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Laser Printers Emit Indoor Pollution

Some home and office laser printers emit possibly harmful
amounts of small-particle air pollution, Australian researchers find.

One of the printers gave off as much small-particle pollution as a burning
cigarette, find Lidia Morawska, PhD, director of the International Laboratory
for Air Quality and Health at Queensland University of Technology in Brisbane,
Australia, and colleagues.

"By all means this is an important indoor source of pollution. There
should be regulations," Morawska says in a news release.

The researchers tested 62 printers sold under the Canon, HP Color LaserJet,
Ricoh, and Toshiba brand names. They measured particles given off by the
printers under normal operating conditions in a large, open office setting with
22 desks. They also tested three of the printers in a closed chamber.

Seventeen of the printers emitted high levels of particles, while 37
released no particles at all. The differences were large.
"Medium-emitter" printers gave off 100 times more particles than did
"low-emitter" printers. "High-emitter" printers gave off 1,000
times more particles than did "low-emitter" printers.

So which printers should you avoid? It's not a simple question.

"While the printers were classified into different groups according to
their emission levels, there are no obviously common features which printers in
the individual groups share," Morawska tells WebMD via email. "Printers
by the same manufacturer -- but of different model numbers -- were both in the
high- and low-emitting groups."

Under different circumstances -- such as toner coverage and cartridge age --
the same printer might give off different levels of pollution. For example, the
HP LaserJet 5 printer tested as a nonemitter in one test, and as a high emitter
in another.

The very fine particles emitted by laser printers could be a problem, as
such small particles can be inhaled deep into the lungs.

"Even very small concentrations can be related to health hazards. Where
the concentrations are significantly elevated, there is potentially a
considerable hazard," Morawska says.

Depending on the ventilation conditions of a room or office, the particles
emitted by a laser printer can disperse in a few minutes or hand in the air for
hours, Morawska says.

She advises people who use laser printers to keep their offices well
ventilated. She also suggests that people not sit too close to working

"The closer to the sources -- in this case the printer -- the higher
hazard, as the concentrations are higher," Morawska warns.

The researchers note that the complex particle-emission patterns of laser
printers is "still far from being completely understood" and that
further study is needed.

The findings appear in the Aug. 1 online edition of the American Chemical
Society journal Environmental Science & Technology.

By Daniel DeNoon
Reviewed by Louise Chang
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