An article published this week in Environmental Science & Technology (EST) reports on a study by researchers from Queensland University of Technology in Australia.

Initially, the researchers were requested by the Queensland Department of Public Works to examine whether air quality in an office was affected by a nearby highway. But Professor Lidia Morawska and her colleagues discovered that levels of particulate matter were 500 percent higher during a workday in the nonsmoking office building than even at a spot on the highway.

Suspecting the printers, the researchers tested more than 60 in the building and found a wide variation of emissions. The worst one was as bad for nearby breathers as a cigarette smoker would be.

Ventilation Is Key

The range of emissions was wide. Looking at several brands and models, with a range of toner cartridge ages, the researchers tested some in isolated conditions and others in their office locations. Overall, they found 37 printers were nonemitters, eight were low or medium emitters, and 17 were high.

Patterns were not immediately apparent. One HP LaserJet 5 was a high emitter, for instance, while another was a nonemitter. Eight HP LaserJet 4050 and four Ricoh Aficio series printers had no emissions, but HP's LaserJet 1320 and 4250 were high emitters.

In general, the researchers found that newer toner cartridges, and printing toner-heavy documents, released more particles. Morawska recommended that, regardless of printer model or a toner cartridge's age, offices should maintain good ventilation.

'One Bad Apple'?

The researchers are planning more studies, such as testing multiple printers of the same model. But little research has been conducted on this subject. A 2006 study in Japan found that laser printers increase concentrations of styrene, xylenes, and ozone, and that ink-jet printers emitted pentanol.

Ten years ago, the U.S. Environmental Protection Agency evaluated printers and photocopiers, but modern-day researchers said the data is irrelevant because the technology has changed dramatically.

The range of results from the University of Queensland researchers raises questions about how common high levels of indoor pollution from printers might be, Charles Weschler of the University of Medicine and Dentistry in New Jersey told EST. "Emissions may be highest with a brand-new cartridge, just opened," he said. But he suggested it's also possible that, for instance, the worse-than-smoking printer could have been "one bad apple."

EST also quoted Erik Uhde of the Wilhelm Klauditz Institute in Germany, who pointed out other variables. Even printers in a specific product line from a specific manufacturer could vary, he said, because the sources for their parts might differ. And if the cartridge is the key, Uhde said, it is unclear whether it is the toner or the solvent causing the problem.