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Non-Ionizing Radiation Jan Jakuš
Definition Non-Ionizing radiationincludes all kinds of ele-ctromagnetic (elmg.) radiations with frequen-cies < 1015 Hz and wavelengths λ = 10-8 - 104 m. i.e. ultraviolet radiation ( UV- light),Visible light, Infrared radiation ( IR-light), Microwaves, Long ,Medium, Short, and Ultra-short radiowaves. These elmg. radiations never create electrically charged IONS (cations+ and anions-) when tar-geting atoms or molecules. γ-Rays X-raysUV VL IR R a d i o W a v e s J J I o n i z i ng N o n – I o n i z i n g
1. Ultraviolet Radiation (UV-Light) UV Lightis invisible radiation with λ = 100- 400 nm, Sources: natural (Sun), artificial (mercury lamps ) Classification: UVA- long wave,“black-tanning light“ λ= 315-400 nm UVB- medium wave,“inflammatory“λ = 280 - 315 nm UVC- short wave,“killing germs“λ = 100 - 280 nm (comes only from artificial sources, a part of UV below 100 nm is ionizing) Earth is targeted from Sun by UVA (90%) and UVB (10%)lights. 90% of UVB is absorbed by O3 and O2 Ozone O3 andO2 lower the intensity of UVA and UVB lights and totally absorb UVC light Ozone holes- increase alevel of UV radiation!
Effects of UV Radiation on Human Body Skin:Erythema(Sunburn)„earlyredcoloured skin inflammation“- appearsafter 2-3 hoursofSun (UV) exposure) Tanning(delyedpigmentation, because productionof skin pigment melanine.( itstartsapprox. 24- 48 hoursafterexposure) Vitamine Dproduction-for bone calcification Skin Aging(Wrinkles, Dry skin, Skin cancer- melanoma) Eye: Inflammation- Conjunctivitis, Pain, Cataract IMUNITY: increases.Overexposure- decreases
Protection against UV- light overexposure • Avoid tanning newborns and very young children • Avoid tanning between 10 a.m.- 2 p.m, when intensity of Sun light is the highest (in the Middle Europe) • Always take sunscreens- with anti-UVA and UVB factors, wear anti- UV glasses,cover head by wide hats, protect body with summer dress, and use sunscreens without parfums ( to prevent skin alergy) • Sunscreans for tan must contain both anti UVA and UVB protecting factors (at least No 20 for level of Sun radiation in the Middle Europe) • Do not tan when taking remedies (e.g. antibiotics, sulfonamids, etc.) • Avoid visit solaria frequently - mainly persons with blond hairs and light coloured skin - do it with care! • Take in mind- skin has its own „memory“ and re-members its burning by UV-light overexposure! • Burning of skin in childhood is very dangerous, lea-ding to cancer in adult age, as well ! • Take into account the Solar index, given in Australia, or Mexico
2. Mobile Communication- Ultra High Frequency (UHF) radiowaves • It is an electromagnetic (elmg.) radiation with frequencies btw. 300-3000 MHz, and λ = 1 - 0.1m • Is kind of non-ionizing radiation • Is used at TV and Mobile Transmissions • Mobile Phones work mostly under frequency 900,1800 and 2100 MHz. • Mobile phone is smalltransceiver,periodically connecting by radiowaves with Basic Mobile Station (BMS are placed on the top of hills, on the roofs, etc.) • The intensity of electromagnetic radiation in a vicinity of BMS is very high and danger for body
Effects of Mobile Radiowaves During calling- elmg. radiation from mobile spre-ads to an environment as a radiosignal. The wea-ker is a received signal ( e.g. in car, train, or in buildings builded from steel and concrete)the higher is an intensity of emitted elmg. radiation. This radiation affects the head, ear, neck also the digits and hand of calling person on the side whe-re a phone is taken by a hand.
Absorbtion of Mobile Radiowaves by Body The depht of penetration of mobile radiation to tiss-ues is 1-2 cm (affecting mostly the brain structu-res, also the face , ear and eye structures). The index for Specific Rate of Absorbtion (SAR)for brain tissue was established. N= 1.6 (W.kg-1) For a particular value of SAR valid for phones see the box where the mobileis stored. The intensity of mobile radiation is low (2 W), howe-ver in brain,theintensity maybe add together (summated)above normal value of SAR.Thus the effectsdepend both on the intensity of mobile elmg. radiation and a time of calling(exposure).
Biological Effects of Mobile Radiowaves 1. ThermalEffects-passingthetissueradiowavescreateheat - temperaturewithinthebrainrisesup (approx. per 0.10 C during 12 min. timeofcall), and this, in turnmaydamagetheneurons. Disordersoftheoptic and cochlearnerveswerealsopublishedlately. Also a decreaseofhormonmelatoninewasfound. Subjectivellypersonswerecomplainted on : burning and itchingofearand face skin witherythema, somefeelingofheat in theoutherear, badconcentration, sleepingdisor-ders, etc. 2.Non ThermalEffects-to-datemechanismsare obscure, howeverscientistspresumepossibilityforappearanceofbraincancere.g. astrocytoma(withlocationatthesideofhead, thatisdirectlytouched by phone).
How to use mobiles safely? • Buy only phones with SAR <1.6(W.kg-1):look for SAR number being placed on the box or look for www.pages • Do not call when driving or travelling by train (i.e. avoid do make calls at all places with low signal !) The lower is signal the higher is a phone radiation. Calling when driving lowers the driver attention. Avoid ! (It is under penalty of law) • Do not a call over 2-3 minutes, as well. • Do not touch the head with a part of phone where there is an antena. • Do not allow to children (at least till 6 years of age) to use and make calls from pocket phones. • In pacient with cardiostimulator (pacemaker) do not recommend patients to store the phone in a pocket of a shirt, but at least 20 cm away of the heart (ussually on an opposite side of a body)
