Which device is noted for field screening contamination but not approved for final assessment?

The Photoionization Detector (PID) is instrumental in the initial assessment of air quality and the presence of volatile organic compounds (VOCs) in the environment. This device serves to quickly screen for contamination by detecting the ionization of various organic compounds in the air, making it useful in field scenarios where immediate data is needed. Its sensitivity allows for the identification of potential contamination sources, which can guide further investigation or remediation efforts.

However, while the PID is beneficial for field screening, it is not approved for final assessment due to its inability to differentiate between specific compounds and accurately quantify their concentrations in a reliable manner. This limitation means that while a PID can indicate the presence of contaminants, it cannot provide the definitive and precise data necessary for regulatory compliance or final analyses, which typically require more advanced laboratory methods.

In contrast, devices like the Gas Chromatograph and Portable Spectrometer are designed to provide precise measurements and detailed analysis of specific contaminants, making them appropriate for conclusive evaluations of site contamination. The Soil Moisture Meter focuses on soil moisture content rather than contaminant detection, further distinguishing it from the PID.