Abstract: In a process for controlling the quantity of air in a closed, chargeable and estimable pneumatic level control system of a vehicle, which level control system comprises at least one pressure sensor, one pump, an actuator, a storage reservoir and pressure lines interconnecting these components, at least one vehicle body level sensor, and a temperature sensor, which measures the ambient temperature, from the values measured an air mass of the level control system is calculated on the basis of the air pressures in the components, the level of the vehicle and the ambient temperature. Furthermore, the level of the vehicle, the ambient temperature and a maximum possible change in level from a particular vehicle level are used to calculate a vehicle-specific desired air mass and a desired air pressure in the system. The air mass is increased if the actual air pressure drops below the desired air pressure, and the air mass is reduced if the actual air pressure exceeds the desired air pressure.