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Demystifying radiofrequencies

Telecommunication antennas and wireless devices emit radiofrequencies. Sources of information on the perceived health risks of these radiofrequencies are numerous, and some give the public unnecessary cause for concern. To help clarify, here are some of the main scientific research findings on radiofrequencies.

Description of radiofrequencies

Various applications use radiofrequencies, including the following:

  • Microwave ovens
  • Radios and televisions
  • Cellphone networks
  • Wireless telephones
  • Modems and wireless routers (Wi-Fi)
  • Wireless computer devices
  • Baby monitors

Independent telecommunications networks for police and fire services, air and maritime radars as well as wireless alarm systems also use radiofrequencies.

In each of these networks, the communication uses a determined range of frequencies. This prevents the various networks from interfering with one another. These frequencies are expressed in terms of a unit called “hertz” (Hz). The most commonly used telecommunication networks for applications destined for the general population use frequencies of a few hundred million to several billion hertz (100 MHz to 5 GHz).

Radiofrequency transmission power

The transmission power of different radiofrequency sources varies greatly and depends on the application. For example, antennas that emit FM radio and television waves are very powerful. They transmit these waves over tens of kilometres to our radios and televisions. By contrast, the transmission power of devices using Bluetooth technology is very low given that they usually transmit only a few metres.

The following table shows the transmission power of some common sources of radiofrequency. Transmission power is measured in watts (W).

Transmission power of some sources of radiofrequency

Radiofrequency source

Transmission power (W)


0,001 to 0,025W

Wireless telephones

0,25W maximum


0,1 à 2W maximum

New generation of Hydro-Québec electricity meters (smart meters)


Wireless Internet access (Wi-Fi)

1W maximum

Cellphone antennas

About 30W

FM radio transmitting antennas

100,000W maximum

Television antennas

2,000,000W maximum

Findings of scientific research on the perceived health risks of exposure to radiofrequency fields

Assessment of the perceived health risks of exposure to radiofrequency fields has been the subject of a number of studies. Different sources of radiofrequency have been examined:

These studies conclude that radiofrequency poses no health risk when exposure remains below the limits prescribed by Health Canada’s Safety Code 6 or other recognized regulatory bodies.


The main studies on the risk of cancer associated with radiofrequency energy in humans have been conducted among cellphone users. Cellphones are one of the main sources of exposure to radiofrequency energy even if the power density of the antenna is low. This is explained by the fact that exposure also depends on the distance between the transmitting antenna and the body of the exposed individual, a distance that is very short in the case of a cellphone.

According to the World Health Organization (WHO), “A large number of studies have been performed over the last 2 decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use.” The complete fact sheet entitled Electromagnetic fields and public health: mobile phones This hyperlink will open in a new window., published in October 2014, is available on the WHO website.

Results of the Interphone Study, which was coordinated by the WHO International Agency for Research on Cancer and conducted in 13 countries, including Canada, suggest that no increased risk of glioma or meningioma (brain cancers) could be associated with cellphone use by adults over a 10-year period.

For its part, Health Canada concludes that radiofrequency exposure from cellphones “…poses no confirmed health risks…”

In terms of radiofrequency emissions from cellphone antennas, the Institut national de santé publique du Québec has published a report entitled Antennes de téléphonie mobile et santé publique : état des connaissances This hyperlink will open in a new window. (Cellphone Antennas and Public Health: State of Knowledge – in French only). The report concludes that “…given current knowledge and low levels of radiofrequency exposure from towers, the likelihood of a health risk to the general population and to those living near them can be considered low or non-existent”.

Health Canada also concludes that emissions from cellphone towers that respect established limits offer “…no scientific reason to consider cellphone towers dangerous to the public”.

To learn more, read Safety of cell phones and cell phone towers This hyperlink will open in a new window. on the Health Canada website.

Wireless Internet Networks (Wi-Fi)

Health Canada concludes that wireless Internet network technology is safe: “As long as RF [radiofrequency] energy levels remain below Health Canada’s RF safety guidelines, current scientific evidence supports the assertion that RF energy emissions from Wi-Fi devices are not harmful”. To learn more, read Safety of Wi-Fi Equipment This hyperlink will open in a new window. on the Health Canada website.

For details on the measures taken by Health Canada to ensure that wireless Internet networks remain safe, see the Radiofrequency regulations section.

The Direction de santé publique de Montréal (Montreal Public Health Department) has specifically addressed the safe use of Wi-Fi technology in primary schools. The results of this analysis were published in 2014 in a report entitled Utilisation du Wi-Fi dans les écoles – Évaluation des risques à la santé This hyperlink will open in a new window. (Wi-Fi in Schools – Evaluating the Health Risks – in French only). Health Canada’s opinion on the safety of Wi-Fi technology is along the same lines as the report, which concludes that the levels of exposure to radiofrequency energy emitted by Wi-Fi technology are very low. The report also mentions that results of rigorous scientific studies on the effects of radiofrequency on health show no consequences associated with Wi-Fi technology.

The Public Health Department has thus concluded that the use of Wi-Fi technology in primary schools is not harmful to the health of teachers and students.

Smart meters

The level of radiofrequency energy emitted by smart meters is very low. These devices are considered one of the weakest sources of environmental exposure to radiofrequency energy, even for people who are often within a few metres of them.

The public health authorities of various regions in Québec and Health Canada have concluded that smart meters do not pose a health risk.

To learn more, consult the following:

Demystifying "electromagnetic hypersensitivity"

Some people claim to suffer from what is called “electromagnetic hypersensitivity”. They experience symptoms such as headaches, fatigue, sleep disorders and digestive problems and attribute them to exposure to radiofrequency electromagnetic fields.

These symptoms can be real. Health Canada believes, however, that they are in no way related to radiofrequency emissions from wireless technologies, including Wi-Fi, or electromagnetic fields in general.

Following its analysis of this issue, the World Health Organization (WHO) This hyperlink will open in a new window. concluded that “EHS [electromagnetic hypersensitivity] has no clear diagnostic criteria and there is no scientific basis to link EHS symptoms to EMF [electromagnetic field] exposure. Further, EHS is not a medical diagnosis, nor is it clear that it represents a single medical problem.”

“Electromagnetic hypersensitivity”, including intolerance to Wi-Fi, is therefore not a recognized problem. This conclusion is based on the most recent scientific data available and is not questioned despite the existence of some marginal opinions and wrongful diagnosis by some doctors.

Even if they cannot be linked to wireless technologies, some people’s symptoms may be a real health problem. They must consult a doctor if symptoms persist or worsen.

For further details regarding electromagnetic hypersensitivity, consult:

Radiofrequency regulations

In Canada, the provisions of Health Canada’s Safety Code 6 protect the population from exposure to radiofrequencies. Industry Canada enforces the application of this safety code. Wireless devices and associated infrastructure, such as cellular towers, must comply with the provisions of Safety Code 6 This hyperlink will open in a new window..

Health Canada regularly updates this safety code based on a review of the latest scientific research worldwide. A recent update to the code aims to better protect people of all ages, including infants and children. The current limits for exposure to radiofrequency energy are among the most stringent in the world. For further details, consult the Understanding Safety Code This hyperlink will open in a new window. page on the Health Canada website.

Last update: June 29, 2017


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