Abstract:
Chemical compounds or elements resulting from human and non-human activities may be released into the atmosphere as air pollutants and can harm living things. Traffic dust contains high levels of heavy metals that can affect human health and the environment. Mashhad, as a religious city, hosts millions of pilgrims and travelers every year, resulting in congestion and increased air pollution, especially in the city center and near the holy shrine. Various factors are effective in increasing the amount of air pollutants and increasing the city's dust. By measuring the concentration of heavy metals in samples from urban areas with high traffic volume, the level of pollution was studied and sources of production were investigated. Pollutants and dust were collected from the air filters of public vehicles and the samples were analyzed for a range of elements using methods that included ICP-MS, atomic absorption, XRD and spot analysis from BSE. The results show that copper, nickel, lead and zinc are prominent air pollutants in Mashhad, and the most likely sources of pollution are related to vehicle traffic and to factories and mines around the city.