A fire detector for monitoring an environment and a method of operating a fire detector including a smoke sensor and a volatile organic compound, VOC, sensor are described. A fire detector 10 for monitoring an environment 20 includes a smoke sensor 12 and a volatile organic compound, VOC, sensor 14, the fire detector 10 is configured to adjust a smoke sensitivity of the fire detector 10 based on a VOC concentration detected by the VOC sensor 14. The smoke sensitivity is decreased when increased VOC concentrations are detected.