How bad is your air?
Myhealth Beijing summarises some of the issues, crystallized for Beijing's extreme case.
3M definitely was a consistent performer in almost any category, and certainly remains my personal gold standard for masks. Another standout is the MASKin brand, which was just as solid as 3M in all three reports.[…]]
Another “winner” seems to be masks with exhalation valves, which usually performed well with filtration but especially in the other categories with improved resistance and decreased leakage. For what it’s worth, my current personal favorite mask is the disposable, foldable 3M 9001V which I grab from my local 7-Eleven. […]
All three reports still didn’t test most of those most commonly used reusable masks in the expat community,[…], since I am a data geek and this is a HONCode-certified evidence-based blog, it’s now a bit difficult to really recommend any of those commercial, reusable brands at this time as a first choice. None of these are officially on the NIOSH-approved N95 list;
The reusuable/fashion masks are a bit less awkward. But do they work? respro have TBH too damn many options; I get confused. They are wildly expensive, but garner cycling hipster approval for the ultralight. vogmask and cambridge masks look nice, but do they actually stop particles? The latter two seem to be pretty loose fits. For all of these the real approval you want is independent lab testing of their goodness.