Homemade masks, fly it?
The moment, the new crown pneumonia epidemic spread throughout the world. In the United States, the CDC has recommended that the general public to wear masks in public. However, the United States and N95 surgical masks a serious shortage of reserves, still unable to meet the needs of front-line health care workers, let alone the public. Therefore, people have begun to spontaneous production of masks. However, the use of common materials around the masks fly it? To answer this question, the University of Chicago professor Supratik Guha team tested the masks made common textile barrier properties of aerosol particles, research results have been published in ACS Nano on. Respiratory droplets is a new coronavirus pneumonia (COVID-19) major route of transmission. Respiratory droplets size distribution is wide, down to 100 nm, up to 10 μm. Usually 1-10 μm wherein the particles by gravity and can not be suspended in the air for a long time; and small particle size range between 1 nm to 100 nm may be floating in the air to form an aerosol. Due to the relatively closed environment of prolonged exposure to high concentrations of aerosol infection COVID-19 possible, therefore homemade masks can effectively cut off from the tiny aerosol particles become the key to the effectiveness of masks. The authors used a machine to produce a particle diameter of 10 nm to produce 6 μm aerosol droplets and aerosol particles blown by blowing the masks made. By detecting through the mask before and after aerosol particles concentration in the gas mask filter performance evaluation. The results showed that by a layer of a tightly woven cotton and two polyester – polyurethane silk (Chiffon) production mask can block 80-99% of aerosol particles, the performance is quite N95 masks (FIG. A) [123 ]. Replaced silk natural silk (natural silk), flannel (Flannel) even filled polyester cotton blankets (quilt) have similar filtration performance. The authors pointed out that the developed masks barrier material has been able to depend on a large number of aerosol particles used. Tightly woven cotton support structure, surface is charged by silk electrostatic repulsion barrier aerosol particles . However, while wearing a mask and facial must ensure snug fit . The results showed that leaving only 1% of the interval will result in reduced filtration efficiency masksHalf or more (FIG. B) . Thus, whether medical mask or masks made, need to ensure the right size when worn, close contact with the face. FIG. (A) Comparison of different masks for each size of aerosol filtration efficiency. (B) Comparison of medical masks and masks made aerosol filtration efficiency when there are voids close to the face and the face. FIG. Source: ACS Nano. More experimental details see the original: https: //pubs.acs.org/doi/abs/10.1021/acsnano.0c03252 (open-access)