Evaluating the filtration efficiency of commercial facemasks’ materials against respiratory aerosol droplets

Patra, Satya S.; Nath, Jyotishree; Panda, Subhasmita; Das, Trupti; Boopathy, R.

doi:10.1080/10962247.2021.1948459

Cited by 9 publications

(9 citation statements)

References 22 publications

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“…Whiley et al ( 53 ) found that the filtration efficiency of surgical masks, N95 masks, and three-layered cotton masks was 99.3, 98.5, and 65.8%, respectively, when the size of microspheres was 2.6 μm; and that the filtration efficiency became 99.9, 99.6, and 54.4%, respectively, when the size of the microspheres was 6 μm. Patra et al ( 54 ) examined the efficiency of some commonly used face masks in filtrating microspheres sized from 0.3~10 μm, and found out that the filtration efficiency of N95 masks, which proved to be the most effective, was 91.8%; the filtration efficiency of surgical masks was 77.8%, and the filtration efficiency of one-layered T-shirt fabric masks was 64.8% and the least effective. Nonetheless, these studies showed that masks can filtrate aerosol/droplets.…”

Section: Discussionmentioning

confidence: 99%

Associations Between Wearing Masks and Respiratory Viral Infections: A Meta-Analysis and Systematic Review

Chen

Wang

Quan

et al. 2022

Front. Public Health

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BackgroundRespiratory viral infections (RVIs) are a major health concern, and some previous studies have shown that wearing masks was effective in preventing RVIs, while others failed to show such effect. Therefore, a systematic review and meta-analysis was conducted to investigate the effectiveness of wearing masks.MethodsPubMed, ScienceDirect, Web of Science, the Cochrane Library, EMBASE, MEDLINE, China National Knowledge Infrastructure (CNKI), and Chinese Scientific Journal Database (VIP database) were searched for studies evaluating the effectiveness of wearing masks. The risk ratio (RR) was used to measure the effectiveness of wearing masks in preventing RVIs for randomized controlled trials (RCTs) and cohort studies, and the odds ratio (OR) was used for case-control studies. Forest plots were used to visually assess pooled estimates and corresponding 95% CIs. The I2 test was used to examine the heterogeneity, and subgroup analysis was used to explore the possible explanations for heterogeneity or compare the results between subgroups. Sensitivity analysis was conducted to assess robustness of the synthesized results. Begg's test and Egger's test were used to assess the publications bias.ResultsThirty-one studies (13,329 participants) were eligible for meta-analyses. Overall, the results showed that wearing masks was effective in preventing RVIs. The sensitivity analysis showed that the results of those meta-analyses were robust and reliable. There was no significant publication bias in meta-analysis of case-control studies and most subgroup analyses.ConclusionsWearing masks might be effective in preventing RVIs. To reduce their RVI risk, people should wear masks when they go out in public.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42021296092.

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Section: Discussionmentioning

confidence: 99%

Associations Between Wearing Masks and Respiratory Viral Infections: A Meta-Analysis and Systematic Review

Chen

Wang

Quan

et al. 2022

Front. Public Health

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“…Although the labeled particle removal efficiency of commercially available face masks is usually higher than 99%, the actual removal efficiency for exhaled particles ranged from 40% to 78% for surgical masks and 80% to 95% for N95 masks 47–50 . For surgical masks, the protection effectiveness may not be sufficiently high in environments with high infection risk.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have measured the size‐dependent particle filtration efficiency for surgical mask and N95 mask [e.g., Ref. 47–50],

{\eta}_{\mathrm{mask},{d}_p}

. Since the inlet boundary was set as the outer surface of the mask, the particle concentration can be defined as

{C}_{\mathrm{cough},{d}_p}\left(1-{\eta}_{\mathrm{mask},{d}_p}\right)

at the inlet boundary of the mask material leakages, i.e., S 2 for surgical mask and N 3 for N95 mask.…”

Section: Boundary Conditions Of Airflow From a Cough With A Maskmentioning

confidence: 99%

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Boundary conditions for exhaled airflow from a cough with a surgical orN95mask

et al. 2022

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Wearing surgical or N95 masks is effective in reducing the infection risks of airborne infectious diseases. However, in the literature there are no detailed boundary conditions for airflow from a cough when a surgical or N95 mask is worn. These boundary conditions are essential for accurate prediction of exhaled particle dispersion by computational fluid dynamics (CFD). This study first constructed a coughing manikin with an exhalation system to simulate a cough from a person. The smoke visualization method was used to measure the airflow profile from a cough. To validate the setup of the coughing manikin, the results were compared with measured data from subject tests reported in the literature. The validated coughing manikin was then used to measure the airflow boundary conditions for a cough when a surgical mask was worn and when an N95 mask was worn, respectively. Finally, this study applied the developed airflow boundary conditions to calculate person‐to‐person particle transport from a cough when masks are worn. The calculated exhaled particle patterns agreed well with the smoke pattern in the visualization experiments. Furthermore, the calculated results indicated that, when the index person wore a surgical and a N95 mask, the total exposure of the receptor was reduced by 93.0% and 98.8%, respectively.

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“…According to Conte et al (2019), non-exhaust traffic emissions account for a sizable portion of total traffic-related emissions, particularly in the coarse mode. Being coarse mode particles, they would thus tend to settle down (Patra et al, 2021c). As a result, it is likely that the non-exhaust fraction of traffic emissions will contribute to further increasing particle concentrations at low levels.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Analysis of the Near-road Fine Particulate Exposure to Pedestrians at Varying Heights

Patra

Vanajakshi

2021

Aerosol Air Qual. Res.

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Scientific literature has overlooked how PM 2.5 concentrations vary with varying pedestrian heights near a roadway. Understanding this is important because walking is an essential commuting element of a sustainable transportation system, and pedestrians' height varies widely.Therefore, the focus of the current study is to bridge this gap using results from CALINE 4 model and mobile PM2.5 measurements. In CALINE 4, a simple pedestrian pathway depicting the selected study site located near the Sardar Patel Road, Chennai, India, was simulated. The PM2.5 concentrations were estimated on this pathway at varying heights (0.1-1.8 m) in 135 simulated runs. Subsequently, the sensitivity of the PM2.5 exposure difference across heights was explored with varying ambient PM2.5 concentrations, wind speed, traffic volume, and traffic compositions.Results indicated that the PM2.5 concentrations reduced with increasing heights of pedestrians in all the modelled runs. When this PM2.5 exposure difference was investigated with varying surrounding conditions, it was found that the difference in PM2.5 exposure across heights was influenced by the wind speed, traffic volume, and traffic composition. Ambient PM2.5 concentrations had no discernible effect on it. Car-dominated traffic with a higher mode share of heavy commercial vehicles was marked with the highest PM2.5 exposure difference across heights.For traffic volume, it was observed that for every 100 vehicles hr -1 increase in traffic volume, the PM2.5 exposure difference increased by 0.13 µg m -3 m -1 in the range of pedestrian's height. For wind speed, calculations suggested that for every 1 m s -1 increase in wind speed, the PM2.5 exposure difference was reduced by 0.095 µg m -3 m -1 in the range of pedestrian's height. Finally, to bolster the modelling results, mobile PM2.5 measurements (using portable, low-cost optical particle sensors) were conducted near a busy urban roadway at two different heights, 80 cm and 150 cm, during peak and off-peak hours. The results of mobile measurements were found to be consistent with CALINE 4 modelled results.

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Evaluating the filtration efficiency of commercial facemasks’ materials against respiratory aerosol droplets

Cited by 9 publications

References 22 publications

Associations Between Wearing Masks and Respiratory Viral Infections: A Meta-Analysis and Systematic Review

Associations Between Wearing Masks and Respiratory Viral Infections: A Meta-Analysis and Systematic Review

Boundary conditions for exhaled airflow from a cough with a surgical orN95mask

Analysis of the Near-road Fine Particulate Exposure to Pedestrians at Varying Heights

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