Abstract: The invention relates to a method to regulate a circulating air and/or intake air portion (Vs, Vo) in a passenger compartment of a vehicle, in particular a motor vehicle, with a sensor for detecting hazardous gas concentrations in the passenger compartment and for supplying a triggering signal (1CO2) of a control unit for the circulating air and/or intake air portion (Vs, Vo) in a passenger compartment. To achieve air supply in a passenger compartment that does justice to demand and is optimized with respect to energy consumption, the sensor for detecting hazardous gas concentrations is a temperature-compensated sensor, whereby the sensor for detecting the ambient temperature along with the sensor for detecting the hazardous gas concentration supply signals (1t, 1CO2) for triggering a control unit for the circulating air and/or intake air portion (Vs, Vo).

Abstract: A method for implementing measures to avert danger for living beings in a compartment in a motor vehicle, in which a carbon dioxide variable describing the carbon dioxide content or the rate of increase of the carbon dioxide content of the air in this space is detected; and in which a temperature variable representing the room temperature in this space is determined. The temperature variable is compared to a temperature-threshold value, and in the event that the temperature variable exceeds a temperature threshold value, the danger-averting measures in response to the temperature threshold value being exceeded are implemented only if the carbon dioxide variable has exceeded a carbon dioxide threshold value.