Science says that surgical masks allow about 70% of the outside air moves through the mask and about 30% travels around the sides, Fabric masks also allow air in around the sides, but lack non-woven, moisture-repelling layers. They impede only about 2% of airflow in. All of this leakage in surgical and fabric masks are why public health officials generally don't believe that wearing a mask prevents anyone from catching a virus that is already floating around in the environment. They are virtually useless per scientific studies.