Emission Source of Atmospheric Ultrafine Particles Clarified by Simultaneous Sampling and Data Comparison with PM2.5

摘要

Atmospheric samplings of PM0.1 (Dp < 0.1 μm; PM0.1) and PM2.5 (Dp < 2.5 μm; PM2.5) were conducted from August 7 to 19 and the sampling duration time was 11.5 h to observe the variation of chemical components between daytime and nighttime. An inertial filter sampler operated at 40 L/min and a PM2.5 cyclone operated at 16.7 L/min were used for collection of PM0.1 and PM2.5, respectively. The collected samples were analyzed for carbonaceous (organic carbon and elemental carbon) and ionic compounds using a thermal/optical carbon analyzer based on IMPROVE method and ion chromatograph, respectively. The relative contribution of carbonaceous compounds accounted for 80 ~ 90 % in PM0.1 and accounted for 40 % in PM2.5 at two sites, respectively. Generally, the carbonaceous and ionic components in PM0.1 and PM2.5 tended to increase in the daytime during summer, whereas some samples tended to increase in the nighttime due to stable atmospheric condition. In this study, we found that PM0.1 at the roadside was affected by the source of not only primary vehicle but also secondary particle formation. In contrast, at the background site, secondary particle formation and transportation by wind were more strongly affected to PM0.1 than the vehicle emission.