An environmental control system (ECS) having particulates in air therein includes a sensor, an air purification subsystem, and a controller in communication with the sensor and air purification subsystem. The sensor detects particulates in the air, and generates a particulate concentration signal. The controller: compares the particulate concentration signal to a predicted particulate concentration threshold that is based on one of a probability of odor detection, a probability of sensory irritancy detection, and a combination thereof. When the particulate concentration signal reaches the predicted particulate concentration threshold, the controller commands the air purification subsystem to alter a condition in the air containing the particulates.