A control system for a mitigation device includes a processor and a computer-readable medium that includes instructions executable by the processor. The instructions include monitoring a first measured particulate matter (PM) level of a conditioned space. The first measured PM level includes PM having a first range of sizes. The instructions further include monitoring a second measured PM level of the conditioned space. The second measured PM level includes PM having a second range of sizes. The first and second ranges are different but overlapping. The instructions also include asserting, in response to the first measured PM level being greater than a first predetermined threshold, an activation signal. The activation signal forces operation of a fan of the mitigation device. The instructions include asserting, in response to the second measured PM level being greater than a predetermined percentage of the first measured PM level, the activation signal.