I have some soot in my interior wall but i don't know where it is coming from. I live in a multi-complex building on the last floor. I had this problem before but the landlord only sent someone to clean the soot off my walls. I have them on all the wall on the rooms even in the ceiling. The heating system here is fuel(oil). Is there anything i should know about soot and is it dangerous. Can this job be done in the winter because my landlord said that there is nothing they can do about it. Is that true. I feel that by cleaning the surface and painting over it its not going to solve the problem. i need to know if this is dangerous to my health? Any suggestion.