I've developed applications with the Senseair K30[1] and found it to be robust and very accurate over the long term. You can use it either over I2C or UART, so

I've developed applications with the Senseair K30[1] and found it to be robust and very accurate over the long term. You can use it either over I2C or UART, so it would work fine in combo with this board! [1] https://www.co2meter.com/products/k-30-co2-sensor-module https://www.co2meter.com/products/k-30-co2-sensor-module