I don't like the smell of laser toner, and it turns out that it could be more than just annoying.
In his blog, Dennis Rockstroh references an article on ConsumerAffairs.com that calls out that laser printers are fairly active polluters.
"Working around some laser printers, especially in a closed area, may be equivalent to breathing in cigarette smoke, says a study."
The study referenced is from the Queensland University of Technology, at Brisbane, where researchers "believe tiny particles of that toner escape from the cartridge during ordinary use, especially when the cartridge is shaken."
From the article...
"[The researchers] say the problem can be mitigated by placing printers in a well-ventilated area so the particles can escape. Printers should not be placed in small, closed rooms, they say.
"The researchers said they investigated 62 different laser printers and classified 17 of them as “high emitters.” They characterized the worst of the 17 as releasing particles at a rate comparable to emissions from cigarette smoke."
The researchers looked at printers from Canon, HP, Ricoh and Toshiba -- my Brother laser wasn't referenced -- and published their report in a recent issue of Environmental Science and Technology.
IMHO, good to keep the window open, or consider adding a fan vent to your printer room.