Let's create haze on the following image. We will use Glow and Color pairs effects.
Let the haze cover only the top of the image, in this case we shall choose one of the colors of the sky as a glowing color. The haze color is set by a gradient between gray and almost white. Adjust the radius value so that haze covers the sky and a part of the mountain. The glowing color have to be completely lightened, therefore we'll set the Keep glowed value to 0:
As a result, we have a gray haze on the blue sky, which covers not only the sky, but a part of the mountain as well.
To create a more realistic haze it is necessary to adjust the sky color. Let’s make the sky more dark and gloomy. To do so, we'll change the light-blue colors of the sky on more dark colors.
As a result of two effect application we have the following image:
