Electromagnetic fields (EMF) having a frequency between 3 kHz up to 300 GHz are commonly known as radiofrequency (RF) EMF. RF-EMF are emitted from an antenna to a receiver and are used to transfer information quickly over great distances. RF-EMF are therefore used for radio and TV broadcasting, mobile communication, cordless phones, Wi-Fi and Bluetooth connections, and other telecommunication purposes. RF fields may also be used within appliances such as microwave ovens to heat food, but also in industrial settings to heat or seal plastics and other low-conductivity materials.
-500x254.jpg)
The most important source of public exposure to RF fields is the mobile phone. Exposure levels of the public to RF fields from mobile phone antennae (also known as base stations) are low. Assessments of EMF levels around telecommunication sites or “masts” are routinely carried out by the Commission for Communications Regulation (ComReg), and are published on ComReg’s SiteViewer as well as here.
At a certain distance from the antenna (known as far-field), only the electric fields (E) need to be measured, since, under these conditions, the magnetic fields (H) can be easily extrapolated from the measured electric fields. Thus, RF surveys for public exposure usually include measurements of electric fields only. The table below summarises the levels of electric fields associated with typical RF sources in everyday environments. These levels are typically well below recommended exposure limits. See the Note under the table for details about recommended exposure limits for these RF sources.
| Source | Distance 1 (near) | Distance 2 (far) |
|---|---|---|
| Mobile phone (handset) 1 | ≈100 V/m at ear | ≈10 V/m at 5 cm |
| Mobile phone (base station) | ≈2 V/m at 30 m | ≈0.01 V/m at 100 m |
| TV (UHF) broadcasting antenna | ≈5 V/m at 500 m | ≈1 V/m at 1 km |
| TV (VHF) broadcasting antenna | ≈2 V/m at 500 m | ≈0.1 V/m at 1 km |
| Radio (AM) broadcasting antenna | ≈10 V/m at 100 m | ≈0.1 V/m at 1 km |
| Radio (FM) broadcasting antenna | ≈2 V/m at 500 m | ≈0.1 V/m at 1 km |
| Radar (police road traffic) | ≈1 V/m at 30 m | ≈0.1 V/m at 300 m |
| Radar (air traffic) | ≈2.5 V/m at 200 m | ≈0.01 V/m at 600 m |
| Microwave oven (domestic) 2 | ≈40 V/m at 5 cm | ≈2 V/m at 1 m |
Note: The most restrictive reference level for RF (whole-body) public exposure is 28 V/m (EU 1999).
1 The estimates for mobile phone handset represent maximum exposure levels assuming a typical phone with an average SAR=1 W/kg. The current exposure limit for head exposure is 2 W/kg.
2 The reference level for (whole-body) exposure to sources such as domestic microwave ovens (which typically work at 2.45 GHz) is 61 V/m. Unless otherwise stated, electric field estimates come from Mantiply et al 1997 and Valberg et al 2007.
