Atmospheric particles, especially water-soluble inorganic ions are hazardous to human body. Motor vehicle exhaust is the greatest contributor to atmosphere pollution in Tianjin. In order to explore the emission characteristics of different road types, PM2.5 and PM10 from four types of roads were sampled and analyzed by water-soluble ions component analysis and Pearson correlation analysis during the period of April to May, 2015 to discover the ratio of PM2.5 to PM10 and the major pollutants. The results showed that water-soluble inorganic ions mainly existed in fine particles varying with different road types, which mainly came from secondary pollution. The quantities of secondary ions in PM2.5 were twice as high as that in PM10, which were the key components of the water-soluble inorganic ions. This was probably due to the increase of automobiles and their emissions, as well as the transmission and spreading of pollutants in the surroundings. Furthermore, water-soluble inorganic ions might exist in the forms of NaNO3, NH4Cl, NH4NO3, (NH4)2SO4, KCl, KNO3, K2SO4, MgCl2, CaCl2, etc. K+, Mg2+, Na+and Ca2+ showed high homology and the contributors of PM2.5 and PM10 were mainly the mixture of combustion and secondary pollutants, then followed by the mixture of re-suspended dust and traffic source.
Keywords: PM2.5 and PM10; correlation analysis; particle size characteristics; principal component analysis; road distribution characteristics.