| abstract |
Filter media for filtering particulates from air or other gases include a membrane and a deep filtration layer upstream of the membrane and in fluid contact therewith. The depth filtration layer comprises a nanoweb layer and a pre-filtration layer upstream of and in fluid communication with the nanoweb layer. The pre-filtration layer may be a nonwoven, and in one embodiment specifically a meltblown nonwoven, which may also be charged. |