Scent
Source Alien Core pg. 210
Scent involves sensing creatures or objects by smell and is usually a vague sense. The range is listed in the ability, and it functions only if the creature or object being detected emits an aroma (for instance, incorporeal creatures usually don't exude an aroma).
If a creature emits a heavy aroma or is upwind, the GM can double or even triple the range of scent abilities used to detect that creature, and the GM can reduce the range if a creature is downwind.
If a creature emits a heavy aroma or is upwind, the GM can double or even triple the range of scent abilities used to detect that creature, and the GM can reduce the range if a creature is downwind.