According to Madhhab:
If a person inhales the smoke of Agarbatthi whilst fasting, will his fast be nullified?
If any scent or bad odour enters the nose whether intentionally or unintentionally, it does not nullify the fast. This ruling applies to all forms of scents, medication, etc. However, if a person burns incense sticks and intentionally takes the smoke into the throat, the fast will be nullified.
Re:- Fataawa Mahmoodiyya pg.169 vol.15