This article got me thinking about how little I know in regards to masks. From what I can tell by searching the internet the majority of the "safest bird-flu" masks out thre are of the N95 rating. So I called 3M (wonderful customer service) and asked a few questions. I asked 3M how does the NIOSH approval N95 rating span across different models. Essentially, model numbers offer no additional filtration, only mask construction features. Hence, it seems these two masks offer the same protection, just different construction (obviously the R8511ES is going to hold up better in damp/humid conditions): 3M Particulate Respirator, N95, R8511ES (10 Pack)

Home Depot: 3M N95 Fiberglass Particulate Respirator (20 Pack)

This information is not a product endorsement nor should it be considered clinical information. I'm not making any claims as to the protection offered by these masks. Before you purchase any mask, do your own research to ensure you are getting the protection you feel you need.