The average printer releases toner particles that can get deep into the lungs and cause respiratory problems and cardiovascular trouble, according to Morawska's team, part of the International Laboratory for Air Quality and Health, and specialists in atmospheric particles.
The team tested 62 laser printer models--all relatively new--and found that 17 of them were "high emitters" of toner particles. Despite using similar technology, office photocopiers do not emit particles, the team found.
The printer emissions data were discovered by chance when an investigation of office ventilation systems, carried out jointly between the university and the Queensland Department of Public Works, found five times as many particles indoors as those produced by traffic outdoors. Using an electronic sniffer, researchers traced the emissions to printers. The emissions were found to increase during the day, when printers were left on standby or in full operation.
Following the revelation, Morawska's team tested their own printers and moved the unhealthy ones away from people. The researchers are now calling for regulations on printer emissions. The study included Canon, HP LaserJet, Ricoh and Toshiba printers. The university had not released comprehensive results by the time this story was published.
"Vigorous tests under standardized operating conditions are an integral part of HP's research and development, and its strict quality-control procedures," the company said in a statement. "As part of these quality controls, HP assesses its LaserJet printing systems, original HP print cartridges and papers for dust release and possible material emissions to ensure compliance with applicable international health and safety requirements."
Peter Judge and David Meyer of ZDNet UK reported from London.