The Concentration, Size Distribution, Composition And Source Apportionment Of Particulate In Air Of Ningbo, China

The progress in research on airborne particulate matter was reviewed. The methods for sampling, analyses and source apportionment of particulate in air were described in detail. The charaterization of particulate, chemical prosess, health-, and climate-effect were discussed.The research on the concentration, size distribution, composition and source apportionment of particulate in air were conducted in Ningbo in 2003. The results show that PM10 and TSP average concentrations in air were 84μg/m3 and 114μg/m3, respectively. For PM10, only 29 days were over second standard degree. The yearly average concentration of PM2.5 was 55μg/m3, which was 2.7 times more than EPA standard (15μg/m3). The ratios of PM2.5/TSP and PM10/TSP were 48.2% and 73.3%, respectively. Size distribution, chemical component and source apportionment were investigated. The Pb, NH4+, SO42-, NO3- and PAHs were mainly existed in PM2.5, whereas Cd, Mg, Cu and Cl- were mainly found in the 2.5-10μm fraction ;Ca, Fe, Mn were mainly existed in >10μm fraction. Three main sources for the fine particulate were discussed. The exhaust gas accounts for 56% PAHs in PM10; secondary particles including SO42-, NO₃, NH4+ account for 26.3% of PM2.5 mass; the dust collection efficiency of four typical dust catchers are very low. The ratios of PM₁0 and PM2.5 to TSP in the exhaust dust were 36.3% and 92.4%, respectively. Thus, industry source is also the main source of fine particles in air.