The Study Of APM In Beijing By Neutron Activation Analysis

A long-term study on airborne particulate matter (APM) and air pollution trend in Beijing has been undertaken supported by International Atomic Energy Agency (IAEA) and National Natural Science Foundation of China. Sampling was carried out using Gent SFU sampler at a sampling station (traffic representative) in Beijing city. More than 400 samples were collected since Dec 1998 in two size fractions of PM10 (coarse) and PM 2.5 (fine). About 47 elements were determined for most of samples by the use of Instrumental Neutron Activation Analysis (INAA) and hybrid K0&relative software developed by our lab. Elemental correlation analysis Enrichment factoranalysis and Positive matrix factorization were performed and six potential sourece of pollution were preliminarily identified. The source profile and relative contribution to receptor of determined soil/fly ash,constrction locate,incinerator,sea spary,exaust and non-ferror was deduced by PMF2. Among them,soil and fly ash contributes 40% to receptor.Enrichment factor analysis were also performed to identify possible sources in Beijing urban area with die data measured in the study. The fine particles usually have larger EFs than coarse ones for pollution elements;EF values of Al,Ba,Ca,Ce,Mg,Dy,La,Lu,Sm,Tb,Yb,Ta,V,Th,Hf,Sc,Fe,Mg,Ti are close to one,indicating their dust and soil origin. The same conclusion can be drawn from the factor analysis. The elements having prominently high EFs such as As,Br,Cd,Hg,I,In,Se,Sb,S,Zn,etc.,clearly indicate their anthropogenic pollution origin. Some interesting correlation was found between sandstorm episodes and elements concentrations variation. The concentrations of pollution elements such as As,Cl,Sb,W,Zn decrease compared to those at "normal conditions" . It indicates that theseelements were not transported by the storm,but had local origin and dispersed and diluted by thestorm.