A filter element arrangement comprising: (a) a media pack having a substrate comprising first and second opposite flow faces and a plurality of flutes wherein in said media pack; (i) each of said flutes have a first end portion adjacent to said first flow face and a second end portion adjacent to said second flow face; (ii) selected ones of said flutes being open at said first end portion and closed at said second end portion; and selected ones of said flutes being closed at said first end portion and open at said second end portion (iii) said substrate at least partially covered by a layer comprising polymer fine fiber comprising a fiber with a diameter of 0.01 to 0.5 microns, the fiber comprising a polymer selected from the group consisting of i) a polyvinylalcohol crosslinked with 1 to 40 wt.% of a crosslinking agent, and ii) a condensation polymer, the fiber also comprising a resinous additive comprising an oligomer having a molecular weight of 500 to 3000 and an aromatic character wherein the additive miscible in the condensation polymer; wherein the substrate at least partially covered by a layer, when tested under conditions of exposure for a test period of 3 hours to test conditions of 140°F (60°C) air at a relative humidity of 100%, retains greater than 50% of filter efficiency of the fine fiber layer, as calculated according to the following calculation: F r = F x / F i wherein F r is the filter efficiency of the fine fiber layer which is retained, F x is the post exposure fine fiber layer efficiency, F i is the initial fine fiber layer efficiency, wherein F i = 1 − EXP Ln 1 − initial efficiency of filter media − Ln 1 − initial efficiency of substrate, F x = EXP Ln 1 − post-exposure efficiency of filter media − Ln 1 − post-exposure efficiency of substrate, and wherein the efficiencies of the media and substrate are measured according to ASTM Standard F1215-89 with monodisperse 0.78 μm polystyrene latex particles at a flow rate of 6.1 m/min (20 fpm). (a) a media pack having a substrate comprising first and second opposite flow faces and a plurality of flutes wherein in said media pack; (i) each of said flutes have a first end portion adjacent to said first flow face and a second end portion adjacent to said second flow face; (ii) selected ones of said flutes being open at said first end portion and closed at said second end portion; and selected ones of said flutes being closed at said first end portion and open at said second end portion (iii) said substrate at least partially covered by a layer comprising polymer fine fiber comprising a fiber with a diameter of 0.01 to 0.5 microns, the fiber comprising a polymer selected from the group consisting of i) a polyvinylalcohol crosslinked with 1 to 40 wt.% of a crosslinking agent, and ii) a condensation polymer, the fiber also comprising a resinous additive comprising an oligomer having a molecular weight of 500 to 3000 and an aromatic character (i) each of said flutes have a first end portion adjacent to said first flow face and a second end portion adjacent to said second flow face; (ii) selected ones of said flutes being open at said first end portion and closed at said second end portion; and selected ones of said flutes being closed at said first end portion and open at said second end portion (iii) said substrate at least partially covered by a layer comprising polymer fine fiber comprising a fiber with a diameter of 0.01 to 0.5 microns, the fiber comprising a polymer selected from the group consisting of i) a polyvinylalcohol crosslinked with 1 to 40 wt.% of a crosslinking agent, and ii) a condensation polymer, the fiber also comprising a resinous additive comprising an oligomer having a molecular weight of 500 to 3000 and an aromatic character i) a polyvinylalcohol crosslinked with 1 to 40 wt.% of a crosslinking agent, and ii) a condensation polymer, the fiber also comprising a resinous additive comprising an oligomer having a molecular weight of 500 to 3000 and an aromatic character F r is the filter efficiency of the fine fiber layer which is retained, F x is the post exposure fine fiber layer efficiency, F i is the initial fine fiber layer efficiency, wherein F i = 1 − EXP Ln 1 − initial efficiency of filter media − Ln 1 − initial efficiency of substrate, F x = EXP Ln 1 − post-exposure efficiency of filter media − Ln 1 − post-exposure efficiency of substrate, and wherein the efficiencies of the media and substrate are measured according to ASTM Standard F1215-89 with monodisperse 0.78 μm polystyrene latex particles at a flow rate of 6.1 m/min (20 fpm).