This report provides information of quality assurance for PM2.5 sampling activities from October 27, 2016 through October 26, 2018. The mission of the project comprises implementation of inspection, performance audit, and collocated comparison for field sampling and lab analyzing, so that requirements and goals for PM2.5 monitoring will be fulfilled. 　　The performance audit used independent instruments and standards to inspect the deviation between the monitoring value and the standard value (accuracy). 372 stations were completed in two years. The acceptance rate was 99.1%. In addition, 187 stations, 2 items of procedure check for field operators were also included. And must follow up tracking the results of defects improvement. 　　A quality system check for laboratory refers to the organizational resources, processes and procedures to implement quality management. 24 Lab system audits and 4 inter-lab weighting comparisons have been accomplished in two years. Only three of the comparisons failed to meet the requirement. 　　The semi-annual collocation measurement is mainly based on the published method NIEA A205.11C by EPA Environmental analysis laboratory, to enhance the reliability of monitoring data. Four times of collocated measurement between standard instruments were conducted in two years, and precision showed between 1.65%~4.36% which were all meet the requirement. 248 field stations collocated comparisons were done in two years. 236 times valid comparisons were under circumstances of PM2.5 concentrations greater than 3 μg/m3. 0~±1 μg/m3 of concentration bias indicate a high credibility of PM2.5 manual monitoring data. 　　Data verification and validation were mainly focus on worksheet filling, concentration calculations and quality management of laboratory, to meet the requirement of NIEA method. 7,562 pieces of data validations were carried out in this project. Among these data, 188 were marked “sample failed”, 10 were marked “quality assurance failure”, and 5 were marked “not executed sample.” The overall rate of available data is 97.3%. 　　All defects from field performance audit and Lab check will be require to improve within certain days discussed in monthly routine data reviewing meeting, The EPA and this project will track situation of defects improvement.

Fine Particulate Matters, Field Check, Collocated Measurement