A microprocessor controlled hazardous condition detection system with volatile and non-volatile memory containing a sensor package and an alarm element associated with the sensor package through a microprocessor, wherein a clean air value is loaded into the volatile memory; where the microprocessor receives periodic readings of predetermined environmental conditions from the sensor package, stores the periodic readings in the volatile memory, calculates an average of a plurality of said periodic readings and generates a new clean air value by shifting the clear air value loaded into said volatile memory by a differential between the calculated average environmental reading and the established clean air value and generates an alarm if the difference exceeds an established threshold.