I was sure that I had seen a plugin for this, but it may have been with another video editor or photo program.
I have Pixelan FilmTouch Pro 2.0 and I asked how to do this. Here is the reply:
"Haze reduces contrast and saturation and any of the FilmTouch contrast-related controls can be used to reduce haze. The attached "ho.jpg" is the original image, in h1 "Mid Contrast" and "Gamma" controls are used, h2 uses Gain/Offset controls. Some blending modes in Diffusion section also enhance contrast and saturation and can be used with a Blur 0% to reduce minor haze (alone or together with above controls) like in h3. And if the haze is stronger in the upper half of the frame "Vignette" section allow a stronger correction there (h4). The corresponding FilmTouch Pro presets are attached, you can put the presets in C:\Users\Public\Documents\Pixelan\Masters\Effects\FilmTouch 2.0 Pro\--My Favorites
-- and open via FilmTouch's EffectsBrowser OR Alt-click "Click here to load a preset..." button an open from anywhere."
Thus you can try increasing contrast and saturation, maybe play with the Gamma controls in MEP, add some sharpening.