Can disposable masks be worn more than once?

Chen, Hao; Samet, James M.; Tong, Haiyan; Abzhanova, Aiman; Rappold, Ana G.; Prince, Steven E.

doi:10.1016/j.ecoenv.2022.113908

Cited by 8 publications

(2 citation statements)

References 14 publications

(21 reference statements)

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“…Masks may be an important safety measure in exercises, where dust and debris are generated. However, disposable face masks are reusable, maintaining efficacy up to 40 hours of wear 21 . Therefore, educating students regarding the appropriate use of masks, and encouraging reuse of disposable facemasks for longer when safe to do so will reduce waste and contribute to a safe working environment.…”

Section: Discussionmentioning

confidence: 99%

Simulation clinic waste audit assessment and recommendations at the University of Washington School of Dentistry

Oxborrow,

Dong,

Lin

2024

Journal of Dental Education

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ObjectiveDentistry produces waste contributing to climate change and adverse health outcomes, thus reducing waste is essential; however, there has been minimal emphasis on sustainability or climate action in dentistry. Waste audits quantify the type and amount of waste produced and may inform waste reduction strategies. We conducted a waste audit to identify areas of potential waste reduction and recommend interventions to reduce waste.MethodsIn this cross‐sectional study, we conducted a waste audit of garbage produced during a typical 4‐hour pre‐clinical restorative dentistry simulation exercise. The sample was composed of 72 second‐year dental students. This exercise is part of a standard curriculum with a uniform format regarding supplies used and participants. Potentially infectious materials were not used during this exercise.ResultsIn total, 26.6 kg of waste was discarded. Plastic was the largest contributor by mass (57.5%), followed by paper barriers (19.6%), then impression materials (6.5%). We found 894 gloves and 70 masks discarded.ConclusionsBased on these findings, we categorized waste reduction opportunities into policy changes, purchasing sustainable materials, and increasing awareness through education. Specific suggested actions include: relaxing glove and gown requirements during laboratory simulations; replacing single use items with more sustainable options; increasing use of intraoral scanners; and posting informational signage with examples of what can be recycled.

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Section: Discussionmentioning

confidence: 99%

Simulation clinic waste audit assessment and recommendations at the University of Washington School of Dentistry

Oxborrow,

Dong,

Lin

2024

Journal of Dental Education

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“…Across a variety of manufacturers the average filtration efficiency of N95 at\ 0.3 μm particle size was found to be much higher at 98% and more consistent than 81% for KN95 (Table 2 of [49]). This 98% is reassuringly higher than the 95% filtration efficiency nominally required for N95, although N95 fit [50] and filtration efficiency (Figure 3 of [51]) may degrade with reuse over several hours (and wearing an N95 with poor fit is like closing the windows of a car door but leaving a crack open). The N95 average of 98% requires a 50 times reduction in inhaled aerosols (ACH=30) and KN95 average of 80% requires 5 times (ACH=3) in an unventilated room assuming surface deposition contributes 0.6 to ACH (λ).…”

Section: Introductionmentioning

confidence: 99%

The World Is Completely Unprepared For Detecting Emerging Viruses/Bacteria In The Air

Srikrishna

2022

Preprint

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N95 respirators are useful for reducing risk from a person infected with COVID-19 at both near-field (e.g. < 6 feet) and far-field exposures (e.g. > 6 feet). Although air filtration is not usually effective at near-field, emulating at least the far-field equivalent of N95 requires 95% relative reduction of particles (20x) from an airborne particulate source in each room. To mitigate COVID infection risk with air filtration, there is a wide range of air change per hour (ACH) recommendations from public health agencies (CDC, CDPH, etc.) ranging from 2 to 12 ACH. Tracking the removal of an inert airborne contaminant (e.g. salt water) as a function of time is often used to measure ACH but is cumbersome and generally not desirable in occupied rooms such as a classroom or home. Instead, we describe a procedure using an optical particle counter to track the decay of ambient aerosols (0.3 μm diameter) and fit it to an exponentially decaying curve to measure ACH from the exponential coefficient. Experiments were conducted both in a room (from surface deposition alone and with air filtration) and in a whole, multi-room house (with air filtration). First, the rate of surface deposition in an unventilated room without HVAC ventilation or air filtration enabled was measured to be 0.6 ACH. Second, ACH was measured (verified) with low-noise generating HEPA purifiers ($299-$999) and Do-It-Yourself (DIY) air purifiers ($55-$160, 1"-5", MERV 13-16) in each room. The ACH measured with these air purifiers ranged from 4 to 20. Using the measured ACH and volume of the room/house to estimate the clean air delivery rate (CADR) per $100, it varied by a factor of 3x from below 100 cfm for tested HEPA purifiers to above 300 cfm with tested DIY air purifiers. Using 0.6 ACH as a baseline for an unventilated room, at least 12 ACH is required to reduce exposures equivalent to protection of N95 respirators (95%) at far-field, which is verifiable in a room or building with ambient aerosols using either HEPA or DIY air filtration.

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Carbon dioxide gasification characteristics of disposable COVID-19 masks using bubbling fluidized bed reactor

Nam,

Tokmurzin,

Yoon

et al. 2023

Environmental Research

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Can disposable masks be worn more than once?

Cited by 8 publications

References 14 publications

Simulation clinic waste audit assessment and recommendations at the University of Washington School of Dentistry

Simulation clinic waste audit assessment and recommendations at the University of Washington School of Dentistry

The World Is Completely Unprepared For Detecting Emerging Viruses/Bacteria In The Air

Carbon dioxide gasification characteristics of disposable COVID-19 masks using bubbling fluidized bed reactor

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