ACH and Estimated TB Risk under different ventilation conditions. Box-plot of ACH and estimated TB risk from the various ventilation conditions tested: (1) baseline with windows and door closed, (2) windows open, and (3) windows and door open. Mean ACH and TB risk for each condition is marked with “+”. Median ACH and TB risk is marked by the solid horizontal line, with the upper and lower ends of the box representing the limits of the interquartile range (IQR). The dotted lines represent the range of values. a. ACH b. Estimated TB Risk.