Re: What would happen if you smoked and your lungs crumbled down like cookies?

There is a little invalidity to this questions. The lungs dont crumble 
down like cookies if you smoke for a long period of time.

What you mean to ask perhaps is the effects of long term smoking.
Well when people smoke 1 to 2 packs of cigarettes per day for many years 
the harmfull agents in cigarette smoke including tar and nicotine and the 
1000 other chemicals effect the lungs in many ways.
Many of them cause damage to the lining cells of the lungs and thus cause 
trapping of air in the lungs,'

This leads to emphysema. 
The other important effects are that of causing cancer
The genetic material of cells is altered and they become cancerous.

People then either die from the effects of cancer spreading through out 
the body or from the failure of lungs to exchange oxygen and carbon 
dioxide.

They require oxygen tanks just to be able to survive day to day.

Hope this answer helps