Don't know of any studies of that kind.

Given the choice, I'd have to know what other forms of protection are provided.

For example, air filtration pulling air away from the face (like I had) would alleviate some of the need for an air supply while activated charcoal and chlorella under the tongue would alleviate some of the need for a dam.

Be sure you don't just accept what they are offering without first asking if they would be willing to provide both.