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PM2.5 is the top issue of air pollution in Henan Province in China, especially in autumn and winter. In order to investigate its spatial and temporal distribution characteristics, monitoring data were collected in 17 cities and analyzed by using statistical methods and GIS tools. The results show that 57.16% of the entire days in 2015 met Chinese the national standard on the daily average concentration of PM2.5 in those 17 cities. However, 73.68% of the days in winter, 44.37% of the days in spring, 34.53% of the days in autumn, and 20.08% of the days in summer failed to meet the standard. Analysis shows the average concentration of PM2.5 on weekends was 8.04% higher than that of working days. The fact that the value of PM2.5/PM10 was between 0.50 and 0.65 and that there was a high relevance between the PM2.5 concentration and SO2 concentration suggests that the main air pollutants are coarse particles that are mainly released by coal burning. The positive correlation between PM2.5 and NO2 reveals that vehicle exhaust emissions is another main reason for air pollution. Owing to the influence of the temperature and sunlight changes, the correlativity of PM2.5 concentrations and O3 concentrations presents a remarkable difference in different seasons. The correlation coefficients are 0.003 for spring, 0.496**(p = 0.01) for summer, -0.353*(p = 0.05) for autumn, and -0.315*(p = 0.05) for winter, respectively. The method proposed in this paper has been verified and the research result is helpful for making relevant environmental policy. [ABSTRACT FROM AUTHOR]