Hydrating the respiratory tract: An alternative explanation why masks lower severity of COVID-19
| Autor: | Courtney, Joseph M., Bax, Ad |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Coronavirus disease 2019 (COVID-19)
Mucociliary clearance facemask Respiratory System Biophysics seasonality of disease Severity of Illness Index Article 03 medical and health sciences 0302 clinical medicine medicine Humans Relative humidity Respiratory system 030304 developmental biology 0303 health sciences SARS-CoV-2 Biophysical Letter business.industry Respiratory disease Masks humidity COVID-19 food and beverages Humidity medicine.disease respiratory disease humanities medicine.anatomical_structure Anesthesia During expiration business 030217 neurology & neurosurgery Respiratory tract |
| Zdroj: | Biophysical Journal medRxiv article-version (status) pre article-version (number) 2 |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/j.bpj.2021.02.002 |
| Popis: | Seasonality of respiratory diseases has been linked, among other factors, to low outdoor absolute humidity and low relative humidity in indoor environments, which increase evaporation of water in the mucosal layer lining the respiratory tract. We demonstrate that normal breathing results in an absorption-desorption cycle inside facemasks, where super-saturated air is absorbed by the mask fibers during expiration, followed by evaporation during inspiration of dry environmental air. For double-layered cotton masks, which have considerable heat capacity, the temperature of inspired air rises above room temperature, and the effective increase in relative humidity can exceed 100%. We propose that the recently reported, disease-attenuating effect of generic facemasks is dominated by the strong humidity increase of inspired air.Facemasks are the most widely used tool for mitigating the spread of the COVID-19 pandemic. Decreased disease severity by the wearer has also been linked to the use of cloth facemasks. This well-documented finding is surprising considering that such masks are poor at filtering the smallest aerosol particles, which can reach the lower respiratory tract and have been associated with severe disease. We show that facemasks strongly increase the effective humidity of inhaled air, thereby promoting hydration of the respiratory epithelium which is known to be beneficial to the immune system. Increased humidity of inspired air could be an alternate explanation for the now well-established link between mask wearing and lower disease severity. |
| Databáze: | OpenAIRE |
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