Sorry, I'm not buying the redder sunset thing. I think it sounds like it makes sense on the surface (no pun intended!), but I know I have taken the most vivid shots in Colorado as sunrises, not sunsets. This would ancedotally at least in my experience refute the notion that dust, smoke, other particles of matter in the air create more vivid sunsets than the typically more settled air of sunrises. In fact from what I understand they do not. They soften the light....perhaps make it more illuminating from the standpoint of wavelength of travel....but the things I've read and the many experiences I have had suggest that the CLEARER the air is the more vivid, brilliant, vibrant (whatever adjective you want to use!) it becomes when the sun fading or rising hits.
Think about it....if that wasn't true then Los Angeles and Mexico City would have the most spectacular sunsets, no? Not to say they don't have some.....but I know Arizona, Colorado, New Mexico.....some of the southwestern states have the reputation for having the best sunsets or sunrises. One of the things those states by and large have in common (among other things) is very clean air (except around Denver in the winter!).