On the study of the polluted materials in the street tree leaves between heavy and light traffic parts

Abstract

The investigation was performed to search the polluted materials in the street tree leaves between heavy and light traffic parts. The results obtained are as follows;
1. There were no differences of the polluted materilas per day (dry weight) among the tree species in one month. As a general trends, they were more accumulated in July and August than the others. In comphor trees, materials per day (dry weight) were more accumulated in summer.
2. In heavy traffic parts, materials were more accumulated than the others. Espesially, in August, acacia trees situated in naka-jincho (heavy traffic part) had the highest concentration of the polluted materials.
3. From the loss of the organic materials by theburning method and the lead content in ash part of the polluted materilas, these were confirmed as a originated materials in motor-car gas.
4. Almost of these materials (80-90%) were streamed out by the precipitation (20mm). But some ash parts (mineral materials) was remained in the leaves at the heavy traffic parts (naka-jincho, gobancho).
5. In the individuals of the polluted meterials, the burning materials except of the tar had a higher content at the heavy traffic parts.
6. From the lead contents in the street tree leaves, it was assumed that the air in the dense traffic of a main street were polluted by the motor-car gas.