The present disclosure provides an ethylene oxide sterilization sensor and method of use. The sensor includes: at least one thermal indicator component independently selected from an electronic thermal sensor, an irreversible temperature indicator, and a heat-shrinkable film; an acid-functional porous sorbent or an acid-functional nonwoven fibrous substrate in thermal contact with the at least one thermal indicator component; and an acid having a boiling point above 120° C. and a pKa of no greater than 2.5. The acid is impregnated in or covalently attached to the porous sorbent or is covalently attached to the nonwoven fibrous substrate. The sensor includes at least one of the electronic thermal sensor, the irreversible temperature indicator, or the acid-functional nonwoven fibrous substrate.