Abstract: According to various embodiments of this disclosure, an electrochemical sensor/cell includes 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 attached to a glass or ceramic panel. The glass or ceramic panel may have one or more apertures allowing gas to flow therethrough. The plurality of electrodes include a working electrode configured to react a molecular species (e.g., gas or aerosolized substance) that diffuses through the one or more apertures, wherein said reaction produces ions mobile in the ionic conductor between two or more of the plurality of electrodes. The lid assembly may further include a three-phase interface positioned over at least a portion of the plurality of electrodes.