Decontamination of surgical face masks and N95 respirators by dry heat pasteurization for one hour at 70°C

A review on medical waste treatment in COVID-19 pandemics: Technologies, managements and future strategies

Since the outbreak of COVID-19 few years ago, the increasing of the number of medical waste has become a huge issue because of their harmful impact to environment. A major concern associated to the limitation of technologies for dealing with medical waste, especially conventional technologies, are overcapacities since pandemic occurs. Moreover, the outbreak of new viruses from post COVID-19 should become a serious attention to be prevented not only environmental issues but also the spreading of viruses to new pandemic near the future. The high possibility of an outbreak of new viruses and mutation near the future should be prevented based on the experience associated with the SARS-CoV-2 virus in the last 3 yr. This review presented information and strategies for handling medical waste during the outbreak of COVID-19 and post-COVID-19, and also information on the current issues related to technologies, such as incineration, pyrolysis/gasification, autoclaves and microwave treatment for the dealing with high numbers of medical waste in COVID-19 to prevent the transmission of SARS-CoV-2 virus, their advantages and disadvantages. Plasma technology can be considered to be implemented as an alternative technology to deal with medical waste since incinerator is usually over capacities during the pandemic situation. Proper treatment of specific medical waste in pandemics, namely face masks, vaccine vials, syringes, and dead bodies, are necessary because those medical wastes are mediums for transmission of the SARS-CoV-2 virus. Furthermore, emission controls from incinerator and plasma are necessary to be implemented to reduce the high concentration of CO2, NOx, and VOCs during the treatment. Finally, future strategies of medical waste treatment in the perspective of potential outbreak pandemic from new mutation viruses are discussed in this review paper.Implications: Journal of the air and waste management association may consider our review paper to be published. In this review, we give important information related to the technologies, managements and strategies for handling the medical waste and control the transmission of SARS-CoV-2 virus, starting from proper technology to control the high number of medical waste, their pollutants and many strategies for controlling the spreading of SARS-CoV-2 virus. Moreover, this review also describes some strategies associated with control the transmission not only the SARS-CoV-2 virus but also the outbreak of new viruses near the future.

The Rise of Electroactive Materials in Face Masks for Preventing Virus Infections

Air-transmitted pathogens may cause severe epidemics, posing considerable threats to public health and safety. Wearing a face mask is one of the most effective ways to prevent respiratory virus infection transmission. Especially since the new coronavirus pandemic, electroactive materials have received much attention in antiviral face masks due to their highly efficient antiviral capabilities, flexible structural design, excellent sustainability, and outstanding safety. This review first introduces the mechanism for preventing viral infection or the inactivation of viruses by electroactive materials. Then, the applications of electrostatic-, conductive-, triboelectric-, and microbattery-based materials in face masks are described in detail. Finally, the problems of various electroactive antiviral materials are summarized, and the prospects for their future development directions are discussed. In conclusion, electroactive materials have attracted great attention for antiviral face masks, and this review will provide a reference for materials scientists and engineers in antiviral materials and interfaces.

Property assessment of an eco-friendly mortar reinforced with recycled mask fiber derived from COVID-19 single-use face masks

Wearing a face mask is strongly advised to prevent the spread of the virus causing the COVID-19 pandemic, though masks have produced a tremendous amount of waste. As masks contain polypropylene and other plastics products, total degradation is not achievable, and masks may remain in the form of microplastics for several years in the environment. Therefore, this urgent issue ought to be addressed by properly handling waste face masks to limit their environmental impact. In relation to this goal, a novel application of recycled mask fiber (MF) derived from COVID-19 single-use surgical face masks (i.e., shredded mask fiber-SMF and cut mask fiber-CMF) has been undertaken. Eighteen mortar mixes (9 for water and 9 for 10% CO₂ concentration curing) were fabricated at 0%, 0.5%, 1.0%, 1.5%, and 2.0% of both SMF and CMF by volume of ordinary Portland cement-based mortar. The compressive strength, flexural strength, ultrasonic pulse velocity, shrinkage, carbonation degree, permeable voids, and water absorption capabilities were assessed. The outcomes reveal that the compressive strength decreased with an increased percentage of MFs due to increased voids of the mixes with MFs as compared to a control mix. In contrast, significantly higher flexural strength was noted for the mortar with MFs, which is augmented with an increased percentage of MFs. Furthermore, the inclusion of MFs decreased the shrinkage of the mortar compared to the control mix. It was also found that MFs dramatically diminished the water absorption rate compared to the control mix, which reveals that MFs can enhance the durability of the mortar.

Impact of face mask microplastics pollution on the aquatic environment and aquaculture organisms

Microplastic pollution in our environment, especially water bodies is an emerging threat to food security and human health. Inevitably, the outbreak of Covid-19 has necessitated the constant use of face masks made from polymers such as polypropylene, polyurethane, polyacrylonitrile, polystyrene, polycarbonate, polyethylene, or polyester which eventually will disintegrate into microplastic particles. They can be broken down into microplastics by the weathering action of UV radiation from the sun, heat, or ocean wave-current and precipitate in natural environments. The global adoption of face masks as a preventive measure to curb the spread of Covid-19 has made the safe management of wastes from it cumbersome. Microplastics gain access into aquaculture facilities through water sources and food including planktons. The negative impacts of microplastics on aquaculture cannot be overemphasized. The impacts includes low growth rates of animals, hindered reproductive functions, neurotoxicity, low feeding habit, oxidative stress, reduced metabolic rate, and increased mortality rate among aquatic organisms. With these, there is every tendency of microplastic pollution to negatively impact fish production through aquaculture if the menace is not curbed. It is therefore recommended that biodegradable materials rather than plastics to be considered in the production of face mask while recycle of already produced ones should be encouraged to reduce waste.

Evaluating the effects of air disinfectants in decontamination of COVID-19 aerosols

Introduction

Airborne transmission is the most  crucial mode of COVID-19 transmission. Therefore, disinfecting the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) aerosols float can have important implications in limiting COVID-19 transmission. Herein, we aimed to review the studies that utilized various disinfectants to decontaminate and inactivate the SARS-CoV-2 aerosols.

Methods

This study was a review that studied related articles published between December 1, 2019 and August 23, 2022. We searched the online databases of PubMed, Scopus, Web of Science, Cochrane, on August 23, 2021. The studies were downloaded into the EndNote software, duplicates were removed, and then the studies were screened based on the inclusion/exclusion criteria. The screening process involved two steps; first, the studies were screened based on their title and abstract and then their full texts. The included studies were used for the qualitative analysis.

Results

From 664 retrieved records, only 31 met the inclusion criteria and were included in the final qualitative analysis. Various materials like Ozone, H₂O₂, alcohol, and TiO₂ and methods like heating and using Ultraviolet were described in these studies to disinfect places contaminated by COVID-19. It appeared that the efficacy of these disinfectants varies considerably depending on the situation, time, and ultimately their mode of application.

Conclusion

Following reliable protocols in combination with the proper selection of disinfectant agents for each purpose would serve to achieve desired elimination of the SARS-CoV-2 transmission.

Assessment of the awareness about COVID-19 and the following-up of guidelines for biomedical wastes in Jaipur city

In this COVID-19 era, isolating people and reviewing their contacts has proven to be insufficient to control the COVID-19 pandemic as there was a huge gap between exposure to the virus and isolation due to the late onset of symptoms. This led to the spread of infection and people faced the consequences not only of viral infection, but also of financial and occupational crises. People followed best management practices, however, new variants emerged that caused infection. With little information on new COVID-19 variants and their transmission, the disease spread rapidly in humans. Until now, the link between the spread of COVID-19 and the disposal of biomedical waste with household waste has not been established. Therefore, the only way to prevent infection is to make people aware. It is still necessary to open the doors for research to find the possible cause of the appearance of a new variant of COVID-19. To cope with the situation, the level of awareness among the public and their action towards the prevention of spread of infection caused by COVID-19 and its emerging variants must be known. Therefore, a survey was conducted in Jaipur from January to February 2022 to find out the status of awareness. Results of the survey revealed that both people are aware about the infection caused by COVID-19 and its variants. They are also aware about the precautions to be followed to protect themselves from acquiring COVID-19 infection. Most of the people are using masks but not gloves to prevent themselves from the infection. Merely, 71.6% of young, 100% of adults, 40% of old people sanitize their masks and gloves before disposal. Only 66.5% people are using separate bags for the collection of wastes. Despite of awareness about biomedical waste, 25% of young never sanitize, and 26.13% of young seldom sanitizes their waste before disposal. Such types of cases were not observed in adults and old age groups. Similarly, 2.3% of young did not sanitize PPE kit prior to disposal. Results of this study revealed that there is awareness about the different strains of corona virus and biomedical wastes. However, some people showed casual behaviour in the waste disposal practices. The strict implementation of rules to dispose biomedical waste will be useful for dealing with biomedical waste in this pandemic period.

Reusing COVID-19 disposable nitrile gloves to improve the mechanical properties of expansive clay subgrade: An innovative medical waste solution

The COVID-19 pandemic not only poses an unprecedented threat to global health but also severely disrupts the natural environment and ecosystems. Mitigating the adverse impacts of plastic-based personal protective equipment (PPE) waste requires the cooperation of professionals from various fields. This paper discusses a novel, cleaner approach to soil stabilisation by repurposing the nitrile gloves into a sustainable road material to improve the mechanical properties of expansive clay soil as pavement subgrade. For the first time, extensive geotechnical testings, including standard compaction, unconfined compressive strength (UCS), unsoaked California bearing ratio (CBR), repeated load triaxial (RLT), and swelling-shrinkage tests, were carried out to investigate the engineering performance of different proportions of the shredded nitrile gloves (SNG) (e.g., 1%, 1.5%, 2%) were blended with expansive clay (EC). In addition, surface roughness, scanning electron microscopy (SEM), and X-ray micro-CT analyses were conducted, and images were obtained to study the microstructural modification of the EC-SNG mixtures. The experimental results indicated that the blend of expansive clay with SNG helped in increasing the compressive strength, resilient modulus, and CBR and assisted in reducing the swelling and shrinkage of the soil. SEM and surface roughness analyses indicated the interaction between the soil matrix interface and the rough surface of the SNG. The main reasons for increasing the strength and stability of clay soil could be attributed to the high tensile strength of the SNG and the formation of the three-dimensional grid, and friction between the soil particles and SNG. According to the X-ray micro-CT test results, the incorporation of SNG led to an increase in closed porosity.

Bacterial Cellulose: Nano-biomaterial for Biodegradable Face Masks- A Greener Approach Towards Environment

The use of face masks aids to stop the transmission of various deadly communicable ailments, and therefore widespread mask wearing habit is advocated by nearly all health organisations including the WHO to curb the COVID-19 pandemic. Recent studies predicted a shocking requirement of masks globally, approximately billions of masks per week in a single country, and maximum of them are disposable masks, which are made up of nonbiodegradable material such as polypropylene. With expanding review on improper masks disposal, it is imperative to perceive this inherent environmental hazard and avert it from resulting in the subsequent problematic situation due to plastic. The shift towards biodegradable biopolymers alternatives such as bacterial cellulose and newly evolving sustainable scientific knowledge would be significant to dealt with upcoming environmental problem. Bacterial cellulose possesses various desirable properties to replace the conventional mask material. This review gives an overview of data about accumulation of waste masks and its potential harm on environment. It also focuses on diverse characteristics of bacterial cellulose which make it suitable material for making mask and the challenges in the way of bacterial cellulose production and their possible solution. The current review also discussed the report on global bacterial cellulose market growth.

Filtration efficiency of N95 filtering facepiece respirators during multi-cycles of “8-hour simulated donning + disinfection”

Background

Aerosol-borne diseases such as COVID-19 may outbreak occasionally in various regions of the world, inevitably resulting in short-term shortage and corresponding reuse of disposable respirators.

Aim

To investigate the effective disinfection methods, reusable duration and frequency of N95 respirators.

Methods

Based on the self-built respirator simulation test system, and under combinations of experimental conditions of three N95 respirators × 0–200 nm NaCl aerosols × three simulated breathing flow rates (15, 50 and 85 L/min) × two disinfection methods (dry heating and ultraviolet (UV) radiation), this study continuously measured the changes in filtration efficiency of all respirators during multi-cycles of ‘8-h simulated donning + disinfection’ until the penetration reached ≥5%.

Findings

Multi-cycles of dry heating and UV radiation treatments on the reused (i.e., multiple 8-h donning) N95 respirators had a minimal effect (<0.5%) on the respirator filtration efficiency, and even at 85 L/min, all tested N95 respirators were able to maintain filtration efficiencies ≥95% for at least 30 h or four reuse cycles of ‘8-h donning + disinfection’, while a lower breathing flow rate (15 L/min) plus the exhalation valve could further extend the N95 respirator's usability duration up to 140 h or 18 reuse cycles of ‘8-h donning + disinfection’. As the respirator wearing time extended, aerosol penetration slowly increased in a quadratic function with a negative second-order coefficient, and the penetration increment during each cycle of 8-h donning was less than 0.9%.

Conclusion

Multi-cycles of N95 respirator reuse in combination with dry heating or UV irradiation disinfection are feasible.

Design, manufacture, and testing of customized sterilizable respirator

The respirator as one of the personal protective equipment is essential for industrial activities (e.g., mining, painting, woodcutting, manufacturing) for protection from contaminants in the air and during the Covid-19 pandemic to protect the wearer from infection. The respirators nowadays are commonly made of rigid plastic. They are expensive, cumbersome, and not comfortable to wear. The many components with complex structures prevent it from cleaning and reusing. We develop a practical and scalable strategy to create customized respirators with durability using computational modeling and 3D printing. It is shown that by morphing the shape according to the user's photo, the respirator is designed to fit a user's face without air leaks. Using a printing-mold-casting method, this respirator can be manufactured by silicone rubber with accuracy, which is highly durable, with its mechanics primarily not affected by sterilization. These features provide the current respirator adaptivity and convenience in carrying and storing, as well as more comfort for long-time wearing.

Use of COVID-19 single-use face masks to improve the rutting resistance of asphalt pavement

Today, the world faces an enormous increase in plastic waste pollution caused by the emergence of the COVID-19 pandemic. Plastic pollution has been already one of the greatest threats to our planet before the Coronavirus outbreak. The disposal of millions of personal protective equipment (PPE) in the form of face masks has significantly contributed to the generation of plastic waste and has exacerbated plastic pollution. In an attempt to mitigate pollution caused by the excess PPE waste, an innovative way was developed in this research to reduce pandemic-generated wastes by using the shredded face mask (SFM) fibers as an additive to hot mix asphalt (HMA) to enhance rutting resistance. Rutting or permanent deformation is one of the major distresses of asphalt pavement. Since the SFM behaves as a semi-liquid between 115.5 and 160 °C, which is in the range of HMA mixing and paving temperature, it can function as a binding agent to glue the aggregates. When the pavement is cooled down to ambient temperature, the hardened SFM can provide stability and stiffness to HMA. Based on the results of this study, the modified mixes exhibited excellent resistance to permanent deformation under the Asphalt Pavement Analyzer (APA), as rutting depth values were reduced from 3.0 mm to 0.93 mm by increasing the SFM content from 0% to 1.5%. From the rutting test results and premature distress mechanism study, the appropriate addition of SFM modifiers could improve the high-temperature properties of HMA that can be used to strengthen high-compression and shearing zones in the pavement structure.

Efficacy and self-similarity of SARS-CoV-2 thermal decontamination

Dry heat decontamination has been shown to effectively inactivate viruses without compromising the integrity of delicate personal protective equipment (PPE), allowing safe reuse and helping to alleviate shortages of PPE that have arisen due to COVID-19. Unfortunately, current thermal decontamination guidelines rely on empirical data which are often sparse, limited to a specific virus, and unable to provide fundamental insight into the underlying inactivation reaction. In this work, we experimentally quantified dry heat decontamination of SARS-CoV-2 on disposable masks and validated a model that treats the inactivation reaction as thermal degradation of macromolecules. Furthermore, upon nondimensionalization, all of the experimental data collapse onto a unified curve, revealing that the thermally driven decontamination process exhibits self-similar behavior. Our results show that heating surgical masks to 70 °C for 5 min inactivates over 99.9% of SARS-CoV-2. We also characterized the chemical and physical properties of disposable masks after heat treatment and did not observe degradation. The model presented in this work enables extrapolation of results beyond specific temperatures to provide guidelines for safe PPE decontamination. The modeling framework and self-similar behavior are expected to extend to most viruses-including yet-unencountered novel viruses-while accounting for a range of environmental conditions.

Microplastics waste in environment: A perspective on recycling issues from PPE kits and face masks during the COVID-19 pandemic

During the COVID-19 pandemic, the extensive use of face masks and protective personal equipment (PPE) kits has led to increasing degree of microplastic pollution (MP) because they are typically discarded into the seas, rivers, streets, and other parts of the environment. Currently, microplastic (MP) pollution has a negative impact on the environment because of high-level fragmentation. Typically, MP pollution can be detected by various techniques, such as microscopic analysis, density separation, and Fourier transform infrared spectrometry. However, there are limited studies on disposable face masks and PPE kits. A wide range of marine species ingest MPs in the form of fibers and fragments, which directly affect the environment and human health; thus, more research and development are needed on the effect of MP pollution on human health. This article provides a perspective on the origin and distribution of MP pollution in waterbodies (e.g., rivers, ponds, lakes, and seas) and wastewater treatment plants, and reviews the possible remediation of MP pollution related to the excessive disposal of face masks and PPE kits to aquatic environments.

Effect of five decontamination methods on face masks and filtering facepiece respirators contaminated with Staphylococcus aureus and Pseudomonas aeruginosa

Introduction. In the context of the global pandemic due to SARS-CoV-2, procurement of personal protective equipment during the crisis was problematic. The idea of reusing and decontaminating personal surgical masks in facilities was explored in order to avoid the accumulation of waste and overcome the lack of equipment.

Hypothesis. Our hypothesis is that this work will show the decontamination methods assessed are effective for bacteria, such as Staphylococcus aureus and Pseudomonas aeruginosa .

Aim. We aim to provide information about the effects of five decontamination procedures (UV treatment, dry heat, vaporized H2O2, ethanol treatment and blue methylene treatment) on S. aureus and P. aeruginosa . These bacteria are the main secondary bacterial pathogens responsible for lung infections in the hospital environment.

Methodology. The surgical masks and the filtering facepiece respirators were inoculated with two bacterial strains ( S. aureus ATCC 29213 and P. aeruginosa S0599) and submitted to five decontamination treatments: vaporized H2O2 (VHP), UV irradiation, dry heat treatment, ethanol bath treatment and blue methylene treatment. Direct and indirect microbiology assessments were performed on three positive controls, five treated masks and one negative control.

Results. The five decontaminations showed significant (P<0.05) but different degrees of reductions of S. aureus and P. aeruginosa . VHP, dry heat treatment and ethanol treatment adequately reduced the initial contamination. The 4 min UV treatment allowed only a reduction to five orders of magnitude for face mask respirators. The methylene blue treatment induced a reduction to two orders of magnitude.

Conclusions. The three methods that showed a log10 reduction factor of 6 were the dry heat method, VHP and ethanol bath treatment. These methods are effective and their establishment in the medical field are easy but require economic investment.

Sterilization of paper during crisis

Paper sheets represent one of the infection risk sources inside educational and administrative institutions under biological pandemics. So, the present study aimed to validate the efficiency of gamma radiation or dry heat techniques to sterilize contaminated paper sheets with different indicator pathogens while retaining their structure. The results showed that gamma radiation at 6, 12, or 24 kGy can successfully kill Gram-positive bacteria such as Bacillus cereus and Staphylococcus aureus, Gram-negative bacteria such as Escherichia coli and Salmonella typhi, and fungi such as Candida albicans. Moreover, dry heating at 100 °C for 60 min, 150 °C for 30 min, or 200 °C for 15 min can be successful in paper decontamination of all tested species. Surprisingly, scanning electron microscopy (SEM) micrographs proved that gamma radiation at 6 kGy, dry heat at 100 °C for 60 min or 150 °C for 30 min or 200 °C for 15 min, is suitable for paper sheet sterilization while maintaining their structure. Ultimately, dry heat is a simple, effective, fast, safe, and inexpensive technique for paper sterilization. It may be used as a precautionary step inside educational institutions, especially during written examination periods, to ensure a safe life for academic members during biological pandemics such as COVID-19.

Plastic accumulation during COVID-19: call for another pandemic; bioplastic a step towards this challenge?

Plastic pollution has become a serious transboundary challenge to nature and human health, with estimation of reports published - predicting a twofold increase in plastic waste by 2030. However, due to the COVID-19 pandemic, the excessive use of single-use plastics (including face masks, gloves and personal protective equipment) would possibly exacerbate such forecasts. The transition towards eco-friendly alternatives like bio-based plastics and new emerging sustainable technologies would be vital to deal with future pandemics, even though the use or consumption of plastics has greatly enhanced our quality of life; it is however critical to move towards bioplastics. We cannot deny the fact that bioplastics have some challenges and shortcomings, but still, it is an ideal option for opt. The circular economy is the need of the hour for waste management. Along with all these practices, individual accountability, corporate intervention and government policy are also needed to prevent us from moving from one crisis to the next. Only through cumulative efforts, we will be able to cope up with this problem. This article collected scattered information and data about accumulation of plastic during COVID-19 worldwide. Additionally, this paper illustrates the substitution of petroleum-based plastics with bio-based plastics. Different aspects are discussed, ranging from advantages to challenges in the way of bioplastics.

Effect of dry heat treatment between room temperature and 160 °C on surgical masks

The Covid-19 crisis has led to a high demand and use of surgical masks worldwide, causing risks of shortages and pollution. Therefore, decontamination of surgical masks could be an opportunity to reduce these risks. In our study, we applied dry heat to the masks for 15 min at different temperatures and studied the consequences of heat on surface chemistry and fiber morphology. We focus here on the effects of dry heat treatment on the masks and not on the verification of mask disinfection, which has been thoroughly studied in existing literature. The masks that were heated to 70 °C, 100 °C, 130 °C, 140 °C, 150 °C did not show significant changes at the nanometric scale and the standard deviation of the surface temperature of the worn masks is similar to that of the unheated control mask. However we show a slight heating altered the hydrophobicity of the surface, and induced a significative modification of the wetting angle of water droplets. The mask heated to 157 °C has a higher surface temperature standard deviation and fused fibers are observed by scanning electron microscopy. The mask heated to 160 °C melted and then hardened as it cooled making it completely unusable.

“Re-engineering of a food oven for thermal sanitization of Personal Protective Equipment against Sars-CoV-2 virus”

One of the main issues addressed by the recent COVID-19 pandemic which affected the whole world is the availability of Personal Protective Equipment (PPE) (e.g., face masks, white coats, or disposable gloves). This issue impacts on sustainability from different perspectives, such as more generated waste or environmental pollution, both for manufacturing and disposal, or more inequalities deriving from who can afford and access PPE and who cannot, since many shortages were recorded during the pandemic as well as fluctuating unit prices. Moreover, quite often PPE intended for single use are improperly used more times, thus generating a biological risk of infection. In an attempt to propose an innovative solution to face this problem, in this paper the re-design of an oven originally intended for food purposes is presented, with the aim of operating a thermal sanitization of PPE. The machinery and its components are detailed, together with physical and microbiological tests performed on non-woven PPE to assess the effect of treatment on mechanical properties and viral load. The pilot machinery turned out to be effective in destroying a bovine coronavirus at 95 °C and thus reducing contaminating risk in one hour without compromising the main properties of PPE, opening perspectives for the commercialization of the solution in the near future.

Masks for COVID-19

Sustainable solutions on fabricating and using a face mask to block the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread during this coronavirus pandemic of 2019 (COVID-19) are required as society is directed by the World Health Organization (WHO) toward wearing it, resulting in an increasingly huge demand with over 4 000 000 000 masks used per day globally. Herein, various new mask technologies and advanced materials are reviewed to deal with critical shortages, cross-infection, and secondary transmission risk of masks. A number of countries have used cloth masks and 3D-printed masks as substitutes, whose filtration efficiencies can be improved by using nanofibers or mixing other polymers into them. Since 2020, researchers continue to improve the performance of masks by adding various functionalities, for example using metal nanoparticles and herbal extracts to inactivate pathogens, using graphene to make masks photothermal and superhydrophobic, and using triboelectric nanogenerator (TENG) to prolong mask lifetime. The recent advances in material technology have led to the development of antimicrobial coatings, which are introduced in this review. When incorporated into masks, these advanced materials and technologies can aid in the prevention of secondary transmission of the virus.

Reuse of COVID-19 face mask for the amelioration of mechanical properties of fat clay: A novel solution to an emerging waste problem

Not only has the COVID-19 pandemic caused a global health crisis, but it has also changed the dynamics of waste generation around the world. This situation demands a productive solution for face mask (FM) waste management to solve several associated environmental issues. In the current study, a novel soil treatment method is proposed for the improvement of mechanical characteristics of fat clay by using FM as fiber reinforcement and silica fume (SF) as the cementitious agent in the form of a composite binary admixture (CBA). The performance of the proposed CBA is compared with SF and FM as the lone stabilizers by conducting extensive geotechnical testing. The SF treatment exponentially improves the strength characteristics of soil but it marginalizes the ductility of soil, inviting sudden failure and instability under dynamic loadings. It is observed that the proposed CBA not only improves the strength characteristics more than SF but also regulates the ductility and deformability of treated soil due to the presence of FM fibers. In addition, the policies and protocols on the logistics of collecting FM waste and making it ready for the proposed geotechnical application are reviewed; associated health risks, socioeconomic conditions and available technologies are the major governing factors to formulate and implement these policies. Moreover, the prolonged storage of COVID-19 FM waste for disinfection is found to be suitable for the proposed soil stabilization method as per the literature. The current study helps in achieving cost-effective filler/foundation material, solving COVID-19 FM waste problems and promoting resource conservation.

Exploring Reusability of Disposable Face Masks: Effects of Disinfection Methods on Filtration Efficiency, Breathability, and Fluid Resistance

To curb the spread of the COVID-19 virus, the use of face masks such as disposable surgical masks and N95 respirators is being encouraged and even enforced in some countries. The widespread use of masks has resulted in global shortages and individuals are reusing them. This calls for proper disinfection of the masks while retaining their protective capability. In this study, the killing efficiency of ultraviolet-C (UV-C) irradiation, dry heat, and steam sterilization against bacteria (Staphylococcus aureus), fungi (Candida albicans), and nonpathogenic virus (Salmonella virus P22) is investigated. UV-C irradiation for 10 min in a commercial UV sterilizer effectively disinfects surgical masks. N95 respirators require dry heat at 100 °C for hours while steam treatment works within 5 min. To address the question on safe reuse of the disinfected masks, their bacteria filtration efficiency, particle filtration efficiency, breathability, and fluid resistance are assessed. These performance factors are unaffected after 5 cycles of steam (10 min per cycle) and 10 cycles of dry heat at 100 °C (40 min per cycle) for N95 respirators, and 10 cycles of UV-C irradiation for surgical masks (10 min per side per cycle). These findings provide insights into formulating the standard procedures for reusing masks without compromising their protective ability.

Reusing and/or reprocessing the N95 face respirator mask or equivalent: An integrative review

OBJECTIVE

to analyze the scientific evidence available on the different reprocessing methods and the necessary conditions for reuse of the N95 face respirator mask or equivalent.

METHOD

an integrative literature review. The PICO strategy was used to elaborate the question. The search was conducted in four databases: PubMed, SciVerse Scopus, WebofScience and EMBASE, considering any period of time.

RESULTS

a total of 32 studies were included from the 561 studies identified, and they were presented in two categories: "Conditions for reuse" and "Reprocessing the masks". Of the evaluated research studies, seven(21.8%) addressed the reuse of the N95 face respirator mask or equivalent and 25(78.1%) evaluated different reprocessing methods, namely: ultraviolet germicidal irradiation(14); hydrogen peroxide(8); vapor methods(14); using dry heat(5) and chemical methods(sodium hypochlorite[6], ethanol[4] and sodium chloride with sodium bicarbonate and dimethyldioxirane[1]). We emphasize that different methods were used in one same article.

CONCLUSION

no evidence was found to support safe reprocessing of face respirator masks. In addition, reuse is contraindicated due to the risk of self-contamination and inadequate sealing.

Unmasking People’s Opinions behind Mask-Wearing during COVID-19 Pandemic—A Twitter Stance Analysis

Wearing a mask by the general public has been a controversial issue from the beginning of the COVID-19 pandemic as the public authorities have had mixed messages, either advising people not to wear masks if uninfected, to wear as a protective measure, to wear them only when inside a building/room with insufficient air flow or to wear them in all the public places. To date, the governments have had different policies regarding mask-wearing by the general public depending on the COVID-19 pandemic evolution. In this context, the paper analyzes the general public’s opinion regarding mask-wearing for the one-year period starting from 9 January 2020, when the first tweet regarding mask-wearing in the COVID-19 context has been posted. Classical machine learning and deep learning algorithms have been considered in analyzing the 8,795,633 tweets extracted. A random sample of 29,613 tweets has been extracted and annotated. The tweets containing news and information related to mask-wearing have been included in the neutral category, while the ones containing people’s opinions (for or against) have been marked using a symmetrical approach into in favor and against categories. Based on the analysis, it has been determined that most of the mask tweets are in the area of in favor or neutral, while a smaller percentage of tweets and retweets are in the against category. The evolution of the opinions expressed through tweets can be further monitored for extracting the public perspective on mask-wearing in times of COVID-19.

Assessment of the reuse of Covid-19 healthy personal protective materials in enhancing geotechnical properties of Najran's soil for road construction: Numerical and experimental study

The COVID-19 pandemic has not only caused a global health crisis, but it has also had significant environmental and human consequences. During the COVID-19 pandemic, this study focused on emerging challenges in managing healthy personal protective materials (HPPM) in Kingdom of Saudi Arabia, using silty sand (SM) soil as an example since it covers large areas in KSA and in the whole world. The main objective of this paper is to find a novel way to minimize pandemic-related waste by using HPPM as waste materials in road construction. For the first time, a series of experiments was conducted on a mixture of different percentages of shredded HPPM (0, 0.5, 1 and 2%) added to the silty sand (SM) soil for road applications, including soil classification according to the USCS, modified compaction, UCS, UPV, and CBR. In addition, a numerical simulation was performed using geotechnical-based software Plaxis 3D to study the performance of the soil-HPPM mix as a subbase layer in the paving structure under heavy traffic loading. The modified compaction test results show that there is an increase in the optimum moisture content with increasing the HPPM contents from 0.5% to 1% and 2%. However, a reduction in the maximum dry density is observed. The values of dry density and water content at 0%, 0.5%, 1% and 2% pf HPPM are 2.045, 1.98, 1.86 and 1.8 g/cm³ and 7.65% 8%, 8.5% and 9.5%, respectively. The soaked CBR values at 0, 0.5, 1 and 2% HPPM are 23, 30, 8, 2% with the maximum value attained with the addition of 0.5% HPPM. The results of UCS were with the same percentages of HPPM 430, 450, 430 and 415 kPa, respectively, with the maximum value attained with 0.5% HPPM addition as well. In contrast, the values of UVP at 0%, 0.5%, 1% and 2% are 978.5, 680.3, 489.4 and 323.6 m/s, respectively, confirming the trends obtained by modified compaction test results. The simulation results confirm this conclusion that the soil-HPPM mix show a superior performance when used as a subbase layer and reduced vertical displacement by a percentage of 11% compared to the normal subbase material. By eliminating HPPM especially facemasks from the landfill lifecycle, incorporating them into high quality construction material production has the potential to deliver significant environmental benefits.

Decontaminating N95/FFP2 masks for reuse during the COVID-19 epidemic: a systematic review

BACKGROUND

With the current COVID-19 pandemic, many healthcare facilities have been lacking a steady supply of filtering facepiece respirators. To better address this challenge, the decontamination and reuse of these respirators is a strategy that has been studied by an increasing number of institutions during the COVID-19 pandemic.

METHODS

We conducted a systematic literature review in PubMed, PubMed Central, Embase, and Google Scholar. Studies were eligible when (electronically or in print) up to 17 June 2020, and published in English, French, German, or Spanish. The primary outcome was reduction of test viruses or test bacteria by log3 for disinfection and log6 for sterilization. Secondary outcome was physical integrity (fit/filtration/degradation) of the respirators after reprocessing. Materials from the grey literature, including an unpublished study were added to the findings.

FINDINGS

Of 938 retrieved studies, 35 studies were included in the analysis with 70 individual tests conducted. 17 methods of decontamination were found, included the use of liquids (detergent, benzalkonium chloride, hypochlorite, or ethanol), gases (hydrogen peroxide, ozone, peracetic acid or ethylene oxide), heat (either moist with or without pressure or dry heat), or ultra violet radiation (UVA and UVGI); either alone or in combination. Ethylene oxide, gaseous hydrogen peroxide (with or without peracetic acid), peracetic acid dry fogging system, microwave-generated moist heat, and steam seem to be the most promising methods on decontamination efficacy, physical integrity and filtration capacity.

INTERPRETATION

A number of methods can be used for N95/FFP2 mask reprocessing in case of shortage, helping to keep healthcare workers and patients safe. However, the selection of disinfection or sterilization methods must take into account local availability and turnover capacity as well as the manufacturer; meaning that some methods work better on specific models from specific manufacturers.

SYSTEMATIC REGISTRATION NUMBER

CRD42020193309.

Reusing Face Covering Masks: Probing the Impact of Heat Treatment

The COVID-19 pandemic resulted in imminent shortages of personal protective equipment such as face masks. To address the shortage, new sterilization or decontamination procedures for masks are quickly being developed and employed. Dry heat and steam sterilization processes are easily scalable and allow treatment of large sample sizes, thus potentially presenting fast and efficient decontamination routes, which could significantly ease the rapidly increasing need for protective masks globally during a pandemic like COVID-19. In this study, a suite of structural and chemical characterization techniques, including scanning electron microscopy (SEM), contact angle, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman were utilized to probe the heat treatment impact on commercially available 3M 8210 N95 Particulate Respirator and VWR Advanced Protection surgical mask. Unique to this study is the use of the synchrotron-based In situ and Operando Soft X-ray Spectroscopy (IOS) beamline (23-ID-2) housed at the National Synchrotron Light Source II at Brookhaven National Laboratory for near-edge X-ray absorption spectroscopy (NEXAFS).

Reusing Face Covering Masks: Probing the Impact of Heat Treatment

The COVID-19 pandemic resulted in imminent shortages of personal protective equipment such as face masks. To address the shortage, new sterilization or decontamination procedures for masks are quickly being developed and employed. Dry heat and steam sterilization processes are easily scalable and allow treatment of large sample sizes, thus potentially presenting fast and efficient decontamination routes, which could significantly ease the rapidly increasing need for protective masks globally during a pandemic like COVID-19. In this study, a suite of structural and chemical characterization techniques, including scanning electron microscopy (SEM), contact angle, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman were utilized to probe the heat treatment impact on commercially available 3M 8210 N95 Particulate Respirator and VWR Advanced Protection surgical mask. Unique to this study is the use of the synchrotron-based In situ and Operando Soft X-ray Spectroscopy (IOS) beamline (23-ID-2) housed at the National Synchrotron Light Source II at Brookhaven National Laboratory for near-edge X-ray absorption spectroscopy (NEXAFS).

Functionalized Masks: Powerful Materials against COVID-19 and Future Pandemics

The outbreak of COVID-19 revealed the vulnerability of commercially available face masks. Without having antibacterial/antiviral activities, the current masks act only as filtering materials of the aerosols containing microorganisms. Meanwhile, in surgical masks, the viral and bacterial filtration highly depends on the electrostatic charges of masks. These electrostatic charges disappear after 8 h, which leads to a significant decline in filtration efficiency. Therefore, to enhance the masks' protection performance, fabrication of innovative masks with more advanced functions is in urgent demand. This review summarizes the various functionalizing agents which can endow four important functions in the masks including i) boosting the antimicrobial and self-disinfectant characteristics via incorporating metal nanoparticles or photosensitizers, ii) increasing the self-cleaning by inserting superhydrophobic materials such as graphenes and alkyl silanes, iii) creating photo/electrothermal properties by forming graphene and metal thin films within the masks, and iv) incorporating triboelectric nanogenerators among the friction layers of masks to stabilize the electrostatic charges and facilitating the recharging of masks. The strategies for creating these properties toward the functionalized masks are discussed in detail. The effectiveness and limitation of each method in generating the desired properties are well-explained along with addressing the prospects for the future development of masks.

N95 respirator reuse, decontamination methods, and microbial burden: A randomized controlled trial

PURPOSE

To evaluate the effectiveness and ease of N95 respirator decontamination methods in a clinic setting and to identify the extent of microbial colonization on respirators associated with reuse.

METHODS

In a prospective fashion, N95 respirators (n = 15) were randomized to a decontamination process (time, dry heat, or ultraviolet C light [UVC]) in outpatient clinics. Each respirator was re-used up to 5 separate clinic sessions. Swabs on each respirator for SARS-CoV-2, bacteria, and fungi were obtained before clinic, after clinic and post-treatment. Mask integrity was checked after each treatment (n = 68). Statistical analyses were performed to determine factors for positive samples.

RESULTS

All three decontamination processes reduced bacteria counts similarly. On multivariate mixed model analysis, there were an additional 8.1 colonies of bacteria (95% CI 5.7 to 10.5; p < 0.01) on the inside compared to the outside surface of the respirators. Treatment resulted in a decrease of bacterial load by 8.6 colonies (95% CI -11.6 to -5.5; p < 0.01). Although no decontamination treatment affected the respirator filtration efficiency, heat treatments were associated with the breakdown of thermoplastic elastomer straps. Contamination with fungal and SARS-CoV-2 viral particles were minimal to non-existent.

CONCLUSIONS

Time, heat and UVC all reduced bacterial load on reused N95 respirators. Fungal contamination was minimal. Heat could permanently damage some elastic straps making the respirators nonfunctional. Given its effectiveness against microbes, lack of damage to re-treated respirators and logistical ease, UVC represents an optimal decontamination method for individual N95 respirators when reuse is necessary.

N95 respirator decontamination: a study in reusability

The coronavirus disease 2019 (COVID-19) pandemic had caused a severe depletion of the worldwide supply of N95 respirators. The development of methods to effectively decontaminate N95 respirators while maintaining their integrity is crucial for respirator regeneration and reuse. In this study, we systematically evaluated five respirator decontamination methods using vaporized hydrogen peroxide (VHP) or ultraviolet (254 nm wavelength, UVC) radiation. Through testing the bioburden, filtration, fluid resistance, and fit (shape) of the decontaminated respirators, we found that the decontamination methods using BioQuell VHP, custom VHP container, Steris VHP, and Sterrad VHP effectively inactivated Cardiovirus (3-log10 reduction) and bacteria (6-log10 reduction) without compromising the respirator integrity after 2-15 cycles. Hope UVC system was capable of inactivating Cardiovirus (3-log10 reduction) but exhibited relatively poorer bactericidal activity. These methods are capable of decontaminating 10-1000 respirators per batch with varied decontamination times (10-200 min). Our findings show that N95 respirators treated by the previously mentioned decontamination methods are safe and effective for reuse by industry, laboratories, and hospitals.

Indonesian medical frontliners during the coronavirus disease 2019 pandemic: Have we been protecting them enough?

BACKGROUND AND AIM

The coronavirus disease 2019 pandemic has brought deteriorating physical and mental burdens to health care workers (HCWs) in Indonesia, mainly attributed to the lack of protection and screening among HCWs, patients' concealment of their travel and medical history, and perceived social stigma and discrimination. Hence, we deliver our perspectives and recommendations based on the current situation in Indonesia to enforce their safeties. We encourage stakeholders to implement a systematic approach by employing stringent prevention strategies, ensuring adequate personal protective equipment (PPE) provision and equitable PPE distribution, and routine HCWs screening to prevent nosocomial clusters, in addition to the provision of psychosocial support to HCWs by offering social aids and psychological sessions. Furthermore, social stigma and discrimination toward HCWs and patients should also be addressed and mitigated, thus preventing concealments of patients' history and alleviating emotional burdens. We believe that providing continuous support to HCWs would lead to key benefits in ensuring a winning battle against the COVID-19 pandemic.

RELEVANCE FOR PATIENTS

HCWs are pivotal players in winning the battle against the COVID- 19 pandemic. Ensuring their safety and well-being will enable them to deliver better healthcare services, thus resulting in mutual benefit for themselves, the patients, and the nation's recovery.

Healthcare Workers' Experiences and Views of Using Surgical Masks and Respirators, and Their Attitudes on the Sustainability: A Semi-Structured Survey Study during COVID-19

A universal mask use was instituted in healthcare during COVID-19 pandemic in 2020. The extensive growth in the consumption of surgical masks and respirators brought new challenges. Healthcare workers had to get accustomed to wearing the facemasks continuously, raising concerns on the patient, occupational, and environmental safety. The aim of this study is to describe frontline healthcare workers and other authorities’ views and experiences on continuous use of surgical masks and respirators (facemasks) and their attitudes towards environmental and sustainability issues. A cross-sectional web-based survey was conducted in Finland during the COVID-19 pandemic in autumn 2020. The respondents(N = 120) were recruited via social media, and the data were collected using a purpose-designed questionnaire. Descriptive statistics and inductive content analysis were used to analyze the quantitative data and qualitative data, respectively. The healthcare workers perceived their own and patient safety, and comfortability of facemasks as important, but according to their experiences, these properties were not evident with the current facemasks. They considered protection properties more important than environmental values. However, biodegradability and biobased material were seen as desired properties in facemasks. Based on the results, the current facemasks do not meet users’ expectations well enough. Especially the design, breathability, and sustainability issues should be taken more into account.

Mask decontamination methods (model N95) for respiratory protection: a rapid review

BACKGROUND

N95 respiratory protection masks are used by healthcare professionals to prevent contamination from infectious microorganisms transmitted by droplets or aerosols.

METHODS

We conducted a rapid review of the literature analyzing the effectiveness of decontamination methods for mask reuse. The database searches were carried out up to September 2020. The systematic review was conducted in a way which simplified the stages of a complete systematic review, due to the worldwide necessity for reliable fast evidences on this matter.

RESULTS

A total of 563 articles were retrieved of which 48 laboratory-based studies were selected. Fifteen decontamination methods were included in the studies. A total of 19 laboratory studies used hydrogen peroxide, 21 studies used ultraviolet germicidal irradiation, 4 studies used ethylene oxide, 11 studies used dry heat, 9 studies used moist heat, 5 studies used ethanol, two studies used isopropanol solution, 11 studies used microwave oven, 10 studies used sodium hypochlorite, 7 studies used autoclave, 3 studies used an electric rice cooker, 1 study used cleaning wipes, 1 study used bar soap, 1 study used water, 1 study used multi-purpose high-level disinfection cabinet, and another 1 study used chlorine dioxide. Five methods that are promising are as follows: hydrogen peroxide vapor, ultraviolet irradiation, dry heat, wet heat/pasteurization, and microwave ovens.

CONCLUSIONS

We have presented the best available evidence on mask decontamination; nevertheless, its applicability is limited due to few studies on the topic and the lack of studies on real environments.

Role of additive manufacturing in medical application COVID-19 scenario: India case study

This paper reviews how the Additive Manufacturing (AM) industry played a key role in stopping the spread of the Coronavirus by providing customized parts on-demand quickly and locally, reducing waste and eliminating the need for an extensive manufacturer. The AM technology uses digital files for the production of crucial medical parts, which has been proven essential during the COVID-19 crisis. Going ahead, the 3D printable clinical model resources described here will probably be extended in various centralized model storehouses with new inventive open-source models. Government agencies, individuals, corporations and universities are working together to quickly development of various 3D-printed products especially when established supply chains are under distress, and supply cannot keep up with demand.

COVID-19: Performance study of microplastic inhalation risk posed by wearing masks

Wearing face masks has become the new normal worldwide due to the global spread of the coronavirus disease 2019. The inhalation of microplastics due to the wearing of masks has rarely been reported. The present study used different types of commonly used masks to conduct breathing simulation experiments and investigate microplastic inhalation risk. Microplastic inhalation caused by reusing masks that underwent various treatment processes was also tested. Results implied that wearing masks considerably reduces the inhalation risk of particles (e.g., granular microplastics and unknown particles) even when they are worn continuously for 720 h. Surgical, cotton, fashion, and activated carbon masks wearing pose higher fiber-like microplastic inhalation risk, while all masks generally reduced exposure when used under their supposed time (<4 h). N95 poses less fiber-like microplastic inhalation risk. Reusing masks after they underwent different disinfection pretreatment processes can increase the risk of particle (e.g., granular microplastics) and fiber-like microplastic inhalation. Ultraviolet disinfection exerts a relatively weak effect on fiber-like microplastic inhalation, and thus, it can be recommended as a treatment process for reusing masks if proven effective from microbiological standpoint. Wearing an N95 mask reduces the inhalation risk of spherical-type microplastics by 25.5 times compared with not wearing a mask.

Face masks against COVID-19: Standards, efficacy, testing and decontamination methods

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the novel coronavirus disease 2019 (COVID-19), has caused a global pandemic on a scale not seen for over a century. Increasing evidence suggests that respiratory droplets and aerosols are likely the most common route of transmission for SARS-CoV-2. Since the virus can be spread by presymptomatic and asymptomatic individuals, universal face masking has been recommended as a straightforward and low-cost strategy to mitigate virus transmission. Numerous governments and public health agencies around the world have advocated for or mandated the wearing of masks in public settings, especially in situations where social distancing is not possible. However, the efficacy of wearing a mask remains controversial. This interdisciplinary review summarizes the current, state-of-the-art understanding of mask usage against COVID-19. It covers three main aspects of mask usage amid the pandemic: quality standards for various face masks and their fundamental filtration mechanisms, empirical methods for quantitatively determining mask integrity and particle filtration efficiency, and decontamination methods that allow for the reuse of traditionally disposable N95 and surgical masks. The focus is given to the fundamental physicochemical and engineering sciences behind each aspect covered in this review, providing novel insights into the current understanding of mask usage to curb COVID-19 spread.

Safety in the practice of decontaminating filtering facepiece respirators: A systematic review

BACKGROUND

Considering the new SARS-CoV-2 pandemic and the potential scarcity of material resources, the reuse of personal protective equipment such as filtering facepiece respirators (FFRs) for N95 filtering or higher is being discussed, mainly regarding the effectiveness and safety of cleaning, disinfection and sterilization processes.

AIM

To analyze the available evidence in the literature on the safety in processing FFRs.

METHODS

A systematic review conducted by searching for studies in the following databases: PubMed, CINAHL, LILACS, CENTRAL, EMBASE, Web of Science, and Scopus.

RESULTS

Forty studies were included in this review. The disinfectant/sterilizing agents most frequently tested at different concentrations and exposure periods were ultraviolet irradiation, vaporized hydrogen peroxide and steam sterilization. Microbial reduction was assessed in 21 (52.5%) studies. The only disinfectants/sterilizers that did not caused degradation of the material-integrity were alcohol, electric cooker, ethylene oxide, and peracetic acid fogging. Exposure to ultraviolet irradiation or microwave generated-steam resulted in a nonsignificant reduction in filter performance.

CONCLUSION

There is a complex relationship between the FFR raw materials and the cycle conditions of the decontamination methods, evidencing the need for validating FFRs by models and manufacturers, as well as the process. Some methods may require additional tests to demonstrate the safety of FFRs for use due to toxicity.

The COVID-19 pandemic and N95 masks: reusability and decontamination methods

BACKGROUND

With the current SARS-CoV-2 pandemic, many healthcare facilities are lacking a steady supply of masks worldwide. This emergency situation warrants the taking of extraordinary measures to minimize the negative health impact from an insufficient supply of masks. The decontamination, and reuse of healthcare workers' N95/FFP2 masks is a promising solution which needs to overcome several pitfalls to become a reality.

AIM

The overall aim of this article is to provide the reader with a quick overview of the various methods for decontamination and the potential issues to be taken into account when deciding to reuse masks. Ultraviolet germicidal irradiation (UVGI), hydrogen peroxide, steam, ozone, ethylene oxide, dry heat and moist heat have all been methods studied in the context of the pandemic. The article first focuses on the logistical implementation of a decontamination system in its entirety, and then aims to summarize and analyze the different available methods for decontamination.

METHODS

In order to have a clear understanding of the research that has already been done, we conducted a systematic literature review for the questions: what are the tested methods for decontaminating N95/FFP2 masks, and what impact do those methods have on the microbiological contamination and physical integrity of the masks? We used the results of a systematic review on the methods of microbiological decontamination of masks to make sure we covered all of the recommended methods for mask reuse. To this systematic review we added articles and studies relevant to the subject, but that were outside the limits of the systematic review. These include a number of studies that performed important fit and function tests on the masks but took their microbiological outcomes from the existing literature and were thus excluded from the systematic review, but useful for this paper. We also used additional unpublished studies and internal communication from the University of Geneva Hospitals and partner institutions.

RESULTS

This paper analyzes the acceptable methods for respirator decontamination and reuse, and scores them according to a number of variables that we have defined as being crucial (including cost, risk, complexity, time, etc.) to help healthcare facilities decide which method of decontamination is right for them.

CONCLUSION

We provide a resource for healthcare institutions looking at making informed decisions about respirator decontamination. This informed decision making will help to improve infection prevention and control measures, and protect healthcare workers during this crucial time. The overall take home message is that institutions should not reuse respirators unless they have to. In the case of an emergency situation, there are some safe ways to decontaminate them.

Repurposing of COVID-19 single-use face masks for pavements base/subbase

The coronavirus (COVID-19) pandemic has not only created a global health crisis, but it is also now threatening the environment. A multidisciplinary collaborative approach is required to fight against the pandemic and reduce the environmental risks associated with the disposal of used personal protective equipment (PPE). This paper explores an innovative way to reduce pandemic-generated waste by recycling the used face masks with other waste materials in civil constructions. In this research, for the first time, a series of experiments, including modified compaction, unconfined compression strength and resilient modulus tests, were conducted on the blends of different percentages of the shredded face mask (SFM) added to the recycled concrete aggregate (RCA) for road base and subbase applications. The experimental results show that RCA mixed with three different percentages (i.e., 1%, 2% and 3%) of SFM satisfied the stiffness and strength requirements for pavements base/subbase. The introduction of the shredded face mask not only increased the strength and stiffness but also improved the ductility and flexibility of RCA/SFM blends. The inclusion of 1% SFM to RCA resulted in the highest values of unconfined compressive strength (216 kPa) and the highest resilient modulus (314.35 MP). However, beyond 2%, increasing the amount of SFM led to a decrease in strength and stiffness.

Preliminary evaluation of the feasibility of using polypropylene fibres from COVID-19 single-use face masks to improve the mechanical properties of concrete

With the ongoing global pandemic due to Coronavirus (COVID-19), the use of personal protective equipment (PPE), specifically single-use surgical masks, have been on a sharp incline. Currently, many countries are experiencing second and third waves of COVID-19 and as such have resorted to making face masks a mandatory requirement. The repercussions of this have resulted in millions of single-use face masks being discharged into the environment, washing up on beaches, floating beneath oceans and ending up in vulnerable places. The global pandemic has not only affected the economy and health of the world's population but now is seriously threatening the natural environment. The main plastic in single-use face masks is polypropylene which in landfill can take more than 25 years to break down. This paper explores an innovative way to use pandemic waste in concrete construction with the main focus on single-use face masks. Single-use masks have been cut-up by first removing the ear loops and inner nose wire to size and spread throughout five different mix designs to explore the possible benefits and uses within concrete. The masks were introduced by volume at 0% (control), 0.10%, 0.15%, 0.20% and 0.25% with testing focusing on compressive strength, indirect tensile strength, modulus of elasticity and ultrasonic pulse velocity to test the overall quality of the concrete. The introduction of the single-use face masks led to an increase in the strength properties of the concrete samples, as well as an increase in the overall quality of the concrete. However, beyond 0.20%, the trend of increasing strength began to decrease.

Filtering efficiency measurement of respirators by laser-based particle counting method

Respirators are one of the most useful personal protective equipment which can effectively limit the spreading of coronavirus (COVID-19). There are a worldwide shortage of respirators, melt-blown non-woven fabrics, and respirator testing possibilities. An easy and fast filtering efficiency measurement method was developed for testing the filtering materials of respirators. It works with a laser-based particle counting method, and it can determine two types of filtering efficiencies: Particle Filtering Efficiency (PFE) at given particle sizes and Concentration Filtering Efficiency (CFE) in the case of different aerosols. The measurement method was validated with different aerosol concentrations and with etalon respirators. Considerable advantages of our measurement method are simplicity, availability, and the relatively low price compared to the flame-photometer based methods. The ability of the measurement method was tested on ten different types of Chinese KN95 respirators. The quality of these respirators differs much, only two from ten reached 95% filtering efficiency.

Disposal Behavior of Used Masks during the COVID-19 Pandemic in the Moroccan Community: Potential Environmental Impact

The spread of coronavirus disease-2019 (COVID-19) levied on the Moroccan authorities to increase their mask production capacity, which reached up to 12 million facemask units produced per day. This increase in personal protective equipment (PPE) production and consumption is an efficient tool to address the spread of COVID-19. However, this results in more plastic and microplastic debris being added into the land and marine environments, which will harm the ecosystem, wildlife, and public health. Such a situation needs deep individual behavior observation and tracking, as well as an assessment of the potential environmental impact of this new type of waste. For this reason, we assessed the Moroccan population's behavior regarding the use and disposal of facemasks and gloves. An exploratory survey was prepared and shared via social media and email with the population of Rabat-Salé-Kénitra and Casablanca-Settat regions. Additionally, we calculated the estimated number and weight of daily and weekly PPE used and generated by the studied regions. The survey showed that 70% of the respondents threw their discarded masks and gloves in house trash or trash bins after their first use, whereas nearly 30% of respondents admitted that they did not wear masks because they did not leave their homes during the lockdown, while from the 70% of facemask users, more than five million (equivalent to 40,000 kg) of facemasks would be generated and disposed of daily by the community of these regions, which presents 35% of the total engendered facemask waste in Morocco. Accordingly, the environment impact of facemasks showed that the greenhouse gas footprint is about 640 kT CO2 eq./year for the whole of Morocco, while the energy footprint is around 60,000 GWh/year. Furthermore, an urgent multidisciplinary environmental assessment of the potential impact of PPE must be conducted among the 12 Moroccan regions. This study demonstrated the real impact of the COVID-19 PPE on human behavior and the environment and suggests a need for providing new didactic management of facemasks and gloves.

COVID-19 and the emerging research trends in environmental studies: a bibliometric evaluation

The ongoing pandemic of the coronavirus disease 2019 (COVID-19) is a global health emergency. Thousands of articles have been published to tackle this crisis. Here, a bibliometric study of the publications in environmental studies has been conducted to identify the emerging research trends in this field in the era of COVID-19. Bibliometric analysis serves as a useful tool to evaluate research productivity and scholarly trends in a field. For this, publications were searched in nine environment-related subject categories indexed in Science Citation Index Expanded (SCI-EXPANDED) database of the Web of Science Core Collection. A bibliometric evaluation of 495 relevant documents was performed to identify various essential research indicators, including the type of the publication, the most prominent journals, subject categories, authors, institutions, and the countries, that contributed significantly to this theme. Major focus of this bibliometric study is to illustrate the potential research hotspots emerged during this pandemic. It has been found that significant amount of research has been conducted for the assessment of environmental quality and its contribution in environmental transmission of COVID-19. In addition to its positive impacts on environment, COVID-19 has contributed indirectly in worsening many environmental threats such as increased exposure to disinfectants and antimicrobials, poor solid waste management, and food insecurity. Researchers have also been focusing on the strategies for the planning of post-COVID-19 cities and buildings and to protect the ecology. This bibliometric study allowed the visualization of research agenda in the field of environmental studies during this pandemic.

Environmental challenges induced by extensive use of face masks during COVID-19: A review and potential solutions

The ongoing COVID-19 disease significantly affects not only human health, it also affects the wealth of country' economy and everyday routine of human life. To control the spread of the virus, face mask is used as primary personal protective equipment (PPE). Thus, the production and usage of face masks significantly increase as the COVID-19 pandemic still escalating. Further, most of these masks contain plastics or other derivatives of plastics. Therefore, this extensive usage of face masks generates million tons of plastic wastes to the environments in a short span of time. This study aims to investigate the environmental impact induced by face mask wastes and sustainable solution to reduce this waste. An online survey was carried out to identify the types of face mask and number of masks used per week by an individual from 1033 people. Based on this survey and available literature, this study quantifies the amount of plastics waste generated by face masks. However, this survey was limited with certain ages, country and durations (July-August 2020). Thus, the prediction of plastic waste generation, only provide fundamental knowledge about the mask wastes. Results revealed that there is a huge plastic waste remained in land and marine environment in the form of mask waste, which will contribute to micro-plastic pollution. Therefore, this paper also highlights the sustainable approach to the mask production by integrating the use of natural plant fiber in the woven face mask technology to reduce the plastic waste induced by masks. Further, upcycling the mask waste and producing construction materials also discussed.

COVID-19 global pandemic planning: Dry heat incubation and ambient temperature fail to consistently inactivate SARS-CoV-2 on N95 respirators

The ongoing pandemic of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has placed a substantial strain on the supply of personal protective equipment, particularly the availability of N95 respirators for frontline healthcare personnel. These shortages have led to the creation of protocols to disinfect and reuse potentially contaminated personal protective equipment. A simple and inexpensive decontamination procedure that does not rely on the use of consumable supplies is dry heat incubation. Although reprocessing with this method has been shown to maintain the integrity of N95 respirators after multiple decontamination procedures, information on the ability of dry heat incubation to inactivate SARS-CoV-2 is largely unreported. Here, we show that dry heat incubation does not consistently inactivate SARS-CoV-2-contaminated N95 respirators, and that variation in experimental conditions can dramatically affect viability of the virus. Furthermore, we show that SARS-CoV-2 can survive on N95 respirators that remain at room temperature for at least five days. Collectively, our findings demonstrate that dry heat incubation procedures and ambient temperature for five days are not viable methods for inactivating SARS-CoV-2 on N95 respirators for potential reuse. We recommend that decontamination procedures being considered for the reuse of N95 respirators be validated at each individual site and that validation of the process must be thoroughly conducted using a defined protocol.

Is it possible to decontaminate N95 masks in pandemic times? integrative literature review

OBJECTIVE

To evaluate the protocols on decontamination/reuse of N95 masks available in the literature in times of the Covid-19 pandemic.

METHOD

Integrative literature review, in the period from 2010 to 2020, on the databases MEDLINE/PubMed, Science Direct, Cochrane, SAGE journals, Web of Science, Scopus, Embase and Wiley, with the descriptors Masks AND Respiratory protective devices; Mask OR N95 AND Covid-19; N95 AND Respirators; Decontamination AND N95 AND Coronavirus; Facemask OR Pandemic.

RESULTS

Twelve studies were included, of which 3 (30.0%) used ultraviolet germicidal irradiation and indicated mask deterioration between 2 and 10 cycles, 4 (40.0%) used hydrogen peroxide vapor, and seal loss varied from 5 to 20 cycles, 4 (33.3%) evaluated the structural integrity of the N95 mask through visual inspection and 6 (54.4%), its filtration efficiency.

CONCLUSION

Reuse strategies to overcome a shortage of devices in the face of the pandemic challenge the current concept for good practices in health-product processing.

Decontamination of N95 and surgical masks using a treatment based on a continuous gas phase-Advanced Oxidation Process

A gas-phase Advanced Oxidation Process (gAOP) was evaluated for decontaminating N95 and surgical masks. The continuous process was based on the generation of hydroxyl-radicals via the UV-C (254 nm) photo-degradation of hydrogen peroxide and ozone. The decontamination efficacy of the gAOP was dependent on the orientation of the N95 mask passing through the gAOP unit with those positioned horizontally enabling greater exposure to hydroxyl-radicals compared to when arranged vertically. The lethality of gAOP was independent of the applied hydrogen peroxide concentration (2-6% v/v) but was significantly (P<0.05) higher when H2O2 was introduced into the unit at 40 ml/min compared to 20 ml/min. A suitable treatment for N95 masks was identified as 3% v/v hydrogen peroxide delivered into the gAOP reactor at 40 ml/min with continuous introduction of ozone gas and a UV-C dose of 113 mJ/cm2 (30 s processing time). The treatment supported >6 log CFU decrease in Geobacillus stearothermophilus endospores, > 8 log reduction of human coronavirus 229E, and no detection of Escherichia coli K12 on the interior and exterior of masks. There was no negative effect on the N95 mask fitting or particulate efficacy after 20 passes through the gAOP system. No visual changes or hydrogen peroxide residues were detected (<1 ppm) in gAOP treated masks. The optimized gAOP treatment could also support >6 log CFU reduction of endospores inoculated on the interior or exterior of surgical masks. G. stearothermophilus Apex spore strips could be applied as a biological indicator to verify the performance of gAOP treatment. Also, a chemical indicator based on the oxidative polymerization of pyrrole was found suitable for reporting the generation of hydroxyl-radicals. In conclusion, gAOP is a verifiable treatment that can be applied to decontaminate N95 and surgical masks without any negative effects on functionality.

Plastics in the time of COVID-19 pandemic: Protector or polluter?

The COVID-19 pandemic has reemphasized the indispensable role of plastics in our daily life. Plastics in terms of personal protective equipment (PPEs) and other single-use medical equipment along with packaging solutions owing to their inherent properties have emerged as a life-savior for protecting the health and safety of the frontline health workers and the common citizens during the pandemic. However, plastics have been deemed as evil polluter due to their indiscriminate littering and mismanagement amid increased plastic usage and waste generation during this unprecedented crisis. This article reviews and assesses to dwell upon whether plastics in the time of pandemic are acting as protector of the public health or polluter of the environment. Considering the utilities and limitations of plastic along with its management or mismanagement, and the fate, an equitable appraisal suggests that the consumers' irresponsible behavior, and attitude and poor awareness, and the stress on waste management infrastructure in terms of collection, operation, and financial constraints as the major drivers, leading to mismanagement, turn plastic into an evil polluter of the environment. Plastic can be a protector if managed properly and complemented by the circular economy strategies in terms of reduction, recycle and recovery, and thereby preventing leakage into the environment. To safeguard the supply chain of PPEs, several decontamination techniques have been adopted worldwide ensuring their effective reprocessing to prioritize the circular economy within the system. Policy guidelines encouraging to adopt safer practices and sustainable technical solutions along with consumers' education for awareness creation are the need of the hour for preventing plastic to turn from protector with high utility to polluter.

Technological Scenario for Masks in Patent Database During Covid-19 Pandemic

Since January 2020, the World Health Organization announces COVID-19 outbreak a case of public health emergency of international interest, and declaring it a pandemic on March. Due to the high transmission of this disease, rate precautions have been implemented, such as the use of masks by the population, personal protective equipment (PPE), and safety protocols, mainly to health workers. Thus, we performed a patent review to evaluate the current patents related to the protective mask. The review was carried out in the patent database in the period of May 2019 to May 2020. After the process of screening and eligibility, 563 patents were selected for our analysis according to the aim of the study which used masks such as a PPE against dust particles and pathogens, mostly when it is about airborne transmission, such as viruses and bacteria. Here, an overview of the main materials used in the mask manufacturing and their efficiency was described. The results of the review showed that most of the masks used cotton, nylon, silver fiber fabrics, among others as fabrics to develop the masks. It also makes an analysis of masks composed of nanotechnology which provide high filtration efficiency. Moreover, the review also brought possibilities of masking the population, which already have been done in countries such as China and Korea and ways of sterilization for reuse of PPE during COVID-19 outbreak. Thus, this review can further researchers in the developing of masks to decrease the spread of a pandemic disease. Graphical abstract.