Toxicological Trivia from February 11, 2010: Australian researchers have discovered that normal exposure to the toner printers can be as dangerous as cigarette smoke (2007). In a recent office study, researchers in Australia found that nearly one-third of laser printers emitted high levels of nanoparticles into the air.  It is mentioned that the level of particles, small enough to penetrate the alveoli of the lungs and cause respiratory diseases, within an environment, increases with the use of a laser printer to:
a) Two times higher;
b) Five times higher;
c) Ten times higher.
than during nonwork hours.

Correct Answer b. Read more in article:  Office Printers Emit Ultrafine Particulates