I initially made this filter to remove the toxic volatile organic compounds and fine particles generated by my 3D printer. It can be, of course, used for other purposes, like filtering the air of a room; just keep in mind it is designed to continuously filter air, not to clean heavy fumes at once.The HEPA filter catches the particules, while the active carbon removes odors.



The box is about 11x11x20 cm big, and contains a HEPA 13 filter and active carbon pellets. The filter is actually a vacuum cleaner filter which seem to be standard, or at least easily findable, and the active carbon pellets can be bought from any aquarium seller, or others.

I mounted a 12V fan, and preferred a silent fan over a powerful one, but you can make different choices. There is a door on the exhaust pipe, used to redirect some of the filtered air back into the printer enclosure (thus keeping a correct temperature inside), which is not mandatory (actually, the exhaust pipe is not mandatory either).

It is difficult to test the filter efficiency without proper tools; at least, the smell inside the printer enclosure is much lighter now that I use this filter...