Filter media comprising a polyethersulfone-based fine fiber layer

A filter media, comprising:

• a PES-based fine fiber layer comprising a plurality of fine fibers comprising a polyethersulfone (PES) material;
• wherein the PES material has a polydispersity index of greater than or equal to 1.9 and less than 2.6;
• wherein the PES material has an intrinsic viscosity of greater than 0.3 dL/g and less than or equal to 2 dL/g;
• wherein the PES-based fine fiber layer has a dust holding capacity of greater than or equal to 2 gsm and less than or equal to 300 gsm;
• wherein the PES-based fine fiber layer has a surface area of greater than or equal to 4 m2/g and less than or equal to 10 m2/g;
• wherein the filter media further comprises an additional layer;
• wherein the additional layer comprises meltblown fibers;
• wherein the additional layer comprises a pre-calendered additional layer;
• and
• wherein the filter media has a thickness of greater than or equal to 0.001 mm and less than or equal to 0.5 mm.