“…In addition to the target gas reactions, there are baseline current reactions taking place at the working electrode, most likely oxygen reduction and electrode oxidation. [3] These result in a non-zero baseline current at the working electrode in the absence of target gas, caused by humidity dependent variations of the sulfuric acid concentration between the working and reference electrodes. [4,5] Electrochemical sensors have been explored as a low-cost method for measuring the concentration of critical pollutant gases in outdoor, typically urban, environments.…”