title: How far do bacteria travel from the exhalation valve of IPPB equipment?
mesh_terms: D000391:Air Microbiology; D003428:Cross Infection / Q000517:prevention & control; D005374:Filtration; D011175:Positive-Pressure Respiration / Q000009:adverse effects; D012140:Respiratory Tract Diseases / Q000628:therapy; D012706:Serratia marcescens