Smart facemask for wireless CO monitoring.

The use of facemasks by the general population is recommended worldwide to prevent the spread of SARS-CoV-2. Despite the evidence in favour of facemasks to reduce community transmission, there is also agreement on the potential adverse effects of their prolonged usage, mainly caused by CO rebreathing. Herein we report the development of a sensing platform for gaseous CO real-time determination inside FFP2 facemasks.