Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain the symptoms of strange smell through nose and in your case as you are smelling cigarette smoke that others cannot experience and no history of bad breath seems consistent with a condition known as Phantosmia.. It can occur due to a number of conditions like nasal infection and polyps, migranes, Oral and dental infection, smoking habit, condition related to Nervous System like Parkinsonism, Alzimer s Disease, Stroke, head injury etc.. I will suggest you to consult a Medicine Specialist or a Neurologist and get evaluated and along with clinical evaluation investigations like Nasal endoscopy, MRI, CT Scan etc can help in diagnosis and treatment can be planned accordingly.. As of now you can do saline nasal irrigation, steam inhalation with few drops of Eucalyptus oil in water,chew flavoured sugar free chewing gum and limit intake of high aroma foods like onion and garlic.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.