Has it been proven that being exposed to WiFi waves is harmful?

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    I've edited: it changes the meaning but makes the question answerable. Otherwise the OP is NARQ. – Sklivvz Mar 23 '11 at 12:28
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    @Henry, @KonradRudolph, I am an RF engineer, the question originally asked if it has been proven harmful. It was clearly biased towards finding wifi harmful, I was pointing out that wifi is not ionizing and not harmful which throws a wrench in the dangerous part. Everyone seems to take this incorrectly, no worries, I work with ionizing radiation, it gives you a warm feeling that WiFi never will. – Kortuk Mar 23 '11 at 23:51
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    There are no special Wifi waves. There are no special cell phone waves. The correct term for either is 'radio waves', which is a subset of 'electromagnetic waves' – Paul Mar 31 '11 at 6:52
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    @chr I fail to see why my edit should respect that principle, or why it should apply in the case of this question. Are you really suggesting we should ban wifi waves and non-ionising radiation tout court, just in case (forgetting basic biophysics)? Why would that point be related to this question, anyways? – Sklivvz May 27 '11 at 6:51
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    @ChrisW One could never prove that WiFi is 100% safe. However if WiFi is not safe, such a thing would be provable. Therefore the burden of proof is on proving that it's not safe. We have evidence that it is safe, that is the lack of finding something harmful after lots of testing. I also can't prove relativity to you, but you could prove it wrong if it were wrong. – Cruncher Feb 19 '14 at 14:29

WIFi is non-ionising radiation and so has similar issues to other radiation using similar frequencies such as mobile telephones and microwave ovens. These produce heating effects. WiFi is not focused, so any impact should be very small and perhaps not measurable.

I am not aware of any health studies specifically on WiFi. There have been studies on mobile phones which has shown that while the phone is in use and held next to the head, there is small but measurable heating effect on human tissue. My guess is that it has less impact than standing at right angles to the Sun so one side of the head gets warmer faster than the other. Even then, these studies have produced no evidence that this has any health impact, positive or negative:

A large body of research exists, both epidemiological and experimental, in non-human animals and in humans, of which the majority shows no definite causative relationship between exposure to mobile phones and harmful biological effects in humans.

And per Dr. Michael Clark of the HPA, WiFi is a fraction of the energy of a cell phone:

“When we have conducted measurements in schools, typical exposures from wi-fi are around 20 millionths of the international guideline levels of exposure to radiation. As a comparison, a child on a mobile phone receives up to 50 per cent of guideline levels. So a year sitting in a classroom near a wireless network is roughly equivalent to 20 minutes on a mobile. If wi-fi should be taken out of schools, then the mobile phone network should be shut down, too — and FM radio and TV, as the strength of their signals is similar to that from wi-fi in classrooms.”

The Sun does emit ionising radiation (ultra violet) and that has significant health effects such as sunburn, pigmentation changes and Vitamin D production. WiFi's impact, if anything, is nothing like this.

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    @Henry, Again, I am seeing a disconnect. Microwaves are not ionizing radiation and this is something that can be verified in a lab setting, and has been. It is not a case of "practice does not contradict" it is a case of "Practice has verified". Microwave radiation will NOT strip an electron from an atom, ever. – Kortuk Mar 24 '11 at 1:09
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    @Henry, non-ionizing can be verified, it has been. That is the point I am making. I understand that you know that, but I am being nit-picky about your language. It is important that people understand that this has been verified through practical tests. Many questions on this SE are related to soft-science where often correlation is the best option, but this is hard science and tests can be conducted to verify theory, and have been. – Kortuk Mar 24 '11 at 2:02
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    I think that @Kortuk is right. There results are stronger that what one may perceive from the tone of the answers. Also, among the effects of ionizing radiation you may want to mention cancer, which of course is quite important. – Agos May 27 '11 at 9:04
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    Remember, while the phone is emitting a few watts of non-ionizing radiation into your brain, your brain is emitting 20 W of non-ionizing radiation into the phone. – endolith May 8 '12 at 19:14
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    There are suggestions that non-ionizing may not be harmless. Here is a good and rightfully skeptical review of some publications claiming that non-ionizing radiation in the mostly 2400Mhz (i.e. 2.4Ghz like Wifi) can cause harmful effects. cancernetwork.com/review-article/…. – seo Nov 6 '15 at 4:20

I am unaware of any research done on this specific question. The closest I've come across was this Dutch study, which states that there may be a connection between Wi-Fi transmissions and tree sickness. The research in itself was not sufficient to make that conclusion.

There are people who report a negative feeling when exposed to Wi-Fi, but those claims don't seem to stand up to proper double-blind testing, see for example:


Our study indicates that short-term exposure to mobile phone base station radiation does not affect the health and well-being of sensitive or control individuals.

Personally, based on my understanding of physics, I doubt that Wi-Fi radiation is harmful.

The explanations that follow are not 100% accurate or bullet-proof, but they should give the general idea.

Wi-Fi transmits at the 2.4 GHz frequency range; that's close to your microwave oven in the kitchen - and it has very much the same effect, that is it heats you up a little bit. Now, while that may be in theory a harmful effect, it should be noted that the change in temperature is much less than due to, say, having a little warmer weather (I'm cheating a little bit here).

But maybe we should look at it in a different way. This is a nice table from xkcd:


While admittedly not the most solid source of information, I do believe it can give the general notion. Look at the lowest dose of radiation that any research ever found to be linked with cancer (100 mSv), and compare how much radiation you are exposed to on your daily life.

xckd radiation excerpt

The difference is quite large. So even with the (rather small) addition of radiation from Wi-Fi, you should be fine.

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    On the same xkcd chart is cell phone radiation, which is much the same as WiFi. It is 0. – John Ripley May 27 '11 at 0:43
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    We commonly test things and assume that large dose == bad, and a diluted dose of whatever negates the effects. In the case of BPA (not a radiation, an organic compound used to coat cans), it was recently discovered that tiny dosages can have harmful effects (which manifest differently than high doses). There is evidence that cellular signals affect bees -- who is to say that those signals don't impact the nervous system in some subtle way? – duffbeer703 May 27 '11 at 1:22
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    @duffbeer703: who is to say that it does? Please source your claims. – nico Mar 11 '12 at 17:29
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    @JohnRipley That's because the xkcd chart only shows "ionizing radiation". – ChrisW Jul 10 '14 at 7:54
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    -1 WiFi does not produce ionizing radiation at all. There is no "small addition". – Tomáš Zato Feb 16 '16 at 12:14

I did find one study about WiFi and trees. Conclusion translated to English from Dutch:

Wageningen University was commissioned by the municipality of Alphen aan den Rijn how the increasing number of sources of electromagnetic radiation, such as masts, could play a role in the deteriorating health of the trees. It was a growing cell the effect of radiation of known WiFi access points on small Esboompjes investigated.

The notes were exposed for more than three months to six sources of radiation with frequencies ranging from 2412 to 2472 MHz and a power of 100 mW EIRP

An association between the studied wifi radiation and the wide range of symptoms in adult trees can not be explicitly placed on the basis of the present study.

Also per this study by the California Department of Health Studies -- be advised, this is about EMFs from power lines, and I'm not clear how much stronger / weaker those are compared to radio frequency EMFs from cell phones and wifi:

On behalf of the California Public Utilities Commission (CPUC), three scientists who work for the California Department of Health Services (DHS) were asked to review the studies about possible health problems from electric and magnetic fields (EMFs) from power lines, wiring in buildings, some jobs, and appliances. The CPUC request for review did not include radio frequency EMFs from cell phones and radio towers. Reviewer 1, Vincent Delpizzo, Ph.D., is a physicist and epidemiologist; Reviewer 2, Raymond Richard Neutra, M.D., Dr.P.H., is a physician epidemiologist; and Reviewer 3, Geraldine Lee, Ph.D., is an epidemiologist with training in genetics. All three have published original research in the EMF area and have followed the field for many years. They were assisted in their reviews by DHS toxicologists, physicians, and epidemiologists.

The EMF Program’s policy analysis required each of the three DHS scientists to express in numbers their individual professional judgments that the range of added personal risks suggested by the epidemiological studies were “real.” They did this as a numerical “degree of certainty” on a scale of 0 to 100. For the conditions with the most suggestive evidence of EMF risk, the three scientists each came up with a graph that depicts their best judgments with a little “x” and the margin of uncertainty with a shaded bar: The differences in certainty between the three reviewers arises primarily from how sure they were that they could rule out study flaws or other explanatory agents and how much the evidence on one disease influenced certainty in the findings for other diseases.

degree of certainty graph

As you can see from the "degree of certainty" from these professionals, the jury is very much out on this one.

In my opinion in the absence of even mildly compelling proof of danger, I don't think there is harm from reasonable, typical exposure to WiFi.

  • The tree study is tough because WiFi hasn't been around for long, trees have a long growth cycle, and utilities hack at the ones near municipal Wifi points. – duffbeer703 May 27 '11 at 1:45
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    xkcd does not that you can only discount a cell phone if it is not a bananaphone. Bananaphones are possibly the source of our child cancer epidemic. – Kortuk May 27 '11 at 11:50

2017 Aug update 3 years down the road, this answer is still down the tube!! Feel free to ignore the facts. Here is one of the latest research https://link.springer.com/article/10.1007/s12020-015-0795-3, and http://time.com/4508432/what-is-wifi-radiation-cancer/

Original 2014 answer: Yes, an increasing body of research links WIFI with cancer and other harmful effects. Here is a study from 2013 dec that involved plant seeds:

In the experiment, they placed six trays in a room without any equipment and another six trays in a room next to two routers. Over 12 days many of the seedlings in the wifi room turned brown and died, whereas those in the others room thrived.


Also, a recent israeli study linked cell phone use with an increased presence of free radicals in saliva!

The results of the study published in Antioxidants and Redox Signaling showed the heavy mobile phone users had significantly greater saliva oxidative stress. “Our study indicates that mobile phone users experience considerable oxidative stress on proximal tissue as shown in the saliva, which mostly originates from the parotid glands,” the researchers concluded. “Oxidative stress is a potential contributor for the risk for developing cancer.”


One more quote for the downvoters from a recent event :D

the International Agency for Research on Cancer (IARC), a division of the World Health Organization (WHO), classified mobile phone use as a possible cause of cancer. After examining a body of evidence on mobile phone use, the IARC yesterday announced it will now classify mobile phone signals as ‘possibly carcinogenic’ due to some study results suggesting a link to some types of brain cancers.


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    Your first reference is to the Daily Mail citing school-children. Hardly reliable. It has been frequently debunked including right here. My unscientific rule of thumb: Every single fantastic scientific breakthrough, genius patented invention and political explanation offered by minors and shared by newspapers is just complicated enough to confound the journalists, but is not actually true, and anybody trained in the field can instantly explain why - but who would consult them for a story? – Oddthinking Jan 20 '14 at 13:05
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    Welcome to Skeptics!. @Giorgio79: LOL. Your cherry-picking of write-ups of the same research has backfired. "So it is impossible to draw firm conclusions from this study – and when set against the overwhelming body of evidence from larger studies, does not alter the conclusion that mobile phones are unlikely to increase the risk of brain tumours or other cancers.” High schoolers may have access to tools (but not experience nor expertise). The conclusion of the cited students is still bunk. – Oddthinking Jan 20 '14 at 13:42
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    I hope you will remain open to the quantity of evidence to change your mind. This has been an issue that has been scaring people for over 30 years, and yet the evidence is clearly in. Even if you don't choose to own a phone (and reap the safety benefits it brings), I hope you will stop misleading others. – Oddthinking Jan 20 '14 at 13:55
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    p.s. Oxidative stress was not "proven". The experiment had terrible controls. – Oddthinking Jan 20 '14 at 13:56
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    As far as I see, your second and third points are on cell phone use, not WiFi. Also, you should quote the next two paragraphs of your third source: "[...] the classification means that the link is far from certain, with the IARC saying there is only ‘limited evidence’ of a link to brain tumours in humans[...] Overall, this classification should not be taken to mean that there is a definite link between mobile phone use and cancer, only that some initial (possibly anomalous) study results have highlighted a relationship that needs further robust scientific investigation." – P_S Jul 10 '14 at 7:43

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