I have had people tell me that it might be brake dust or something but I can't seem to figure out why this black powder stuff gets all over my car. Any help is appreciated!

Have you applied tyre shine lately?

Can't be brake dust... Looks like tire shine to me or wet asphalt

Defo not break dust!
Do you have the same on both sides or only one? Did you drive in a muddy puddle perhaps?

Its not tire shine, and its not from water or dirt. I think it may be from my exhaust. I bought this car and it has had this problem since the beginning. My car has a straight pipe underneath (making it louder), so could be the fumes from the exhaust you think?

are these stains greasy?
like they were sprayed sideways on the car?

i had this on my car once when I parked it, i don't know where it came from?
it's like when you step on a grease tube and the content just squirts out of the tube.
these stains got all my panels on passenger side dirty!
looked like stains were sprayed sideways and it was very greasy cleaning the car!
maybe gunk came from the front wheels?

might be oily asphalt like svt ricco said?

Could also hinge on the condition of a road you travel often. Does it only appear after driving on wet roads? Does it always appear? Try washing it once per week and keeping note of weather conditions and where you drive, try to isolate a pattern.

your tires are kicking up something from the road. nothing to do with your exhaust.

Have you looked behind your wheels/hubs to see if any crap is there which shouldn't be there? Have you cleaned the windscreen drain holes as I believe they exit the chassis just behind the wheels

I don't believe it's from the road. It has to be from the inside of the car, possibly behind the wheels like this guy ^ said, or from the exhaust.