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
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,
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
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
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.