No evidence that Wi-Fi in classrooms puts students’ health at risk

Contact | Jackie Kerstetter:, Education Next

No evidence that Wi-Fi in classrooms puts students’ health at risk
Expert examines half-century of research on radio frequency exposure

April 11, 2019— Eighty-eight percent of public school reported having sufficient Wi-Fi in 2017, up from 25 percent just four years earlier. Amid the growing use of Wi-Fi in schools and other public places, anti-Wi-Fi campaigners—including well known anti-vaccine advocate Joseph Mercola—blame exposure for ailments from head­aches and hearing loss to Alzheimer’s and brain cancer. Is Wi-Fi in schools harming students?

In a new article for Education Next, Kenneth R. Foster, professor emeritus of bioengineering at the University of Pennsylvania, examines half a century of research on the health risks of envi­ronmental exposure to radio frequency (RF) energy, commonly associated with Wi-Fi-enabled devices. Foster reports that, despite the concerns of vocal activists, national health agencies have credibly concluded that no adverse health effects have been demonstrated at exposure levels that fall within established safety guidelines, and that exposure from Wi-Fi specifically falls well below those limits.

Among Foster’s key insights:

The energy associated with Wi-Fi-enabled devices does not damage human cells. Unlike x-rays and other forms of potentially dangerous radiation, RF energy does not disrupt molecules in the body to form free radicals, which can damage cells and tissues. Operating between 2.45 and 5 gigahertz, most Wi-Fi-enabled devices work on the same frequency used by household microwaves, baby monitors, and more.

Existing environmental RF energy levels are low and Wi-Fi is responsible for only a fraction of exposure. Even in the unlikely event that a Wi-Fi network is operating at full capacity, the total amount of RF energy transmitted on the network might be roughly comparable to that from a single cell phone in use in the room. Moreover, in a recent study across five European countries, researchers found that Wi-Fi made up an average of only 4 percent of a sample of children’s total exposure to RF signals. The average total exposure across all frequencies was roughly 0.001 percent of the safety limits established by the European Commission, which are similar to U.S. limits.

Thousands of studies have found no harmful effects of RF energy. As of 2018, more than 3,700 studies have been published on the health and biological effects of RF exposure. Health agency reviews of this literature have consistently failed to find convincing evidence for health hazards of RF exposure below internationally accepted limits. In France, for example, a three-year analysis by 16 independent experts commissioned by the Agency for Food, Environmental and Occupational Health & Safety concluded that “no available data makes it possible to propose new exposure limit values for the general population.”

Wi-Fi opponents cherry-pick research. Few existing studies of the biological effects of exposure to RF energy use a rigorous research design and many studies use RF exposures well above established safety limits. Yet, Anti-Wi-Fi cam­paigners, in the oft-cited BioIntiative Report or efforts chronicled by the 2018 documentary Generation Zapped, seem to gravitate to studies that support their views regardless of methodological quality.

To receive an embargoed copy of “Is Wi-Fi a Health Threat in Schools? Sorting fact from fiction” or to speak with the author, please contact Jackie Kerstetter at The article will be available Tuesday, April 16 on and will appear in the Summer 2019 issue of Education Next, available in print on May 24, 2019.

About the Authors: Kenneth R. Foster is professor emeritus of bioengineering at the University of Pennsylvania and an engineering consultant to government and industry. In 2012 he participated in a review of the literature related to health effects of Wi-Fi for the Wi-Fi Alliance, an industry group.

About Education Next: Education Next is a scholarly journal committed to careful examination of evidence relating to school reform, published by the Education Next Institute and the Program on Education Policy and Governance at the Harvard Kennedy School. For more information, please visit

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