Polluting printers contaminate office air
UPdate Fall 2007

Office air five times more polluted than the nearby freeway? That’s what researchers in Australia discovered recently. The pollution was not coming from outdoors, as might be expected. The major culprit turned out to be laser printers.

“ We were studying the efficiency of ventilation systems to protect office settings from outdoor air pollutants,’ explained Lidia Morawska, Ph.D in environmental physics. “We soon realized that we were seeing air pollution originating indoors, from laser printers.” The researchers tested 62 printers, all major brands. They found 17 of them were “high emitters.” High emitters increased the level of small particle emissions ten times above the expected background level. Standing next to the worst emitting printer was comparable to standing next to a cigarette smoker.

The particles given off by printers are ultra-fine. This makes them a greater health risk than larger particles because they are more easily inhaled deep into the lungs, where they can have serious effects. Although the researchers did not analyze the composition of the particles, they suspect that toner, an ultra-fine powder used in laser printers instead of ink, is the source of the emissions. The health risks can range from respiratory irritation to cardiovascular problems or cancer, said Morawska. “Even very small concentrations can be related to health hazards,” she explained. “Where the concentrations are significantly elevated means there is potentially a considerable threat.”

Not all the laser printers tested were particle polluters. Over half of the printers released no particles at all, including one printer which was the identical model as the printer which measured as the worst offender. Researchers found that emission levels varied, depending on whether the toner was new or old, and that particle levels increased when graphics were printed. Printing graphics uses greater amounts of toner.

User manuals provided with laser printers instruct that the machines should always be ventilated outdoors. These instructions are more often ignored than followed, both in the work environment and at home. Ventilating laser printers outside decreases particle levels indoors.

“This is an important indoor source of pollution, Morawska said. “There should be regulations.” The impact of printers on indoor air has been the subject on only a handful of studies, and there are no government standards for printer emissions. A few studies have looked at the emissions of volatile organic compounds, ozone and toner particles from office printers and copiers. But there are broad gaps in the scientific understanding of particle emissions, the report states.

Unlike laser printers, ink-jet printers do not require toner. They are also generally lower in emissions of volatile organic compounds, especially those with solvent-free ink.