A multiple diffusion channel filter assembly is disclosed. The filter assembly provides filtration of air entering and exiting an electronic enclosure through a breather hole. In one implementation, the filter assembly contains a housing with an adsorbent component and a first diffusion channel and a second diffusion channel. In another implementation, the filter assembly contains a first layer and a second layer which surround an adsorbent component and a first and a second diffusion channel that are in fluid communication with the interior space defined by the first and second layers. In yet another implementation, the invention, includes a filter accessory containing a diffusion channel configured to work in conjunction with a separate filter assembly thereby adding an additional diffusion channel to the existing design.