Sorry it took so long.... Finally found the video. At 17:26 in the video, they reference the trail of mask use and transmission. Quantifiable results for transmission. IIRC it is only for surgical masks but it makes an excellent point. This was required viewing by my medical director and the training devision. Hope it helps.

https://www.youtube.com/watch?v=osoPNZxnayQ&feature=youtu.be