The three stages of smoking a cigarette
Below is a picture of a cigarette and I have split it into 3 parts with an explanation for each third of it smoked.
Stage 1
First 3rd
After the first few inhalations of a cigarette the serious harm has begun. Smoke has to travel through the entire length of the cigarette carrying with it tar and nicotine, and then concentrating it in the last 3rd of the cigarette.
Small particles of nicotine and other chemicals start to irritate the delicate tubes inside the lungs.
Stage 2
Second 3rd
More smoke is inhaled and the chemicals then start to coat the tubes with an oily tar substance, forcing them to produce thick phlegm. This in turn makes the lining of the tubes more prone to infection by germs, causing even more damage.
Stage 3
Third 3rd
Tobacco smoke that is now inhaled is so concentrated with tar that it coats the lungs, causing more irritation and producing much more clinging phlegm than the other two parts put together !
