An economical, high capacity, medium efficiency air filter designed for applications where a 1" disposable panel filter may be used. The filter element is a cotton/polyester blended material laminated to a galvanized steel expanded metal support grid. When tested in accordance with ASHRAE 52.1-1992 Test Standard, the fiber blend maximizes dust retention capabilities while giving the mono pleat an average arrestance of 85-90%, and an average efficiency of 20-25%.