Aspects of the subject disclosure may include, receiving an electrical signal, and generating on an outer surface of a transmission medium, according to the electrical signal, electromagnetic waves having a target wave mode. At least a portion of electric fields of the electromagnetic waves has a spatial alignment that reduces a propagation loss of the electromagnetic waves when the electric fields of the electromagnetic waves propagate through a substance disposed on the outer surface of the transmission medium in a direction of propagation of the electromagnetic waves. Other embodiments are disclosed.