Replying to
@aeva the patterned Zimi filters still claim 98% filtration efficiency , so they should be tested as such . printing should have negligible impact , if accounted for during the manufacturing process . i have one of their fabric-looking filters , and it's not ordinary fabric—they seem to have designed the material specifically for this purpose ! that's a good question to be asking though . KN95s are less carefully regulated than N95s , but i haven't found any information indicating that Zimi is untrustworthy .
regarding extremely cold weather , i don't know of any resources directly addressing this use case . part of the increased covid risk in cold weather is due to a lack of humidity and warmth in your nose [1] , which respirators may help with by retaining the heat and moisture from your breath [2] . one idea is to wear a balaclava over a half or full face respirator , with holes cut out for the filters to go through . this thread [3] has comments from people with experience wearing respirators in negative-degree weather .
there are masks that claim to warm and humidify cold air , like the Airtrim sport mask [4] , but they don't protect against viruses . you may be able to combine one of these with an elastomeric somehow !
[1] https://www.medicalnewstoday.com/articles/how-does-weather-affect-covid-19
[2] https://www.nih.gov/news-events/news-releases/researchers-propose-humidity-masks-may-lessen-severity-covid-19
[3] https://www.reddit.com/r/Masks4All/comments/1hintm4/what_happens_to_respirators_in_extreme_cold
[4] https://pioneermidwest.com/products/airtrim-sport-mask-blue
