To this end, the project has the help of seamstress cooperatives that will be organized by the company Social Fabric. According to Professor Paulo Artaxo, from USP’s Physics Institute and one of those responsible for the project, it was necessary to test masks of different materials to measure the efficiency of each one in retaining nanometric particles. After all, the new coronavirus is 120 nanometers on average – for comparison, 1 nanometer is a billion times smaller than 1 meter. The study was made from an aerosol generator capable of producing particles the size of the coronavirus, associated with an electronic detection system. “There is already scientific evidence that the efficiency in retention for such small particles varies a lot between masks of the same class and between different products used to make them”, explains the professor. This means that not all masks protect you from the virus. The focus of this study is hospital masks, which need to be made of TNT. However, the researchers also included cotton in the research, in order to measure the quality of homemade masks. At the end of the analysis, the materials studied showed between 60% and 97% filtration. “Some TNTs have a 97% efficiency in particle retention, similar to the mask material needed by medical teams that deal directly with contaminated patients.”, Says professor at USP Polytechnic School and also project coordinator, Vanderley John. As demonstrated in the previous graph, homemade masks made with cotton from a T-shirt, an affordable and practical option, have a 60% retention. “Products with this level of efficiency can be good for those who go out or go shopping and would be able to be exposed to the virus momentarily.”
