Question:
If there is a person in the sukkah who smells, or I don't feel comfortable being near him for whatever reason, am I pottur from sukkah?
Answer:
Try moving to a different part of the sukkah, or try to find a different succah to sit in. specially if it isn't your succah and you are only a guest in someone else's succah.
As a side point I once heard from Horav Zeidel Epstein zt"l, true a person may be mitztaer in the succah, and he will be patur, but who tells you to be mitztaer! ( Be happy that you have the opportunity to be in Hashem's succah, to spend time in the divine presence, and that should make you happy)
Have a good Yom Tov: