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Due to rapid economic growth of the country in the last 25 years, particulate matter (PM) has become a topic of great interest in China. The rapid development of industry has led to an increase in the haze created by pollution, as well as by high levels of urbanization. In 2012, the Chinese National Ambient Air Quality Standard (NAAQS) imposed 'more strict' regulation on the PM concentrations, i.e., 35 and 70 μg/m for annual PM and PM in average, respectively (Grade-II, GB3095-2012). The Pearson's correlation coefficient was used to determine the linear relationship of pollution between pollution levels and weather conditions as well as the temporal and spatial variability among neighbouring cities. The goal of this paper was to investigate hourly mass concentration of PM and PM from June 1 to August 31, 2015 collected in the 11 largest cities of Gansu Province. This study has shown that the overall average concentrations of PM and PM in the study area were 26 and 66 μg/m. In PM episode days (when concentration was more than 75 μg/m for 24 hrs), the average concentrations of PM was 2-3 times higher as compared to non-episode days. There were no observed clear differences during the weekday/weekend PM and other air pollutants (SO, NO, CO and O) in all the investigated cities. [ABSTRACT FROM AUTHOR]