Studies Show WiFi Radio Waves Are Not a Health Concern
Concern over the potential health effects of wireless signals has been around since the early 1990s, with most of the attention focused on cell phones. The FCC adopted limits for safe exposure to radio frequency (RF) energy. Radiofrequency radiation (RFR) is the propagation of electromagnetic energy through space. It has two basic properties: frequency and intensity. The effects of RFR are measured is by absorption in human tissue. The unit for this measurement is called the specific absorption rate (SAR) and is expressed in watts per kilogram (W/kg).
The biological effects of WiFi are typically connected to studies on cell phone technology. Cell phones and WiFi operate on different levels of power intensity, but the standard for SAR is the same. While some research has been conducted on the biological effects of WiFi on human tissue, more research has is available on the effects of cell phone use.
The FCC requires cell phone manufacturers to ensure that their phones comply with these objective limits for safe exposure. Any cell phone at or below these SAR levels (that is, any phone legally sold in the U.S.) is a "safe" phone, as measured by these standards. The FCC limit for public exposure from cellular telephones is an SAR level of 1.6 watts per kilogram (1.6 W/kg), or between 0.6 watts and 3 watts. Robert Bradley, director of consumer and clinical radiation protection at Canada's federal health department indicates "If you look at the body of science, we're confident that there is no demonstrable health effect or effects from wireless technology,". A study was performed in 2005 at the Foundation for Research on Information Technologies in Society in Zürich, Switzerland.
This study conclusively showed that by operating at a distance of 20 cm, WiFi equipment is well below the U.S. standards for W/kg. Dr. John Moulder, a professor of radiation oncology at the Medical College of Wisconsin, who has researched and reviewed the biological effects of RFR, indicated that WiFi posses no health risks. Moulder and others point out that WiFi equipment emits less intense radiation than cell phones. Whereas most cell phones have a peak power output of 2 W, most WiFi routers have a peak power output of less than 100mW which is typical of indoor access points, and 400mW for outdoor units, but unlike cell phones and their base stations, WiFi devices do not communicate continuously. Dr. Kenneth Foster, a professor of bioengineering at the University of Pennsylvania, recently completed a study of WiFi, taking over 350 measurements at 55 sites across four countries. According to his research, not only does WiFi equipment emit less radiation under load, it does so in much smaller bursts. “When the networks were not being used, the duty cycle was 0.01 percent or so. That means that it is radiating power for 0.01 percent of the time.” While WiFi and microwaves use the same 2.4 GHz frequency, a microwave oven sends much more intense emissions than a WiFi device or cell phone. However, “Studies have shown that environmental levels of [radiofrequency] energy routinely encountered by the general public are far below levels necessary to produce significant heating and increased body temperature,” stated a 1999 FCC paper entitled “Questions and Answers about Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Fields.”
Dr. Linda Erdreich, who has studied the biological effects of RFR for many years, and is now a senior managing scientist at Exponent, a scientific consulting firm, agrees with this assessment “We know that there is an adverse effect [associated with RFR] and it starts with heating tissue, but all of these things are well below the standard,” she says. Outside the United States, similar conclusions have been made by related entities in Canada, Europe and Australia. The Australian Radiation Protection and Nuclear Safety Agency and the Canadian Spectrum
Management and Telecommunications use the same United States SAR value of 0.08 W/kg in an uncontrolled environment. Despite this internationally compiled body of factual evidence regarding the health effects of WiFi, there remain a few concerned citizens who are not convinced. Dr. Erdreich says “I think that the reason why there are differences of opinions is because people are looking at single studies and not at the whole picture.”
On a related note...
Industry sighs in relief as court throws out brain-cancer suits
The Superior Court of the District of Columbia today threw out six brain-cancer lawsuits against the mobile-phone industry, potentially removing a legal cloud that could have cost wireless carriers and manufacturers billions of dollars.
The decision to dismiss the suits was based on jurisdictional grounds, with Judge Cheryl Long agreeing with the wireless industry and the Federal Communications Commission that the complaints were pre-empted by federal law. The six suits have bounced between Superior Court and federal court since being filed several years ago. Today’s ruling was the biggest for the wireless industry since a 2002 federal court decision that tossed out an $800 million brain-cancer lawsuit against wireless companies because of inadequate scientific evidence.
Long was unequivocal in her ruling.
“This is not a close question. Having found that multiple alternative pre-emption doctrines are controlling, this court has no discretion to allow the claims to proceed any further,” stated Long in the 69-page decision.
Cellphone trade association CTIA declined comment, saying only it would let the ruling speak for itself.
It is unclear whether the plaintiffs will seek an appeal.
Jeffrey Morganroth, an attorney for the plaintiffs, said he wanted to review the ruling before commenting.
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