Electromagnetic Fields 2015 Update

6. Intermediate frequency (IF) fields like those from induction ovens

• 6.1 What are the sources of intermediate frequency fields (IF fields)?
• 6.2 What possible health effects of intermediate frequency fields have been studied?

6.1 What are the sources of intermediate frequency fields (IF fields)?

In this summary, intermediate frequency (IF) fields designate electromagnetic fields with frequencies ranging from 300 Hz to 100 kHz, roughly the frequencies that are lower than radio frequencies (RF) and higher than extremely low frequencies (ELF).

Applications generating intermediate frequency fields have been increasing in recent years and will likely continue to do so. Examples are some anti-theft devices operated at the exits of shops, induction hotplates, computers, compact fluorescent lamps, as well as some radio antennas. Such fields are also generated by some industrial uses such as inductive metal heating and welding. In most cases exposure is limited, but for radio transmitters and industrial applications, exposure can be above the recommended limits, so safety precautions should be taken.

Some medical applications lead to exposures in this frequency range, like interference current nerve and muscle stimulators.

6.2 What possible health effects of intermediate frequency fields have been studied?

Well-known biological effects at the IF range are nerve stimulation at the lower end of the range and heating at the upper end of the range. These are explained by the mechanisms known to occur in the RF and ELF ranges.

There are still too few new studies on health effects from IF exposures in general, and no epidemiological studies have appeared. The data are thus still too limited for a specific risk assessment in this frequency range.

In view of the increasing exposure to IF, experimental studies on biomarkers and health outcomes in this area have been identified as a priority for research.