Transcript Diapositive 1

MOLL Charlotte
BABY Roxane
2°8
I) Where do we find them in our life?
II) How does it work?
III) Are there consequences and impacts on our health?
1. Radio waves do not have any effects on our health and could be
beneficial to people’s health.
2. Radio wave health effects : Real and Imagined Dangers
V) Conclusion
 Recommendations
I) Where do you find them ?
 We find them everywhere:
• in outer space (radiations spread around the Earth)
• in lines (ducting , in a coaxial cable or a waveguide)
 We use them in our daily objects:
• phones
• microwave ovens
• Radars
• Satellites
• Radio
• Television
• Wi-fi
II)How does it work ?
An electromagnetic wave having a wavelength between 1 millimeter and 30,000
meters, or a frequency between 10 kilohertz and 300,000 megahertz.
 The ionosphere is important for radio
wave (AM only) propagation....
 The ionosphere is composed of the D, E,
and F layers.
 The D layer is good at absorbing AM radio
waves.
 The D layer disappears at night.... the E
and F layers bounce the waves back to the
earth.
 This explains why radio stations adjust
their power output at sunset and sunrise.
III) Are there consequences and impacts
on our health?
People are exposed to radio waves from many different sources in
everyday life and there is no clear evidence of adverse health effects at the levels
normally encountered, which are below internationally agreed guidelines.
However, there is a distinction between biological and health effects :
– A biological effect
– A health effect
We don’t know yet the effects, the consequences of the radio waves on our
health, the various discoveries and assumptions are not all scientifically proved.
This question is very important in our society and divides the population between
different opinions.
III) Are there consequences and impacts on our
health?
1.
Radio waves do not have any effects on our health and could
be beneficial to people’s health.
Mobile communications would not be possible without radio waves.
However, a substantial number of scientific studies conducted by various
research bodies have indicated that electromagnetic fields cause no
adverse effects to human health.
Indeed, in June 2000 WHO (World Health Organization), announced
that there is no indication that radio waves emissions from cellular phones
or their base stations will cause or promote cancer, there are also no other
effects on the human body which adversely affect health.
The radio frequency waves emitted by the phones, far from being
harmful, are beneficial for the memory!
III) Are there consequences and impacts
on our health?
2.
Radio wave health effects : Real and Imagined Dangers
When people are exposed to radio waves, they absorb some of the
transmitted energy in their bodies. At frequencies above 10 MHz, the main
effect is heating and partial body temperature rise.
In large doses, RFs can break down tissue in the body and wreak havoc with
DNA. Some people living near high voltage power lines (cordless phone)
complain headache, sleep disturbances, chronic fatigue, anxiety or stress ...
Since no definitive truth exists on the safety of radio frequencies in the
environment around us, consumers should at least be aware that there
could be dangers:
 Cell phone RFs (radio frequencies) may instigate brain tumors.
 Exposures to RFs have been unofficially linked to sleep disorders, headaches,
and other neurological problems.
CONCLUSION
 The tallest transmitter of radiowaves of the world is at the observatory of
Arecico, in Porto Rico, his spherical antenna measures 305 m diameter .
 Radio waves everywhere : in our daily objects.
 Many kinds of studies were done but few consistent and concrete results
have been rendered.
 So one might imply that the different scientific studies really has no idea
of the “actual” effect of RFs on people.
 Radio waves are known to have the longest wavelength
and lowest frequency.
 Recommendations:
– cell phone away from the head, heart and belly of a pregnant woman;
– teenagers under 15 years old shouldn’t have access to a mobile;
– limit the number and duration of calls;
– phone under conditions of maximum reception.
CONCLUSION