This Lutron EMF-827 EMF meter is a simple to use hand held meter which has been designed for measuring electromagnetic fields (EMF) between 0.1 milli gauss and 200 milli gauss. The Lutron EMF 827 gauss meter can be used to confirm the presence of electro magnetic field radiation by reading the value and then by searching with the detection probe the radiation source / sources maybe identified. The detection range includes industrial electrical currents at 50Hz/60Hz & their harmonics. Unit displays in Tesla.
A lot of people are worried about the long term effects and the biological consequences* on the human body. Electromagnetic fields EMF are the resultant of an electrical field component and a magnetic field component: transformers (including sub stations), high voltage power lines mounted on pylons, electro magnets, cathode screens, electric ovens etc.
These often high level fields create disturbances in their immediate environment, with a variety of effects: buzzing in telephones, oscillating picture on cathode ray tubes (TV and monitors), defective reading of magnetic tapes, EMC coupling problems in cables high and low currents.
* It is now accepted that the proximity of high voltage electricity lines or major sources of electrical current
(underground /overhead cables) can cause serious health problems for some people.
Here are 2 useful links that may be of interest:
NRPB (National Radiological Protection Board): about EMF & Electromagnetic Radiation
A review of Electromagnetic Fields associated with Motorised Appliances produced for the HSE (Health and Safety Executive)