Any mask study that states masks work will likely have been done in the past 6 months. Any before 2020, I would bet are fake, cannot be verified on Internet history websites. I have read from cdc, cadth(canadian), and the newer danish study that masks don't work for airborne particulates. There was an Oxford study too that stated the same, but it got scrubbed already and I didn't get a snapshot. On mobile rn and can't link

Edit: oops, had already posted them elsewhere.

https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article

https://d3926qxcw0e1bh.cloudfront.net/post_photos/d8/67/d8671995ec7240b0db39001cac0eb6da.jpeg