Unfavorable consequences of superfluous

influences of UV-radiation on an organism.


Taking into account the high biological activity of UVR it is especially necessary to underline that the overdose of UV-rays is fraught with serious consequences. Even the single long-term stay in a bare form under sunbeams can be the reason of origin in a few hours on the irradiated areas of skin of inflammatory reaction - photoerythema, rise in temperature of body and common indisposition, sunstroke. At the permanent superfluous irradiation worsening of feel, decrease of capacity for work and resistance to action of harmful agents, sometimes weight loss, intensification of diseases of the cardio-vascular system and chronic inflammatory processes, including tuberculosis and others are developing. It is proved that superfluous insolation because of the mutagenic influence of UV-rays results in the increase of morbidity by the cancer of skin.

Negative action shows up in case of occurring of erythema with the edema of skin. Sometimes there is the full-blown dermatitis with the blushing and edema, appearance of bubbles. In cases of sensorialization of skin, its sensitiveness to UV-rays rises sharply. It is characteristic for patients with leaden intoxication, patients with a measles. The full-blown influence of ultraviolet rays on a skin can cause dermatitises with a diffuse eczema, edema, burning and itch. Such generaltoxic symptoms as headache, dizziness, rise in temperature of body, nervous excitement and other manifestations are the result of influencing on CNS..

The dose of sun radiation, in 70 times exceeding erythemous causes a blastomogenic effect - cancer of skin. Blastomogenic effect of UV-rays with a wave-length 303-280 nm is proved in the experiments on animals.

Finally UV-rays especially with a wave-length less than 320 nm are causing the diseases of organs of vision. Mainly UV-rays damage fore-part of eye and first of all cornea and conjunctiva. More frequent this influence shows up as photoelectric ophthalmia that arises up after a latent period by pain in eyeballs, decrease of acuity of vision, hyperemia and edema of conjunctiva, eyelids and eyeball, blepharospasm, lacrimation, photophobia, narrowing of pupils. Illness is accompanied by general symptomatology - headache, sleeplessness, rapid pulse, general nervousness (snow blindness).

It is experimentally proved, that artificial radiation possesses greater biological activity as compared to the natural one because the sun radiation coming to the earthly surface is actually dies out on a wave-length of 290 nm.

In connection with wide application of UV-rays in medicine medical staff undergoes the influence of it. Nowadays in connection with application of the arc welding and melting of metals, plasma cutting and sputtering, use of gas-unloading lamps the role of ultraviolet radiation increases. Workers of autogenous and electric welding, arc-furnace stoves, cameramen, movie actors during shooting can incur the influence of ultraviolet rays.

The industrial radiations that have in their structure UV-rays with a wave-length shorter 280 nm can cause electro-ophthalmia at irradiation of eyes. The characteristic symptoms of electro-ophthalmia are pain, burning, feeling of sand in eyes, headache. The edema and blushing of eyelids, swelling, conjunctivitis, photophobia, blepharospasm and lacrimation are objectively marked. Usually the disease proceeds 1-2 days.


Prophylaxis of the superfluous influence of the UV- radiation on the organism


For prevention of superfluous irradiation it is necessary to observe medical recommendations during the administration of sun-baths and implementation of physical work under an opened sun. Children, elderly and people with the diseases of vessels and heart can get the necessary dose of ultraviolet radiation in the shade (by the diffused radiation).

For prevention of super irradiation by the artificial sources of UV-radiation with the temperature of heating over 2000 C°, by luminescent sources in a polygraphy, chemical and woodworking production, agriculture, at filming, in crack detection, at disinfection of water, foodstuffs, and also in medical establishments, the admissible intensity of irradiation of workers on workplaces on height of 0,5 - 1,0 m above the floor at the presence of unscreened areas of body with their area not more than 0,2 m2 (face, neck, hands) must not exceed the values given in the table 4.


Table 4.

Admissible intensity of UV-irradiation (CH 4557-88)


Continuance

Surface density of stream (Watt/m2) in ranges (nm)

Single irradiation

Pauses

Irradiation during shift

UV-A 400-315

UV-B 315-280

UV-C 280-200

Less than 5 minutes

more than 30 minutes

less than 60 minutes

50

0,05

0,001

More than 5 minutes

it is not taken into account

50% of shift

10

0,01

is not allowed


Individual security facilities such as glasses, shields and helmets, supplied by the special dark glasses, or masks with glasses detaining UV-rays and protecting eyes from the high brightness of volt arc at the arc welding have the highest importance in the system of prophylactic measures. The great importance has application of self-powered head, separated isolated booths during conduction of stationary works and movable screens in the absence thereof of the permanent workplace of the welder.. In the apartments, where everyday the electric welding is held it is recommended to paint walls and ceilings by oily paints containing the oxide of zinc and oxide of iron, which absorb ultraviolet rays and prohibit from their reflection from these surfaces.

During work with mercury-quartz lamps in medical establishments protective glasses and insulating screens are applied.

During filmings volt arcs are screened by glasses that do not pass UV-rays through. In the studios it is also recommended to paint walls and ceilings by paints absorbing ultraviolet rays what prevent their reflection.

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