A filtration system to filter air from a toilet bowl includes: a fan assembly having a fan and an air flow channel in fluid communication with the toilet bowl to draw air from the toilet bowl; a housing interposing the toilet bowl and the fan assembly, the housing having a filter receptacle to receive a filter unit therein, the received filter unit being in fluid communication with the air flow channel wherein the fan assembly draws air through the filter unit to exhaust the air out of the air flow channel; an activator to activate the fan assembly; and, a decimator for killing or eliminating particulate matter in the air flow.