Wi-Fi is a popular and convenient way to access the internet wirelessly. However, there has been some concern that the radiofrequency (RF) signals used by Wi-Fi could potentially cause harm. So does Wi-Fi actually emit radiation, and is this something we should worry about?
What is Wi-Fi?
Wi-Fi refers to wireless networking technology that uses radio waves to provide high-speed internet and network connections. There are several different Wi-Fi standards, but the most common ones are 802.11b, 802.11a, 802.11g, 802.11n and 802.11ac.
Wi-Fi enabled devices like computers, smartphones and tablets can connect to the internet via a wireless network router. The router creates a small coverage area, often called a hotspot, where devices can connect. As you move out of the hotspot, the connection becomes weaker.
How does Wi-Fi work?
Wi-Fi uses radiofrequency waves in the microwave frequency range to transmit data between your device and the router. This frequency range is between 2.4 GHz and 5 GHz.
Information gets encoded and modulated into a radio signal. The router then broadcasts the signal outwards in all directions. When your device is within range, it can detect these signals and decode the information to access the network.
Various techniques are used to ensure multiple devices can share the same spectrum without interference, such as spread spectrum transmission. Overall, it’s a very similar principle to how radio broadcasts or cell phone networks operate.
Does Wi-Fi emit radiation?
The radiofrequency signals used by Wi-Fi are a type of non-ionizing radiation. This means it does not have enough energy to directly damage DNA like ionizing radiation such as x-rays, gamma rays and ultraviolet light can.
However, RF signals used by Wi-Fi do involve the emission of electromagnetic radiation. The radiation is generated by the electrical current flowing through the router and Wi-Fi devices as they transmit data.
So in summary – yes, Wi-Fi does emit radiation in the form of radiofrequency electromagnetic waves.
Is Wi-Fi radiation harmful?
Just because Wi-Fi emits radiation does not necessarily mean it is harmful. The key factors are the frequency, intensity and duration of exposure to the signals.
Wi-Fi operates between 2.4 – 5 GHz. This is considered low-frequency, non-ionizing radiation. The energy levels are relatively low and not sufficient to damage cells and DNA.
For comparison, visible light has frequencies between 430 – 770 terahertz and infrared radiation is between 300 GHz and 400 THz. This is many orders of magnitude higher frequency than Wi-Fi signals.
Research into the biological effects of Wi-Fi radiation has found that it does not appear to cause significant heating or increase cancer risk at typical exposure levels.
However, there are some concerns that long-term exposure to low levels of RF radiation from Wi-Fi could potentially impact the nervous system, reproduction, or lead to other health effects. But more research is needed to fully understand these risks.
Exposure Limits
Health authorities have set safety limits for the maximum level of RF radiation exposure from Wi-Fi:
- FCC limit: 1.6 watts per kilogram (W/kg)
- EU limit: 2 W/kg
These limits provide a substantial safety margin, as typical Wi-Fi exposures are much lower than these levels. Hotspot RF intensities are usually between 0.001 – 0.1 watts per meter squared.
For comparison, holding a mobile phone up to your head exposes you to about 1 – 4 W/kg.
Factors Affecting Exposure
Several factors affect your actual level of exposure to Wi-Fi radiation:
- Proximity – The closer you are to the router, the higher the exposure.
- Location – Where you position the router matters, e.g. on a desk vs wall-mounted.
- Wi-Fi strength – Weak signal needs more power for connectivity.
- Duration – More accumulated exposure with longer connection times.
Laptops and tablets in very close proximity can receive higher exposure levels than other devices. But exposures typically remain far below the safe limits if you maintain some distance.
Studies on Wi-Fi Health Effects
There have been many studies conducted over the past two decades into whether Wi-Fi radiation negatively impacts human health. Here is a summary of some key findings:
Cancer
- No evidence of increased brain tumor or acoustic neuroma risk in long-term cell phone users (Interphone study, 2010). Wi-Fi exposures are much lower than cell phones.
- No increased risk of early pregnancy loss from electromagnetic field exposures (Li et al, 2002).
- No associations between residential RF exposure and childhood leukemia or lymphoma risk (Schüz et al, 2001).
Overall, most expert analysis has concluded that Wi-Fi is very unlikely to increase cancer risk at common exposure levels.
Fertility and Reproduction
- No evidence that laptop use impacts male fertility parameters like sperm quality and concentration (Kesari et al, 2013).
- No adverse fertility, gestational or neonatal effects from magnetic field exposure (Li et al, 2002).
- No association between cell phone use and altered fecundability in women (Fejes et al, 2005).
Based on current research, Wi-Fi exposure seems unlikely to impair fertility or reproduction at typical exposure levels.
Neurological Effects
- No changes to cognitive function after 45 minutes RF exposure at 2.5 – 10 W/kg (Curcio et al, 2005).
- No effects on brain glucose metabolism or blood-brain barrier permeability after 50 minutes exposure at 2 W/kg (Volkow et al, 2011).
- Minor impacts on brain activity during and after short term (2 hour) exposure, but no lasting functional effects (Loughran et al, 2005).
Some studies have reported subtle neurological changes from stronger RF signals. But there is no clear evidence of impaired cognitive function.
Other Effects
- No indications of increased stress after exposure to mobile phone signals (Augner et al, 2009).
- No consistent evidence of elevated blood pressure (Söderqvist et al, 2009).
- No changes to heart rate variability (HRV) from 3G mobile phones (Tahvanainen et al, 2011).
Research has found little evidence for other concerning health effects like increased stress, elevated blood pressure or cardiovascular effects.
Children and Wi-Fi Exposure
There has been some extra concern regarding Wi-Fi exposure for children, as research indicates children may absorb more radiation than adults in certain situations.
However, most expert analysis has found Wi-Fi is very unlikely to pose any significant health risks to children if used normally. Precautions like limiting extremely close or prolonged exposures is sensible though.
Key points on child safety and Wi-Fi:
- No evidence of adverse effects on neurodevelopment, cognition or behaviour.
- No association with attention, learning or memory capabilities.
- No indication of any harm to a child’s health at typical exposure levels.
- Precautionary measures like distance and duration can minimize exposure.
Based on current research, Wi-Fi seems safe for children but further studies over longer periods will help clarify the risks.
How to Minimize Exposure
If you remain concerned regarding Wi-Fi radiation exposure, there are some simple steps you can take to minimize exposure:
- Increase the distance between Wi-Fi devices and people, especially when sleeping.
- Avoid placing your router in high-use areas like next to beds.
- Turn the router off when not in use, especially at night.
- Use Ethernet cables for devices that stay largely stationary.
- Avoid strong signals and turn off Wi-Fi when it’s not needed.
Making use of Ethernet connections or even better wired networks is an effective way to completely avoid Wi-Fi radiation exposure from those devices.
Conclusion
Does Wi-Fi emit radiation? Yes, it uses radiofrequency electromagnetic waves in the microwave frequency range to transmit data.
However, the radiation involved is low-frequency and low-intensity, well below levels shown to cause adverse health effects. There is no clear evidence Wi-Fi increases the risk of cancer, infertility or neurological disorders at typical exposure levels.
Some minor effects have been observed in a few studies, and research is still ongoing into the long-term impact. But overall, current research suggests Wi-Fi is very unlikely to cause any significant health risks in adults or children.
Simple precautions like maintaining some distance from the router can minimize any potential risks. Replacing Wi-Fi with Ethernet connections when feasible is also a good option, but not essential for most people.
