Every day, we’re surrounded by Wi-Fi signals, whether from our routers, smartphones or connected objects. This constant exposure raises a legitimate question: can these electromagnetic waves have a harmful effect on our bodies? In the light of public concern and ongoing scientific research, we need to examine the nature of Wi-Fi waves, their mechanisms of action and possible recommendations for more prudent use.
What are electromagnetic waves?
Electromagnetic waves are disturbances propagating in space in the form of electric and magnetic fields oscillating perpendicularly to one another. They are characterized by their frequency (in hertz) and wavelength (in meters), which are inversely proportional. These waves are used to transmit information in various forms: radio, television, mobile telephony, Wi-Fi, etc.
Wi-Fi waves belong to the radio wave family and are used to transmit data wirelessly over short distances. They propagate through the air, but can be attenuated by physical obstacles such as walls or interference from other electronic devices.
Wi-Fi uses two main frequency bands:
- 2.4 GHz: an older band, with greater range but lower throughput.
- 5 GHz: a more recent band, offering higher speeds but shorter ranges.
- The 6 GHz band (Wi-Fi 6E) has recently become available, improving speed and reducing interference.
To better understand where Wi-Fi stands in relation to other types of electromagnetic waves, here’s a comparison chart :
| Wave type | Frequency range | Examples of use | Approximate wavelength |
|---|---|---|---|
| Radio waves | 3 kHz – 300 GHz | AM/FM broadcasting, Wi-Fi, mobile telephony | 100 km – 1 mm |
| Microwaves | 300 MHz – 300 GHz | Wi-Fi, microwave ovens, satellite communications | 1 m – 1 mm |
| Mobile telephony | 700 MHz – 3.5 GHz | Mobile networks (2G, 3G, 4G, 5G) | 42 cm – 8 cm |
| Wi-Fi 2.4 GHz | 2.4 GHz | Home wireless networks | ~12.5 cm |
| 5 GHz Wi-Fi | 5 GHz | High-speed wireless networks | ~6 cm |
| 6 GHz Wi-Fi | 6 GHz | Next-generation Wi-Fi (Wi-Fi 6E) | ~5 cm |
Electromagnetic waves fall into two broad categories:
- Non-ionizing radiation: this type of wave has insufficient energy to extract electrons from atoms. It includes radio waves, microwaves, infrared and visible light. Wi-Fi falls into this category and therefore presents no proven danger to human health, according to current standards.
- Ionizing radiation: this type of wave has sufficient energy to ionize atoms and potentially damage DNA, which can have harmful effects on health. It includes ultraviolet (UV) rays, X-rays and gamma rays.
Wi-Fi uses frequencies in the microwave and radio wave range. It is a non-ionizing radiation and does not present the risks associated with ionizing radiation such as X-rays or gamma rays.
Find out how to recover your Wi-Fi password in clear text under Windows 11.
Global players are unanimous
Wi-Fi waves belong to the radiofrequency (RF) spectrum and are the subject of a growing number of investigations to assess their potential impact on health. Several lines of research (ranging from in vitro studies on human cells to epidemiological surveys, not to mention the opinions of international health organizations) now provide a global and nuanced view of this issue.
In vitro studies provide a first level of analysis for understanding the direct effects of Wi-Fi waves on human cells. Numerous studies, published in specialist journals such as Bioelectromagnetics and Environmental Research, have exposed cells to electromagnetic fields under controlled experimental conditions. These studies focus on several biological markers:
- Cell viability: In the majority of experiments, exposure to RF levels corresponding to international standards (set by ICNIRP) does not appear to induce significant changes in cell survival.
- Gene expression and oxidative stress: Some research has suggested that exposure may influence the expression of certain genes, or increase oxidative stress associated with alterations in cellular function. However, these effects are generally observed under conditions of intensive or prolonged exposure far exceeding the exposure levels to which the population is normally subjected (extreme cases).
- Cellular repair and apoptosis processes: Some studies have investigated the activation of DNA repair and apoptosis mechanisms, without revealing any alarming disturbances when exposure remains in line with international recommendations.
Overall, the majority of in vitro studies indicate that under experimental conditions mimicking everyday exposure, effects on human cells remain weak or even non-existent. These results underline the importance of continuing investigations to better understand the potential mechanisms of unconventional exposure.
Is Wi-Fi dangerous for plants?
Wi-Fi waves, widely used for wireless connectivity, emit radiofrequency (RF) electromagnetic fields in the 2.4 GHz and 5 GHz ranges. While the impact of these waves on human health has been widely studied, their influence on plants remains less documented. Some experiments suggest physiological changes in plants exposed to electromagnetic waves, but there is no consensus in the scientific community on the results.
Electromagnetic waves and plant physiology
As autotrophic organisms, plants respond to environmental stimuli such as light, temperature and humidity. Exposure to electromagnetic waves (EMW), such as those emitted by Wi-Fi, could influence their development through indirect effects on cellular processes, notably via :
- Germination and growth
- Cellular metabolism and oxidative stress
- Membrane permeability and gene expression
Research on the subject has produced contrasting results, partly due to varied methodologies and different experimental conditions.
Experimental studies on the effect of Wi-Fi waves on plants
Studies have investigated whether exposure to Wi-Fi waves can affect seed germination and plant growth. One of the most widely publicized experiments was carried out in 2013 by a group of Danish high school girls. They placed watercress seeds close to a Wi-Fi router and observed reduced growth compared with unexposed seeds. These results were widely publicized, but criticized by scientists for a lack of experimental rigor.
As the experiment was interrupted as early as day 13, the available data are not sufficient to conclude that these were serious adverse effects and not simply growth retardation.
A more controlled study by Halgamuge examined the effect of electromagnetic waves on the germination of seeds from different plant species. The results suggest altered germination rates and slower growth in some plants exposed to RF, although the effects vary according to species and exposure conditions.
However, other research has found no significant effect of Wi-Fi waves on germination. A study in the Journal of Plant Physiology analyzed the growth of corn seeds exposed to RF at 2.4 GHz and found no significant difference compared to unexposed conditions.
Influence on oxidative stress and cellular metabolism
Some studies have shown that exposure to electromagnetic waves can induce oxidative stress in plants, a phenomenon that can disrupt cellular metabolism.
- Research conducted by Blaise Pascal University in Clermont-Ferrand has revealed an increase in free radical production in tomato plants exposed to 900 MHz RF (similar to Wi-Fi frequencies).
- Another study reported that exposure to electromagnetic fields could alter membrane permeability and disrupt nutrient uptake in certain plants, although these effects remain limited to prolonged exposures.
These effects are not always observed under natural conditions, where plants are subjected to a wider range of environmental factors.
Current studies do not allow us to conclude that Wi-Fi waves have a systematic and significant effect on plant growth and health. Although some results suggest a physiological response to electromagnetic fields, particularly in terms of oxidative stress and gene expression, these effects are generally observed under exposure conditions that are far removed from reality.
Given the current state of knowledge, Wi-Fi waves do not appear to represent a threat to plants in a domestic or natural environment. However, further research is important to better understand possible long-term interactions between electromagnetic fields and living organisms.
