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Cellphones and Cellsites
In this section:
Cellphones
Safety of cellphones
Cellphones are low-powered, portable radio transceivers (transmitters and receivers of radio signals). The user holds the cellphone very close to his or her head, and this proximity has raised questions about possible health effects for users.
Are cellphones safe?
The balance of current research evidence suggests that exposures to
the radiofrequency energy produced by cellphones do not cause health
problems provided they comply with international guidelines. Reviews
of all the research have not found clear, consistent evidence of any
adverse effects.
Exposures from cellphones available in New Zealand, both digital and analogue, all comply with limits recommended in the relevant New Zealand Standard (NZS 2772.1:1999). This Standard is based on international exposure guidelines published by the International Commission on Non-Ionizing Radiation Protection. The ICNIRP is composed of scientists working in government, university or other independent research establishments, and is recognised by the World Health Organization as having expertise in this area.
Should I reduce my exposure?
Current research does not indicate the need to reduce exposures if
they already comply with safety limits. Nevertheless it is never
possible to prove safety absolutely (of radiofrequency energy or any
other agent), and there is uncertainty about the significance of
some experimental data. If individuals wish to reduce their
exposure, there are several simple methods to do so:
- Use the phone in places with a good signal strength. This allows the phone to transmit at low power (up to 100 times lower than its maximum value), with exposures reduced accordingly
- Minimise the length of time spent on calls
- Extend the antenna and hold it away from the head
- Use a conventional phone or car kit with an external antenna
Using a cellphone in a car (with or without a car kit) while driving is not recommended, as several studies have demonstrated that the consequent distraction leads to a substantially increased risk of an accident.
Is it safe for children to use cellphones?
The limits in the New Zealand exposure standard take account of
differences between adults and children, and are designed to provide
protection for all age groups. If there are any subtle effects which
have not yet been discovered, then children under 16 might be more
vulnerable due to their slightly greater absorption of
radiofrequency energy and longer lifetime exposure (although there
is currently no evidence of any effect which accumulates over time).
A recent UK review recommended that, as a precautionary measure,
non-essential use of cellphones by under-16s should be discouraged.
Use of cellphones by children should be a matter for informed choice by parents, bearing in mind also that cellphones can improve personal safety.
Do hands-free kits or other devices reduce exposures?
Tests of hands-free kits have generally found that they reduce
exposures by up to 98%. To reduce exposure to all parts of the body,
the phone should be placed away from the body when making a call.
There is little test data available for other devices (such as shielded covers or small discs which fit over the earpiece) which are claimed to reduce exposures from cellphones. The only valid tests would be ones which realistically simulate actual phone use and compare exposures to a model head with and without the shielding device. Currently, most of the performance data provided with such devices is obtained using test set-ups which bear no resemblance to the way a phone is used in practice.
How can I obtain information on the exposure from a
cellphone?
Exposure from cellphones is measured as the specific absorption
rate, usually abbreviated to SAR and measured in watts per kilogram
(W/kg). This number expresses the rate at which radiofrequency
energy is absorbed in the body.
Although cellphone manufacturers have agreed in principle to provide this information, it is not expected to be widely available until 2002. The SAR figure provided will be the maximum level when the phone is working on full output. The Ministry of Consumer Affairs and National Radiation Laboratory are working with suppliers to ensure that information is provided in a standard format.
The measured SAR might be one factor to consider when purchasing a phone. However, it does not give a complete picture of exposures in actual use, as it does not account for the reduction in output in areas of good or intermediate signal strength, which may vary between different models of phone.
In the New Zealand exposure Standard, the maximum SAR level permitted over any 10 g of body tissue is 2 W/kg, provided the average SAR over the whole body is less than 0.08 W/kg.
Are there any differences between digital and analogue phones?
It has been speculated that the pulsed nature of the transmissions
from digital phones may mean that they are more liable to interact
with the body than analogue phones. However, reviews of the evidence
provide little support for this theory, and even less to suggest
that there may be consequential effects on health.
For more information go to:
IS 21 Safety of cellphones
(an information sheet containing the same information as presented
above).
A range of information on cellphones from the United States FDA is
available at
www.fda.gov/cellphones.
A review on studies of brain cancers in cellphone users,
commissioned by the Swedish Radiation Protection Authority, found no
causal association between cellphone use and cancer. The report can
be downloaded at
www.ssi.se/english/Press_release_rapp2001_16.html.
Health Council of the Netherlands review of mobile phones (January
2002) www.gr.nl/pdf.php?ID=377
(Follow the links from the URL to: Publications - reports - Mobile
telephones; an evaluation of health effects.)
Several reports and sources of information consider both cellphones
and cellsites. Links to these sources can be found
here.
Back to top:
Exposures from cellphones
Information on exposures from some models of phone can be obtained
through the following web site:
www.mmfai.org/public/sar.cfm?lang=eng.
This information is normally included in the phone operating manual.
Some information is available through the United States Federal
Communications Commission, which requires data to be submitted as
part of its approvals process for phones. This can be
accessed through: www.fcc.gov/oet/rfsafety.
Hands-free kits:
Tests on hands-free kits commissioned by the United Kingdom
Department and Trade and Industry have confirmed that the kits
do reduce exposures to the head. A summary of the report, and
the report itself, can be accessed here:
www.dti.gov.uk/cii/regulatory/telecomms/telecommsregulations/handsfree_mobilephones.shtml.
Results of tests on various types of devices which are purported to
reduce exposures from cellphones can be downloaded from:
www.dti.gov.uk/files/file13248.pdf.
Cellsites
Cellsites (sometimes referred to as cellphone base stations) are moderate to low powered radio transmitters, used to communicate with mobile phones in the surrounding area. They are designed to transmit most of the radio signals away from the site, rather than in the area immediately around it.
Measurements carried out by the National Radiation Laboratory around several dozen cellsites have shown that maximum exposures are typically about 1 or 2% of the exposure limit recommended in New Zealand and international exposure standards. In most areas they are less than that. No health effects are anticipated at such low exposures.
For more information go to:
Cellsites (PDF - 103 kB) A more detailed information booklet about cellsites (A4 format to be printed double-sided in booklet mode).
Health Council of the Netherlands review of GSM cellsites (June
2000)
www.gr.nl/pdf.php?ID=34
(Follow the links from the URL to: Publications - reports - GSM Base
Stations.)
Back to top:
The following links discuss both cellphones and cellsites
The WHO has a continuing project investigating possible health effects of electromagnetic fields, including the low frequency fields from power lines and other electrical equipment and cabling. The project's home page is at www.who.int/emf. They have also issued two fact sheets: Electromagnetic fields and public health: mobile telephones and their base stations and on Base stations and wireless technologies.
The report of the UK Independent Expert Group on Mobile Phones, published in May 2000, is available at www.iegmp.org.uk.
Royal Society of Canada: A review of the potential health risks of radiofrequency fields from wireless communication devices. (May 1999, with updates 2001, 2004). www.rsc.ca//index.php?lang_id=1&page_id=120.
www.mcw.edu/gcrc/cop/cell-phone-health-FAQ/toc.html
This site, maintained by Dr J E Moulder at the Medical College of
Wisconsin, has a comprehensive set of questions and answers relating
to cellsites and cellphones.
Health Effects from radiofrequency electromagnetic fields – the report of an independent Advisory Group on Non-ionising radiation reporting to the British National Radiological Protection Board, published in January 2004.
The Health Council of the Netherlands published Electromagnetic fields: Annual update 2003 at the beginning of 2004. The 2006 Annual update reviewed UMTS base stations and DECT phones, and is available here.
The Swedish Radiation Protection Authority SSI appointed an independent expert group to evaluate research on electromagnetic fields and health, which produced its first report in December 2003. The fourth report, published at the beginning of 2007, can be found here.
Information sheets on cellphones and cellsites published in Australia by the Australian Communications and Media Authority and the Australian Radiation Protection and Nuclear Safety Agency can be found at emr.acma.gov.au (note that the sections on planning regulations do not apply to New Zealand).
Research in this area is monitored in New Zealand by an interagency committee reporting to the Director-General of Health. Periodically this Committee prepares a report to Ministers. The most recent report, which covers both radiofrequency and extremely low frequency fields, was published in November 2004 and is available here (PDF 161 kB).