A humidity sensor element includes a dielectric substrate, a nonporous conductive electrode disposed on the dielectric substrate, a permeable conductive electrode having a thickness in a range of from 4 to 10 nanometers and permeable by water vapor, and a detection layer disposed between the nonporous conductive electrode and the permeable conductive electrode. Both conductive electrodes have respective conductive leads attached thereto. The detection layer includes a sulfonated copolymer including monomeric units comprising (I) and (II), Wherein x and y are independently integers in the range of from 2 to 6, and wherein each M independently represents H or an alkali metal. A humidity sensor including the humidity sensor element is also disclosed.