[en] There are arguments that Broad Line Region (BLR) in AGN is tightly connected with the underlying accretion disk. The clouds most likely originate from the disk in the form of a wind. We develop a model of the dynamics of Low Ionization Line (LIL) part of the BLR which is based on dust radiation pressure launching. It allows to predict the cloud distribution, the radius-luminosity relation, broad emission line profiles, depending only on the dust evaporation temperature. Current observations with GRAVITY resolved only two cases of LIL, but the future observations combined with reverberation mapping will allow to test the model in much detail. Once the model is firmly established it would be able to effectively turn the AGNs into cosmological candles.
