Re: Nook 3G
As an electronics engineer I can tell you that all electronics emit EMF radiation to some extent.
There is much controversy as to what EMF (electromagnetic field) level can be considered safe. Since the experts have not arrived at any consensus, you will have to decide for yourself. Many utility and government documents report the usual ambient level of 60-Hz magnetic (house current in your walls) field to be 0.5 mG. ("mG" stands for milliGauss)
Therefore, any reading higher than 0.5 mG is above the 'usual' ambient exposure. Many public officials and experts, as well as the few governments that have made an effort to offer public protection, have adopted the 3 mG cut-off point. The EPA has proposed a safety standard of 1 mG. Sweden has set a maximum safety limit of 1 mG.
With wifi and 3G turned off, the EMF from a nook will probably barely register. Even with it on, you will most likely not get a reading above 0.5 mG. My iPhone doesn't even register on my EMF meter. The average compact fluorescent puts out 30-40 times more EMF than a cell phone or laptop.
The point is, no one knows exactly what the safe limits of electromagnetic radiation are, but the computer you used to post on this board probably puts out far more EMF than the nook even with wifi and 3G turned on. The only way to limit exposure to EMF in this technological age is by eliminating all electronics and electricity from your life and moving to a log cabin in the middle of nowhere. 
