This study investigates the decay of particle lung-deposited surface area (LDSA) concentrations following indoor particle emissions, with a focus on cooking activities. Two decay functions were derived and validated using measurement data. Applying the functions, it is shown that from 66.5 to 82.9 % of the exposure to cooking-generated particles occurred during the decay phase following the active cooking event. This highlights both the applicability and importance of the derived decay functions.