A study published by The Lancet in 2020 tested the "stability" of the SAR-CoV-2 virus on different materials at room temperature. Among the items tested (like paper, cloth, wood, and plastic), the one on which the virus survived the longest was a surgical mask. In the words of the authors, "Strikingly, a detectable level of infectious virus could still be present on the outer layer of a surgical mask on day 7," about 0.1% of the initial virus. Likewise, a study published in 2020 by the journal Nature found that the highest concentrations of C-19 aerosols in various areas of two hospitals were located in the rooms where healthcare workers removed their protective apparel (like masks). The paper thus concluded that "virus-laden aerosols" are likely emitted "from the surface of the protective apparel worn by medical staff while they are removing the equipment."