The rollout of smart meters around the world continues to encounter various objections. Some people view the meters as an invasion of privacy, or worry about the potential for hackers to access their home-energy data. Others are concerned the meters — which typically use radio waves to transmit data — pose a health hazard.
A few in that group say smart meters have already caused them to suffer from a range of debilitating impacts: tingling sensations, dizziness, nausea, heart palpitations, difficulty in concentrating, etc.
What does science say? Following are 10 things we know about radio frequency emissions and their use in smart metering:
- Radio frequency emissions, or radio waves, have frequencies ranging from 300 GHz (gigahertz) (wavelengths of around 1 millimeter) to 3 hertz (wavelengths of around 100 kilometers). They are the lowest-energy/longest-wavelength form of radiation on the electromagnetic spectrum, which also includes microwaves, visible light, ultraviolet light and x-rays.
- Radio frequency energy is used in a wide range of medical procedures to provide targeted heating to seal IV fluid bags, reshape the cornea for vision correction, heat and destroy tumors, cauterize tissue and generate images of internal body structures through magnetic resonance imaging.
- Radio frequency emissions can produce both thermal (ie, heating for such applications as those described above) and non-thermal effects. These non-thermal effects include ways in which cells respond to increases in temperature (caused by radio-induced thermal heating) or to the electromagnetic waves themselves.
- In addition to smart meters, a wide variety of other common household electronic devices — cellphones, cordless phones, microwaves, wireless routers, hairdryers, wireless-enabled laptops, etc. — produce radio frequency emissions.
- A number of studies have investigated electromagnetic hypersensitivity, or EHS. People who say they have EHS report feeling a variety of health impacts from exposure to electromagnetic fields from a range of sources: power lines, cellphones, computers, smart meters and so on. To date, however, research has found no clear, consistent connection between electromagnetic field emissions and EHS. Most studies find people who say they are sensitive to electromagnetic emissions cannot detect exposure in controlled tests any more than non-sensitive people can.
- People who say they have EHS are clearly suffering from something — researchers just can’t pinpoint what yet. “EHS is characterized by a variety of non-specific symptoms that differ from individual to individual,” notes the World Health Organization (WHO). “The symptoms are certainly real and can vary widely in their severity.” However, WHO adds, “EHS has no clear diagnostic criteria and there is no scientific basis to link EHS symptoms to EMF exposure. Further, EHS is not a medical diagnosis, nor is it clear that it represents a single medical problem.”
- Smart meters used only for periodic, automated meter readings (AMR) don’t emit radio frequency waves in the period between meter readings. “This means that the typical smart meter in this initial (AMR) use would not transmit any RF signal at least 96 – 98 percent of the time,” notes a 2011 report by the California Council on Science and Technology (CCST) on the health impacts of smart meter-generated radio frequency.
- Exposure to radio waves from smart meters varies by distance. According to the CCST study, “While the estimated maximum exposure level at 1 foot from the meter with a duty cycle of 50% is 180 μW/cm2 (microwatts per square centimeter) (far below the FCC guidelines), at a distance of about 10 feet, the power-density exposure approaches zero.” (“Duty cycle,” as defined in the study, is “the fraction of time a device is transmitting.”)
- The radio frequency power density of a cellphone held to your ear ranges from 1,000 to 5,000 microwatts per square centimeter, according to the CCST report. For a microwave oven operated from a distance of one foot, that power density ranges from 200 to 800 microwatts per square centimeter. The power density for a smart meter with a duty cycle of 50% (that is, transmitting radio signals half of the time) is 200 microwatts per square centimeter at a distance of one foot, and 20 microwatts per square centimeter at a distance of three feet.
- In addition to distance, building walls also reduce radio frequency exposure from a smart meter. A study by the Electric Power Research Institute (EPRI) found that a bank of 10 smart meters operating at 250 microwatts of power produced, at a distance of one foot, an exposure level that was 8 percent of the maximum recommended by the Federal Communications Commission (FCC). From eight inches behind the wall those meters were on, exposure fell to 0.6 percent of the FCC limit, even when the meters were transmitting 100 percent of the time.