Mobile electrochemical air quality meter

An electrochemical sensor assembly is disclosed. In some implementations, the electrochemical sensor assembly comprises at least one electrochemical sensor/cell including a substrate with a cavity formed on a first side of the substrate, an ionic conductor is disposed within the cavity, and a lid assembly positioned over the cavity. The lid assembly may include a plurality of electrodes and a gas permeable region positioned over the plurality of electrodes, where the plurality of electrodes include a working electrode configured to react a molecular species when the molecular species is received through the gas permeable region. The lid assembly may be sealed to the substrate with a bonding layer disposed between the lid assembly and the substrate. The bonding layer may be curable with light or thermally curable at a suitably low temperature to avoid thermal damage to the ionic conductor.