  The location of warm dust producing the Mid-infrared (MIR) emission in Type 1
Active Galactic Nuclei (AGNs) is complex and not yet fully known. We explore
this problem by studying how the MIR covering factor (CF_{MIR}
=L_{MIR}/L_{bol}) correlates with the fundamental parameters of AGN accretion
process (such as L_{bol}, black hole mass MBH, and Eddington ratio L/LEdd) and
the properties of narrow emission lines (as represented by [O III] 5007), using
large data sets derived from the Sloan Digital Sky Spectroscopic Survey (SDSS)
and the Wide Infrared Sky Survey (WISE). Firstly we find that the luminosity of
the [O III] wing component (Lwing) correlates more tightly with the continuum
luminosity (L5100) than the luminosity of the line core component (Lcore) does,
which is in line with our previous conclusion that the wing component,
generally blueshifted, originates from the polar outflows in the inner
narrow-line region (NLR). We then find that the MIR CF shows the strongest
correlation with Lwing/L_{bol} rather than with Lcore/L_{bol} or the above
fundamental AGN parameters, and the correlation becomes stronger as the
infrared wavelength increases. We also confirm the anti-correlations of
CF_{MIR} with L_{bol} and MBH, and the lack of dependence of CF_{MIR} on the
Eddington ratio. These results suggest that a large fraction of the warm dust
producing MIR emission in AGNs is likely embedded in polar outflows in the NLR
instead of in the torus.
