Covid Action Cowichan

Filter Materials

*WARNING* Not all HEPA filters are safe and MANY utilize fiberglass! 3M filters do not contain fiberglass, they are a poly plastic, so these are relatively safe, but if you are not 100% sure AVOID HEPA filters

Blue shop towels are the most easily available and cheapest option.

Blue Shop Towels
Blue shop towels make excellent filters


Polypropylene interfacing is a highly recommended material for masks. Be sure to get the right kind, as not all are made with the optimal filter pattern. Please see the study below.

DIY Mask Testing on commonly available materials.