I have a 2009 Ford Escape 2.5L XLT and am thinking of putting on wheel brake dust shields to prevent brake dust on the rims. My concern is that this shield could limit the cooling of the brakes and possible cause damage.

Any thoughts ??

limit the cooling of the brakes
Bingo!

The brake dust is proof that the spaces in the rims are important for airflow around the discs.

The discs are vented and will pump cooling air when rotating whether the Kleen Wheels are on or not. However, they will have an effect. Chances are, if you drive normally and do not pull a trailer, you will not have a problem with brake fade. However, hotter rotors are more likely to warp, develop cracks and glaze pads (which reduces their effectiveness).