Dust emission from open-yard stockpile is an important source of atmospheric particulate pollution. However, there were few literatures on on-site sampling analysis to study the effects of secondary dust lifting on atmospheric particulate matter concentration in open-yard stockpile. Field testing was the most effective means of verifying the accuracy of wind tunnel tests and numerical simulation methods. In order to study the contribution of secondary dusts to the ambient particulate matter pollution in the open-yard stockpile, field tests are carried out on three typical stockpiling sites of Haihua thermoelectric coal-fired power plant surface coal pile, Open-air soda ash heap in Haihua soda ash plant and Yingyang flavour and fragrance company boiler coal stack. The test results show that the contribution rates of thermal power plant coal pile to particulate matter 2.5 micrometres or less in diameter (PM2.5) and particulate matter 10 micrometres or less in diameter (PM10) are 34.3 % and 26.1 %, the contribution rates of soda plant slag pile to PM2.5 and PM10 are 22.3 % and 36.2 % respectively, and is greatly influenced by the local wind direction and wind speed. The research results provide a solid field test data basis for identifying the contribution of secondary dust to the surrounding atmospheric environment and the law of dust diffusion, which is of great significance for winning the blue sky war.