A system (20) and method (100) using decentralized trace gas sensors (44a, 44b, 44c) and a central control element (46) to detect smoldering material in particulate material processing equipment (26) with continuous air flow (22, 24, 34). First and second sensors (44a, 44c) measure gas concentrations at an air inlet (22) and an air outlet (34), respectively. The control element (46) receives the measurements from the sensors (44a, 44c) simultaneously, considers the first and second concentrations simultaneously to determine an amount of gas being produced in the processing equipment (26), determines whether the amount of gas being produced exceeds a threshold value indicative of smoldering, and if so, activates an alarm. A user interface (48) allows a user to interact with the control element (46), including resetting the alarm, viewing current and stored sensor and system information, and initiating a test of the system by exposing the sensors (44a, 44b, 44c) to gas released from a gas reservoir (50a, 50b, 50c).