Construction waste hauling trucks (or `slag trucks') are among the most commonly seen heavy-duty vehicles in urban streets, which not only produce significant NOx and PM emissions but are also a major source of on-road and on-site fugitive dust. Slag trucks are subject to a series of spatial and temporal access restrictions by local traffic and environmental policies. This paper addresses the practical problem of predicting slag truck activity at a city scale during heavy pollution episodes, such that environmental law enforcement units can take timely and proactive measures against localized truck aggregation. A deep ensemble learning framework (coined AI-Truck) is designed, which employs a soft vote integrator that utilizes BI-LSTM, TCN, STGCN, and PDFormer as base classifiers to predict the level of slag truck activities at a resolution of 1km$\times$1km, in a 193 km$^2$ area in Chengdu, China. As a classifier, AI-Truck yields a Macro f1 close to 80\% for 0.5h- and 1h-prediction.