Size distribution, emission rate, and decay characteristics of particles emitted by printers

Abstract

The particulate matter (PM) emitted by printers during printing pollute the indoor air, which can pose a health hazard for the people indoors. The source strength, decay characteristics, and mechanism of the PM emitted by printers were studied. A sealed chamber was used for printing experiments, and the particle number concentrations were monitored in real time using an Electrical Low-Pressure Impactor (ELPI+). Our findings highlight the negative impact of printing on the indoor environment. The printers directly emitted particles covering three size ranges: 15.8–94.5 nm, 94.5–313 nm, and 313–949 nm. The emission rates of PM_0.1 and PM_0.1-1 by the printers were 1.57×10⁸–53.83×10⁸/min and 3.46×10⁸–143.81×10⁸/min, respectively. The printer and the amount of toner used both affected the emission of particles, especially PM_0.1-1. The particles emitted were mostly decayed within 1 h after printing; moreover, the decay of PM_0.1-1 was slower than that of PM_0.1. The decay rates of PM_0.1 were 0.016–0.083/min in the 0–30 min period and approached 0 in the 30–60 min period. The decay rates of PM_0.1-1 were 0.015–0.127/min within 60 min after printing and differed little across periods. One hour after printing, all but a very small proportion of particles measuring 54.5–94.5 nm was decayed in the chamber, indicating that particles of that size were decayed with greater difficulty.