Many first responders are outfitted with electronic personal dosimeters to recognize and be alerted to radiological hazards during their response operations. These dosimeters provide invaluable measurement data for force protection, allowing the first responder to assess a response situation and take protective measures for themselves and other individuals involved based on instrument readings of dose rate or cumulative dose. However, capabilities of common electronic personal dosimeters to identify and distinguish various contributions to the instrument reading, in particular from natural radiological sources, are rather limited. An algorithm has been developed for two-channel electronic personal dosimeters that quantifies the signal contribution from radon progeny and allows for background subtraction from radon and radon progeny in the instrument reading. This algorithm will be particularly useful in operational scenarios where first responders may be subject to rapidly changing levels of natural background radiation, which could mimic the presence of anthropogenic sources of ionizing radiation.