Evidence map›Paper›PMID 34966168›Full record

ArticleScientific reports2021

Discrepancy of particle passage in 101 mask batches during the first year of the Covid-19 pandemic in Germany.

Lukas T Hirschwald, Stefan Herrmann, Daniel Felder, Anna M Kalde, Felix Stockmeier, Denis Wypysek, Michael Alders, Maik Tepper, Jens Rubner, Peter Brand and 3 more

Abstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in Scientific reports, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

13 authors.

Lukas T Hirschwald *AVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany.
Stefan Herrmann *AVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany.
Daniel Felder *AVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany.
Anna M Kalde *AVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany.
Felix Stockmeier *AVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany.
Denis Wypysek *AVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany.
Michael AldersAVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany.
Maik TepperAVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany.
Jens RubnerAVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany.
Peter BrandInstitute for Occupational, Social and Environmental Medicine, RWTH Aachen University Hospital, Pauwelstr. 30, 52074, Aachen, Germany.
Thomas KrausInstitute for Occupational, Social and Environmental Medicine, RWTH Aachen University Hospital, Pauwelstr. 30, 52074, Aachen, Germany.
Matthias WesslingAVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany.
John LinkhorstAVT.CVT - Chair of Chemical Process Engineering, RWTH Aachen University, Forckenbeckstraße. 51, 52074, Aachen, Germany. manuscripts.cvt@avt.rwth-aachen.de.

Funding

Bundesministerium für Bildung und Forschung Excellence InitiativeDeutsche Forschungsgemeinschaft WE 4678/12-1European Research Council 694946Ministerium für Kultur und Wissenschaft des Landes Nordrhein-Westfalen Excellence Initiative
6 · The paper itself

Abstract

During the first wave of Covid-19 infections in Germany in April 2020, clinics reported a shortage of filtering face masks with aerosol retention> 94% (FFP2 & 3, KN95, N95). Companies all over the world increased their production capacities, but quality control of once-certified materials and masks came up short. To help identify falsely labeled masks and ensure safe protection equipment, we tested 101 different batches of masks in 993 measurements with a self-made setup based on DIN standards. An aerosol generator provided a NaCl test aerosol which was applied to the mask. A laser aerosol spectrometer measured the aerosol concentration in a range from 90 to 500 nm to quantify the masks' retention. Of 101 tested mask batches, only 31 batches kept what their label promised. Especially in the initial phase of the pandemic in Germany, we observed fluctuating mask qualities. Many batches show very high variability in aerosol retention. In addition, by measuring with a laser aerosol spectrometer, we were able to show that not all masks filter small and large particles equally well. In this study we demonstrate how important internal and independent quality controls are, especially in times of need and shortage of personal protection equipment.

Indexed as

AerosolsCOVID-19FiltrationGermanyHumansMasksN95 RespiratorsOccupational ExposurePandemicsPersonal Protective EquipmentQuality ControlRespiratory Protective DevicesSARS-CoV-2Aerosols

Identifiers

PMID34966168
PMCPMC8716525

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.