Particles size distribution of PM11 and its impact on visibility in urban Shijiazhuang during spring

Atmosphere particles collected by Andson AN-200, were divided into PM_0.43- PM_0.43~0.65, PM_0.65~1.1, PM_1.1~2.1, PM_1.1~2.1, PM_2.1~3.3 and PM_3.3~4.7, PM_4.7~7 and PM_7~11, in total eight ranks . After calculating the particles mass concentration of all ranks and studying the correlation coefficient between particles mass concentration and visibility, we conclude: The finer particles pollution is the main reason for the atmosphere particles pollution in spring of Shijiazhuang, The particles mass concentration of PM_0.43 is the highest (0.040 mg/m³). The proportion of PM_2.1 in PM₁₁ is 53.7%. The air pollution particularly finer particles of pollutes is the most serious. The correlation coefficient between particles mass concentration and visibility is r _0.43~0.65 >; r _0.65~1.1 >; r ₀₄₃ >; r _1.1~2.1. The correlation coefficient between other particles mass concentration and visibility is not significant at the 0.01 level (2-tailed). The finer particles are the main factors that lead to low visibility. The correlation coefficient is -0.684 between visibility and relative humidity in urban Shijiazhuang during spring. The correlation coefficient is 0.395 between visibility and wind.