TECHNICAL FEATURE otherwise would be moving around the space for an extended period of time (depending on the relative location of contaminant source and supply and return outlets of the central air-conditioning system), can be quickly and effectively removed by the purifier. Ballroom Both the classroom and banquet settings in a large ballroom were tested. Figure 8 presents the contaminant distribution without and with using the TAP (at 114 m3/h [67 cfm]), under the classroom setting, respectively, at t = 5 s and t = 20 s after the cough started. With the conventional HVAC systems, the contaminant showed a strong movement in the space and might transfer through multiple front and back rows depending on the source location in the space. The air purifier, placed between every two FIGURE 8 Contaminant distribution in the classroom setting in a ballroom. (a) t = 5 s With Purifier Off (b) t = 12 s With Purifier Off FIGURE 7 Contaminant distribution in the dining setting in a restaurant. (c) t = 5 s With Purifier On (d) t = 12 s With Purifier On (a) t = 5 s With Purifier Off (b) t = 20 s With Purifier Off (c) t = 5 s With Purifier On (d) t = 20 s With Purifier On 36 ASHRAE JOURNAL ashrae.o rg O CTO B E R 2021http://ashrae.org