  This work focuses on the properties of dusty tori in active galactic nuclei
(AGN) derived from the comparison of SDSS type 1 quasars with mid-Infrared
(MIR) counterparts and a new, detailed torus model. The infrared data were
taken by the Spitzer Wide-area InfraRed Extragalactic (SWIRE) Survey. Basic
model parameters are constraint, such as the density law of the graphite and
silicate grains, the torus size and its opening angle. A whole variety of
optical depths is supported. The favoured models are those with decreasing
density with distance from the centre, while there is no clear tendency as to
the covering factor, i.e. small, medium and large covering factors are almost
equally distributed. Based on the models that better describe the observed
SEDs, properties such as the accretion luminosity, the mass of dust, the inner
to outer radius ratio and the hydrogen column density are computed. The
properties of the tori, as derived fitting the observed SEDs, are independent
of the redshift, once observational biases are taken into account.
