In modern society, electromagnetic field (EMF) pollution is becoming severe and widespread, as electrical appliances and electronic devices becoming pervasive in our workplace, home and environment. As most appliances and devices draw their power from the power grid (60Hz or 50Hz depending on your country), power line related (i.e. power transmission network as well as power-drawing equipment and devices) noises are most prominent in our living environment. In addition to strong power line related EMF pollutions (generally <500Hz), there are additional higher frequency EMF pollutions emitted by switching power adapters (generally from 10KHz to 1MHz), and various radio-frequency (RF) emissions by communication equipments from 10MHz all the way to 10GHz or higher, transmitted by radio stations, TV stations, cordless phones, cell phone towers and cell phones, and WiFi stations.
Since human body does operate with electromagnetic principles (such as our brain, nervous system, as well as cellular operations), our body does react to external EMF stimuli, even if not always detectible or noticeable by our senses. The biological system itself generally operates at <300Hz, and so EMF pollution within DC to 300Hz spectrum should be of particular interest to us. At higher frequencies, it may be the embedded modulations (at lower "content" frequency) that can interact with biological system. At still higher frequency (such as used by cell phone, WiFi, etc.), the direct absortion and heat generation from such RF energy may cause "cooking" and damaging to our microscopic cellular structures.
Please search the web and follow the link http://en.wikipedia.org/wiki/Electromagnetic_radiation_and_health to find out more information.
Human body (essentially a saline bag) is a conductor and an antenna that absorbs and interacts with all the EMF pollutions in our vicinity. In fact, human body itself is an excellent antenna and measuring instrument for assessing our environment. We just need to measure the actual EMF picked up by our body.
1. we need a measuring instrument that's totally isolated from any of the utility sources. A portable bio-sensor kit for measuring EEG or ECG using battery is an excellent choice. Choose the bio-sensor with full-differential inputs (or "bipolar" configuration) to minimize common mode noises that may artificially amplify certain ambient noises. Also make sure the bio-sensor does not filter out utility noises intentionally, otherwise the true EMF pollution level cannot be determined.
2. Simply walk through your environment and get close to each appliance or equipment without touching them directly or through any solid material, while your sensor is turned on and recording. Stay at locations of interest for at least 10 seconds and enter suitable tags if needed to identify the locations of interest.
3. Play back the recorded data to see all the EMF pollution picked up by your body at various locations, applying EMF pollution filter (50Hz, 60Hz and all their harmonics) to get power density readings for all the locations.
4. Play with each appliance and equipment to identify the suitable safety distance when it's operating. Record down your own safety instructions based on the EMF pollution limits you're comfortable with for you and your family members.