[ RadSafe ] Efficiency of Workers Wearing Respiratory Protection

[Treadaway, Walter A]

It seems logical to assume that a worker doing a job wearing respiratory protection would be slower than the same worker without respiratory protection.  However, I can't find a reference in a peer-reviewed publication to support this assumption.
Does anyone have a reference "in their back pocket" or can anyone point me in the right direction?

Thanks!

Allen Treadaway for Ron Morgan, LANL