LOW EMF COMPUTERS
3/31/10
There is presently no such thing as a zero EMF monitor or computer. Some are much lower than others, but all radiate EMFs. It is impossible to shield all the emissions (see my article: EMF Scams). Most computer manufacturers are in denial about EMF sensitivity. I don’t think we can expect anything but inadvertent help from them for many years.
Everyone who is electrically sensitive has their own particular frequencies that bother them the most - each person is different. Furthermore, there are no reliable criteria that enable one to predict which computers have less emissions. This is a very complex subject, but in general, some laptops (Apple's new MacBook; they also do a good job as far as low odor) and some netbooks have a better chance of working for people than most towers/desk-top units. Unfortunately it is trial and error: buy only with a money-back return policy (though this may be impossible in the case of Apple). It is best to get a device that operates off of batteries, and only use it while it is NOT plugged in to its charger. And leave the charger/power supply/power brick unplugged from the wall when you are not charging. Use the screen only at full brightness, since brightness reduction brings a dimmer-switching circuit into play which generates much more EMF. Using an external keyboard and mouse is usually better than keeping your hands directly on the laptop. The old-style mechanical roller-ball mouse or trackball usually has less emissions than the modern optical mice. Keyboards vary widely in their emissions (they all contain their own microprocessors). The Macally IceKey may be better than most. For further EMI reduction, optical fiber USB and DVI cables are available.
A solid-state hard drive will have less EMF emissions and will provide a longer battery life than the standard mechanical hard disk drive, and many of the newest laptops and netbooks offer a solid-state drive as an option. This option usually costs more, but the prices are coming down rapidly.
New models of the Intel Atom microprocessor are entering the market all the time. These processors use very low power, and tend to have relatively low levels of EMF. The latest models will have the graphics functions integrated onto the chip, and this should reduce emissions considerably. They may provide up to a 10 hour battery life. In the middle of this year an even more compact processor with 32 nanometer traces will be introduced, which should have even lower emissions. Look for netbooks or laptops with the 32 nanometer Intel Atom chip.
Some persons have tried to use a projector or pocket projector as their monitor so that they can sit farther away than from the usual monitor screen, but unfortunately, all of the projectors I have tried or know about have far stronger (even at a distance) EMFs than an LCD monitor. This is due to the switching power supply necessary to power the lamp, or the pulsing of the LEDs in a projector with a LED source.
LCD screens with LED backlight are usually no better than the old fluorescent backlight as far as EMFs go, because the LEDs are usually pulsed, and their supply is of the switching type.
For a chemically sensitive person, any of the Apple iMac models would be a dangerous choice for the following reason: about one-half of chemically sensitive persons eventually develop electrical sensitivities, especially from sitting near computers for a long time, and the iMac places not only the monitor, but also the computer processor, drive and switching power supply irrevocably only two feet from your face. On the other hand, when the computer is separate from the monitor, you have the option of moving it further away from you. In general, most EMI emissions decrease with distance much faster than you might expect; the intensity is often inversely proportional to the square of the distance. This means that the intensity at 4 feet can be 1/4 of that at 2 feet, and at 8 feet it can be reduced to 1/16th. This is helpful, but not as helpful as it seems, because unfortunately living cells are logarithmic in their sensitivity (see my discussion of this in part 4.D in my article "EMF Scams").
In general, laptops have lower emissions than desktops, not only because they can be run on their internal batteries, to avoid a main switching power supply, but also because they are highly integrated, compact and more efficient in their use of power. It is probably best to get one with a unibody metal case, which may provide some shielding.A solution (but probably an imperfect one) for an electrically sensitive person could be a relatively low emission netbook or laptop running only on its internal battery (possibly an Apple MacBook Pro model), placed at some distance and used together with a wired keyboard and mouse, and with an external monitor if you can find a monitor you are not too sensitive to. The best bet for a monitor would be a model with an external rather than internal power supply, especially if that external switching supply were to be replaced by a linear type of supply (which has far less RF emission).
I have had success (much reduced EMF) with a projector I designed and built myself, and with TV's in which I have replaced EMF-noisy switching power supplies with quiet linear-type power supplies, and with portable, battery powered DVD players. I have been modifying LCD's for use as TV's or monitors for others on a custom basis, but this is quite expensive.