Transcript Non-ionizing Radiation
Non-Ionizing Radiation
Jan Jakuš
Definition
Non-Ionizing radiation includes all kinds of ele ctromagnetic (elmg.) radiations with frequen cies < 10 15 Hz and wavelengths λ = 10 -8 - 10 4 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-rays UV VL IR R a d i o W a v e s
J I o n i z i n g N o n – I o n i z i n g
1. Ultraviolet Radiation (UV-Light)
UV Light is invisible radiation with λ = 100- 400 nm, Sources: natural (Sun), artificial (mercury lamps ) Classification: UVA nm long wave,“black-tanning light “ UVB λ = 315 - 400 medium wave,“inflamatory“ λ = 280 - 315 nm UVC short wave,“killing germs“ λ = 100 - 280 nm (comes only from artificial sources) Earth is targeted from Sun by UVA (90%) (10%) lights. 90% of UVB and is absorbed by O 3 UVB and O 2 Ozone O 3 and O 2 lower the intensity of UVA and UVB lights and totally absorb UVC light Ozone holes increase a level of UV radiation!
Ozone Hole-
Depletion of Stratospheric O 3
Effects of UV Radiation on Human Body
Skin
:
Erythema -
„
early
red coloured skin inflam mation“(appears after 2-3 hours) Tanning (delyed pigmentation, because production of melanine.
( it starts approx. 24- 48 hours after expo sure) Vitamine D production Skin Aging (Wrinkles, Dry skin, Skin cancer melanoma) Eye
:
Inflammation- Conjunctivitis
,
Pain, Cataract
IMUNITY:
increases.
O
verexposure
-
decreases
UV-light: Penetration Through Skin
1.
2.
3.
4.
5.
6.
7.
8.
9.
Protection against UV- light overexposure
Avoid tanning newborns and small 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 - wear glasses with UVA and UVB factors, cover head by wide hats , protect body with summer dress, and use grease without perfums SUNNSCREENS must contain both UV-A protecting factors (at least N o and UV B 20 for level of Sun radiation in the Middle Europe) Do not tann when taking remedies (e.g. antibiotics, sulfonamids, etc.) Avoid visit solaria blond hairs and frequently - mainly persons with light coloured skin - do it with care! Take in mind skin has its own a„ 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
• • • • • •
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 and 1800 MHz.
Mobile phone is small transceiver, 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 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).
The index for Specific Rate of Absorbtion (SAR
)
for brain tissue was established
.
N= 1.6- 2.0 (W.kg
-1 ) For a particular value of SAR in different types of phones see the box where the mobile is stored.
The intensity of mobile radiation is low (2 W), howe ver in brain, the intensity may be add together
(
summated) above normal value of SAR.
Thus,the effects depend both on an intensity of mobile elmg. radiation and a time of calling (exposure)
Biological Effects of Mobile Radiowaves
1
.
Thermal Effects passing the tissue radiowaves create heat temperature within the brain rises up ( approx. 0.1
0 C during 12 min. time of phone call ), and this, in turn may damage the neurons. Disorders of the optic and cochlear nerves were also published lately. Also a lower production of hormon melatonine was found. Subjectivelly, persons are complainted on : burning and itching of skin with erythema, some feeling of heat in the ear, bad concentration, sleeping disorders, etc.
2. Non Thermal Effects to-date mechanisms are obscure, however scientists presume possibility for appearance of brain cancer e.g. astrocytoma (with location at the side of head, that is directly touched 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 Do not call when driving or travelling by train (i.e. avoid do make calls at all places with low signal !) Do not call over 2 minutes , as well. Rather use „ hands free“ set.
Do not touch the head with an antena Do not allow to children ( at least till 6 years of age) to use and make calls from mobiles In pacient with cardiostimulator (pacemaker) store the mobile in pocket at least 20 cm from pacemaker and heart (ussually on an oppo site side of body)