If you’re desperate for a surgical mask but you can’t get one, you can always try making your own. This is most likely only slightly better than nothing, but if you just have to do it a team of researchers has some advice about which materials work the best. Here are the results:
The vacuum cleaner bag is the best filter by a large margin, “but the bag’s stiffness and thickness created a high pressure drop across the material, rendering it unsuitable for a face mask.” Ditto for the tea towel. In the end, the pillowcase and the 100 percent cotten t-shirt “were found to be the most suitable household materials for an improvised face mask.” However, the authors are killjoys about the whole thing anyway:
An improvised face mask should be viewed as the last possible alternative if a supply of commercial face masks is not available, irrespective of the disease against which it may be required for protection. Improvised homemade face masks may be used to help protect those who could potentially, for example, be at occupational risk from close or frequent contact with symptomatic patients. However, these masks would provide the wearers little protection from microorganisms from others persons who are infected with respiratory diseases. As a result, we would not recommend the use of homemade face masks as a method of reducing transmission of infection from aerosols.
File this under “last resort measures in case of the apocalypse.”