... by intercepting airborne particles. Some particles can be absorbed into the tree, though most particles that are intercepted are retained on the plant surface. The intercepted particle often ... canopy (e.g., automobiles), the forest canopy could have the inverse effect by minimizing the dispersion of the pollutants away at ground level. The greatest effect of urban trees on ozone, sulfur ... Oxidant Air Pollution Impacts in the Montane Forests of Southern California: A Case Study of the San Bernardino Moun- tains. Springer, New York, pp. 235-269. Cardelino, C. A., Chameides, W....