Thanks, all your comments.
In fact, my first impression, when shooting the #1, "The Day After Tomorrow".
It was in the morning right before I get to work. I was watching thick pieces of fog moving slowly, streaming down the hill, running in between buildings. Together with the sun and the ray beams, I just keep on shooting as many as I can (it will be costly if using film).
I am using Nikon 5700. I pushed the color saturation up 1 step. That might cause the grainy. For sure, colour will be much rich if using positive film.