Analytical Screening of Low-cost CO₂ Sensors for Clinical Infection Control Applications

We evaluated the accuracy and reliability of 12 low-cost CO₂ sensors that are commercially available and promoted for infection control in indoor settings, considering their potential use in clinical environments. A stepwise CO₂ injection protocol and alcohol exposure tests were conducted in a controlled acrylic chamber. Our results showed that only 3 out of 12 sensors (25%) responded reliably to actual CO₂ concentrations and could be calibrated with acceptable accuracy, whereas 67% failed to detect CO₂ but falsely responded to alcohol vapors, frequently present in health care environments. These findings highlight the need for staff development educators to promote accurate sensor selection and propose a practical 3-step screening method that clinical engineers can use without specialized equipment.