A long-term investigation of the electromagnetic environment with respect to radiation exposure limits

A continuous wideband (0.1-1350 MHz) survey of the electromagnetic environment has been conducted for one year. This was done using an automated measurement system installed on a rooftop laboratory near Zurich, Switzerland. The goal was to obtain a detailed picture of the electromagnetic radiation levels at a site not strongly dominated by a single source nor containing significant EMI sources outside the normal lawful limits, and to relate these results to the exposure limit values for the general population issued by IRPA (International Radiation Protection Association). It was found that exposure is dominated by signals in the medium and short wave bands, although significant activity was seen across the measured spectrum, reflecting the densely populated and industrialized monitoring location. No outstanding illegal EMI sources were detected. The authors show that values of the EM field of up to 130 dBμV/m may be obtained for the frequency range 0-30 MHz