Anecdotally speaking sunsets are more colorful and spectacular. Scientifically speaking, I don't have any evidence to site, but I think one can consider it logically and perhaps come to some general potential differences. What does the warmth of the sun through the day do to the amount of particulates in the atmosphere, for example? My guess is it increases them for a couple reasons. First, because of evaporation of volatiles due to heating, and second, due to rising of existing particles in the atmosphere as they are heated. Perhaps there are other mechanisms too. The greater the amount of particulates in the air, the redder the atmospheric scattering would tend to be (depending on particulate characteristics). You can logically contemplate other effects of the conditions of sunrise vs. sunset as well. Or... just find some real sources, if any studies have been done. I'm curious myself, but thought that the "thinking it through" approach might have benefit too...
- Oshyan