3M 6200 mask outlet vent surgical mask filter holder

thingiverse

For those using the 3M 6200 respirator, take note that the exit valve is not really filtered. This means the mask does a great job of keeping outside contamination out, but to be a responsible user in the COVID-19 outbreak, we need to think about protecting others as well - you might be walking around with the virus without symptoms. This attachment allows a standard surgical mask to be used as a filter for droplets you exhale. The design fits the outlet vent after adding the filter and securing it with a retainer clip. After some testing, I left a 5mm buffer space between the mask vent and the filter to prevent the filter from becoming a valve that restricts exhalation, which could lead to shortness of breath and dizziness. For hygiene purposes, since this is an inward-facing filter catching your own droplets, if you don't have symptoms, you can change the filter every other day or even longer. I spray disinfectant on it from the inside when I get home and plan to use it for several days. Coupled with Lucifer01's model for the surgical mask filter adapter, one can reuse a standard surgical mask at least six to ten times.