SARS-CoV-2(4) medical masks(3) Natural materials(3) Antimicrobial air filters(3) carbon nanomaterials(3) Metallic materials(3) RPE, respiratory protective equipment(1) UVGI, ultraviolet germicidal irradiation(1) Particle(1) CDC, Centers for Disease Control and Prevention(1) TCID50, fifty-percent tissue culture infectious dose(1) EtO, ethylene oxide(1) NIOSH, National Institute for Occupational Safety and Health(1) Rt, effective reproduction number(1) TPI, threads per inch(1) ΔP, differential pressure across a mask or filter material(1) WHO, World Health Organization(1) ECDC, European Centre for Disease Prevention and Control(1) UV, ultraviolet(1) MGB, Mass General Brigham(1) PP, polypropylene(1) SARS-CoV-2, acute respiratory syndrome coronavirus 2(1) VFE, viral filtration efficiency(1) Mask(1) FDA, Food and Drug Administration(1) R0, basic reproduction number(1) FFR, filtering facepiece respirator(1) NNU, National Nurses United(1) RH, relative humidity(1) COVID-19, Coronavirus disease 2019(1)