And the sampling site should be located in the downwind direction of the highway. However, if possible, grid point sampling can also be used to analyze the diffusion process of pollutants. The height of the sampler must be greater than ~3 m above the ground to avoid impaction of resuspended particles. Samples: Traffic emissions are a source of air pollution, such as EC (elemental carbon), OC (organic carbon), iron and metals9,10. For measuring air pollution generated by traffic. Considering the main components of air pollutants generated by traffic. We will focus mainly on the analysis of the main components of traffic emissions, the inorganic and organic constitution of particles and the concentrations of pollutants in the gaseous phase, such as carbon monoxide, nitric oxide, nitrogen dioxide, sulfur dioxide and ozone. In this case, different sampling methods will be used.(1) To analyze inorganic trace elements, such as iron, lead and aluminium, total suspended particles will be collected on Whatman 41 filters using a high volume sampler. The sampling method and filter pretreatment procedure will follow Morton's