Characterization of size distribution and concentration of atmospheric particles during summer in Zhuzhou, China

In order to provide a sound basis for the performance evaluation of a local government’s air pollution prevention and abatement measures, the mass concentrations of PM2.5 and PM10 and the concentrations of different sized particles were measured in August 2013. Meanwhile, the influencing factors and sources of atmospheric particulate matters were analyzed by combining meteorological factors and gaseous pollutants. The results indicated that PM2.5 and PM10 in Zhuzhou were (30.3±12.2) μg·m⁻³ and (56.4±26.6) μg·m⁻³, respectively. The mean values of the particle number concentration in the size range of 0.5~1 μm and 1~2.5 μm on sunny days were (121.2±75.9) cm⁻³ and (6.8±3.7) cm⁻³, respectively, whereas in the rainy days they sharply increased to (868.7±262.1) cm⁻³ and (347.9±238.6) cm⁻³, which accounted for 71.0% and 28.4% of the total number of concentrations, respectively. Backward trajectory analysis demonstrated that the air masses in Zhuzhou city mainly came from three directions: southeast (52.2%), southwest (24.7%), and northeast (23.1%). Although accounting for a minor fraction, the northeast air mass had the largest effect on particle concentrations in Zhuzhou and also carried a lot of gaseous primary pollutants.