A sensing system for use in identifying at least one substance in a region of interest, the sensing system comprising a certain number of sensor units, each sensor unit comprising: at least one measurement unit, and a sample flow path configured and arranged to stream a sample medium from a region of interest towards an inlet of the measurement unit, wherein the sample flow path comprises at least one heating unit extending therealong and configured to heat the sample medium flowing thereinside by one or more heater elements to an evaporation temperature of said at least one substance prior to entering the measurement unit through said inlet, each measurement unit comprising a plurality of sensor elements (50, 51, 52, 53, 54, 55, 56, 57), each of the sensor elements being configured and operable to be responsive to at least one substance in the vicinity thereof and to generate a response signal indicative of said at least one substance, wherein each of the sensor elements is mounted in its own compartment (60, 61, 62, 63, 64, 65, 66, 67) having an inlet and an outlet thus defining an environmental region in the vicinity of the sensor element separated from the surroundings of the compartment and from the other compartments containing other sensor elements in said measurement unit, the compartments (60, 61, 62, 63, 64, 65, 66, 67) with the sensor elements (50, 51, 52, 53, 54, 55, 56, 57) are arranged along a circular path in a spaced-apart relationship with respect to one another and are mounted on a measurement matrix having a cavity in fluid communication with the outlets of the compartments to thereby ensure substantially uniform and concurrent distribution of the evaporated and transported sample medium among all the compartments (60, 61, 62, 63, 64, 65, 66, 67). at least one measurement unit, and a sample flow path configured and arranged to stream a sample medium from a region of interest towards an inlet of the measurement unit, wherein the sample flow path comprises at least one heating unit extending therealong and configured to heat the sample medium flowing thereinside by one or more heater elements to an evaporation temperature of said at least one substance prior to entering the measurement unit through said inlet, each measurement unit comprising a plurality of sensor elements (50, 51, 52, 53, 54, 55, 56, 57), each of the sensor elements being configured and operable to be responsive to at least one substance in the vicinity thereof and to generate a response signal indicative of said at least one substance, wherein each of the sensor elements is mounted in its own compartment (60, 61, 62, 63, 64, 65, 66, 67) having an inlet and an outlet thus defining an environmental region in the vicinity of the sensor element separated from the surroundings of the compartment and from the other compartments containing other sensor elements in said measurement unit, the compartments (60, 61, 62, 63, 64, 65, 66, 67) with the sensor elements (50, 51, 52, 53, 54, 55, 56, 57) are arranged along a circular path in a spaced-apart relationship with respect to one another and are mounted on a measurement matrix having a cavity in fluid communication with the outlets of the compartments to thereby ensure substantially uniform and concurrent distribution of the evaporated and transported sample medium among all the compartments (60, 61, 62, 63, 64, 65, 66, 67).