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A majority of early-type galaxies contain interstellar dust, yet the originof this dust, and why the dust sometimes exhibits unusual polycyclic aromatichydrocarbon (PAH) ratios, remains a mystery. If the dust is internallyproduced, it likely originates from the large number of AGB stars associatedwith the old stellar population. We present GALEX and WISE elliptical aperturephotometry of $\sim310$ early-type galaxies with Spitzer mid-infraredspectroscopy and/or ancillary data from ATLAS3D, to characterize theircircumstellar dust and the shape of the radiation field that illuminates theinterstellar PAHs. We find that circumstellar dust is ubiquitous in early-typegalaxies, which indicates some tension between stellar population age estimatesand models for circumstellar dust production in very old stellar populations.We also use dynamical masses from ATLAS3D to show that WISE W1 (3.4 $\mu$m)mass-to-light ratios are consistent with the initial mass function variationfound by previous work. While the stellar population differences in early-typegalaxies correspond to a range of radiation field shapes incident upon thediffuse dust, the ratio of the ionization-sensitive $7.7\mu$m to $11.3\mu$m PAHfeature does not correlate with the shape of the radiation field, nor tovariations with the size-sensitive $11.3\mu$m to $17\mu$m ratio. The $7.7\mu$mto $11.3\mu$m PAH ratio does tend to be smaller in galaxies with proportionallygreater $H_2$ emission, which is evidence that processing of primarily smallergrains by shocks is responsible for the unusual ratios, rather than substantialdifferences in the overall PAH size or ionization distribution.

Circumstellar Dust, PAHs, and Stellar Populations in Early-Type Galaxies: Insights from GALEX and WISE