Front wheels are dirtier than rears, get dirty fast as well?

It's happened for awhile now but I took my car to the car wash 4 days ago, and my front rims/wheels are already dirty. The front left is dirty but the front right is even dirtier, a little blacker than the left side.

My car is a 2004 ford explorer eddie bauer 4.6L. I believe the wheels are aluminum.

That's called brake dust.

Brake dust. Your truck is big and heavy. It also has to use regular brake pad material instead of ceramics because it needs the stopping power more than quietness and less brake dust.

Ron is right, that's brake dust. Most likely caused by semi-metallic brake pads. Did you have the front brakes serviced lately?
Every time the brakes are used, some of the "pad" is worn off, and the static electricity created by the vehicles motion, acts as a magnet and causes the metallic dust from the pad to cling to the metal wheel.
While all pads create dust when they're used, a good ceramic pad 5 to 10 times cleaner.