The most efficient respirator is an N100 or P100 elastomeric, not N95.
Generally, you should not wear anything over a FFP N95 because it can distort the shape of the mask and allow air to leak in around the mask.
If you are in a setting where you need to protect against splashed liquids as well as from airborne particles, then consider wearing a face shield, or wear a medical N95 that is resistant to body fluid splashes.
If you are trying to protect against current variants of the SARS-CoV-2 virus, you should wear an N100 or P100, especially if you are in an enclosed space with someone who is symptomatic, because an N95 may not filter out enough of the virus particles to prevent infection.
>"I'm not sure why anyone who understands #covid19 transmission would wear a respirator with an exhaust valve?"
- When you properly wear an N100/P100 elastomeric respirator whenever you are in a potentially contaminated environment, your chances of becoming infected approach zero, which means you're not a source, so source control is unnecessary. (In effect, the source control occurs during inhalation.)
- If the valve is properly maintained, it will not allow leakage under negative pressure.
- Source control in the general population is only effective when nearly everyone practices it (and then only partially effective). When half of the people are running around without any mask at all, it becomes pointless.
- An exhaust valve greatly increases comfort, especially when wearing the respirator for long periods.
Hi @Pat, you and I discussed this before. I'm posting about a community setting. Without fit testing, I wouldn't recommend a N100 over an N95.
To be totally literal, the best mask is a powered air-purifying respirator (PAPR) and a hazmat suit. But that isn't a very useful or practical recommendation. Thanks for following and for your comments.
>"Without fit testing, I wouldn't recommend a N100 over an N95."
Many elastomerics have special valves for closing the the inlets during a seal check. If someone knows how to do that (which is very easy to learn), then those respirators can provide a much better seal and more efficiency than an N95 FFP.
>"Thanks for following and for your comments."
Thank you for the discussions...
@cmclase
Also, if are worried about source control, you can wear a procedure mask or surgical mask over the exhaust valve of your elastomeric (on some models), but make sure it is loose enough so that is doesn't interfere with the seal of the mask. (If you need complete source control, then you'll need a SCBA respirator, and lots of other protocols.)