Polymeric fiber and glass fiber composite filter media

A composite filter comprising:

• a first upstream layer of polymeric fibers;
• the first upstream layer comprising about 10% to about 60% by weight polymeric microfibers having a mean fiber diameter between about 2.5 and about 4.5 microns, about 25% to about 60% by weight polymeric loft fibers having a mean fiber diameter between about 4 and about 14 denier, and about 15% to about 30% by weight polymeric binder fibers having a mean diameter between about 2 and about 4 denier;
• the upstream layer having a weight between about 2.0 and about 7.0 grams per square foot;
• the first upstream layer having a major upstream surface adapted to be oriented relative to a gas flow being filtered so that a major component of the gas flow being filtered is directed at an acute angle to the major upstream surface;
• and
• a second downstream layer comprising a blanket of glass fibers bonded together at their points of intersection by a binder and bonded to the first upstream layer;
• the blanket having a weight between about 1.2 and about 2.7 grams per square foot;
• the glass fibers having an average fiber diameter within a range from 3.0.times.10.sup.-5 to 4.1.times.10.sup.-5 inches;
• and the blanket having an average air filtration efficiency of at least 80%.