Government policies for electromagnetic fields should be evidence based, harmonised internationally and draw on the existing recommendations by expert bodies such as the World Health Organization and the International Telecommunications Union.
Human Exposure Standards
The International Commission on Non-Ionizing Radiation Protection (ICNIRP) developed human exposure guidelines that are recommended by the World Health Organization (WHO) and the International Telecommunications Union (ITU). The ICNIRP guidelines were developed following reviews of the scientific literature, including thermal and non-thermal effects, and are designed to provide protection to all people (including children) against all established health hazards. They are structured around basic restrictions, measures of RF energy deposited in the body, and reference levels, external field levels that are more easily measured for compliance purposes. In general reference levels are used for base station compliance and basic restrictions for devices used close to the body.
In September 2009 the ICNIRP issued a statement confirming that its present recommendations remain valid.
It is important to emphasize that exposure limits are not emission limits, the former apply to locations accessible to workers or members of the general public. Thus, it is possible to achieve compliance by limiting access to areas where the exposure limits are exceeded. Emission limits are technical equipment specifications.
Compliance Standards
Compliance standards describe the methods used to determine that exposures from wireless antennas or mobile devices are less than the recommended exposure limits.
In cases were the source is distant from the human body free-field exposure measurement methods can be used and limits are specified in units such as volts per meter (V/m) or power density (Watts / square metre).
When the radio transmitter is used close to the head or body the method uses robot positioned measurement probes in phantom humans containing tissue simulating liquids and limits are specified in terms of the Specific Absorption Rate (SAR) with units of watts per kilogram (W/kg).
Compliance standards are produced by international organizations such as the IEC and the ITU.
Precautionary Policies
The international safety recommendations endorsed by the WHO are designed to provide protection against all known health hazards, however, some groups have argued for additional measures on a ‘precautionary’ basis in order to respond to scientific uncertainty or public concern. There are more effective ways to respond to scientific uncertainty and public concern. Responding to Scientific Uncertainty (pdf)
The WHO has warned that some precautionary approaches may undermine confidence in exposure guidelines. Supporting this warning is research showing that precautionary policies increase concern because the public interpret the measures as evidence of possible risk.
In respect of mobile phones, the current WHO advice is that:
‘A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use.’
For those who are concerned, the WHO notes that exposure can be reduced by text messaging, using a “hands free” device and using the phone in areas of good reception. The WHO states: ‘The use of commercial devices for reducing radiofrequency field exposure has not been shown to be effective.’
The WHO has also stated for mobile networks that:
‘It is difficult to envision a consistent and equitable cautionary policy that would minimize radiofrequency EMF exposures from cellular telephone base stations given the presence of far higher powered sources in the same urban area. Indeed, attempts to implement a cautionary policy for cellular telephone masts have typically been done on a piecemeal basis, with no attention to other (much stronger) sources of RF energy in the environment.”
0 Comments