Monitoring of cold rooms, beverage dispensing systems, and tea kitchens with water carbonators. 1400 ppm of CO2 in rooms is considered "very poor air," while the permissible exposure limit (MAK) in Germany is 5000 ppm. The GX-D33 only triggers an alarm well above this level. Therefore, in the event of defects in technical CO2 systems under pressure, an immediate alarm is activated, but in crowded rooms with many people (e.g., open-plan offices), the elevated levels are reliably ignored. Additionally, the GX-D33 alerts with a loud alarm tone in dry ice storage areas when ventilation is inadequate.