Printer Particles Form In Air

Laser printers can be a significant source of ultrafine particles, generating levels in some offices equal to those of busy roadways (C&EN Online, Latest News, Aug. 1, 2007). Inhaling such particles can lead to respiratory problems. A new study now elucidates the chemical composition of airborne, printer-related particles and the mechanisms by which they form. Lidia Morawska of Queensland University of Technology, in Brisbane, Australia, and colleagues demonstrated in lab studies that the particles are not emitted directly from the printers. Rather, the particles form in the air from volatile organic compounds originating from the paper and hot toner (Environ. Sci. Technol., DOI: 10.1021/es802193n). Particles form via either spontaneous homogenous nucleation or secondary particle formation involving ozone that is created during the printing process, Morawska explains. Analysis of particles showed mostly organic components, ranging from ethylbenzene to decanes. The particles also contain inorganics such as iron, from iron oxide in the toner, and calcium, traced to a calcium carbonate coating on the paper. The findings may help the printer industry reduce printer emissions, the researchers suggest.