[Analysis of inter-laboratory comparison results of sulfur dioxide in workplace air and explore the influence factors...

Objective: To assess the sulfur dioxide detection capabilities of occupational health laboratories through a comparative study of workplace air sulfur dioxide measurement proficiency, and to analyze the primary factors influencing measurement accuracy. Methods: From June to September 2024, sulfur dioxide comparison samples were prepared, undergoing homogeneity testing and stability evaluation, followed by collaborative calibration. The test results from participating laboratories were evaluated using the designated reference value range method. Analysis of non-compliant results was conducted by reviewing laboratory reports and records, with further investigation into measurement influencing factors. Results: The statistical F-value for homogeneity testing was below the critical threshold (P>0.05), indicating uniform sulfur dioxide distribution in the samples. The t-value for stability testing was also below the critical threshold (P>0.05), confirming sample stability under room temperature conditions for three months. The overall pass rate for laboratory comparisons was 85.0% (150/180). Non-compliance primarily stemmed from issues with reference standards, reagents, and testing conditions. Key influencing factors for sulfur dioxide determination by the formaldehyde method included the addition method of chromogenic reagents and precise control of reaction duration and temperature. Conclusion: The participating laboratories demonstrated generally high sulfur dioxide detection proficiency, though some institutions require further improvement in testing capabilities. Precise control of testing conditions and enhanced quality control measures are crucial for improving the accuracy of sulfur dioxide measurement results.