[This is a guest post by my partner Alexandra van Geel.]

Disclaimer: I am not an expert, just a private individual summarizing available information. Please correct me if I’ve gotten something wrong.

TL;DR

• I suggest: (a) the Vogmask valveless mask or (b) the O2 Canada Curve Respirator. If (b), make sure you cut some an extra filter into two small circles and put the material in the respirator to cover the exhale valves.

• If you use a homemade cloth mask, pick one that lets you get a good seal all around. Use one with a pocket for a filter – preferably, one made out of polypropylene.

• If you use a disposable surgical-style mask, alter it to get at tighter fit, like this.