| Previous studies investigated some factors of the face masks quality but few studied their changing patterns with usage, which are significant in guiding the reuse of masks. This work tested three times to supplement more accurate data as references in masks designing. Moreover, this work provided both qualitative morphological analysis with optical microscopes and quantitative professional data on changes in quality factors with a Particle Filtration Efficiency Tester. It also utilized ATR-FTIR for material characterization. Experiments showed that surgical masks should be decontaminated within 8h to 12h exposure to PM0.3 to PM1.0 and N95 masks should be decontaminated within 8h exposure to PM0.3. The quality factor of cloth masks was found limited but their performance within 1.5h of wash and 1h of drying were more stable due to the checks and balances of three opposite factors. On top of it, weaving techniques were found to be correlated to the durability of the masks and porosity were found to be correlated to the quality factor of the masks, which can be convenient parameters in predicting the performance of masks. |
