The EM Spectrum starts from radio waves (long wavelength, smaller frequency) to gamma rays (very short wave length, bigger frequency).
-It is produced when electricity flows through a conductor thereby inducing a magnetic field.-Both the electric and magnetic field make up the Electro-magnetic field and this field radiates out from the source.
Electrosmog is the invisible electromagnetic radiation resulting from the use of both wireless technology and mains electricity. It is considered as the 4th type of pollution. The common sources of electrosmog are Cordless phones, Cordless baby alarms, Mobile/cellular phone masts / towers, cell phones, WiFi, High Tension Cables, Radar / Server or Control Rooms, Areas of high density of Electrical / Electronic equipment.
Radiofrequency(RF)300Hz – 300MHz
Microwaves(MW)300MHz – 300GHz
http://www.who.int/peh-emf/about/WhatisEMF/en/ http://altered-states.net/barry/newsletter143/booklet.htm http://www.bafu.admin.ch/elektrosmog/01077/index.html?lang=en http://www.lessemf.com/fabric.html
The need for shielding comes from the mounting evidence that seem to show detrimental health effects from over exposure to electro-smog/EM radiation. Below is a summary from the The Federal Office for the Environment FOEN, Switzerland that explains the concern about electro-smog.
Referenced from :
Low-frequency magnetic fields and cancer Assessment of scientific studies in the low dose range.Status as of August 2008 Summary of the publication «Niederfrequente Magnetfelder und Krebs» www.umwelt-schweiz.ch/uw-0934-d
evidences from radars and mobile communication systems Experimental oncology 33, 62-70, 2011 (June)
Health Implications for Navy Personnel Aviators & other Military Servicemen/Radar Personnel