Abstract: An air quality determination method including a temperature control step, an acquisition step, a determination step, and an output step. The temperature control step includes controlling a temperature of a sensitive unit exposed to a sample gas to cause the temperature of the sensitive unit to vary in a temperature variation pattern including at least one temperature rising period in which the temperature of the sensitive unit rises and at least one temperature falling period in which the temperature of the sensitive unit falls. The acquisition step includes acquiring an electrical characteristic value of the sensitive unit exposed to the sample gas. The determination step includes determining, using a learned model to determine an air quality condition of the sample gas, the air quality condition of the sample gas based on a variation in the electrical characteristic value. The output step includes outputting a decision made in the determination step.