Smoking cigarette is a chemical process.
Carcinogens
The amount of nicotine in each cigarette is approximately 1 mg. This makes it a very small percentage of all of the chemicals in a cigarette. (Just the nicotine is the addictive component.)
I think 4,000 chemical compounds.
carbon monoxide
Heavy cigarette smoking causes about 80-90% of all emphysema cases
Emphysema causes lower oxygen levels in the blood.
Cigarette smoking, on a chronic long-term basis, is the chief cause of emphysema (COPD, or chronic obstructive pulmonary disease). There are many other causes, including the various pneumoconioses.
Basically cigarette smoking
All types of smoke have tar, which gets into the lungs and causes emphysema and/or chronic bronchitis. The only difference between pipe smoke and cigar/cigarette smoke is that pipe smoke - in my opinion - smells better.
Smoking causes disease and is a slow way to die. The strain of smoking effects on the body often causes years of suffering. Emphysema is an illness that slowly rots your lungs. People with emphysema often get bronchitis again and again, and suffer lung and heart failure. Emphysema makes it difficult to breath and cannot be cured.
There is never a safe way to smoke a cigarette. Smoking causes a variety of health problems including lung cancer, emphysema, stroke, and bronchitis.
In 99% cases it is, as a major risk factor is cigarette smoking.
emphysema
The related link below will tell you everything about emphysema, causes and treatment.
Smoking cigarette is a chemical process.
its tar because of its sticky property