Study On Organic Matters And Heavy Metals Of PM_2.5 Particles In Suzhou

Haze and fog weather frequently has a serious effect on visibility of residents, in turn,affect the their health, PM_2.5 gradually entered the view of the ordinary people, has attracted the attention of them. Organic matter and heavy metals as the major component of particulate matter, the existence of great potential threat to the environment. To investigate and study organic matter and heavy metals of PM_2.5 particles of Suzhou atmosphere, and evaluate the air quality of Suzhou city. This topic from January to may,2015, monitoring PM_2.5 of Suzhou four functional areas, to analyze and determine the content of organic matter and heavy metals and their source. The content of this article probably can be summarized as the following aspects:1 Simply expounded the origin and harm of the organic matter and heavy metal elements in PM_2.5, and the research advances on the determination of organic compounds and metals both at home and abroad. Also, introduced an overview of research area in suzhou, and the different and application in sample pretreatment technology today.2 Experiment has proved the uniform distribution of particles on the membrane filter.So it can be used to optimize the conditions of ASE and research the pollution characteristics of organic matter and heavy metals by dividing a membrane filter. Using uniform method to get the best experimental sample optimization of ASE extraction conditions: extraction solvent is acetone and methylene chloride, volume ratio is 1:1.extraction temperature is 140 ?; the system pressure is 10 mpa; heating time is 5 min;static extraction time is 5 min; nitrogen purging is 60s; cycle 2 times.3 The monitoring datas from four sampling points of five months showed that, in January and February, PM_2.5 particles daily average concentration in four sampling was higher, almost all over the secondary standard of our country PM_2.5 daily mean value,PM_2.5 concentrations in February was highest, showed that environment is the most serious in February, and in April and May the air quality is better.4 PAHs in PM_2.5 were analyzed, according to the sampling area: from sampling points of PAHs in turn from high to low was: industrial park > scenic area > traffic arteries >residential area; According to the sampling time : February was most polluted, lowest concentration was in May. Respectively by using the ratio method and factor analysis method to analyze the sources of PAHs, the results showed: the most serious pollution areais industrial parks, the last one is district residential. In February, pollutants are hard to spread, so the total concentration of PAHs is highest, which is the lowest in May. Finally,through the factor analysis of the source of PAHs, and the results show that the source of PAHs mainly comes from the motor vehicle emission, high temperature heat source, diesel exhaust emission, the contribution rate is 51.02%, 22.83%, 13.05%.5 Metals in PM_2.5 were analyzed, according to the sampling time: the content of metals is highest in February, and the lowest in May, so the metal content in particulate matter that seasonal feature is obvious. According to the sampling area : the most serious pollution area was the scenic spot and traffic arteries, the last one was district residential And. Finally, through the enrichment factor method and factor analysis to analyze the metals source of PM_2.5, the results show that the Al?Cd is formed by natural and artificial sources, and Na?K?Ca are from man-made pollution, the other elements are all from natural source; Factor analysis results show that mainly comes from metallurgy chemical industry and automobile exhaust,soil dust, traffic, fuel oil, sea salt and contributed 33.831%?23.392%?15.003%,?7.29%and 6.038% of the total variance, respectively.