Cumulative distributions of the infrared residuals defined in Fig. 9 for the red and control QSO samples, split into two bins of low (left panel) and high C IV velocity shifts (right panel). An enhancement of residuals can be seen for red QSOs with high C IV velocity shifts, a signature of potential winds or outflows. This difference is not seen for control QSOs, which show overall a low incidence of residuals. These results are consistent with our [O III] study at low redshifts (z < 1), and support the proposed scenario of a connection between QSO reddening and the presence of dusty winds.