A Fully Integrated Smart Facemask for Ultrafast and Humidity-Resistant Exhaled CO2 Monitoring

Abstract Exhaled CO2 monitoring offers critical insights into respiratory, cardiac, and metabolic functions. However, its broader adoption is hindered by the lack of compact, fast-responding, and humidity-resistant sensing systems capable of accurately tracking rapid breathing cycles in real time. Here, we present a fully integrated wireless facemask for continuous exhaled CO2 monitoring that overcomes these challenges. We developed a nanocomposite colorimetric sensing material, mCP/ZIF-8-NH2@fCOF, which possesses an ultrafast response time of 60 ms and a hydrophobic shell that mitigates humidity interference. By coupling its optical response with a convolutional neural network, the facemask can identify various breathing patterns with 94% accuracy and diagnose chronic obstructive pulmonary disease with 93% accuracy. Furthermore, the facemask has proven effective for exercise monitoring and sleep apnea detection. This nonintrusive, highly compact, and versatile device provides a practical pathway toward ubiquitous respiratory monitoring and personalized health management.