The Lajnah Daa’imah was asked the following question,
“Some of my co-workers smoke while I am observing Sawm (Fast) the six days of Shawwal; does the smell of smoking invalidate Sawm? Please note that I do not smoke, all praise be to Allah.”
“Someone’s Sawm is not invalidated if dust or smoke gets into their throat, for this is beyond their control. However, you should advise the people who smoke to give up and repent from smoking, because it is Haram (prohibited) and a sin.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.
The Permanent Committee for Scholarly Research and Ifta’ ” End quote. [Reference]
AbdulFattaah Bin Uthman