The value cited is then the maximum level measured in the body part studied over the stated volume or mass.
Depending on the size and capabilities of the phone, additional testing may also be required to represent usage of the device while placed close to the user's body and/or extremities.
[4][5] Frey reports that the microwave hearing effect occurs with average power density exposures of 400 μW/cm2, well below SAR limits (as set by government regulations).
An additional safety factor of 5 is introduced for exposure of the public, giving an average whole-body SAR limit of 0.08 W/kg.
The FCC guide "Specific Absorption Rate (SAR) For Cell Phones: What It Means For You", after detailing the limitations of SAR values, offers the following "bottom line" editorial: ALL cell phones must meet the FCC’s RF exposure standard, which is set at a level well below that at which laboratory testing indicates, and medical and biological experts generally agree, adverse health effects could occur.
Such studies can possibly shed light on thresholds of non-ionizing radiation effects and cell capabilities (e.g., oxidative response).
Whole body SAR is a widely accepted measure for relating adverse thermal effects to RF exposure.