The Plumen does contain some mercury but it is applied in very low quantities compared with CFLs of old and also in gas form so it won't run out as a liquid if the glass breaks. No need to leave the room I would say providing you don't smash a few at the same time. Oh and yes i burns nice and clean and comes on instantly.

Any idea of the lumens this gives off or what its colour temperature in kelvin might be? just curious as to how bright one bulb would light up a room.

Thanks in advance :]

Hi Danny, sure I do know. The Plumen gives off 680 lumens. Colour-wise it's 2700k. Does that help?