An international collaboration is monitoring the variable Seyfert galaxy NGC 5548 in the optical spectral range since 1988. In Fig. 1 (left) the Hα light curves of the blue wing (–6000 until – 1000 km s−1) and the red wing (+1000 until + 6000 km s−1) are shown for the first year of the monitoring campaign from Dec.1988 until Oct.1989. It can be seen that these line components of the Hα profile have different amplitudes in the light curves. The mean Hα and Hβ difference spectra with respect to the minimum state are plotted in Fig. 1 (right) for the same period. The relative strength of the blue component at vrel = −2000 km s−1 is different with respect to the core of the line profiles. Therefore, these components originate under different physical conditions or in regions with different dust content. This work has been supported by DFG grant Ko 857/13-1