Abstrakt: |
The purpose of this study is to clarify the chemical characterization of PM2. 5and PM10in diesel exhaust particles (DEP). Sampling of PM2. 5and PM10in DEP was carried out in November 1999 using an automobile exhaust testing system at the National Traffic Safety and Environment Laboratory, with a diesel truck (engine type: direct injection, displacement: 7961 cc, carrying weight: 2020 kg, equivalent inertia weight: 5600 kg) placed on a chassis dynamometer. Sampling conditions included idling, constant speed of 40 km/h, M-15 test pattern and 60%-revolution/40%-load of maximum power. Samples were collected on a polycarbonate membrane filter (Nuclepore®, pore size: 0. 8 µm) using a MiniVol Portable Air Sampler (Airmetrics Co., Inc.). The concentrations of several elemental and ionic species in the PM2. 5and PM10samples were determined by particle induced X-ray emission (PIXE) and ion chromatography analysis. PIXE analysis of the PM2.5and PM10samples revealed 15 elements, of which Na, Mg, Si, S, Cl, Ca, Fe and Zn were found to be the major components. Ionic species were Cl–, NO2–, NO3–, SO42–, Na+, NH4+, K+and Ca2+. Concentrations of elements and ionic species under the sampling condition of 60%-revolution/40%-load were highest in comparison with those of the other sampling conditions. The elemental and ionic species data were compared for PM2. 5and PM10; PM2. 5concentrations were 70% or more of PM10concentrations for the majority of elements, and concentrations of ionic species in PM2. 5and PM10were almost identical. |