In 2016, 28 EU Member states (UK included) transposed Directive 2013/35/EU into National Law. Workplaces must ensure staff exposure to pulsed microwave radiation, is below sensory effect llimits. Below are some excerpts from the Directive
- Page 2 (1) In these Regulations—
“direct biophysical effects” means effects in the human body directly caused by its presence in an electromagnetic field, including—
(b) non-thermal effects, such as the stimulation of muscles, nerves or sensory organs. These effects might have a detrimental effect on the mental and physical health of exposed employees. - Page 3, “sensory effects ELVs” means those ELVs above which employees might be subject to transient disturbed sensory perceptions and minor changes in brain functions
- Page 15, Annex I (S.I. 337 of 2016). Specific energy absorption (SA) is an energy absorbed per unit mass of biological tissue, expressed in joule per kilogram (Jkg-1). In the Directive, it is used for establishing limits for effects from pulsed microwave radiation.
- Page 22, Sensory effects exposure limit values (ELVs) spectrum range = 0.3 GHz to 6 GHz
Examples of wireless technology using the above spectrum include: Wi-Fi, Bluetooth, Wireless Smart Meters, 2G/3G/4G & 5G NR1
Page 23. Table A2 – Max exposures for pulsed microwave radiation.
Using 1998 ICNIRP guidelines (below). We can estimate a 2.4Ghz signal of approximately 250mW/m2 will cause an SA of circa 10mJkg-1
The microwave hearing effects have been attributed to a thermoelastic interaction in the auditory cortex of the brain, with a threshold for perception of about 100–400 mJ for pulses of duration less than 30 ms at 2.45 GHz (corresponding to an SA of 4–16 mJ kg-1). Repeated or prolonged exposure to microwave auditory effects may be stressful and potentially harmful.
Page 89 of EMF Safety Guidelines Volume 1, advise the following:
Exposure to high frequency fields below the relevant action level (AL) may cause interference with the normal functioning of active implanted medical devices or body-worn medical devices. Any malfunction could have potentially serious consequences. Passive medical implants that are metallic may serve as absorbing antennas resulting in local increases in RF exposure of tissues and possible injury.
The first indication of exposure to high frequency fields may be the sensation of warmth. However this may not always be the case and feeling warm is not a reliable warning signal. It is also possible to ‘hear’ pulsed fields between 300kHz to 6Ghz, so clicking, buzzing or hissing noises may be heard by exposed workers.’