Unsafe Materials
Do not use household materials as filters
We do not recommend household materials such as furnace filters or dried baby wipes. Evidence on household filters is limited. In our review, we found one study of tissue paper and paper towel, which did not report high efficiencies. Some materials such as vacuum cleaner bags and landscape cloth may contain harmful materials such as pesticides. Instead, we recommend a third or fourth layer of industry-grade polypropylene. If you have pocket masks, you can use a rectangle of this material as a reusable filter in a pocket mask and wash it with the mask - just remember to hang to dry - it will melt in a tumble dryer.
Reduce your risk of unsafe nose wires
Nose wires should be made from materials with a blunt end and that do not break easily. Avoid paper clips, wire with sharp points and other items that may damage your mask. Carefully check your mask each time you wear it to ensure the fabric is not worn and the nose wire is securely in place. More evidence-based information on nose wires can be found here.