SB 2.6.2
sarvasunam ca vayos ca
tan-nase paramayane
asvinor osadhinam ca
ghrano moda-pramodayoh
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
His two nostrils are the generating centers of our breathing and of all other airs, His smelling powers generate the Asvini-kumara demigods and all kinds of medicinal herbs, and His breathing energies produce different kinds of fragrance.