Preliminary Analysis of Influcening Factors of Expressway Runoff Pollution

The road runoff samples from two expressways in Chongqing were collected to analyze preliminarily the external influencing factors of pollution characteristics of runoff preliminarily.The result shows that(1)the difference of pollutant concentrations of runoff between the general expressway and suspended bridge deck is not significant,but the impact of traffic on the runoff may be related to the settlement of vehicle exhausted organic waste on the ground;(2)the order of contamination levels in season is spring,winter,summer and autumn;(3)there is no obvious correlation between water qualities of rainfall and runoff;(4)the finer the dust particle on road,the higher the contained concentration of pollutant,and the pollution is more serious;(5)more than 80% of the pollutants accumulate in the dust below 2.0 mm;(6)leaching rate of the pollutants by acid rain is from 0.76% to 15.94%,this means the soluble pollutants into the runoff is not much,more is particulate pollutants produced with the rain.