Sewing a face mask

Dear fellow crafters,
I have an important question for you today. I’d like to sew a face mask for a young woman, and it needs to have a few special features.
Among other things, it should have a slot for filter pads. Does anyone have a sewing pattern or an idea for this? A side slot that’s easy to use would be ideal, since the young woman has very poor eyesight. And she should be able to put it on without help.
I’d really appreciate any ideas.
Thank you, and I wish you all a wonderful holiday season.
Renate

I sewed myself a face mask with a filter pocket; I used a double layer, finished the edges with bias tape, but sewed the top so that I could attach two KamSnaps to insert a filter. I added straps to tie the mask at the back, and the shape was rectangular.
I used dimensions of 17 cm x 15 cm and folded it to fit my face.

Here are some pictures of how I sewed this mask

That’s a great idea with the CamSnaps, dear Akela. Thank you so much! I’ll move the opening to the bottom, so the nose clip can still be inserted even while wearing glasses. That way, I can let my sweetheart go to the workshop without worry—she’s finally gotten a spot there.
That’s a huge help—thank you!
Best regards,
Renate