[en] The conventional XRF analysis is wide used and suitable analytical method for various fields, especially environmental studies. Air pollution associated with atmospheric particulate matter (PM) is a serious problem in Ulaanbaatar city, the capital of Mongolia. According to World Bank estimation Ulaanbaatar is one of most polluted city. In this paper, we have done XRF analysis on Air Particulate Matters for determining to identification sources and its contributions which was the first time in Mongolia. Main pollution sources for PM2.5 particles of Ulaanbaatar by the result of XRF analysis are soil, combustion and vehicles.