I have a bedroom window that looks out over the east (a backyard with mostly tiles and little plants) with a roller shutter which over the past couple of years has gotten a serious buildup of some sort of black soot, which I can't really figure out where it comes from.
Below are a couple of pictures. Apologies for the reflection of my bedroom, I can't open 2 of the windows and the 3rd has a mosquito screen which I'd rather not remove now that those critters are appearing again.
This soot covers pretty much the entire side of the shutters and I'm worried it might be more than that based on a question on here about black mold that looks suspiciously like what I have. Only thing is my shutters are plastic, not wood.
If this is black mold, would it be safest to just have the entire shutter plus the casing side of my bedroom replaced?