Abstract: During the grid monitoring of volatile organic compounds (VOCs) in industrial parks using low-cost PID equipment, the monitoring data deviation between equipment is large, resulting in insufficient accuracy and stability. This is a common problem affecting the evaluation and control of VOCs in the parks. To investigate the cause of this deviation, eight sets of PID monitoring equipment of four different brands were selected for field testing in an industrial park to study their applicability. The results showed that: (1) After installing a dehumidifier, the PID monitoring equipment worked normally in high humidity stages. Moreover, the field test of standard gases with different humidity showed that the dehumidifier had no effect on the accuracy of the test data. Therefore, using a dehumidifier can improve the accuracy of PID monitoring data in high-humidity areas. (2) During environmental air testing, the total VOC concentration measured by the eight PID equipment showed a similar trend to that measured by GC-FID equipment. The correlation coefficients between each PID equipment and the FID equipment were all above 0.82, with the highest correlation coefficient reaching 0.96. However, the correlation between the two pieces of equipment was not ideal in the low-concentration stage (50×10⁻⁹) of GC-FID equipment, indicating that PID equipment is suitable for rapid alarm detection with concentrations above 50×10⁻⁹. (3) For the monitoring of VOCs in industrial parks, this study proposes the method of comparing the monitoring data from PID equipment and GC-FID equipment after corresponding calculation, and the correlation of the former method is better than that of the latter method, compared with the method of comparing the monitoring data from PID equipment and GC-FID equipment after simple summation. (4) The research shows that the accuracy of PID monitoring can be improved by specifying the concentration of PID devices to trigger alarms in industrial parks, clarifying the comparison with commonly used devices, and adding condensation devices. This helps to determine the application positioning of PID devices in the industrial park and lay the foundation for managing O₃ precursor substances in industrial parks.