The nicotine is the addictive substance, however it is the tar within the cigarette which is harmful to the human body. This tar sufficiently reduced the surface area of the alveoli to perform gas exchange. This black tar fills up and blocks the lungs making it harder for the smoker to breathe - causing breathlessness. This tar build up also leads to Heart diseases and such.
I think its the tar in the cigarette that causes irritation in the bronchioles and therefore cause bronchitis...
The White Part
tar.
Cigarette produces a certain amount of a substance called tar in our lungs which causes cancer. After an year this tar becomes so much in amount that it can cause any disease in our body
nickateen
Over 1,000 different substance all in them
harmful mutation
carcinogen
corrosive
it can cause harmful sun rays which causes cancer disease
TOBACCO MOSAIC VIRUS is harmful virus as it causes cancer and other lungs disease
The answer is: Tar
Antigen
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.
The nicotine is this compound.