A study into potential health risks

At BRICT, we place the highest priority on children’s safety, and we believe it is important for children to grow up and develop as naturally as possible. It’s in our DNA. When it comes to many things that are considered normal in our modern society, we ask ourselves whether they offer only benefits or whether there are negative consequences, particularly for children.

This led us to the topic of ‘Wi-Fi’, which we had the option of incorporating into one of our projects. On the one hand, we hear that Wi-Fi is completely harmless, whilst on the other hand we hear serious warnings. We take these warnings very seriously, but we cannot make decisions based solely on people’s opinions. We therefore decided to conduct our own research in order to reach a conclusion.

What is Wi-Fi?

We’ve started looking into exactly what Wi-Fi is. Everyone is familiar with Wi-Fi from everyday use, but what technology does it actually involve? And what are the differences between Wi-Fi and, for example, the old-fashioned radio signals you used to listen to music on an AM or FM radio?

Wi-Fi modules, the components found in laptops, for example, are small transmitters and receivers with limited power. Traditional radio stations have powerful transmitters. Some small transmitters have a power output of 0.5 kW, whilst larger ones can have a power output of 2,000 kW or more [1] . Wi-Fi modules are permitted to transmit within the EU at a maximum power of 100 mW [2] , which is considerably lower than the power used by radio transmitters. Of course, Wi-Fi only needs to cover a distance of a few hundred metres at most, whereas radio transmitters cover tens or hundreds of kilometres.

Is Wi-Fi radiation dangerous?

To determine whether something is dangerous, we must first identify the potential risks associated with a particular technology. The potential danger posed by Wi-Fi stems from the electromagnetic radiation generated by (radio) transmitters. In our research, we have identified three mechanisms that could cause harm to the human body.

Energy transfer (ionisation and heating)

Energy radiation can ionise atoms or molecules, which means that electrons are removed, causing chemical bonds to break and potentially leading to DNA damage or cell mutations. Ionisation only occurs with radiation having an energy of approximately 10 eV (electron volts) or higher [3] , which corresponds to frequencies of approximately 2.42 PHz or higher [4] . Wi-Fi signals operate at a frequency of 2.4 GHz (802.11b and 802.11g) or 5 GHz (802.11n), which falls within the Super-high frequency (SHF) band. SHF has a frequency range of 3 to 30 GHz [5] and an energy between 12.4 μeV and 124 μeV. Wi-Fi can therefore never cause ionising effects.

It is possible for cells to heat up, provided sufficient transmission power is used. Within the European Union, a Wi-Fi module is permitted to transmit at a maximum of 100 mW (20 dBm). The International Commission on Non-Ionising Radiation Protection (ICNIRP) states that no harmful heating occurs if the radiation power is below 10 W per kilogram of body weight [6] .

A Wi-Fi module typically operates at its maximum power when transmitting, i.e. 100 mW continuously. Of course, a Wi-Fi module does not transmit continuously, but for the sake of argument we will use the maximum values and assume that a Wi-Fi module does transmit continuously.

The effective power reaching a person’s body depends on the distance between the Wi-Fi module and the body. The effective power decreases very rapidly. To calculate this, the following formula applies:

S = P / (4πr²)

Where S is the effective power at a distance r (in metres) with a transmission power of P (in watts). Below are three calculations of the effective power of Wi-Fi at distances of 10 cm, 30 cm and 1 metre.

• At 10 cm:  0.1 / (4π·0.1²) ≈ 0.796 W/m².
• At 30 cm:  0.1 / (4π·0.3²) ≈ 0.088 W/m².
• At 1 metre:  0.1 / (4π·1²) ≈  0.00795 W/m².

Now that all this data is known, it needs to be applied to the most vulnerable members of our society, namely babies. The amount of energy transfer depends on a baby’s body surface area. This can be calculated using Mosteller’s formula [7] , which reads:

S = 

On average, a baby girl weighs 3,374 grams and is 50 cm long [8] . The average surface area of her skin is therefore

S =  = 0.216 m²

At a distance of 10 cm, we can therefore conclude that a baby is exposed to 0.796 W/m² * 0.216 m² = 0.172 W of power. The limit for the same baby is 10 W/kg, or 10 W/kg * 3.374 kg = 33.374 W. This means there would be no risk of heating due to energy transfer for babies, let alone for older children or adults.

Chemical and biological reactions

Depending on its frequency and intensity, non-ionising radiation can influence biological processes (e.g. thermal stress or, in some cases studied, subtle signalling pathways), but evidence of harmful non-thermal effects is generally limited or unclear.

Some studies suggest that Wi-Fi causes oxidative stress in the body’s cells [9] , whilst others dispute this or, to some extent, downplay it. It is important to base conclusions on facts rather than opinions, and at present there have been too few in-depth studies to reach a conclusion. It is unclear whether few such studies have been conducted because this is a complex subject, making targeted studies costly, or whether industry interests may be at play here.

Accumulation and dose-dependence

In addition to the direct effects of electromagnetic radiation, cumulative exposure also plays a role. This effect is well known to specialists who work with X-rays, for example. A single exposure to X-rays at a specific dose is generally not harmful. However, with repeated exposure, there is a greater risk of harmful effects. That is why these specialists must stand behind a protective wall or window during every X-ray, whilst the patient is briefly exposed to the radiation.

The same phenomenon applies to electromagnetic radiation. Regular exposure to small doses may pose risks in the long term. There are currently no guidelines on this. Furthermore, Wi-Fi is a relatively new technology. Whereas electromagnetic radiation used to be caused by a limited number of powerful (radio) transmitters, we now have Wi-Fi modules which, although they transmit at low power, are located in a great many places in our immediate surroundings.  It is not yet clear what the long-term consequences of this will be.

Conclusion

Wi-Fi technology is a fantastic way of enabling wireless communication. There are now many useful (and also useless) applications made possible by this technology; it is difficult to imagine a modern world without Wi-Fi. At the same time, however, there is still much uncertainty surrounding the health risks associated with Wi-Fi.

For us, children’s health and safety are our top priority. There are alternatives for enabling communication between devices, both wired and wireless. That is why we choose to use Wi-Fi technology as little as possible—preferably not at all—in our solutions. Infrared, for example, is a very interesting alternative that we will be investigating further in the near future.