Laser Printers Emit Potentially Hazardous Indoor Pollution,Study Says

Wednesday, August 01, 2007

By Daniel J. DeNoon

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 said 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 said 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 said.

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 said.

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

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

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.

This article was reviewed by Louise Chang, MD