The PM2.5 monitoring and calibration laboratory was built in 2015, focuses on metrological standards and calibration technologies for PM2.5 mass concentration and separation efficiency measurements. We developed a standard gravimetric measurement instrument and a calibration system as the highest standard for PM2.5 mass concentration in China, the accuracy was verified with NPL through a bilateral comparison. The first public metrological standard for PM2.5 mass concentration monitors in China were established based on the standard instrument and the calibration system, to provide the calibration service for PM2.5 monitors. In addition, we developed 15 Certified Reference Materials for PM2.5/PM10 monitors for the separation efficiency measurement of samplers. Based on these achievements, we drafted 1 national standard and 2 national calibration specifications. The standard instruments, reference materials and calibration service are now widely promoted in the metrology, environmental protection and epidemic prevention areas.