“…Table summarizes the best performing multivariate transfer function ARMAX and ARIMAX time series models for CO 2 and CO that were identified to be based on a set of five and three independent variables, respectively, from an initial estimate of 12 independent variables [indoor temperature, indoor relative humidity, ambient temperature, ambient relative humidity, wind speed, precipitation, passenger density, light vehicles (cars/SUVs), heavy vehicles (buses/trucks), bus condition/ventilation settings (run/close, idle/open, idle/close)]. Kadiyala and Kumar provided more details on the ste‐by‐step approach to choosing the best performing MTS models using the SPSS software. This software review paper utilized the identified input variables from MTS methods (refer Table ) to develop valid CO 2 and CO RBFNN MTS models in accordance with the identified ARMAX and ARIMAX models of the orders (1,0,5) and (2,1,2) as noted by Kadiyala and Kumar .…”