This can be made with elastic sew into side ends or a seam where elastic slips in and is then tied or sewn together as one continual piece which makes it adjustable.
You can also use a 4 1/2 - 5 1/2 inch piece of pipe cleaner and insert it into the pocket, slide it up towards seam where nose is, and hand stitch below pipe cleaner some to give yourself more formation to the nose by shaping pipe cleaner on nose.
½ yard cotton quilting fabric
Elastic ¼ to 1/8 inch wide (or elastic of your choice)
1 - 4 ½ to 5 ½ inch piece of pipe cleaner to form around nose (optional)
Pinking Sheers (optional)
Cut 2 of top mask (1 for outer and 1 for lining)
Cut 1 pocket for filter
2 - 11 ½ pieces of ¼ or 1/8 inch elastic (this runs through sides and tie or sew ends of elastic
2 - 5 inch pieces (for smaller face) or 2 - 6 inch pieces (for larger face) of ¼ or 1/8 inch elastic (this gets sewn into sides and loops around ears.
1. Take pocket filter piece and turn bottom ends ¼ inch and press, then turn another ¼ inch and press again for a hem. Stitch hem ends.
NOTE: If mask is to tall or wide, adjust your seam allowance.
this will open in Google Docs