What characteristic makes the Photoionization Detector (PID) effective in measuring airborne contaminants?

The effectiveness of a Photoionization Detector (PID) in measuring airborne contaminants is primarily due to its use of ionization with ultraviolet (UV) light. When UV light is emitted from the PID, it creates ions from the molecules of various gases in the air. The detector measures the electrical current produced by these ions, allowing for the detection of a range of volatile organic compounds (VOCs) and some inorganic gases.

This ionization process is crucial because it enables the detection of low concentrations of contaminants, making PIDs sensitive and effective in identifying airborne pollutants. This technology allows for quick, real-time measurements, which is essential in hazardous materials management and response situations.

Other characteristics, such as portability, while beneficial, do not contribute directly to its effectiveness in measuring airborne contaminants when compared to the fundamental operation involving UV light ionization. High specificity to one gas does not apply to PIDs, as they are designed to detect multiple compounds simultaneously, and direct measurement of pH is not relevant to the function of a PID, which focuses on gas detection rather than liquid properties.