A vapor sensor (100; 300) for sensing at least one organic vapor, the vapor sensor comprising: a capacitance-related property sensor element (110; 310), the capacitance-related property sensor element (110; 310) comprising: a dielectric substrate; a first conductive electrode (130; 330) disposed on the dielectric substrate, the first conductive electrode (130; 330) having first and second ends (134, 136; 334, 336); a second conductive electrode (140; 340); and a dielectric layer comprising a microporous material disposed between and contacting the first conductive electrode (130; 330) and the second conductive electrode (140; 340); a heater circuit element having first and second conductive members (174, 176), wherein the first and second conductive members (174, 176) are in reversibly interruptible electrical communication with the first and second ends (134, 136; 334, 336) of the first conductive electrode (130; 330), respectively; a capacitance-related property measurement circuit element, the capacitance-related property measurement circuit element having first and second conductive members (137, 139; 337, 339), wherein the first conductive member (137; 337) of the capacitance-related property measurement circuit element is in reversibly interruptible electrical communication with the first conductive electrode (130; 330), and wherein the second conductive member (139; 339) of the capacitance-related property measurement circuit element is in electrical communication with the second conductive electrode (140; 340); at least one switch member, wherein said at least one switch member is capable of reversibly interrupting the electrical communication between the first and second conductive members (174, 176) of the heater circuit element to the respective first and second ends (134, 136; 334, 336) of the first conductive electrode (130; 330), wherein said at least one switch member is capable of reversibly interrupting the electrical communication between the first conductive member (137; 337) of the capacitance-related property measurement circuit element to the first conductive electrode (130; 330), characterised in that the microporous material comprises a polymer of intrinsic microporosity that is hydrophobic. a capacitance-related property sensor element (110; 310), the capacitance-related property sensor element (110; 310) comprising: a dielectric substrate; a first conductive electrode (130; 330) disposed on the dielectric substrate, the first conductive electrode (130; 330) having first and second ends (134, 136; 334, 336); a second conductive electrode (140; 340); and a dielectric layer comprising a microporous material disposed between and contacting the first conductive electrode (130; 330) and the second conductive electrode (140; 340); a dielectric substrate; a first conductive electrode (130; 330) disposed on the dielectric substrate, the first conductive electrode (130; 330) having first and second ends (134, 136; 334, 336); a second conductive electrode (140; 340); and a dielectric layer comprising a microporous material disposed between and contacting the first conductive electrode (130; 330) and the second conductive electrode (140; 340); a heater circuit element having first and second conductive members (174, 176), wherein the first and second conductive members (174, 176) are in reversibly interruptible electrical communication with the first and second ends (134, 136; 334, 336) of the first conductive electrode (130; 330), respectively; a capacitance-related property measurement circuit element, the capacitance-related property measurement circuit element having first and second conductive members (137, 139; 337, 339), wherein the first conductive member (137; 337) of the capacitance-related property measurement circuit element is in reversibly interruptible electrical communication with the first conductive electrode (130; 330), and wherein the second conductive member (139; 339) of the capacitance-related property measurement circuit element is in electrical communication with the second conductive electrode (140; 340); at least one switch member, wherein said at least one switch member is capable of reversibly interrupting the electrical communication between the first and second conductive members (174, 176) of the heater circuit element to the respective first and second ends (134, 136; 334, 336) of the first conductive electrode (130; 330), wherein said at least one switch member is capable of reversibly interrupting the electrical communication between the first conductive member (137; 337) of the capacitance-related property measurement circuit element to the first conductive electrode (130; 330), characterised in that the microporous material comprises a polymer of intrinsic microporosity that is hydrophobic.