There are basically two types of electromagnetic exposure. One is to microwaves such as emitted by smart meters as well as devices using radio frequencies, including cell phones, microwave ovens, cordless phones, as well as wifi and blue tooth devices.
The second type has to do with electrical wiring and surges in electrical flow, particularly with certain appliances containing circuit boards. This is discussed on the page dealing with Dirty Electricity.
This map shows wifi radiation as measured from a car while circling the loop. It shows the position of the cell tower in relationship to the readings taken from the street. The map was created by Dr. Carl Botefuhr after testing with the Acoustimeter AM-10.