Pollution characteristic and control measures of street dust in small towns

To examine the pollution status in street dust in small towns,the distribution of pollutants in small towns of Yongchuan District,Chongqing City,was investigated.The results showed that particulate matter above PM 200 μm is the predominant fraction in street dust from Industrial Area and Xuefu Road(e.g.,65% and 72%,respectively),while below 200 μm is the main proportion for Commercial Area and Shuangzhu Street(e.g.,72% and 60%,respectively).The highest concentrations of organic matter,total phosphorus,total nitrogen,Zn,Pb and Cd were found in street dust in Commercial Area(e.g.,103.04 mg·g-1,785.48,1672.04,439.72,133.30,8.44 mg·kg-1,respectively),and the highest contamination levels of Cu,Ni appeared in roads located in Industrial Area(e.g.,241.52 mg·kg-1 and 92.30 mg·kg-1,respectively).The result of pollutants assessment with geoaccumulation index indicated that street dust in Commercial Area and road in Industrial Area had higher contamination risk,especially Ni in Commercial Area dust and Cd in road dust in Industrial Area,which are at the heavily contaminated level and extremely contaminated degree,respectively.Highlight was given to the control of street dust contamination in small towns,and three parts were proposed to be essential for more efficient management of street dust.