If you are a computer user, computer radiation may be your largest single source of electromagnetic radiation.
Although the intensity of radiation from
computers may be far less than from, say, a high-voltage power line,
people get much closer to their PC.
Many of us spend our working days in front
of computer monitors, surrounded by nearby electronic equipment, each
item emitting radiation. Because of the duration of this exposure (many
hours every day), computer radiation is a real health hazard.
This type of radiation, known as Extremely Low
Frequency (ELF), is also emitted from power lines, electrical
sub-stations, TVs and other electrical and electronic appliances.
Another type of dangerous electromagnetic radiation found near computers is microwave radiation.
Microwaves are used to provide radio communication between
wireless-networked equipment, including computers, printers, modems,
routers and other cordless or wi-fi devices.
A typical computer user, not too careful about equipment choice and placement, could be exposed to
|
Type of Radiation
|
Field Strength
|
|
ELF radiation from computers
|
3-6 milligauss
|
|
Microwave from wi-fi devices
|
100-200 µW/m2
|
Each of these levels individually is far from safe. Taken together they create a very serious health risk.
Fortunately there are simple measures to reduce this radiation, which you will read about on this page.
Computer Radiation Health Effects
For many years it has been known that ELF
radiation can cause, or contribute to, various health problems - ranging
from sleep interference and allergic reactions, through to heart
disease, cancer and alzheimer's disease. To learn more about how
computer radiation causes these health problems, see our EMF Health Effects page.
Most people would not want to sit at a desk
under high voltage power lines. But they will happily sit a foot away
from a computer screen, with a computer and printer on the desk next to
them, and perhaps a power supply (UPS) near their feet.
They will work like this for several hours
every day, for many years, absorbing as much (or more) ELF radiation
than if their desk was close to a high-voltage power line! See our table
of Power Line EMF Levels for comparison.
Computer radiation is easily subdued!
Computers contain
power supplies, fans, drives and other electrical units which generate
ELF radiation strong enough to cause concern at distances up to about 60
cm (about 2 feet).
For example, the
desktop PCs in our office each produce computer radiation of about 1
milligauss (borderline safe) at 60 cm, stronger towards the rear of the
unit.
The magnetic
portion of this electromagnetic radiation is the most dangerous part. It
can penetrate just about anything (including, of course, you). It does
not help to place a shield or screen between you and the computer. (See
our page What is Electromagnetic Radiation.)
But this ELF radiation
naturally falls away very quickly with increasing distance, because the
radiation is from a low power source.
The simple solution
is to position your computer as far away from you as cables allow (at
least 60 cm, preferably more). If possible, keep it on the floor, not on
your desk.
You want to minimise
the computer radiation to all parts of your body, but especially your
head and your trunk.
Computer monitor radiation
The item most likely
to cause a health hazard in some offices is the computer monitor, or
screen. The old box-shaped cathode-ray tube (CRT) computer monitors
generally have quite high levels of radiation at around 30 cm.
The CRT computer
monitor in our office produced 3 milligauss of radiation at 30 cm,
measured from the front and 4 milligauss at the same distance from the
sides. This is a fairly recent model. Computer monitor radiation from
older equipment can be even higher.
A constant
3 mG of computer monitor radiation is a health hazard in itself, but
remember that this same user is probably also absorbing low-frequency
radiation from computers, printers, power supplies (ups), florescent
lights and mobile phones as well as microwave energy from wireless
modems, routers, networks and printers.
No wonder computer users get sick so often!
Fortunately,
technology has come to our aid with the LCD monitor (the flat one),
which emits minimal radiation. For example, the LCD screens in our
office create an EMF of 0.3 milligauss at 30 cm, from the front or back -
and practically nothing at the sides. This is a much safer level.
More recent still are
LED monitors. I have one fitted to my laptop. EMF levels on this monitor
are very similar to the LCD monitors, so nothing to worry about there.
If you use the older
CRT type for long periods every day, perhaps it's time it was replaced.
(Speak to the boss!)
Pregnant women
should be particularly careful about using CRT screens - which have been
associated with higher rates of miscarriage and possibly birth defects.
Laptop radiation
Laptop or notebook
computer radiation is generally lower than from desktop PCs, partly
because the components are smaller, the laptop is battery-operated and
the laptop screen is invariably an LCD or LED.
But the problem with
laptop radiation is that you may be very close to it indeed, especially
if you operate the laptop on your laptop!
In fact, as you will see from our Table of EMF Values, laptop radiation may be as little as 1 milligauss at 30cm, but as much as 20 milligauss at point-blank range.
So keep your distance
when operating your laptop computer. It should be positioned on a table
or desk. Make sure that you are at least 30 cm away from it (except for
your hands on the keyboard) to minimise computer radiation. A separate
keyboard and mouse (not wireless!) would also be a good idea.
Laptop computers
produce RF EMF when they are being used wirelessly, either with wi-fi or
3G connectivity. I use the wireless capabilities of my laptop for short
periods when I am on holiday, but for normal usage in my office, I use a
cable connection, and keep my laptop's wireless ability switched off.
EMF from netbook computers (the little jobs) is similar to that from notebooks.
The Kindle book
reading device produces no EMF in normal use. (The page display uses no
power.) Only the tiniest flicker on my Trifield needle was observed when
the page-turn button was pressed. But when using wi-fi or 3G
communications a substantial RF EMF is produced, similar to a cellphone
or laptop computer.
Radiation from computer power supply (UPS)
Many
people have a UPS (uninterruptible power supply) to provide backup power
for their computers. These little guys pack a powerful radiation punch.
My UPS
produces radiation of 20 milligauss at 30 cm, and over 1 milligauss at 1
metre, even when apparently switched off (but still connected to mains
electricity, and charging its battery).
If you
need a UPS, position it as far away from yourself and others as cables
allow - I suggest at least 1.5 metres.
Radiation from larger computer/office equiment.
For larger (generally
floor-standing) computer equipment such as printers, photocopiers,
mini-computers and all racked equipment, assume that a substantial
amount of computer radiation will be produced, unless you know
differently.
Position these items
at a safe distance (at least 1.5 metres) from where people work. (The
occasional visit to the photocopier or printer need not be a cause for
concern, because the duration is short).
For mainframe computer
operators, engineers and other personnel, it is essential to measure
both types of radiation with suitable meters, and minimise your contact
with high-EMF areas.
Radiation from printers and other computer devices
Small (desktop)
computer printers generally produce less than 0.5 milligauss at 60cm in
standby mode and up to twice that amount when printing. As this is
probably not be the only source of computer radiation at your desk, do
not keep your printer too close to you.
Some corded
desktop devices are practically harmless, including keyboards,
mouses(!), small speakers and modems. The same applies to telephones
(landlines only). You can have these as close as you like.
Large sub-woofers that
are becoming popular as part of a home computer's sound system can emit
more than just (astonishing levels of) bass - ours produces 20
milligauss of ELF radiation at 0 cms, 3 mG at 60 cm (1') and .5 mG at 60
cm (2') whenever the speaker is powered (even when it is producing no
sound).
So don't use your
sub-woofer as a footrest! It needs to be at least 90 cm (3') away from
you. (Closer than that it would deafen you anyway!)
Wi-fi Radiation from wireless networks, routers, printers and modems
Wi-fi information networks, wireless routers,
modems and other wireless devices are becoming very pervasive. All of
them emit electromagnetic radiation, mainly microwave or radio (also
known as RF) radiation, as they keep in touch with each other.
These wireless devices are not safe. In
fact there is strong evidence that the information content (pulsed
digital signal added on to the microwave carrier) may interfere with
biological processes.
Wi-fi networks are now installed in many public and private places. You may be exposed to them without knowing it.
Most concerning is the practice in some schools
of installing wi-fi networks in the computer centre and classrooms.
Children are particularly vulnerable to electromagnetic radiation. See
our page Who is at risk? Schools and libraries should always install wired networks.
For your home and office too, rather use wired
products. You may still be exposed to someone else's wi-fi, but at
least it will be further away. If you still have reason to be concerned,
obtain a suitable radio-frequency EMF meter to run a check.
Achieving acceptable computer radiation levels
In most cases, applying these recommendations will cause computer radiation to be reduced to acceptable levels.
For example, in the small office
where I work (about eight hours a day with two other people) there are
three desktop computers and one laptop. We have arranged the office to
minimise computer radiation for all of us:
-
Computer (tower) cases are all on the floor next to the user's desk, as far away from the user as possible.
-
The UPS is far away from everyone - at max cable stretch.
-
Screens are all LCD.
-
There is no cordless equipment (keyboard, mouse, telephone etc.) in our office.
-
On a table next to my desk are two
desktop printers and a laptop computer. The nearest printer is about 75
cm (30") away from me. At this distance my EMF meter can barely detect
it's presence.
-
The computers and printers are all networked together into our (wired) office network .
- Our internet connection is by DSL with a wired modem connected to a wired telephone line.
I don't think there is much more
we can do to reduce computer radiation, unless we change our line of
work! So what's the result?
Zero Radiation? Not quite
At my desk, my feet are exposed
to electromagnetic radiation of about 0.5 milligauss and my head to
about 0.2 milligauss, with an average whole body EMF of about 0.3 mG.
The two other people who share this office have similar levels.
Microwave radiation levels in the office are fairly low (about 0.15 microwatts/m2). The microwave radiation is probably due entirely to the cell phone tower, which I estimate is just over 400 metres away.
I'd prefer zero radiation, but in the real world one has to accept a small amount!
Now arrange your own workplace
You can probably achieve similar or better levels in your home or office.
To optimise your exposure and check your results, you would need an EMF meter.
A good one for low-frequency work (including computer radiation) is the TriField Electromagnetic Field meter
and for microwave radiation you can look at the Electrosmog meter. They are both reviewed on
our EMF Meters page.
and for microwave radiation you can look at the Electrosmog meter. They are both reviewed on
our EMF Meters page.
But if you cannot lay your hands
on a meter, great benefit can still be achieved just by stretching the
distance between you and each item of equipment. You won't know exactly
how much you have reduced your exposure to radiation, but your health
will still benefit!
And forget that myth about
putting a cactus on your desk to absorb all the radiation in the room!
It would be an easy solution, but it doesn't work. Plants have no effect
on EMF, I'm afraid.
