Do you know what is W/sq-m, dBm and milliGauss?

The W/sq-m measures how many watts (RF power) per square meter in the field.

The dBm is how many times of power level compared to 1mW, use 1mW as reference (most commonly used in RF communication), 10 dBm means 10 times the 1 mW therefore it is 10 mW.  NOTE: dBm is in log scale, 3dBm = 10log2 ( 2mW, 2 times of 1mW), 10dBm = 10log10 (10mW, 10 times of 1Mw)

This is used to reduce the number of zero while calculate the powers.  0dBm is 1mW, 10dBm is 10mW, 20dBm is 100mW, 30dBm is 1,000mW and 40dBm is 10,000mW, -10dBm is 0.1mW, -20dBm is 0.01mW, -30dBm is 0.001mW, -40dBm is 0.0001mW, -50dBm is 0.00001mW.

The milliGuass (mG) is used to measure the magnetic flux density, how strong the magnetic field changes from the low frequency current, used in measuring the field level of AC power lines, transformer, etc.  Anything using coil to transform power will generate the magnetic field radiation. 

MilliGauss is normally used to see the safety level.  Normally less than 10mG is preferred in the living environment (based on some research) the RF field and magnet field reduced by squre of distance.  Therefore, keep a good distance from the source will reduce the radiation level very fast.

There are RF/EMF/LF meters and detectors in the market  if the above units of measurement.