A photoionisation detector PID is a sort of gas detector. PID gas sensors measure the presence of volatile organic compounds over a wide range of concentrations. Volatile organic compounds are some other chemical compounds which have significant vapor pressures and may have harmful effects on human health and the environment. The monitoring of volatile organic chemicals is significant because although VOCs are usually not acutely toxic, the adverse health effects they cause are compounding, long term and slow to show signs.

PID gas sensors are a vital Security device in many businesses and offices, especially in the army, in chemical plants, anyplace where solvents such as paints and adhesives are used frequently, or at any confined spaces like mining shafts. PIDs are used together with ventilation systems to regulate and enhance the quality of the atmosphere, especially in indoor environments. PID type gas detection products can also be utilized in applications like arson investigation and monitoring of environmental contamination.

PID gas sensors work using the principles of Paper Chromatography. PIDs detect the presence of certain ions in the atmosphere by using ultraviolet light to bombard the molecules which pass through the gas detection equipments. The UV light excites the electrons that are targeted, causing the molecules to lose electrons and become positively charged ions. Because of this, the positively charged ions create an electric current that is the outcome of the gas detection equipments. PIDs also give quantitative evaluation of the volatile organic compounds found through quantifying the strength of the electrical current. The larger concentration of VOCs from the atmosphere, the stronger the electrical current will be.

PID sensors can either be Used as stand alone, wide band product of gas detection that ionize any molecules with an ionization energy less than or equal to the lamp output, or as selective gas sensors when combined with a chromatographic technique or a pre-treatment tube. Selective PIDs will only ionize molecules with ionization energies which are similar to or lower than the photons generated from the lamp of the gas detection equipments, which makes it a helpful method for evaluation of certain, especially harmful, compounds.

PID gas sensors require fine Calibration, using isobutylene, for successful identification of particular volatile organic compounds. PIDs able to detect compounds at very low Concentrations and provide instantaneous readings make them ideal for Continuous use in hazardous locations. Highly sophisticated PID gas sensors are Available with humidity damages features which conquer of the Electrical sign, making the PID operable in almost any surroundings.