Abstract. High-temperature iridium-gated field effect transistors based on silicon carbide have been used for sensitive detection of specific volatile organic compounds (VOCs) in concentrations of health concern, for indoor air quality monitoring and control. Formaldehyde, naphthalene, and benzene were studied as hazardous VOCs at parts per billion (ppb) down to sub-ppb levels. The sensor performance and characteristics were investigated at a constant temperature of 330 °C and at different levels of relative humidity up to 60%, showing good stability and repeatability of the sensor response, and excellent detection limits in the sub-ppb range.