Abstract:This study focused on the variation characteristics of PM2.5 and PM10 concentrations and general source types in 2014~2018 in five typical small-medium basin cities (Lanzhou, Yinchuan, Linfen, Taiyuan and Nanyang) in northern China. Apart from the PM2.5 concentrations in 2018 in Yinchuan, the PM10 and PM2.5 concentrations in the other cities are above the level of the 2nd grade standard of the state; The PM10 and PM2.5 concentrations show a downward trend year by year, with the most obvious city being Nanyang; The PM10 and PM2.5 concentrations show an increasing trend year by year in Linfen; The PM10 and PM2.5 concentrations are stable at a high level in Taiyuan. Seasonal variation characteristics of PM10 and PM2.5 concentrations are similar:high concentrations in winter and spring, low in summer and autumn. The ratios of PM2.5/PM10 are greater in winter and summer, resulting from the heating process and frequent rainfall, respectively. The ratios are lower in spring and autumn, resulting from sandstorms and frequent straw combustion as well as high-strength construction of building, respectively. The PM2.5 and PM10 concentrations have a good linear relationship, The proportion of fine particles is in order of Linfen > Nanyang > Taiyuan > Yinchuan > Lanzhou.