The influence of air pollution on Plane (Platanus orientalis L.)

Air pollution is a serious problem in many heavily populated and industrialized areas in the world. Plants growing in urban areas have to face continuously various environmental constraints, of which an important and increasingly concerning one is the pollution by heavy metals. During the last few years, especially the number of vehicles in Iran, mostly operated by leaded fuel, has increased rapidly leading to increasingly high amounts of some heavy metals in the soil, air and trees near highways. The aim of this study was to assess the level of contamination of plants and air by some heavy metals. As a plant species, Platanus orientalis was chosen because it is a tree adapted to different ecological conditions and a widely distributed dominant tree in parks as well as along roads and streets of Iran. As investigation area, Mashhad City was chosen as it is the second largest city in Iran, and the population has experienced an important demographic increase during the last years. This has led, in addition to some industrialization processes, to an exponential increase of small and large vehicles, and motorcycles emitting a high level of air pollution.