Laser Printer Emissions Harmful to Human Health

BRISBANE, Australia, August 1, 2007 (ENS) - Some of the laser printers used in offices and homes release tiny particles into the air that people can inhale deep into lungs where they may pose a health hazard, Australian scientists said today.

One of the 62 printers studied released particles at a rate comparable to the emissions from cigarette smoking, the researchers report.

The study included popular models in the United States and Australia sold internationally under the Canon, HP Color Laserjet, Ricoh and Toshiba brand names.

Environmental physicist Lidia Morawska, PhD, and colleagues the Queensland University of Technology in Brisbane classified 17 out of 62 printers in the study as "high particle emitters" because they released such elevated quantities of particles.

Dr. Lidia Morawska (Photo courtesy Australian Institute of Physics)
A total of 12 models of Hewlett Packard printers and one Toshiba printer are listed as high emitters of tiny particles.

Two printers released medium levels of particles, six emitted low levels, and 37 of the printers tested released no particles at all.

The researchers believe the particles to be toner, the ultrafine powder used in laser printers to form text and images instead of ink.

All printers were monitored in an open office. The study did not consider variables such as printer age or cartridge type, leading to variations even among printers of the same model. For instance, the scientists found one HP LaserJet 5 to be a high emitter, while another was a non-emitter.

Most of the printer-generated particles detected were ultrafine, Dr. Morawska said, explaining that such contaminants are easily inhaled into the smallest passageways of the lungs where they could pose "a significant health threat."

Laser printer in a home office (Photo courtesy

Previous studies have focused on emissions of volatile organic compounds, ozone, and toner particles from office printers and copiers. But the research has left broad gaps in scientific understanding of particle emissions and airborne concentrations of particles, the report notes.

Morawska and colleagues did not set out to close that knowledge gap.

"It wasn’t an area that we consciously decided to study," Morawska said. "We came across it by chance. Initially we were studying the efficiency of ventilation systems to protect office settings from outdoor air pollutants. We soon realized that we were seeing air pollution originating indoors, from laser printers."

The study found that indoor particle levels in the office air increased fivefold during work hours due to printer use.

Printers emitted more particles when operating with new toner cartridges and when printing graphics and images that require greater quantities of toner.

Funded by Queensland Department of Public Works and The Cooperative Research Centre for Construction Innovation, the report includes a list of the brands and models in the study classified by amount of particles emitted.

The study offered no definitive proof of harm, and has concluded that more research into the health effects of printer emissions is needed.

Still, the scientists are calling on government officials to consider regulating emission levels from laser printers.

Laser printers in an office copy room (Photo credit unknown)
"By all means, this is an important indoor source of pollution," Morawska said. "There should be regulations."

The health effects from inhaled ultrafine particles depend on particle composition, but the results can range from respiratory irritation to more severe illnesses, such as cardiovascular problems or cancer, Morawska said.

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

Larger particles also could be unhealthy without reaching the deepest parts of the lung. "Because they are larger," Morawska added, "they contain more mass and can carry more toxins into the body. No matter how you look at it, there could be problems."

To lower risk, people should ensure that rooms in offices or houses are well ventilated to allow airborne particles to disperse.

This study is published in the August 1 online issue of the American Chemical Society’s journal "Environmental Science & Technology."

Copyright Environment News Service (ENS) 2007. All rights reserved.