A new air distribution system comprising of a cylindrical vertical wall-attached jet and a novel mushroom diffuser was presented. The system was termed as a floor-based air distribution with a novel mushroom diffuser (FBAD-MD). The airflow pattern and performance of the cylindrical vertical wall-attached jet were experimentally investigated under an isothermal condition. A two-dimensional particle image velocimetry (2D-PIV) experiment was performed to obtain nephograms and contour maps, streamlines and velocity vector field in two measured cross-sections. The velocity profiles are divided into three characterized regions: Coanda effect zone, jet impinging zone and air lake zone. Firstly, air velocity analysis was conducted in the three characterized regions and the human ankle level, respectively. Secondly, the transient continuous velocity field and the eddy field were investigated in detail. Thirdly, the influences of different supply air velocities and outlet widths were discussed. Furthermore, experimental data were compared with two other different air distribution systems, namely, the displacement ventilation and the impinging jet ventilation. Both the systematic errors and statistical errors of the PIV measurement were analyzed. A novel air distribution system (FBAD-MD) has been developed to obtain a better situation of human comfort and improve the airflow performance. The FBAD-MD system was verified to minimize the velocity fluctuation in the air lake and can be employed in higher air velocity without a sensation of draught at ankle level. (C) 2016 Elsevier B.V. All rights reserved.