We have employed aerosol deposition to form polycrystalline yttrium iron garnet (YIG) films on sapphire at room temperature that are 90-96% dense. We characterize the structural and dynamic magnetic properties of the dense films using scanning electron microscopy, X-ray diffraction, and ferromagnetic resonance techniques. We find that the as-deposited films are pure single-phase YIG formed of compact polycrystallites similar to 20 nm in size. The ferromagnetic resonance mode occurs at 2829 G with a linewidth of 308 G. We perform a series of successive anneals up to 1000 degrees C on a film to explore heat treatment on the ferromagnetic resonance linewidth. We find the narrowest linewidth of 98 G occurs after a 750 degrees C anneal. Published by Elsevier Ltd.