The september issue of Playstation Extreme has some details on San Andreas, most of which we already know, however it is confirmed that we can smoke.

- You can buy cigarettes in certain locations, and after purchasing them you will be able to smoke them

It is not yet confirmed but we would assume this affects Carl's health and make him get out of breath quicker

Links:

GTASanAndreas.net, GTA-San.net (German)