Low-cost light-scattering measurement of facemask efficacy for filtering expelled droplets during speech

Please join via Zoom Meeting ID:91504041339, Passcode: 761560 Abstract: Mandates for mask use in public during the COVID-19 pandemic, worsened by global shortage of commercial supplies, have led to widespread use of homemade masks and mask alternatives. It is assumed that wearing such masks reduces the likelihood for an infected person to spread the disease, but many of these mask designs have not been tested in practice. We have demonstrated a simple optical measurement method to evaluate the efficacy of masks to reduce the transmission of respiratory droplets during regular speech. In proof-of-principle studies, we compared a variety of commonly available mask types and observed that some mask types approach the performance of standard surgical masks, while some mask alternatives offered very little protection. Our measurement setup is inexpensive and can be built and operated by non-experts, allowing for rapid evaluation of mask performance during speech, sneezing, or coughing. I will present our measurement setup and results, some context, and some implications. Bio: Prof. Fischer received his Ph.D. in Physics from The University of Texas at Austin in 2001, studying how cold atoms interact with light traps. He then joined Bells Labs/Agere Systems where he worked on high-speed transmission through optical fiber networks. In 2003, he returned to academics at The University of Pennsylvania to perform research on laser microscopy in skin and hyperpolarized gas MRI in lungs. In 2005, he moved to Duke University where he is now exploring novel optical techniques for molecular three-dimensional imaging in highly complex materials in the areas of biomedicine, materials science, and cultural heritage science. He also directs the newly established Advanced Light Imaging and Spectroscopy facility (ALIS), which aims to provide cutting-edge optical imaging technology that is beyond the reach of commercial instruments.