I'm sure its fine for most situations, but you should be aware: below that entry it states that elastomeric respirators (like you are using with P100) are not included in that category:

> Until more is understood on exhalation valves, elastomeric respirators with unfiltered exhalation valves should not be used as source control in surgical and other healthcare settings due to concerns that air coming out of the exhalation valve may contaminate the sterile field.