Abstract: A portable air cleaner consisting of an upright housing having casters on the bottom to enable it to be moved readily into different locations. The housing has a compartment for containing a roll of filter medium, preferably a filtration paper as disclosed in U.S. Pat. Nos. 4,239,516 and 4,293,378, which may be drawn from the roll compartment across the hollow frame.In use, a fresh section of the filter paper is positioned overlying the frame until it becomes loaded with particles filtered from the airstream flowing through the hollow frame. When the filter medium becomes loaded, a fresh section of the medium is drawn across the frame.An overload device is provided to interrupt energization of the motor driving the fan when the filter medium becomes sufficiently loaded to block flow of air through the filter medium.