The electromagnetic radiation you are exposed to when standing close to an active microwave oven is much higher than a 5G cellular tower, a MyBroadband investigation has shown.
Even though the radiation from the microwave was much higher, it remained within the safety thresholds of the International Commission on Non-Ionizing Radiation Protection (ICNIRP).
MyBroadband sent a researcher to several cellular masts around the Gauteng area to see if the electromagnetic radiation they emit present any danger to the people living around them.
For points of comparison, he also measured the radiation emitted from a microwave oven and Wi-Fi router.
All testing was performed using an RS Pro IM–195 RF Field Strength Meter.
The current scientific understanding is that electromagnetic waves up to the visible light spectrum are unlikely to be harmful to human health below certain power thresholds.
Electromagnetic fields that run at frequencies higher than that of ultraviolet light are known as ionising. Ionising electromagnetic radiation, such as that caused by x-rays and gamma rays, can damage DNA and are known to cause cancers.
Non-ionising radiation does not cause DNA damage as ionising radiation does, but it may be harmful to human health at high enough power levels.
For example, microwave ovens use electromagnetic waves with frequencies around 2.45 gigahertz (GHz). This is in the same vicinity as technologies like Wi-Fi and Bluetooth.
The difference is that microwave ovens emit these waves at a much higher power level, measured in Watt (W), compared to Wi-Fi and Bluetooth devices.
Hertz is a measurement of how many times a wave oscillates every second, whereas Watt is a measure of the wave’s power.
The ICNIRP defines safe reference levels for the general public at the following power densities. As the frequency of the electromagnetic wave increases, the safe power density increases:
- 900MHz — 4.5 W/m2
- 1.8GHz — 9 W/m2
- 1.9GHz — 9.5 W/m2
- 2.0GHz+ — 10 W/m2
To get a sense of the ambient electromagnetic radiation we are exposed to, we took a baseline reading outside, in a suburban neighbourhood.
The measurement varied from about 0.002W/m2 to 0.004W/m2.
We then took measurements at varying distances from a cellphone tower, and the highest reading we got was 0.004W/m2 — entirely within what is considered normal.
Our researcher said it wasn’t possible to get a proper reading from the tower due to the inverse-square law.
The inverse-square law states that the further you move away from a radiation source, the lower the amount of radiation you are exposed to.
If you double the distance between you and a source of radiation, you quarter the level of radiation that you are exposed to.
In practice, this principle causes the strength of the radiation to drop off very quickly as you move away from the source of the radiation.
Since the transmitters are so high up, that means it is safe even directly underneath the tower.
The inverse-square law’s dramatic effect was demonstrated when our researcher measured the radiation from a Wi-Fi router.
We obtained our maximum measurement of 0.8 W/m2 from the router when our field strength meter was right on top of it.
Stepping just a meter or so away from the router resulted in the measurement dropping to our baseline reading of between 0.002W/m2 and 0.004W/m2.
As a final test, our researcher took some readings around the office microwave.
While it also demonstrated the effect of the inverse-square law beautifully, measurements directly in front of the microwave door got up to 4W/m2.
Our researcher noted that the microwave has some small gaps in the Faraday cage along the edges of the door.
At these gaps, the maximum measurement got up to 8W/m2.
This is very close but still under the ICNIRP safe limit of 10W/m2 at 2.45GHz.
It should be noted that the ICNIRP guidelines are reference levels intended to be averaged over 30 minutes across the whole body.
“These tests indicate that current levels of RF exposure are below what is considered safe levels,” MyBroadband’s researcher concluded.
“It also indicated that devices such as microwaves that have been around for more than 50 years should be of greater concern than some new technologies such as 5G mobile networks.”
The following table providers an indicative summary of the readings taken during this experiment.
|Electromagnetic field power density measurements|
Watt per square meter (W/m2)
|4G/5G tower||*0.004 W/m2|
|Wi-Fi router||0.8 W/m2|
|Microwave — 1m away||0.03 W/m2 – 0.05 W/m2|
|Microwave — close||4 W/m2|
|Microwave — at gap in door||8 W/m2|
|ICNIRP safety guideline for 2GHz+||10 W/m2|
|* Electromagnetic radiation from towers was indistinguishable from the ambient/baseline power density measured.|