Facemasks Block Expired Particles, Despite Leakage (IMAGE) University of California - Davis Caption A new study from UC Davis and the Icahn School of Medicine at Mount Sinai confirms that surgical masks effectively reduce outgoing airborne particles from talking or coughing, even after allowing for leakage around the edges of the mask. Professor Chris Cappa of UC Davis tests a mask by speaking in front of a particle counter. Credit Chris Cappa, UC Davis Usage Restrictions May be used with acknowledgement. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.