Abnormal smell? For about 4 days I am detecting an odor that none of my family smell. Worried about brain tumor. It is a dirty ash-tray kind of smell. Old cigarette smell. Very strong. I smell it everywhere. There is no smoking in our house. No smoking f

See your doctor. This is an unusual symptom. There are brain tumors of the temporal lobe that can lead to olfactory auras or hallucinations. Patients typically describe an unusual smell (burning rubber for example) or unusual taste (ie metallic). These are a form of temporal loe seizure and can occur with brain tumors in this region. If your symptoms persist, you should have it checked out.
I . I cannot tell you why you smell something malodorous when your family does not. You mentioned that you have a cracked tooth. If the crack goes under the gum line this could be a breeding ground for germs. If there is an infection in that area it could create an odor that you are aware of but that others may not smell. Try not to jump the conclusion that you have brain cancer. Have your dentist evaluate you to see if she or he can help determine the cause. Good luck.