Lead-Oxygen Sensors (Galvanic Cells) Show Significant Response to Air Pressure Changes

Common lead-containing oxygen sensors with a two-electrode design (galvanic cells) exhibit a rapid increase in current signal when subjected to sudden increases in air pressure. Well-known sensors of this type include the CITY 4OXV, Alphasense O2-A2, DD S+4OX, and other oxygen sensors operating on the same principle. When detectors using these sensors experience sudden shaking, dropping, blockage of the sensor inlet, or blockage of the air outlet (for pump-suction models), the O₂ reading typically surges rapidly to 23–30% vol and triggers a high-oxygen alarm. This is not a quality defect of the oxygen sensor. Waiting  seconds , for the air pressure in the sensor to stabilize, after which the detector's reading will return to normal.

Some expensive detectors take into account the pressure characteristic curve of oxygen sensors and add some correction factors when processing signals, which has some positive effects on improving the situation.