Monitoring of cold rooms, beverage dispensing systems, and tea kitchens with water carbonators. 1400 ppm of CO2 in rooms is considered very poor air quality, while the permissible exposure limit (MAK) in Germany is 5000 ppm. The GX-D33 only issues a warning well above this level. Therefore, in the event of defects in technical CO2 systems that are under pressure, an alarm is triggered immediately; however, in crowded spaces with many people, such as open-plan offices, the elevated values are reliably ignored. Additionally, the GX-D33 alerts with a loud alarm in dry ice storage areas when ventilation is insufficient.