Understanding SAR and WiFi waves: Health and Safety

WiFi waves, cell phones, connected objects... Our daily lives are full of devices emitting electromagnetic waves. With them, one question often comes up: what are the risks to our health? At the heart of this debate lies a key indicator: SAR. This article explains everything you need to know about the Specific Absorption Rate, so you can get a clearer picture.

What is SAR?

SAR, or Specific Absorption Rate, is a measurement that indicates the amount of electromagnetic energy absorbed by the human body when exposed to a device emitting radio waves (such as a cell phone, tablet or WiFi router). This measurement is expressed in watts per kilogram (W/kg). A SAR of 1 W/kg means that one kilogram of body tissue absorbs one watt of power from radio waves. The lower this value, the less intense the exposure.

It can therefore be used to assess the potential effects of electromagnetic waves on biological tissues.
SAR is mainly used to :

• Assess the conformity of devices to safety standards.
• Inform consumers.
• Protect public health.

What are the regulatory limits for SAR in Europe?

To guarantee user safety, health authorities have set limits that must not be exceeded. In Europe, these limits are defined by RED Directive 2014/53/EU and the recommendations of the International Commission on Non-Ionizing Radiation Protection (ICNIRP).
The SAR limit values are as follows:

• Head and trunk SAR: 2 W/kg (for a device used close to the ear or body).
• Limb SAR: 4 W/kg (for a device held in the hand or in a trouser pocket).

These regulations apply to a wide range of equipment, including cell phones, tablets, connected watches, Bluetooth headsets and WiFi routers. In France, the Agence Nationale des FRéquences (ANFR) is responsible for monitoring the compliance of these devices.

Which devices emit the most?

Comparative electromagnetic field intensity according to distance from AP equipment, landline phones, smartphones, laptops and Bluetooth mice

Please note that the measurements expressed in this table are not in W/kg. It is the equipment manufacturers who communicate the SAR in order to access the European market. Manufacturers must compile a file proving that they meet the obligations defined by European Union directives.

This table describes the level of electromagnetic field intensity received by equipment (with standard power) according to distance.
When comparing the equipment most commonly used on a daily basis, the emission power of a WiFi router or computer is much lower than that of a cell phone.
A person working on a computer, connected to a terminal 2m away and having a telephone conversation (in 4G mode) with a customer will be exposed to 19.822 mW of electromagnetic field intensity.
The distance between the device and the body plays a crucial role. A router is usually far away, while a telephone is often glued to the head or carried in a pocket.

Illustration of average SAR by type of equipment*.

Sources: Belgium Public Health and EMF-Portal

All our manufacturing partners' equipment must comply with marketing requirements, particularly with regard to SAR, to ensure the health and safety of our customers and end-users.

WiFi waves and health: untangling preconceived ideas

Organizations such as the WHO, ANSES and the European Commission all agree that, at regulated exposure levels, WiFi poses no proven health risk. However, as a precautionary measure, certain recommendations do exist, such as switching off WiFi at night.
To sum up, SAR is an essential indicator for assessing exposure to electromagnetic waves. While cell phones are the main source of personal exposure, WiFi remains relatively low in intensity, especially given the distance at which it is used: the network infrastructures deployed by Wifirst therefore pose no danger to customers and end-users.