Analysis of the acidity of rainwater and characterization of precipitation runoff pollution from urban area after the once-in-a-century drought

Sampling and monitoring of road and roof runoff and rainwater at Xuefu Road catchment in Kunming City were carried out during the period from March to April 2010, to study the characteristics of urban runoff pollution and analyze the acidity of rainwater after the once-in-a-century drought. It was found that the 3 rains which are not acid rains belong to sulfuric acid dominated type. Both TP and COD mainly exist in particle phase, but Both TN and BOD<;sub>;5<;/sub>; mainly exist in dissolved phase. There is a quite good linear relationship between TSS and TP& COD of samples in the early 20 min of runoff, but the relationship between TSS and TP&COD of samples in the entire runoff is not as close as the early 20 min, which reflects that the quantity of phosphorus and organic substance attached to the particle changes from the perspective of the entire course of runoff.