In situ exposure assessment of intermediate frequency fields of diverse devices

In this study, in situ exposure assessment of both electric and magnetic fields of different intermediate frequency (IF) sources is investigated. The authors investigated smart boards and touchscreens, energy-saving bulbs, fluorescent lamps, a portable hearing unit and an electrosurgical unit (ESU). For most of these sources, the electric field is the dominating quantity. International Commission on Non-Ionizing Radiation Protection reference levels are exceeded for touchscreens (44 kHz: up to 155.7 V m(-1) at 5 cm), energy-saving bulbs (38-52 kHz: up to 117.3 V m(-1)), fluorescent lamps (52 kHz: up to 471 V m(-1) at 5 cm) and ESUs (up to 920 kHz: 792 V m(-1) at 0.5 cm). Magnetic field strengths up to 1.8 and 10.5 A m(-1) were measured close to the ESU and portable hearing unit (69 V m(-1)), respectively. Large differences of measured field values exist among the various operating modes of the IF equipment. Compliance distances for general public range from 15.3 cm (touchscreen) to 25 cm (fluorescent lamps).