- Surveys indicated the most suitable raw materials for protection, with an efficiency of up to 97% in virus retention;
- Nonwoven fabric is the best material after surgical and N95 masks
The Brazilian University of Sao Paulo (USP) has stepped up its pace in providing masks for Brazilian hospitals during the coronavirus pandemic that plagues the world, as Jornal da USP reported. As the demand increases and causes shortages, USP researchers have a special device to measure which material retains most of coronavirus-sized particles.
Surveys indicated nonwoven fabrics as the most suitable raw materials for protection, with an efficiency of up to 97% in virus retention. Based on these results, the project will produce 1 million masks for 8,000 health professionals with groups and cooperatives. USP’s recommendations will be available to industries, NGOs and people interested in producing homemade masks.
According to Professor Paulo Artaxo, from USP’s Institute of Physics, coronavirus averages 120 nanometers in size, and by testing different masks he could measure the efficiency for retaining nanometric particles. The equipment used for measurement by the researchers is an aerosol generator that creates coronavirus-sized particles. It has a scanning mobility particle sizer device, coupled to a condensation particle counter.
Comparing performance of different types of materials to be used in masks, filtration efficiency ranged between 60% and 97% taking surgical masks and N95 as a reference. After surgical and N95, the material that retained the most is the nonwoven fabric, a sort of fabric made of plastics.