|Power Density (µW/cm2) at 1 foot away||FCC Safety Standard |
In general, doubling your distance cuts the "power density" by a factor of four. That’s why at a distance of 10 feet the radio waves from an electric SmartMeter™ are only about one one-thousandth as much as a typical cell phone.
What levels of RF will an electric SmartMeter™ add to the environment?
The meters will add signals that are similar to those produced by 900 MHz cordless phones and wireless routers commonly used within homes for distributing Internet to various computers. Because the transmitter output powers are so low, and because the signal level decreases substantially with greater distance from a meter, the overall aggregate RF field levels that would be expected to be found in a neighborhood with SmartMeters™ will remain very low (whether compared to pre-existing RF fields in a neighborhood or government-health-protection standards for RF fields).
Who regulates RF?
The federal government, particularly the Federal Communications Commission (FCC), has exclusive jurisdiction over RF.
Are SmartMeters™ safe?
Both the federal government and the international community have deemed the low-level RF on which PG&E’s SmartMeters™ rely to be completely safe.
In 1996-97, the Federal Communications Commission (FCC) established a standard for what it calls "Maximum Permissible Exposure" (MPE), i.e., what level of RF-exposure is safe. With input from the Food and Drug Administration (FDA), the Environmental Protection Agency (EPA), and other federal government agencies, it established the following safety standards:
SmartMeters™ are also safe by international standards. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has set its standard for this frequency at approximately 450 µW/cm2, more than 50 times greater than an electric SmartMeter™.
The World Health Organization (WHO) and many other health agencies confirm that there is no persuasive evidence that low level RF exposure (such as those on which SmartMeters™ rely) cause any adverse health effects.
What is the "Bioinitiative Report" and what are the limits set by European standards organizations?
Preliminarily, it is important to note that PG&E’s SmartMeter™ equipment complies by many orders of magnitude with both the applicable federal standard that the FCC has issued, but also with international standards. Whereas the RF-exposure at 1 foot away from a PG&E electric SmartMeter™ is 8.8 microwatts per square-centimeter, the FCC has set its safety threshold at 601 µW/cm^2 and the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has set its standard for this frequency at approximately 450 µW/cm^2. In either case, PG&E’s SmartMeters™ release a mere fraction of what the federal government and international community have deemed safe exposures.
PG&E is aware of the BioInitiative Report. PG&E also is aware of the vast criticism the BioInitiative Report has received within the scientific community. The consensus of the scientific community is that the BioInitiative Report is un-objective, self-selected research. It does not represent the consensus of the international scientific community regarding safe RF exposure, as reflected in the 2009 Technical Information Statement released by the Committee on Man and Radiation ("COMAR"), a technical committee of the Engineering in Medicine and Biology Society ("EMBS") of the Institute of Electrical and Electronics Engineers ("IEEE"):
"The focus of this COMAR Technical Information Statement is to identify quality sources of scientific information on potential health risks from exposure to RF energy. This Statement provides readers with references to expert reports and other reliable sources of information about this topic, most of which are available on the Internet. This report summarizes the conclusions from several major reports and comments on the markedly different conclusions in the BioInitiative Report (abbreviated BIR below). Since appearing on the Internet in August 2007, the BIR has received much media attention but, more recently, has been criticized by several health organizations (see Section titled "Views of health agencies about BIR"). COMAR concludes that the weight of scientific evidence in the RF bioeffects literature does not support the safety limits recommended by the BioInitiative group. For this reason, COMAR recommends that public health officials continue to base their policies on RF safety limits recommended by established and sanctioned international organizations such as the Institute of Electrical and Electronics Engineers International Committee on Electromagnetic Safety and the International Commission on Non-Ionizing Radiation Protection, which is formally related to the World Health Organization." (Emphasis added.)
The IEEE is just one organization that has criticized the BioInitiative Report and instead followed the safety recommendations of the WHO and ICNIRP. The following reflect still more criticism of the BioInitiative Report:
What is the peak power output from an electric SmartMeter™ and why does PG&E’s report use average power density?
It is important to note that the maximum power of the radio in a SmartMeter™ is only one watt.
In an August 6, 2010 letter from Julius Knapp, the Chief of the FCC’s Office of Engineering and Technology, to Cindy Sage, the FCC advised that it is the average power, not the peak power, of a device that is relevant for exposure evaluation.
"Since the purpose of these devices is to provide very infrequent information they transmit in occasional bursts. Thus, for exposure purposes the relevant power is maximum time-averaged power that takes into account the burst nature of transmission, and based on the typical time-averaged transmitter power for many of these devices, they would generally be compliant with the local [specific absorption rate] limit even if held directly against the body." [emphasis added]
Notwithstanding the FCC’s view that peak transmissions are not the relevant measure of RF for purposes of evaluating exposure, it is important to note that the RF from electric SmartMeters™ is very weak and very brief. PG&E’s independent evaluator found that the time-averaged power density at one foot from the meter is 8.8 µW/cm^2 (microwatts per square centimeter) when you conservatively assume a 4-percent duty cycle (a duty cycle is defined as the percentage of time the radio is in an ‘active state,’ or transmitting) , and is well within the FCC exposure limits for time-averaged power density, which is 601 microwatts per square-centimeter. But this very conservative calculation results in an overstatement of the time-averaged power density number, as a 4-percent duty cycle is equal to nearly one hour (57 minutes) of transmission time per day, when the actual transmission time for an electric SmartMeter™ is on average less than one minute per day (45 seconds). If you adjust the calculations for the actual duty cycle, the RF from PG&E’s electric SmartMeters™ is considerably lower.
What happens if multiple meters are located together on the same building, and will this increase the RF signal strength when they send at the same time?
Although it is theoretically possible that two SmartMeters™ in close proximity could transmit at the same time, the very short duration of each signal means that there is little opportunity for overlap and therefore the signals from the meters can be regarded as essentially independent. The signal from an electric SmartMeter™ typically lasts between 2 to 20 milliseconds and the cumulative signaling during a day would typically total, on average, 45 seconds.
The FCC recently wrote in detail on this subject, specifically about SmartMeters™, and stated as follows:
"With respect to multiple adjacent Smart Meter installations, since the antennas for each device are mounted individually on each utility meter, the separation distance from most people for most of the transmitting antennas is relatively large compared to 20 cm and the meters’ contributions to the total potential exposure at any location are small, as only the nearest few transmitters can add meaningfully to the total. Further, as a practical design matter, when several of these meters are placed in a cluster, they have to communicate with a single controller. In order to ensure that the controller receives the information properly, only one transmitter can communicate with the controller at a time, eliminating the potential for exposure to multiple signals at the same time. ...
In addition, the exponential decrease in signal strength over distance and additional signal losses due to non line-of-sight conditions for distant sources ensures that only the contributions of nearby transmitters are significant. ...
Irrespective of duty cycle, based on the practical separation distance and the need for orderly communications among several devices, even multiple units or ‘banks’ of meters in the same location will be compliant with the public exposure limits." [emphasis added]
Are there potential interference problems from SmartMeters™ for people with pacemakers?
The FCC concludes the following about interference with pacemakers from radio frequency signals:
"The FDA requires pacemaker manufacturers to test their devices for susceptibility to electromagnetic interference (EMI) over a wide range of frequencies and to submit the results as a prerequisite for market approval. Electromagnetic shielding has been incorporated into the design of modern pacemakers to prevent RF signals from interfering with the electronic circuitry in the pacemaker. The potential for the "leads" of pacemakers to be susceptible to RF radiation has also been of some concern, but this does not appear to be a serious problem." (FCC Office of Engineering & Technology Bulletin 56: "Questions and Answers About Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Fields" (Fourth Edition, August 1999)
The US Food and Drug Administration (FDA) provides similarly on its website:
"Radiofrequency energy (RF) from cell phones can interact with some electronic devices. This type of interference is called electromagnetic interference (EMI). For this reason, FDA helped develop a detailed test method to measure EMI of implanted cardiac pacemakers and defibrillators from cell phones. This test method is now part of a standard sponsored by the Association for the Advancement of Medical Instrumentation (AAMI). This standard will allow manufacturers to ensure that cardiac pacemakers and defibrillators are safe from cell phone EMI."
The FDA’s website continues on to add that "based on current research, cell phones would not seem to pose a significant health problem for the vast majority of pacemaker wearers."
While all of the foregoing applies to cell phones, SmartMeters™ have two fundamental differences: First, the SmartMeter™ is attached to a house or business and cannot, without great difficulty and a clear intention to do so, be placed next to a person’s chest (i.e., closer than a few inches to the meter’s antenna, which is contained within the metal and plastic of the meter, and thus already a distance from someone nearby). Second, the strength of the signal from a SmartMeter™ diminishes very rapidly with distance, so the inability to carry the meter in your pocket, coupled with an individual’s distance from the meter, limits one’s RF-exposure. It also is worth noting that SmartMeters™ only communicate intermittently for between 2 and 20 milliseconds at a time, totaling on average approximately 45 seconds per day, so the weak RF fields that SmartMeters™ utilize are further limited by time.
Currently, medical device manufacturers advise patients to consult with their physicians when a patient has concerns about RF devices and interference. Although devices like SmartMeters™ have a typical RF exposure that is weak, distant, and extremely brief, PG&E would nevertheless advise any customer with concerns related to a medical device to consult with his or her physician for personal medical advice to best address his or her concern.
How do SmartMeter™ RF signals compare to other common devices?
Examples of RF in the Everyday Environment Compared to SmartMeter™
|Power Density in Microwatts per square centimeter (µW/cm2)|
|Adjacent to a gas SmartMeter™ (1 foot)||0.00166|
|Adjacent to an electric SmartMeter™ (10 feet)||0.1|
|Adjacent to an electric SmartMeter™ (1 foot)||8.8|
|Microwave oven nearby (1 meter)||10|
|Wi-Fi wireless routers, laptop computers, cyber cafes, etc., maximum (~1 meter for laptops, 2 - 5 meters for access points)||10 - 20 |
|Cell phones (at head)||30 - 10,000|
|Walkie-Talkies (at head)||500 - 42,000|
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