You should be able to decrease the haze a bit using a polarizer or haze filter.
- Using polarizing filters to cut through haze and deepen blue skies
- UV, Skylight and Haze Filters
- Cambridge in Color: Filters
Additional Information on Haze filters
A haze filter absorbs a greater about of UV light than a normal UV filter can.
For Tiffen Haze filters:
Haze 1 - Reduces excessive blue haze caused by UV light by absorbing 71% of UV. Great all-around UV control.
Haze 2A - Absorbs all UV light; reduces haze; maintains color and image clarity. Best for high altitude and marine scenes.