Factors Affecting Dirt Pick up of Traffic Paints in Areas with Different Characteristics: Tehran Roads as a Case Study

This study was performed to identify the weight distribution of affecting factors in contamination of traffic paint surfaces from environmental pollutants in different municipal districts. Traffic paint samples were collected from the major roads and less busy ones of different environmental condition in Tehran and was determined using the Energy-dispersive X-ray spectroscopy (EDS). Four pollutant namely fuel consumption, brake wear, tire wear and bitumen traces are considered to be the major environmental sources can affect dirt accumulation on surfaces of traffic paints. The analysis of variance shows that obtained concentration levels of elements under study namely tungsten (W), nickel (Ni), chromium (Cr), zinc (Zn), titanium (Ti), iron (Fe), lead (Pb), calcium (Ca) and copper (Cu) were highly significant in traffic paints collected from different areas. The quantities parameters such as Pollution Load Index and Contamination Factor were employed to identify possible levels of pollution from aforementioned pollution sources. Some elemental pairs such as Fe/Ti (0.72 ), Ni/Cr (0.64 ), Ca/W (0.81 ), Pb/Ni (0.70 ), Fe/Cu (0.71 ), and Zn/Ca (0.81 ) have strong correlation at 5% significant level. From the obtained results, it was concluded that the main source of dirt picked up by traffic paints might be originated from combustion of fuel which is known to contain trace levels of Cr, Ni and Pb. The roads, in which mostly cars of diesel fuel were travelling, had higher contamination levels on the traffic paints than others. Bitumen traces and the frequency of brake use were additional factors that affected the contamination levels. The degree of contamination of traffic paints in crossroads was mostly influenced by the road dust from brake wear.

Keywords:

Traffic paints , Dirt pick up , Tire wear , Bitumen , Brake wear , Fuel combustion