Something Fishy - This smell as well as rubber burning, urine or something burning can be signs of overheating wires which could lead to a fire.
Ammonia - If you haven't been using ammonia cleaning products, you might have something dead in your home.
Damp, Musty Smells - You have some sort of moisture problem somewhere!
Smokey Smells From Your Fireplace - If you're not using your fireplace, but still getting smoky smells, check to be sure the damper is closed, clean out the firebox (could just be dirty). If these things are done, it could mean that water is getting down your chimney and it needs to be checked by a professional.
Chemical Smell - Fresh paint, new furniture and carpet can all give off chemical smells which are not just unpleasant, but can cause health issues. Be sure to open windows and air out your home when you have added new products.
Rotten Eggs - This odor can be caused by sewage gas that is backing up into the home or gas appliances can be having issues. Flush toilets and run water and if it persists anywhere, call a professional.
