What is SAR?
SAR stands for specific absorption rate, is defined as the power absorbed per tissue mass and has the unit watts per kilogram (W/kg).
The current SAR value, which is the maximum permissible exposure level, is two watts per kilogram in Europe and 1.6 watts per kilogram in the USA.
How is the SAR value calculated?
The measurement is usually performed with a phantom head and a phantom body at a small distance (approximately five millimeters). When we measure the specific absorption rate, we calculate how much your body (biological tissue) absorbs some of this energy (in watts per kilogram). In more technical terms, this is the measurement of radio frequency (RF) energy absorbed into grams of biological tissue.
It is usually determined either over the entire body or over a sample volume (typically 1 or 10 grams of tissue). The published SAR value is then the maximum value measured in the body part (for example, the head) and examined over the specified volume or mass.
What are the radiation protection limits in international comparison?
As in Germany, there are binding regulations for high-frequency electromagnetic radiation in many countries worldwide. The ICNIRP guidelines were also endorsed by the European Union in 1999 as part of the EU Council Recommendation. Most EU countries have followed suit. They are also taken into account in many countries outside Europe. In the U.S., Canada and Taiwan, on the other hand, mobile phone limits are based on the recommendations of the IEEE (Institute of Electrical and Electronics Engineers), which are comparable to the ICNIRP guidelines.
Countries that have decided against the ICNIRP limit recommendations, such as Italy, Belgium, Switzerland, Liechtenstein, Luxembourg, Russia and Poland, justify this with an increased desire for precaution. For example, the Swiss Environmental Protection Agency: “The Federal Council could not wait for science to provide the desired answers. The precautionary principle of the Environmental Protection Act requires that exposure should in principle be as low as technically possible.”
Where do the current SAR standards come from?
The first security standards were set in 1997, when a typical cell phone user was military, medical or corporate. In one of the original tests in 1989, the military used the head of a man weighing about 100 kilograms who was among the best of the recruits. The standards they set were to avoid heating their subject’s brain after a six-minute phone call.
The currently valid radiation protection limits
Radiation protection limits are based on the “Guidelines for Limiting Exposure to Time-Varying Electric, Magnetic and Electromagnetic Fields (up to 300 GHz)” published by ICNIRP in 1998. These are based on the thermal effect – the heating of the body tissue.
For example, body temperature can rise when electromagnetic radiation is absorbed by the body and converted into heat energy. Valid limits are based on the radiation strength that warms a lifeless body by one degree Celsius within 30 minutes. Because from this change in body temperature onwards, natural regulatory mechanisms cannot function comprehensively. Consequently, cell phones, for example, must not exceed a value of two watts per kilogram(SAR values), otherwise the thermal effect sets in.
As long as the limits are observed, there is no health risk, according to ICNIRP. But this does not take into account long-term effects and the much greater physiological sensitivity of children’s heads. In addition, the ICNIRP guidelines, which have been in place for 20 years, have not been adapted to the ever-changing technology.
Are the current SAR standards sufficient?
No way. Current standards can be a tool to assess whether the phone is “safe” according to regulatory standards. However, they do not accurately assess the extent to which our health is fully impacted.
Recently, Prof. Gandhi, University of Utah, reported that SAR levels in watts per kilogram measured at zero distance from the body were up to three times higher than the approved European limits and up to eleven times higher than the U.S. limits.
Other reasons why current SARs are not sufficient
- In fact, SAR refers to thermal effects, but the vast majority of recorded biological effects of lifetime chronic exposure are not thermal.
- At much lower SARs than the current safety standard, a number of effects have been reported.
- Insufficient information was provided on the level of RF exposure under typical use and real-world conditions. The exposures tested under laboratory conditions are only for short periods of time, usually up to a few minutes.
- No reflection of the different head and body sizes. The majority of the population has much smaller heads and bodies than the 100 kilogram male military recruit.
- Radiation levels relative to current consumption are much higher than in the past.
- Current laboratory tests do not include variations for energy absorption hotspots.
- Different laboratories can take measurements at different distances from the body.
- The type of cell phone signal is not taken into account. Since it is pulsed in nature, the average power can remain low, but the individual burst signals can be very high.
- A child’s developing brain absorbs much more than an adult’s brain.