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      A life cycle assessment of reprocessing face masks during the Covid-19 pandemic

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          Abstract

          The Covid-19 pandemic led to threatening shortages in healthcare of medical products such as face masks. Due to this major impact on our healthcare society an initiative was conducted between March and July 2020 for reprocessing of face masks from 19 different hospitals. This exceptional opportunity was used to study the costs impact and the carbon footprint of reprocessed face masks relative to new disposable face masks. The aim of this study is to conduct a Life Cycle Assessment (LCA) to assess and compare the climate change impact of disposed versus reprocessed face masks. In total 18.166 high quality medical FFP2 face masks were reprocessed through steam sterilization between March and July 2020. Greenhouse gas emissions during production, transport, sterilization and end-of-life processes were assessed. The background life cycle inventory data were retrieved from the ecoinvent database. The life cycle impact assessment method ReCiPe was used to translate emissions into climate change impact. The cost analysis is based on actual sterilization as well as associated costs compared to the prices of new disposable face masks. A Monte Carlo sampling was used to propagate the uncertainty of different inputs to the LCA results. The carbon footprint appears to be 58% lower for face masks which were reused for five times compared to new face masks which were used for one time only. The sensitivity analysis indicated that the loading capacity of the autoclave and rejection rate of face masks has a large influence on the carbon footprint. The estimated cost price of a reprocessed mask was €1.40 against €1.55. The Life Cycle Assessment demonstrates that reprocessed FFP2 face masks from a circular economy perspective have a lower climate change impact on the carbon footprint than new face masks. For policymakers it is important to realize that the carbon footprint of medical products such as face masks may be reduced by means of circular economy strategies. This study demonstrated a lower climate change impact and lower costs when reprocessing and reusing disposable face masks for five times. Therefore, this study may serve as an inspiration for investigating reprocessing of other medical products that may become scarce. Finally, this study advocates that circular design engineering principles should be taken into account when designing medical devices. This will lead to more sustainable products that have a lower carbon footprint and may be manufactured at lower costs.

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          Critical Supply Shortages — The Need for Ventilators and Personal Protective Equipment during the Covid-19 Pandemic

          New England Journal of Medicine
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            The ecoinvent Database: Overview and Methodological Framework (7 pp)

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              Sterilization of disposable face masks by means of standardized dry and steam sterilization processes; an alternative in the fight against mask shortages due to COVID-19

              Sir The Covid-19 pandemic causes imminent shortages of face masks in hospitals globally. In preparation for that scarcity we performed a study to investigate the possibility of reprocessing disposable FFP2 face masks in order to verify their re-usability with a method that could be applied in practice using already available equipment. Therefore single use FFP2 masks (type 1862+3MTM) were sterilized with a 15-minute procedure at 121 ⁰C, using a dry sterilization process as well as with a regular steam process with the masks in sterilization/laminate bags. The effectiveness of these processes are sufficient to inactivate the coronavirus based on knowledge of inactivation of such viruses. [1, 2] A blind comparison of unused sterilized masks was performed with respect to visual inspection, consistency, face fit and breathing resistance. The results of this comparison were that the investigators were unable to distinguish unused new (slightly curved and folded) masks from reprocessed sterilized masks. We then tested the functionality of the unused and sterilized masks in several ways. First of all permeability properties for bacteria were tested by spraying a bacteria solution of Staphylococcus epidermidis (ATCC 12228) on the masks while air was being drawn through the masks. Unused and multiple sterilized masks showed no differences in the amount of passed bacteria (data not shown). In these experiments it was also observed that the reprocessing procedures of the masks did not appear to affect the water-repellent mask properties. We then assessed pressure/flow and performed particle tests. Before sterilization, the batches were individually packed in laminate bags and sterilized with steam sterilization by means of 121 ⁰C in Getinge autoclaves and in combination with permeable laminate bags, Halyard type CLFP150X300WI-S20. The autoclaves were activated on a 121 ⁰C program and validated accordingly. After sterilization, the samples were tested at Delft University of Technology and at Reinier de Graaf Hospital, and benchmarked with new mouth masks. A custom test set-up was built to measure the pressure drop over the maskers and outflow with regard to the permeability of the masks. A direct comparison between new and sterilized masks did not show substantial differences. Finally, the filtration capacity of the masks was evaluated using a calibrated Lighthouse Solair 3200 particle counter (Lighthouse, San Francisco). It was shown that the mask permeability of small particles did not change after multiple heat sterilization procedures (Table I ). Table 1 Filter efficiency testing of sterilized masks Table 1 New FFP2 1x Heat 121oC (n=2) 3x Heat 121oC (n=4) 5xHeat 121oC (n=2) 10kGy (n=1) 25kGy (n=2) Filter Efficiency % 0.3 μm 99.4 96,9 97.4 96.8 55.4 - 0.5 μm 99.8 98,0 98.4 98.7 79.1 57.5 5.0 μm 99.8 95.2 95.5 94.3 98.1 98.7 We openly shared our positive experiences with the steam sterilization process with other hospitals in the Netherlands that are also preparing for the outbreak. We were informed that their attempts to steam sterilize mouth masks at 134⁰C gave poor results as masks started to deform and became sticky while the elastics lost its resilience. In addition, we tested Gamma radiated masks this process did hamper the filter capacity (Table I). The results of our experiences and experiments indicate that our sterilization process did not influence the functionality of the masks tested. In case of an acute shortage of FFP2 masks, steam sterilization (e.g. in laminate sterilization wrappings) of used masks at 121 ⁰C in laminated bags, is a simple, useful cost-effective and quick procedure that can be used to make used masks available for safe reuse. The sterilization process of available standard autoclaves in hospitals may have to be adjusted in order to use this sterilization method. We also emphasise that we performed these experiments with 3M masks only. However, our method seems to be a potentially useful way to reuse mouth masks; other hospitals facing a shortage of masks may wish to test and validate this approach to reusing masks.
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                Author and article information

                Contributors
                b.j.vanstraten@tudelft.nl
                Journal
                Sci Rep
                Sci Rep
                Scientific Reports
                Nature Publishing Group UK (London )
                2045-2322
                3 September 2021
                3 September 2021
                2021
                : 11
                : 17680
                Affiliations
                [1 ]GRID grid.5292.c, ISNI 0000 0001 2097 4740, Department of BioMechanical Engineering, , Delft University of Technology, ; Mekelweg 2, Building 34, 2628 CD Delft, The Netherlands
                [2 ]GRID grid.5292.c, ISNI 0000 0001 2097 4740, Industrial Ecology, , Delft University of Technology and Leiden University, ; Delft, The Netherlands
                [3 ]GRID grid.425719.c, ISNI 0000 0001 2232 838X, VWS, Ministry of Health, Welfare and Sport (VWS), ; The Hague, The Netherlands
                [4 ]GRID grid.509540.d, ISNI 0000 0004 6880 3010, Amsterdam University Medical Center, ; Amsterdam, The Netherlands
                Article
                97188
                10.1038/s41598-021-97188-5
                8417283
                34480045
                aec932f1-1faf-49cc-a1d2-accccf5a9ded
                © The Author(s) 2021

                Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

                History
                : 15 December 2020
                : 23 August 2021
                Categories
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                © The Author(s) 2021

                Uncategorized
                climate-change ecology,engineering,biomedical engineering
                Uncategorized
                climate-change ecology, engineering, biomedical engineering

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