An electromagnetic field (also EMF or EM field) is a physical field produced by electrically charged objects. It affects the behavior of charged objects in the vicinity of the field. The electromagnetic field extends indefinitely throughout space and describes the electromagnetic interaction.
The potential health effects of the very low frequency EMFs surrounding power lines and electrical devices are the subject of on-going research and a significant amount of public debate. The US National Institute for Occupational Safety and Health (NIOSH) has issued some cautionary advisories but stresses that the data is currently too limited to draw good conclusions. EMFs are also the subject of study by the International EMF Project of the World Health Organization (WHO).
Low-frequency electric fields influence the human body just as with any other material made up of charged particles. When electric fields act on conductive materials, they influence the distribution of electric charges at their surface, causing current to flow through the body to the ground. They also induce circulating currents within the human body, the strength of which depends on the intensity of the EMF. If sufficiently large, these currents could cause stimulation of nerves and muscles or affect other biological processes. EMFs DO induce voltages and currents in the body but these induced currents are very small compared to thresholds producing shock and other electrical effects.
Heating is the main biological effect of EMFs. In microwave ovens this fact is employed to warm up food. The levels of radiofrequency fields to which people are normally exposed are much lower than those needed to produce significant heating, but scientists are investigating the possibility that effects below the threshold level for body heating do occur as a result of long-term exposure.
To date, no adverse health effects from low level, long-term exposure to radiofrequency or power frequency fields have been scientifically documented, but scientists are actively continuing to research this area. It will take some years for this research to be completed, evaluated and published. In the meantime, the World Health Organization has issued a series of recommendations:
- Strict adherence to existing national or international safety standards: such standards, based on current knowledge, are developed to protect everyone in the population with a large safety factor.
- Simple protective measures: barriers around strong electromagnetic field sources help preclude unauthorized access to areas where exposure limits may be exceeded.
- Consultation with local authorities and the public in siting new power lines or mobile phone base stations: siting decisions are often required to take into account aesthetics and public sensitivities. Open communication during the planning stages can help create public understanding and greater acceptance of a new facility.
- Communication: an effective system of health information and communication among scientists, governments, industry and the public can help raise general awareness of programmes dealing with exposure to electromagnetic fields and reduce any mistrust and fears.
Concern about EMF exposure is a recurring theme with our clients. In some cases consultation with a qualified EMF specialist has allayed our clients concerns. Other clients, knowing that the risk factors are not yet completely quantified, opt to err on the side of caution and implement precautionary EMF mitigation and shielding measures. Our recent project, Ho’okipa House in Kihei, Maui, utilized both mitigation techniques and EMF shielding to provide the margin of safety deemed necessary by the owner.