Tiny particles of dust and pollution scatter additional light, making sunsets look more intensely red.

It is not just gas molecules that scatter light. Dust, smoke, and pollution also float in our air. These larger particles scatter even more blue and green light out of the way. This leaves behind a much deeper, richer red and orange glow. For example, when a volcano erupts, it throws massive clouds of dust into the air. This creates incredibly colorful sunsets all over the world for months.