results have been presented (e.g., [@Dwelly:2006fk], [@Lawrence:2010uq]). In this work we have showed that the covering factor-luminosity relationships obtained in the medium and hard X-ray band can explain well the X-ray Baldwin effect in the $10^{42}-10^{44.2}\rm\,erg\,s^{-1}$ luminosity range. In particular our simulations show that it is possible to reproduce the slope of the X-ray Baldwin effect with luminosity-dependent unification for average equatorial column densities of the torus of $\log N_{\rm\,H}^{\rm\,T}\gtrsim 23.1$, and both the slope and the intercept for $\log N_{\rm\,H}^{\rm\,T}\simeq 23.2$ (Fig.\[fig:slope\_NH\]). In the same luminosity range the $\theta_{\mathrm{OA}}-L_{\mathrm{X}}$ IR relationship of @Maiolino:2007bh can explain the X-ray Baldwin effect for $22.9 \lesssim \log N_{\rm\,H}^{\rm\,T}\lesssim 23$. In the quasar regime we have shown that, while the medium X-ray $\theta_{\mathrm{OA}}-L_{\mathrm{X}}$ relationship of @Hasinger:2008ve cannot explain the observations (Fig.\[fig:interc\_sy\_2\]), the slope obtained by the IR $\theta_{\mathrm{OA}}-L_{\mathrm{X}}$ relationship is consistent with our fit to the [*Chandra*]{}/HEG data in the same luminosity band. However, as for the latter relationship the range of values of $N_{\rm\,H}^{\rm\,T}$ required to explain the slope and the intercept do not overlap, it cannot be considered as a likely explanation. The hard X-ray $\theta_{\mathrm{OA}}-L_{\mathrm{X}}$ relationship of @Burlon:2011cr is flat above $L_{\mathrm{X}}^{\mathrm{Q}}$, and would thus produce a constant $EW$ of the 