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Cake day: February 9th, 2022
  • Better_Rough_2554@lemmy.mltoCOVID-19 Pandemic@lemmy.ml•*Permanently Deleted*
    3·
    3 years ago

    I found one last week comparing them on microplastics: Performance study of microplastic inhalation risk posed by wearing masks.

    All the tested masks can help reduce microplastic inhalation from the air when used for less than 2 h compared with not wearing a mask. Wearing low-quality masks for longer than 4 h can pose higher fiber-like microplastic inhalation risk than not wearing a mask. When the masks are reused for a long time, only N95 respirators pose less fiber-like microplastic inhalation risk compared with not wearing a mask. When reused masks are worn for 720 h, fiber-like microplastic inhalation risk is 0.04, 0.54, 0.40, 0.16, 0.73, and 1.17 times higher than that without wearing a mask. The inhalation risks of fiber-like micro­ plastics posed by wearing a reused mask for 2 h are arranged from high to low as follows: no mask > activated carbon mask > surgical-B mask cotton mask > fashion > nonwoven mask > surgical-A mask > N95 respirator. The inhalation risks of fiber-like microplastics posed by wearing a reused mask for 720 h are arranged from high to low as fol­ lows: activated carbon mask > surgical-B mask > cotton mask > fashion mask > nonwoven mask > surgical-A mask > no mask > N95 respi­ rator. This could summarize that most masks after using for 720 h pre­ sent higher fiber-like microplastics than without mask, those fiber-like microplastics could mostly originate from the mask itself. The accumulated amounts of spherical-type microplastic particles observed during the 720 h breathing simulation test using different types of masks are provided in Table 2. The amount of accumulated spherical-type microplastics was significantly correlated with suction time (P < 0.01). When suction time was 2 h, the spherical-type particles observed with the N95, surgical-A, cotton, fashion, nonwoven, surgical- B, and activated carbon masks, and without a mask were 1695, 1808, 2241, 3110, 2152, 3090, 2212, and 3918, respectively. When suction time was increased, spherical-type particle inhalation risk continuously decreased compared with that without mask. The particle amount when N95 was used for 2 h was 43% that of the no mask case and only 4% after 720 h of suction. Nevertheless, spherical-type particle inhalation risk remained high regardless of whether masks were worn or not (the filter membrane image after the breathing test is shown in Fig. S2). In conclusion, reusing all the types of masks tested in this study for 720 h poses less microplastic inhalation risk compared with not wearing a mask. If masks are used as disposable products and changed into new ones every 2–4 h, then the amount of particles inhaled can also be calculated after wearing masks for 720 h (Table S2). The ratio of the predicted particle amount after masks were worn for a long time to the actual counted amount was calculated (Table S3). The results indicated that frequently changing masks, e.g., every 2 h, poses higher particle inhalation risks compared with using old masks for a long time. This finding also implied that wearing masks for a long time reduces the particle penetration rate of masks, particularly for N95 respirators. For example, people are likely to wear masks for 8 h since it is a full working day, it could reduce the microplastics inhalation with a continuous wearing of 8 h instead of change new mask per 2–4 h, if not considering the virus issue (Table 2, Table S2). Meanwhile, breathing rate may also be enhanced because more air is required to pass through the mask. The amount of particles can also change with increasing breathing rate. In this study, a suction rate of 15 L/min was selected on the basis of the average medium breathing rate of humans (Garcia et al., 2015; Tian et al., 2017; Liu et al., 2014). Further research on microplastic inhalation risk under different breathing rates should be conducted in the near future. Fiber-like microplastic inhalation risk posed by wearing masks for less than 168 h (7 days) was lower than that posed by not wearing a mask, except for surgical-B and activated carbon masks. This result implied that reusing masks will not increase fiber-like microplastic inhalation risk. It also suggested that the microplastics were from the air, and only a low percentage of microplastics was rejected by the masks. N95 exhibited the highest rejection performance in all the tested masks. The high fiber-like microplastic inhalation risk posed by using surgical B and activated carbon masks suggested that these masks can generate fiber-like microplastics from the materials used in their manufacture, such as PP and polyethylene (Jung et al., 2020). For spherical-type particles, the amount of microplastic inhalation using N95 was 43% compared with that of the blank case after 2 h of testing and 4% after 360 h of testing. This result implied that spherical-type microplastics from the air that passed through N95 masks decrease with time. Some particles from the air can be ejected into the inner structure hole of N95 masks, reducing spherical-type microplastic inhalation in the long term.