I live on the third floor of an apartment building, for the past few weeks I've noticed a slight rotten egg smell in my bedroom. It's not overpowering but enough for me to notice that it's pretty smelly. Thing is, it's the only room in my apartment that smells that way, I have natural gas but I'm not sure if it would only make one room smell. Any help would be appreciated, I'm not sure what to do or who I should call (gas supplier, landlord, plumber?)