the t shaped suspension elements 2 horizontal member 3 and an outer lip or edge 8 of the air diffuser the filter frame 13 has an inner face and an outer face where the inner face is attached to the filter element 11 as shown in fig2 this attachment is accomplished using an adhesive 12 which can be a conventional hot melt pressure sensitive or like adhesive alternatively a nonadhesive thermoplastic material can be used as the filter retaining material as could a foam or a nonwoven type material which may or may not contain adhesive fibers or an adhesive coating or the like nonwovens or foams could retain the filter by adhesion and or by friction however if friction alone is used the filter must be rigid enough to press into the foam nonwoven or like compressible material the filter frame 13 as shown has a series of ribs 15 16 17 and 18 which provide structural rigidity and can be used to contain the filter 11 retaining material 12 for example the ribs can be used to contain the adhesive material 12 used to hold the filter to the filter frame 13 the filter frame 13 shown in fig1 and 2 also has an extension element 19 which distances the filter from the ceiling this extension element is used to accommodate the possibility that the air diffuser 4 may have diffusion elements 9 which extend below the plane of the ceiling further a rib 7 may be used to provide further support for the air diffuser and greater rigidity to the frame 0014 fig3 and 4 show an alternative embodiment of the invention filter panel where discrete clips or extension elements 28 are provided which extend.