For:
1.Secondarysmokingwillimpartmoreharmsuponotherpeoplewhodonotevensmokethemselves.
2.Publicsmokingtosomeextentsoilthereputationofthecity/country
3.Itmaycauseenvironmentalproblemsaspeopletendtodisposeofthecigaretteanywhere
4.Potentialfirehazards
Against:
1.Itlimitsthebasicrightsoffreedomofthecitizens
Isuggestthatyoucanconsiderdifferentpublicvenues(indoors,outdoors,etc)whichcanfurtherhelpyouargueyourpoints=)