The Health News Express

Study evaluates the filtration efficacy of 227 commercially obtainable face masks in Brazil

Publicado em 02 junho 2021

The novel coronavirus is transmitted primarily by way of inhalation of saliva droplets or respiratory secretions suspended in air, in order that face overlaying and social distancing are the simplest methods to forestall COVID-19 till sufficient vaccines can be found for all. In Brazil, cloth masks are among the many most generally used as a result of they’re low-cost, reusable and obtainable in a number of colours or designs. However, the sort of face overlaying’s capability to filter aerosol particles of a dimension equal to the novel coronavirus can range between 15% and 70%, based on a research performed in Brazil by the University of São Paulo (USP).

The research was supported by FAPESP, and the principal investigator was Paulo Artaxo, a professor within the college’s Physics Institute (IF-USP). It was a part of an initiative known as (respire! to guarantee entry to secure masks for the college neighborhood. The outcomes are reported in an article within the journal Aerosol Science and Technology.

“We appraised the filtration efficacy of 227 fashions offered by drugstores and different widespread forms of retailer in Brazil to see how a lot real safety they afford most people,” Artaxo advised Agência FAPESP.

The scientists performed a check utilizing a tool that contained a sodium chloride answer and emitted aerosol particles of 100 nanometers. SARS-CoV-2 is about 120 nanometers in diameter. A burst of aerosols was triggered, and particle focus was measured earlier than and after the masks.

As anticipated, surgical masks have been best within the check, as have been the FFP2 or N95 fashions licensed for skilled use, filtering 90%-98% of the particles. Next got here masks manufactured from non-woven cloth (TNT) or polypropylene and offered in lots of sorts of retailer, with an effectivity of 80%-90%, adopted by these manufactured from strange cotton, spandex or microfiber, which filtered 40% on common (15%-70%).

Several elements have been crucial in enhancing or decreasing the diploma of safety. “Generally talking, masks with a central seam shield much less as a result of the stitching machine makes holes that improve the passage of air. A tightly becoming prime edge improves filtration considerably. Some masks made of material embrace fibers of nickel, copper or different metals that inactivate the virus and therefore shield the wearer extra successfully. There are even electrically charged fashions that retain extra particles. In all instances, nevertheless, efficacy drops when the masks is washed due to put on and tear,” mentioned Fernando Morais, first writer of the article. Morais is a Ph.D. candidate at IF-USP and a researcher on the Nuclear and Energy Research Institute (IPEN), an company of the São Paulo State Government.


According to Artaxo, dual-layer cotton masks filtered significantly higher than single-layer fashions, however efficacy was hardly altered by a 3rd layer, which decreased breathability.

“The research innovated in a number of methods. One was its analysis of breathability or resistance to air passage,” Artaxo mentioned. “TNT and cotton masks have been finest on this regard. The FFP2 and N95 fashions weren’t as comfy, however paper masks have been the worst. This is necessary as a result of if an individual cannot bear carrying a masks even for 5 minutes, it is ineffective.”

The authors of the article be aware that though masks efficacy varies, all kinds assist cut back transmission of the virus, and mask-wearing along side social distancing is prime to manage the pandemic. They advocate mass manufacturing of FFP2/N95 masks for distribution freed from cost to most people. This “ought to be thought-about in future pandemics,” based on Vanderley John, penultimate writer and coordinator of (respire!, which is organized by USP’s Innovation Agency.

“Transmission of the virus is demonstrably airborne and carrying a masks on a regular basis is without doubt one of the finest prevention methods, in addition to leaving doorways and home windows open to ventilate rooms as a lot as attainable,” Artaxo mentioned.

Cloth face coverings could be as efficient as surgical masks at defending towards COVID-19

More data:

Fernando G. Morais et al, Filtration effectivity of a big set of COVID-19 face masks generally utilized in Brazil, Aerosol Science and Technology (2021). DOI: 10.1080/02786826.2021.1915466


Study evaluates the filtration efficacy of 227 commercially obtainable face masks in Brazil (2021, June 2)

retrieved 2 June 2021