Mystery odors in the built environment could be everything from a nuisance to something that may signal potential short- or long-term health concerns for building occupants. These types of odors could even lower property values, and in commercial and institutional settings, may result in decreased productivity, increased absenteeism, and higher employee turnover rates., , , , These odors could be coming from cigarette smoke or vaping; cooking; cleaning chemicals; and pets. They can also be th.