A method for determining an ozone conversion rate

A method (200) for determining an ozone conversion rate, which comprises: using a first ozone sensor (164-1) comprises a first sensor signal (168-1) is generated indicating a first amount of ozone in air, which flows into a radiator (124) of a vehicle; using a second ozone sensor (164-2) is produced a second sensor signal (168-2) indicative of a second amount of ozone in air flowing out of the radiator (124); and are received, the first sensor signal (168-1) and the second sensor signal (168-2) (208, 212); and determining an ozone conversion rate based on the first sensor signal (168-1) and the second sensor signal (168-2) (216); Air, flowing into the radiator (124) is supplied by a first line (190-1) to the first ozone sensor (164-1); Air which flows out of the radiator (124) using a second line (190-2) to the second ozone sensor (164-2) is delivered; characterized, in that the first (164-1) and second (164-2) ozone sensor outside of an engine compartment (129) of the vehicle are arranged; and an air pump (194-1) in the first line (190-1) is arranged to allow a flow of air to the first ozone sensor (164-1).