Abstract: Study progress on PM_2.5  in atmospheric environment was summarized at home and abroad. Now, the urban haze weather is increasing in most cities of China, so the PM_2.5 monitoring and the corresponding studies became a main focus in relevant departments in China. The current status of PM_2.5 study was summarized, and some advices were brought up such as improving air quality and enhancing the corresponding studies on PM_2.5 The definition of PM_2.5 was introduced, and the disadvantageous effects of PM_2.5 on the human health and visibility were revealed. The studies on PM_2.5could be divided into three types in China, namely, analyzing the relationship between PM_2.5 and meteorological conditions; discussing the characters of PM_2.5 and its source; simulating the values of PM_2.5 with the numerical model. The evolution of studies on PM_2.5 in Shenyang region was reviewed and some measurements were suggested such as ensuring the continuous monitoring to PM_2.5, adjusting the structure and the layout of industry, improving the energy efficiency, developing the clear energy, decreasing the coal consumption and controlling the automobile exhaust pollution.

Key words: PM_2.5, Atmospheric environment, Improvement measurements, Shenyang region