Dark spots on ceiling, dark dust on tiles (2015, house)

[JerseyMaid]

This spots on ceiling have been forming for a while but are darker and darker and there are more and more places I notice something. Also dust even inside cabinets that is normal to some degree (even on stuff that we store for a while before use) is darker than normal dust and it is especially noticeable on tiles in bathroom.

Please give me an opinion on causes of that forming before I call someone to take care of that. I don't want to be lured in some improvements that are costly and I do not really need so every thought is valid.

My personal suspicion when ceiling started to be a little discolored and looked like it's around 2x4 framing was it's from candles we use extensively.
Than, over time it was getting darker and one suspicion from friends close to contractor business, so to speak, was moisture due the fact we have a tiny leak in one of the rooms on 1st floor during heavy rain that last day or two ( not every time bit still). That dark spots on ceiling are forming on both floors but not in every room and are shaped like framing. Also in some places, even two light colored walls, drywall nails are especially noticeable.
Another suggestion from friend was heating steam vents (we have radiators that are quite noisy and sometimes I can see fog on window downstairs) but he pointed to me chimney problems which worries me even more since when we bought house several years ago, a contractor that was sealing roof around chimney and installed cap on it, pointed to me that it looks like whole structure is not new nor solid anymore and it may be even signs it is punctured.

[Retriever]

Does it look like this?




The first thing that you need to do is to determine if your dark spots are actually Black Mold, as that substance can be damaging to your health. Take a look at this info from The CDC:

https://www.cdc.gov/mold/stachy.htm

[JerseyMaid]

No, [url]https://mobile.twitter.com/MarzenaJoanna1/status/835501720402821120/photo/1[/url]
, and dark dots from nails here and there which I was told can come our when nail is not dry and cold periodically over some time.

[JerseyMaid]

I got an estimate for putting something into chimney that makes it I believe like new inside . It's 2k ...
was told spots most likely were created due to carbodioxyde in the attic . Is it possible to carbodioxyde to convert to dark dust I have inside few cabinets I open once a week tops? Spots seem to be dirt mostly and not heavy into a drywall.
I still hope it's from candles giving black smoke...