For gases and vapors that cannot be detected by PID gas detectors, including radioactive gases (Rm), common toxic gases (such as CO, SO2) in air (N2, O2, CO2, H2O), natural gas (methane), acidic gases (such as HCI, HF, HNO3), Freon gas, ozone, etc.

The PID gas detector is capable of detecting extremely low concentrations of volatile organic compounds with high accuracy and can meet the quantitative detection of low concentrations of benzene. It is a non-destructive testing instrument

The calibration of a gas detector is based on the ion current corresponding to a known concentration of gas. The instrument response of other gases is related to their own properties, and a reading of 10ppm indicates that the instrument has generated an ion current that is the same as the 10ppm calibration gas. The actual concentration of other gases obtaining this reading may be higher or lower than this value. Since the PID reading is always related to the calibration gas, this reading should be expressed as the ppm unit related to the calibration gas, and the actual measured concentration value cannot be directly used unless the detected pollutant is the same as the calibration gas, or the instrument reading has been corrected. Usually, PID is calibrated using isobutylene because in the VOC that can be detected by PID, the sensor's response sensitivity to isobutylene is at the average level, which is relatively easy to obtain

The use of PID photoionization sensors in gas detection instruments ensures the accuracy and precision of measurement data, and can measure VOC or other toxic gases ranging from 0.1 to 2000 ppm. PID is a highly sensitive wide range detector that can be seen as a "low concentration LEL detector"