My idea is production of nicotine drops that would have the same effect as cigarettes, but wouldn't spoil the lungs of smokers and the people surrounding them.
Basically the role of lungs in smoking is consumption of nicotine, then it gets into blood and brain. The chemical addiction to smoking, unlike psychological, is based on the effect nicotine has on central nervous system and blood.
So, liquid nicotine could compensate fully for the nicotine consumed from cigarette smoke. However it's concentration in nicotine drops solution should be really small so that nobody overdosed it.