Possible Rusty Paint
 

Ok this is a weird one. We bought a 2012 Mazda 5 with the pearl white finish in February 2011. After last winter I've noticed slight rust specks all over the car. At first I thought the car was rusting but noticed it on the plastic body parts as well. Best I can figure the metal flake in the paint is rusting. Anyone experiencing this with their cars? Once again you need to look real close to see the rust specks.

Thanks everyone.

Answer
 

Well judging by the 90 people that read this thread and had nothing to offer I can only assume they have never heard of this phenomenon either.

I'm a victim of "rail dust". This is what the Mazda dealer explained to me. Google it if you don't believe me. He said that the metal particles from from train wheels rolling on their tracks creates a metal dust that lands on your car and then begins to oxidize. We do cross some rail tracks from a commuter train in our town so it's possible. These particles can come from automobile brakes as well, he explained. The remedy is to go buy something else I've never heard of, a clay bar. Basically after you thoroughly wash your car you rub this chunk of clay over your car. Besides removing the rusting metal particles it will take off bugs, tar and other stubborn malities. I've bought the clay bar but haven't used it yet so I'll report later on the results. The reason this was more prominent on my car is because of the white finish. You probably have it on your car but don''t know it.

The things you learn. I thought at 50 I had heard everything about cars but I guess not. Ok so who else has heard of this?

David

I have heard of this and seen it as well, when I was working at my last job (Caterpillar dealership) we would get some components in on the train that looked yellow with metallic brown paint, we ended up just sanding and repainting most of them so the warranty was preserved. Clay bar should take this off since it is just surface rust and should not be in the paint layers.

I believe what you are experiencing is specs of brake dust. Especially with your colour of car.
Is it more pronounced on the side of the car behind the wheels and not on the hood? if you answered yes to this question, it's brake dust. I had the same thing happen on an earlier vehicle. The hot specs grab on to your car. You may want to inquire about different brake pads.
Z-18 Clay Bar Instructions
Clay Bar Treatment

I believe clay bar will also do the job
You may give it a try for this clay here:
3M Perfect It III 38070 Cleaner Clay Bar Auto Detailing | eBay