Study On The Physico-Chemical Characteristics And Health Effects Of PM₁₀ And PM_2.5 In Beijing-Tianjin-Tangshan City Group

Using the field emission scanning electron microscopy (FESEM), inductively coupled plasma mass spectrometry (ICP-MS), image analysis (IA) and DNA evaluation method (Plasmid Scission Assay) and other technical means, this paper studies the physical and chemical characteristics and the biological activity of PM10 and PM2.5 samples and their relationships in Beijing, Tianjin andTangshan City. FESEM is used to identify unknown particles, soot aggregates, mineral particles and spherical particles. In this city group unknown particles and mineral particles are the main pollutants. Because of the sandstrom weather in Beijing spring, mineral particles with the size> 1?m account over 80% of the whole. The particle size distribution in Tianjin and Tangshan is similar to that in Beijing. Particles the size range 0.1?0.7?m dominate in number while particles with the size range>1?m dominate in volume. ICP-MS analysis revealed that all Beijing, Tianjin city group dissolved trace elements in PM10 are Cr, Ni, Cu, Zn, Sr, Ba, Pb, Fe and other elements of higher concentration; PM10 concentrations of trace elements vary considerably in the soluble part. Zn has the highest concentration, followed by Ni, Pb, Mn and so on. Plasmid DNA results shows the DNA damage rates at the dosage of 500?g/mL of the whole fractions of the sample in the Beijing-Tianjin-Tangshan city group during spring are 31.2%,41.76%,45.3% respectively while 52.8%,68.4%,65.3% respectively during summer. The damage rate is serious in summer and light in spring. The analysis of the toxicity of PM10 shows that the main source of particulate matter toxicity is from Cu, Zn, Co, Ni and other elements in three cities.