Correction factors are scaling factors used to calibrate gas detection sensors to specific gases. They allow sensors to be calibrated using inexpensive surrogate gases instead of the target gas. For catalytic LEL sensors, correction factors adjust the sensor reading to compensate for differing sensor responses to different gases. Correction factors are provided for common gases like acetone, ethanol, gasoline, and propane to calibrate LEL sensors accurately for those gases. PID sensors also require correction factors since their response depends on a gas's ionization potential, with factors given for gases like benzene, methylene chloride, and carbon monoxide.