Mobile phone base stations and your health
While most people welcome more mobile phone coverage, we at Vodafone recognise that some people are concerned about possible health effects of base stations and we are committed to addressing these concerns.
This fact sheet is designed to provide a straightforward discussion of the regulation and monitoring of mobile base stations.
Mobile phones and base stations
Mobile phones are sophisticated two-way radios that use radiofrequency (RF) signals to transmit and receive voice and data. When you make or receive a call, your mobile phone communicates with a network of low powered radio transceivers called base stations. Each base station covers a small geographic area, referred to as a "cell", and cells are interlinked to create the cellular network.
RF signals are a form of energy. RF signals travel through the atmosphere as electromagnetic waves. Information from the mobile handset and the base station is encoded onto these carrier waves to transmit voice and data.
RF exposure levels near base stations
RF exposure levels around Vodafone base stations do not pose a health risk to anyone because these levels are always well within the National and International science-based limits.
Vodafone ensures the electromagnetic energy (EME) levels of RF signals are within National and International guidelines. The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) has developed a standardised industry methodology for monitoring and reporting on the predicted EME levels of base stations.
This methodology is used to keep the community informed about base station proposals under the Australian Communications Industry Forum (ACIF) Code for Deployment of Mobile Phone Network Infrastructure. RF exposure levels are calculated by considering factors such as power output, cable loss, antenna gain, path loss, and height and distance from the source. The ARPANSA report requires calculations of highest RF exposure levels out to 500 metres. The calculations are given as a percentage of the ARPANSA Standard general public exposure limit.
The calculations generally provide a prediction for a fully loaded base station - a scenario and exposure level reached for only a very small percentage of the time. Many sample sites that have been independently measured for RF exposure levels following deployment have produced readings that are actually lower than the respective prediction.
What happens with the RF exposure levels when you co-locate with other carriers or add new antenna systems like 3G to a site?
The actual RF exposure levels depend on many factors including the type of equipment used, the power and the antenna orientation, although carrier base stations do not differ greatly from one another in terms of overall RF exposure. As an estimate, when two carriers co-locate, the RF exposure level approximately doubles.
When new antenna systems like 3G are added, RF exposure levels increase only slightly. The resultant RF levels are predicted prior to the installation of the new facilities to ensure the base station remains within ARPANSA Standard general public exposure limit (most new antennas contribute a fractional increase of RF signals). These calculations are made available to the public.
Can you just keep on adding more antennas to a base station thereby continually increasing RF exposure levels?
No. Mobile phone networks, because of their "cellular" nature are inherently low-powered. Technical constraints such as controlling interference with adjacent "cells" mean that mobile phone base stations are designed to cater for a limited capacity of simultaneous calls. A typical Vodafone base station accommodates approximately 40-60 simultaneous voice or data signals.
Regular high usage at one base station requires an additional base station to be installed at another location.
Is there a limit to the number of carriers who can put transmitters at the same location?
Technical constraints make it difficult to accommodate more than two or three mobile phone carriers at the same location. Rooftop locations can sometimes accommodate more, provided the area is sufficient to create a suitable separation distance between transmitters. But no matter how many base stations are located at the same location, the RF signals from the combined facilities must still operate within strict ARPANSA limits.
The Australian Communications and Media Authority (ACMA) has developed a mandatory human exposure standard and compliance framework to ensure all RF transmitters at multi-transmitter sites comply with the ACMA's RF exposure limits. The cumulative RF exposure levels at multiple carrier sites cannot exceed the ACMA's limits. These ACMA limits are based on the levels set in the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) radiofrequency Standard.
The ACIF 'Code for the Deployment of Mobile Network Infrastructure' stipulates a level of community consultation to be undertaken prior to the installation of all base stations. The Code also requires carriers to calculate the cumulative level of RF exposure from carriers' existing and proposed antennas using the ARPANSA methodology.
Will the background levels of RF exposure significantly rise due to the increasing number of base stations?
When compared to overall current RF exposure emitted from existing services including television, radio and Emergency Services, the RF exposure from mobile phone base stations is not significant. ARPANSA's National Survey of Base Stations conducted in 1999 showed the average contribution of RF energy from mobile phone base stations when compared with other radio signals was only 1.95% of the total environmental RF measured.
Cell areas for new technologies such as 3G are even smaller than 2G. Thus, 3G uses lower power and therefore this means lower levels of RF exposure. The RF exposure levels from a base station are very low, typically between 0.1%- 1% of the ARPANSA Standard and these levels drop off very rapidly with increasing distance from the base station.
Further Information
Vodafone encourages anyone with further questions about mobile phones or base stations to seek independent reliable expert advice. Below are some organisations that may be able to help.
Australian Communications and Media Authority (ACMA)
Phone: (02) 6219 5555
http://emr.acma.gov.au
Australian Communications Industry Forum (ACIF)
Phone (02) 9959 9111
www.acif.org.au
Australian Radiation Protection & Nuclear
Safety Agency (ARPANSA)
Phone: (03) 9433 2211
www.arpansa.gov.au/eme_pubs.htm
World Health Organization
EMF Project Home Page:
www.who.int/peh-emf/en/
UK Health Protection Agency
http://www.hpa.org.uk/radiation/advisory_groups/agnir
For further information, please contact
Vodafone's EME Manager.
Phone: (02) 9415-7002 or (02) 9415-7008
Email: ememanagement.au@vodafone.com
