Asphalt fractions in airborne particles from highway traffic and the accumulation in plants

With reference to ASTM D4124, asphalt fractions, including polar aromatics (polars),naphthene aromatics (aromatics) and saturates,were characterized both in airborne particles collected in the distances of 2.0 -83.6m from the highway and in the plant samples (including grass,leaves and wheat straw) collected in the distance of 2.0 -10. 0m from the highway. In comparison to the results of diesel particulate, background plant samples and asphalt cernent samples from highway surface, it is concluded that there could be asphalt rnatters in airborne particles and asphalt makes the rnain contributions to the accumulation of the three factions mentioned above in plant species. In the ambient air,the concentrations of the three asphalt fractions are 0. 54- 3.06 ×10-3 mg polars,1. 77- 9. 50 × 10-4 mg aromatics and 0. 21- 1. 23 × 10-4 mg saturates for per cubic meter air. The percentage of bitumen in airborne particles is 1. 61%-11. 02%. In the plant samples, the concentrations are 0. 29- 3.07mg polars, 0.89- 3.89 aromatics and 0. 37-1. 53 mg saturates for per gram dry plant materials.