How is EMF exposure determined?
Instruments can be used to measure electric and magnetic field strengths to which people are exposed. A common measure used in many EMF epidemiological studies is the time-weighted average (TWA) exposure – a measure of the field strength combined with duration of exposure. It has been estimated from the UK Childhood Cancer Study (UKCCS) that less than 3% of children in the UK have a TWA exposure of 0.2 µT or more and about 0.5% exceed 0.4 µT. Exposure to high field strengths for short periods and low field strengths over a much longer period can be numerically equivalent when expressed as TWA.
