An environmental control system having contaminants in air therein, comprising: a sensor; an air purification subsystem; and a controller in communication with the sensor and air purification subsystem, wherein: the sensor: detects a contaminant in the air; and generates a contaminant signal; the controller: compares the contaminant signal to a predicted sensory response threshold, the predicted sensory response threshold being based on one of odor, irritancy, mass, and a combination thereof; when the contaminant signal reaches the predicted sensory response threshold, the controller commands the air purification subsystem to alter a condition in the air containing the contaminant; a comparison is made by the controller between the contaminant signal and a contaminant concentration look up table having information of contaminant concentration equivalents versus percentile of a sample database; a comparison is made by the controller between the probability of contaminant detection versus contaminant percentile in the sample database; and the controller commands the air purification subsystem when the contaminant signal reaches the predicted sensory response threshold based on the sensed concentration equivalents reaching a level that is below a 100% probability of contaminant detection. a sensor; an air purification subsystem; and a controller in communication with the sensor and air purification subsystem, wherein: the sensor: detects a contaminant in the air; and generates a contaminant signal; the controller: compares the contaminant signal to a predicted sensory response threshold, the predicted sensory response threshold being based on one of odor, irritancy, mass, and a combination thereof; when the contaminant signal reaches the predicted sensory response threshold, the controller commands the air purification subsystem to alter a condition in the air containing the contaminant; a comparison is made by the controller between the contaminant signal and a contaminant concentration look up table having information of contaminant concentration equivalents versus percentile of a sample database; a comparison is made by the controller between the probability of contaminant detection versus contaminant percentile in the sample database; and the controller commands the air purification subsystem when the contaminant signal reaches the predicted sensory response threshold based on the sensed concentration equivalents reaching a level that is below a 100% probability of contaminant detection. the sensor: detects a contaminant in the air; and generates a contaminant signal; detects a contaminant in the air; and generates a contaminant signal; the controller: compares the contaminant signal to a predicted sensory response threshold, the predicted sensory response threshold being based on one of odor, irritancy, mass, and a combination thereof; when the contaminant signal reaches the predicted sensory response threshold, the controller commands the air purification subsystem to alter a condition in the air containing the contaminant; a comparison is made by the controller between the contaminant signal and a contaminant concentration look up table having information of contaminant concentration equivalents versus percentile of a sample database; a comparison is made by the controller between the probability of contaminant detection versus contaminant percentile in the sample database; and the controller commands the air purification subsystem when the contaminant signal reaches the predicted sensory response threshold based on the sensed concentration equivalents reaching a level that is below a 100% probability of contaminant detection. compares the contaminant signal to a predicted sensory response threshold, the predicted sensory response threshold being based on one of odor, irritancy, mass, and a combination thereof; when the contaminant signal reaches the predicted sensory response threshold, the controller commands the air purification subsystem to alter a condition in the air containing the contaminant; a comparison is made by the controller between the contaminant signal and a contaminant concentration look up table having information of contaminant concentration equivalents versus percentile of a sample database; a comparison is made by the controller between the probability of contaminant detection versus contaminant percentile in the sample database; and the controller commands the air purification subsystem when the contaminant signal reaches the predicted sensory response threshold based on the sensed concentration equivalents reaching a level that is below a 100% probability of contaminant detection.