scholarly journals Wearing time and respiratory volume affect the filtration efficiency of masks against aerosols at different sizes

2021 ◽  
pp. 102165
Author(s):  
Xia Li ◽  
Pei Ding ◽  
Fuchang Deng ◽  
Yixin Mao ◽  
Lin Zhou ◽  
...  
Keyword(s):  
Filtration Efficiency ◽  
Respiratory Volume

Study of face mask filtration efficiency to prevent fine dust to secure people’s right to health

2020 ◽  
Vol 19 (2) ◽  
pp. 186-193
Author(s):  
Woo-Taeg Kwon ◽  
◽  
Min-Jae Jung ◽  
Bum-Soo Kim ◽  
Woo-Sik Lee ◽  
...  
Keyword(s):  
Face Mask ◽  
Right To Health ◽  
Filtration Efficiency ◽  
Fine Dust

scholarly journals Tanning Wastewater Treatment by Ultrafiltration: Process Efficiency and Fouling Behavior

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 461
Author(s):  
Fu Yang ◽  
Zhengkun Huang ◽  
Jun Huang ◽  
Chongde Wu ◽  
Rongqing Zhou ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Shear Rate ◽  
Membrane Surface ◽  
Filtration Efficiency ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Transmembrane Pressure ◽  
Leather Industry ◽  
Pore Blocking ◽  
The Impact

Ultrafiltration is a promising, environment-friendly alternative to the current physicochemical-based tannery wastewater treatment. In this work, ultrafiltration was employed to treat the tanning wastewater as an upstream process of the Zero Liquid Discharge (ZLD) system in the leather industry. The filtration efficiency and fouling behaviors were analyzed to assess the impact of membrane material and operating conditions (shear rate on the membrane surface and transmembrane pressure). The models of resistance-in-series, fouling propensity, and pore blocking were used to provide a comprehensive analysis of such a process. The results show that the process efficiency is strongly dependent on the operating conditions, while the membranes of either PES or PVDF showed similar filtration performance and fouling behavior. Reversible resistance was the main obstacle for such process. Cake formation was the main pore blocking mechanism during such process, which was independent on the operating conditions and membrane materials. The increase in shear rate significantly increased the steady-state permeation flux, thus, the filtration efficiency was improved, which resulted from both the reduction in reversible resistance and the slow-down of fouling layer accumulate rate. This is the first time that the fouling behaviors of tanning wastewater ultrafiltration were comprehensively evaluated, thus providing crucial guidance for further scientific investigation and industrial application.

Cost-Effective Face Mask Filter Based on Hybrid Composite Nanofibrous Layers with High Filtration Efficiency

Langmuir ◽  
2021 ◽  
Author(s):  
Walaa A. Abbas ◽  
Basamat S. Shaheen ◽  
Loujain G. Ghanem ◽  
Ibrahim M. Badawy ◽  
Mohamed M. Abodouh ◽  
...  
Keyword(s):  
Hybrid Composite ◽  
Cost Effective ◽  
Face Mask ◽  
Filtration Efficiency

scholarly journals Why does the spread of COVID-19 vary greatly in different countries? Revealing the efficacy of face masks in epidemic prevention

2021 ◽  
Vol 149 ◽  
Author(s):  
Jincheng Wei ◽  
Shurui Guo ◽  
Enshen Long ◽  
Li Zhang ◽  
Bizhen Shu ◽  
...  
Keyword(s):  
Social Isolation ◽  
Large Scale ◽  
Experimental Studies ◽  
Weighted Average ◽  
Filtration Efficiency ◽  
Volume Distribution ◽  
Particle Sizes ◽  
Economic Activities ◽  
Protection Measure ◽  
Source Of Infection

Abstract The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is highly contagious, and the coronavirus disease 2019 (COVID-19) pandemic caused by it has forced many countries to adopt ‘lockdown’ measures to prevent the spread of the epidemic through social isolation of citizens. Some countries proposed universal mask wearing as a protection measure of public health to strengthen national prevention efforts and to limit the wider spread of the epidemic. In order to reveal the epidemic prevention efficacy of masks, this paper systematically evaluates the experimental studies of various masks and filter materials, summarises the general characteristics of the filtration efficiency of isolation masks with particle size, and reveals the actual efficacy of masks by combining the volume distribution characteristics of human exhaled droplets with different particle sizes and the SARS-CoV-2 virus load of nasopharynx and throat swabs from patients. The existing measured data show that the filtration efficiency of all kinds of masks for large particles and extra-large droplets is close to 100%. From the perspective of filtering the total number of pathogens discharged in the environment and protecting vulnerable individuals from breathing live viruses, the mask has a higher protective effect. If considering the weighted average filtration efficiency with different particle sizes, the filtration efficiencies of the N95 mask and the ordinary mask are 99.4% and 98.5%, respectively. The mask can avoid releasing active viruses to the environment from the source of infection, thus maximising the protection of vulnerable individuals by reducing the probability of inhaling a virus. Therefore, if the whole society strictly implements the policy of publicly wearing masks, the risk of large-scale spread of the epidemic can be greatly reduced. Compared with the overall cost of social isolation, limited personal freedoms and forced suspension of economic activities, the inconvenience for citizens caused by wearing masks is perfectly acceptable.

scholarly journals Electret Filters—From the Influence of Discharging Methods to Optimization Potential

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 65
Author(s):  
Maximilian Kerner ◽  
Kilian Schmidt ◽  
Stefan Schumacher ◽  
Christof Asbach ◽  
Sergiy Antonyuk
Keyword(s):  
Fine Particles ◽  
Operating Time ◽  
Filtration Efficiency ◽  
Long Term Stability ◽  
Aerosol Filtration ◽  
Charge Decay ◽  
The One ◽  
Testing Standards ◽  
Discharge Efficiency

Electret filters are electrostatically charged nonwovens which are commonly used in aerosol filtration to remove fine particles from gases. It is known that the charge and thus also the filtration efficiency can degrade over time. Thus, many testing standards require to remove the charge by treatment with liquid isopropanol (IPA) or IPA-saturated air. However, the parameters influencing this discharge have not been completely clarified yet. The aim of this work was, on the one hand, to experimentally investigate the influence of the IPA treatment on different electret filters and, on the other hand, to show the optimization potential of electret filters with respect to efficiency and long-term stability by numerical simulations. The experiments revealed that the air permeability is a central influencing parameter. Small pores lead to a reduced discharge efficiency using liquid IPA, while both treatment methods are suitable for larger pores. The simulations showed that a homogeneous charge distribution within the filter depth is advantageous for the initial performance. In contrast, charge penetrating deeper in the filter medium delays the charge decay and thus increases the operating time, with the trade-off of a lower initial performance.

Review of the Breathability and Filtration Efficiency of Common Household Materials for Face Masks

ACS Nano ◽  
2021 ◽  
Author(s):  
Laura H. Kwong ◽  
Rob Wilson ◽  
Shailabh Kumar ◽  
Yoshika Susan Crider ◽  
Yasmin Reyes Sanchez ◽  
...  
Keyword(s):  
Filtration Efficiency

Corrigendum to “Filtration efficiency and ventilation performance of window screen filters” [Build. Environ. 178 (2020) 106878]

2021 ◽  
Vol 191 ◽  
pp. 107612
Author(s):  
Kyungmo Kang ◽  
Taeyeon Kim ◽  
Cheol Woong Shin ◽  
Kichul Kim ◽  
Jiwoong Kim ◽  
...  
Keyword(s):  
Filtration Efficiency ◽  
Ventilation Performance ◽  
Window Screen
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