Release of fine and ultrafine particles from laser printers on real room conditions

The particle release of laser printers of the same type was investigated in eight ordinary used office rooms. Printing conditions were the same for each measurement and work in the office room was continued during the measurements. The number concentration of particles in the size range from 10 nm to 1 mu m in the indoor air was determined with a CPC device, beginning 10 min before and ending 15 min after the printing process, that itself was about 2 min long. It was shown that the use of laser printers can cause an increase of indoor particle concentration. In all cases the particle number concentration in the investigated rooms increased during printing, and in the majority of cases it was higher after than before the printing process. However, the rises of the concentration were quite different. Even the use of the same printer type on same printing conditions resulted in very different particle concentrations over time, which are obviously determined by room conditions, working processes and individual emission properties of the printer devices.