中文摘要：

国内雾霾天气现象日益严重，为更有效防治雾霾天气，对雾霾的主要成分之一PM2.5的研究现状进行了调研。介绍了PM2.5的定义、产生机理、主要成分等内容，并着重对含碳颗粒和重金属元素的浓度在不同地区、不同季节的影响因素进行了综述。针对改善空气质量、监测及去除PM2.5等未来研究方向提出了建议。

英文摘要：

As the phenomena of hazy weather in China are getting more and more serious, to do the prevention of such haze problems more effectively, the recent progress of research on PM2.5, one of the main components in fog and haze, has been investigated. The definition, generating mechanism, major constituents, and etc. of PM2.5 were introduced. The variation of carbonaceous species and heavy metal contents in PM2.5 was summarised and discussed about their potential affecting factors in different regions and seasons. Suggestions on the future research orientation were set out about the improvement on air quality, monitoring and the removal of PM2.5.