A portable light scattering system for detecting expelled droplets to assess Covid-19 transmission risk

The COVID-19 pandemic has caused a marked disruption in the delivery of medical care, resulting in significant negative consequences for patients. Considering Covid-19 spreads primarily through expelled respiratory droplets, the ability to detect and measure droplets is critical to the development of clinical protective practices. However, most available methods are either unsuitable for the clinical setting, or cannot distinguish solid particles from liquid droplets. We developed a robust and portable optical instrument capable of measuring the size and quantity of droplets generated during medical procedures. Here we outline the system design and describe our preclinical measurements, which showed that surgical masks significantly reduce the number of expelled speech droplets.