Electric and Magnetic Fields

There are many sources of EMF in everyday life, this ranges from natural sources such as the earth’s magnetic field, to man-made sources such as wifi, radiowaves and household appliances; in fact all electrical equipment emits some amount of EMF. Electrical systems used for the transmission and distribution of electricity in Australia operate at 50hz and typically emit Extremely Low Frequency EMF; this includes house hold wiring, electrical transformers, substations, electrical distribution and transmission lines.

EMF or Electromagnetic Field is a form of energy that may sometimes be referred to as Electromagnetic Radiation. There are many types of EMF but it is generally categorised non-Ionising or low frequency/energy which includes visible light, microwaves and radio waves and as Ionising or high frequency/energy which includes X-ray and UV radiation. This energy has two principal components, an electrical component and a magnetic component. Typically the electrical component can be readily shielded by household materials, where the magnetic component generally is not easily shielded. As the magnetic field is not easily shielded the majority of research completed on the safety of EMF focuses on magnetic fields. However, both electric and magnetic fields decrease rapidly with distance from the source.

EMF is typically measured in two ways

• Total Surface Power Density (W/m2) – this measurement indicates the energy transmitted by an electromagnetic emitter and is commonly utilised for measuring signal strength.
• Or in its Component
  • Electric field (V/m) measures the electric field strength volts per meter
  • Magnetic flux density (µT) Measures magnetic field strength in microtesla

When considering the safety of EMF from electrical systems typically magnetic flux density (µT) is measurement used as it is not readily shielded.

Extremely Low-Frequency EMF emitted by electrical distribution and transmission equipment is generally considered safe. The World Health Organisation (WHO) states typical maximum public exposure levels. While these maximum exposure levels are precautionary, the WHO also states “Despite the feeling of some people that more research needs to be done, scientific knowledge in this area is now more extensive than for most chemicals. Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low-level electromagnetic fields.”

There are two internationally recognised exposure guidelines:

• International Commission on Non-Ionizing Radiation Protection (ICNIRP) 2010
• Institute of Electrical and Electronics Engineers (IEEE) in the USA 2002.

Australian Radiation Protection and Nuclear Safety Agency’s (ARPANSA) current advice is “The ICNIRP Extremely Low Frequency (ELF) guidelines are consistent with ARPANSA’s understanding of the scientific basis for the protection of the general public (including the foetus) and workers from exposure to ELF EMF”.

Correctly functioning electrical distribution and transmission equipment is low risk and should emit low level magnetic fields. The EMF emitted by this equipment is often lower than that of common household appliances such as hair dryers and food processors. If you believe that equipment located near you is emitting higher than normal EMF, contact your local network service provider.

The Australian Electricity Industry follows a prudent avoidance approach to manage EMF exposure. The position is summarised in the EMF Policy statement.