It might help to understand a bit about how masks work. There are some useful wiki pages on here;https://en.wikipedia.org/wiki/N95_maskhttps://en.wikipedia.org/wiki/Face_mask ... _FFP_maskshttps://en.wikipedia.org/wiki/Cloth_face_mask
I previously posted some info on here;viewtopic.php?f=49&t=136728
“N95” is a US guv-munt equipment standard. The Chinese equivalent is KN95, which is roughly equivalent to the EU FFP2 standard. The European mask standard is EN149 with subsets FFP1 (a simple face covering) FFP2 (stops 94% of particulates and droplets) and FFP3 (a full on rubber face). In the UK the EU standards are usually rendered as P1, P2 and P3. Recently I have seen single use disposable masks advertised for sale described as P3 which have KN95 in the small print, so as usual it is buyer beware.
The current requirement to wear masks in enclosed public spaces is likely to become stronger as the UK tries to reduce physical distancing down to the WHO recommended 1 metre. That requirement to wear masks might last for a couple of years. Your purchasing choices are likely to be either frequent repeat buying of single use disposable masks or buy more expensive reusable masks with changeable filters or DIY home made.
Round here we are using home made masks made from two layers of polycotton (flowery Laura Ashley) with a pocket for a removable filter layer. There are loads of basic design patterns out there. Close fitting to the face is key. Once the mask has taken shape, present it to your face and pinch in bits of edge material with a couple of stitches to achieve an improved fit; “darting” the sewers among us call this process. Our filters are cut from a kitchen extractor filter. We have four DIY masks each to allow for washing and drying.
Masks can only be effective if they are used carefully. Our current regime is; don the mask while approaching the supermarket queue, on exit from the shop move in to a clear space before removing the mask, roll the mask inside out and place in a small plastic bag, clean hands with alcohol gel, go home and put away shopping, extract and bin the mask filter along with the small plastic bag, put the mask into the empty kitchen sink, thoroughly wash hands, soak the mask in boiling water straight from the kettle, hang the mask up in the sun to dry.
It’s not just masks. Covid19 spreads by droplet contamination via the recipients mouth, nose and eyes. In a high risk environment (say, in a crowded underground train or around any suspected patient) eye cover is a good idea. When removing the eye protection clean it with an alcohol wipe and then clean your hands.