Medical face masks offer self-protection against aerosols: An evaluation using a practical in vitro approach on a dummy head

Sterr, Christian; Nickel, Inga-Lena; Stranzinger, Christina; Nonnenmacher-Winter, Claudia; Günther, Frank

doi:10.1371/journal.pone.0248099

Cited by 25 publications

(22 citation statements)

References 22 publications

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“…We have shown that the quality of filtration of different masks varies by mask, and by aerosol particles at different size. To the best of our knowledge, this is not the “first experiment” to explore the FEs of different mask types ( Whiley et al, 2020 , Leung et al, 2020 , Pan et al, 2021 , Sterr et al, 2021 , Ueki et al, 2020 ). But this study shows that FE decreases significantly as the wearing time or respiratory volume increases.…”

Section: Discussionmentioning

confidence: 99%

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

Ding

Deng

et al. 2022

Environmental Technology & Innovation

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Face masks are critical in preventing the spread of respiratory infections including coronavirus disease 2019 (COVID-19). Different types of masks have distinct filtration efficiencies (FEs) with differential costs and supplies. Here we reported the impact of breathing volume and wearing time on the inward and outward FEs of four different mask types (N95, surgical, single-use, and cloth masks) against various sizes of aerosols. Specifically 1) Mask type was an important factor affecting the FEs. The FEs of N95 and surgical mask were better than those of single-use mask and cloth mask; 2) As particle size decreased, the FEs tended to reduce. The trend was significantly observed in FEs of aerosols with particle size < ; 3) After wearing N95 and surgical masks for 0, 2, 4, and 8 h, their FEs (%) maintained from 95.75 ± 0.09 to 100 ± 0 range. While a significant decrease in FEs were noticed for single-use masks worn for 8 h and cloth masks worn >2 h under deep breathing (30 L/min); 4) Both inward and outward FEs of N95 and surgical masks were similar, while the outward FEs of single-use and cloth masks were higher than their inward FEs; 5) The FEs under deep breathing was significantly lower than normal breathing with aerosol particle size ¡1 m. In conclusion, our results revealed that masks have a critical role in preventing the spread of aerosol particles by filtering inhalation, and FEs significantly decreased with the increasing of respiratory volume and wearing time. Deep breathing may cause increasing humidity and hence decrease FEs by increasing the airflow pressure. With the increase of wearing time, the adsorption capacity of the filter material tends to be saturated, which may reduce FEs Findings may be used to provide information for policies regarding the proper use of masks for general public in current and future pandemics.

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Section: Discussionmentioning

confidence: 99%

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

Ding

Deng

et al. 2022

Environmental Technology & Innovation

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“…Largest differences were observed between the items "mouth feels dry" and "lips feel dry", most probably as wearing face masks is likely to change the breathing pattern. However, airflow and breathing resistance vary between different face masks based on mask material and proportion of leakage: KN95-/FFP2-masks and community masks were reported to result in higher breathing resistance than medical face masks, leading to potential leakage [15]. Dry mouth is most probably perceived due to a change of the breathing pattern from nasal to oral breathing while wearing masks [16].…”

Section: Discussionmentioning

confidence: 99%

COVID-19 Pandemic: Effect of Different Face Masks on Self-Perceived Dry Mouth and Halitosis

Kanzow

Dylla

Mahler

et al. 2021

IJERPH

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Due to the COVID-19 pandemic, the use of face masks has increased, resulting in potential health-related side-effects. Therefore, the study aimed to analyse the effect of wearing face masks on self-perceived dry mouth and halitosis. A questionnaire addressing the daily wearing time of different face masks (community masks, surgical/medical masks and KN95-/N95-/FFP2-masks) and self-perceived dry mouth and halitosis was given to adults attending or working at a university hospital. Statistical analysis was performed using Wilcoxon signed-rank test and multiple linear regression analysis (p < 0.05). 3750 participants (age: 50.4 ± 15.5 years; 60.0% female) were included. During the pandemic, face masks were used for 4.7 ± 3.8 h per day: community masks: 0.9 ± 2.0 h, medical/surgical masks: 1.9 ± 2.8 h and KN95-/N95-/FFP2-masks: 1.9 ± 2.5 h per day. The use of face masks significantly increased self-perceived dry mouth and halitosis (both p < 0.001). Self-perceived dry mouth and halitosis increased with increasing wearing time (community masks: dry mouth: p < 0.001, halitosis: p = 0.014; medical/surgical masks: both: p < 0.001; KN95-/N95-/FFP2-masks: dry mouth: p < 0.001, halitosis: p = 0.011). The perception of dry mouth and halitosis was increased in females compared to males (both: p < 0.001). Participants used to wearing face masks prior to the pandemic perceived dry mouth to a higher extent (p = 0.043). Self-perceived halitosis was lower in older than in younger participants (p < 0.001). Due to the increased perception of dry mouth and halitosis, people might abstain from wearing face masks. Further studies need to analyse measurable changes in dry mouth or halitosis.

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“…Different aspects of the pharmacological and toxicological interactions of drugs should also be considered in relation to many other complex factors and sectors, which are continuously identified in relation to the progress of COVID-19 including molecular, multi-genomic and other effects, as well as other methods for trying to curb the COVID-19 [128][129][130][131][132].…”

Section: Pharmacological and Toxicological Aspects Of Drugs Against Covid-19mentioning

confidence: 99%

The need for a multi-level drug targeting strategy to curb the COVID-19 pandemic

Kontoghiorghes¹,

Fetta²,

Kontoghiorghe³

2021

Front. Biosci. (Landmark Ed)

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Introduction 3. The effects of vaccines on the COVID-19 pandemic 4. Drug based concepts for the prevention of COVID-19 4.1 Factors contributing to variable susceptibility to SARS-CoV-2 infection 4.2 Drug based examples of prevention targets against COVID-19 infection 5. Drug targeting based theory and methods against SARS-CoV-2 6. Examples of drugs that are widely used in COVID-19 patients 7. Examples of drugs that could be used in COVID-19 8. Pharmacological and toxicological aspects of drugs against COVID-19 9. New developments affecting multi-level drug targeting strategies against COVID-19 10. Conclusions 11. Author contributions 12. Ethics approval and consent to participate 13. Acknowledgment 14. Funding 15. Conflict of interest 16. References Abbreviations: ACE2, angiotensin converting enzyme 2; ARDS, acute respiratory distress syndrome; EMA, European medicines agency; FDA, food and drug admin-istration; FIASMA, inhibitors of acid sphingomyelinase; GM-CSF, granulocyte-macrophage colony-stimulating fac-tor; COVID-19, coronavirus disease 2019; IL, interleukin, e.g., IL-1, IL-6, IL-8; iv, intravenous; IND, investigational new drugs; LDH, lactate dehydrogenase; LMWH, low molecular weight heparin; MERS-CoV, Middle East Respiratory Syndrome coronavirus; p.o., oral administration; QALY, quality-adjusted life years; SARS-CoV-1, severe acute respiratory syndrome coronavirus 1; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; sc, sub-cutaneous; TMPRSS2, transmembrane protease serine 2; WHO, world health organization.

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Medical face masks offer self-protection against aerosols: An evaluation using a practical in vitro approach on a dummy head

Cited by 25 publications

References 22 publications

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

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

COVID-19 Pandemic: Effect of Different Face Masks on Self-Perceived Dry Mouth and Halitosis

The need for a multi-level drug targeting strategy to curb the COVID-19 pandemic

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