Reference: Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-‘Ilmiyyah wal-Iftaa. – Volume 13, Page 57, Question No.2 and 3 of Fatwa No.8982
Question: What is the Sharee’ah ruling regarding one who sells all types of cigarettes? I smoke and when I hear the muadhdhin, I enter the masjid. [So] is it obligatory upon me to repeat my wudhoo or is it enough to just rinse my mouth, and I know that smoking causes various diseases?
Response: Selling cigarettes is haraam because of its evilness and many harmful effects, and one who does so becomes a faasiq (open sinner). It is not obligatory to repeat the wudhoo as a result of smoking. However, it is legislated for him to remove the offending smell from his mouth with that which will do so, in addition to promptly seeking repentance from Allaah for that.
And with Allaah lies all success and may Allaah send prayers and salutations upon our Prophet (sal-Allaahu ‘alayhi wa sallam) and his family and his companions.