Miniature sensor cell for gaseous and aerosol air pollutants

A miniature cell with built-in radiation source can be brought in such mode of operation, when alternating field is applied across its electrodes, that provides the conditions in which reactant ions are barely reaching the electrodes. When a compound with a high proton affinity is present in the sensor, the effective mobility of ions created in various ion-molecule reactions is lowered, causing a decrease in the ionic current. The effective decrease of the current is measured at the output of the electrometer/integrator.