Study On The Methods Of Analysis And Source Apportionment Of Organic Pollutants In Ambient Air

In this paper, methods of separation and analysis and technologies of source apportionment of the organic pollutants in ambient air were summarized. On the basis of above introductions, the technologies of sampling, pretreatment, separation and analysis of organics in particles and vapour phase in ambient air were respectively and systematically studied in detail. At the same time, the methods of separation and analysis of organics in ambient air were set up and polycyclic aromatic hydrocarbons (PAHs) of ambient air and pollution sources in Jinan were analyzed through these methods. Subsequently the source apportionment of PAHs in TSP were identified and analyzed by specific ratios and the receptor model of chemical mass balances (CMB) respectively. In the end the model and method of source apportionment of the pollution by PAHs of ambient air in Jinan were created, which established the basis of controlling and managing the environmental pollution effectively. The main contents of the paper are as follows1. Study on the analytical method of organic pollutants by collection, Soxhlet extraction and GC/MS analysis in total suspended particulates.Samples of total suspended particles in the atmosphere were collected on glass fibre filters by high-volume samplers, organic pollutants of which were extracted by Soxhlet extractors, concentrated by Kuderna-Danish apparatus and analyzed qualitatively and quantitatively by GC/MS. The factors impacting the extraction efficiency of Soxhlet extraction of organic compounds in airborne particulates were studied systematacially, which were extraction time, recycle rate, the proportion of solvents and samples, solvents and so on. On the basis of these studies we founded the optimal conditions of sample collection, Soxhlet extraction, K-D concentration. It was shown that extraction efficiency would get optimum when extraction time was 24h,recycle rate was 3-4 times per hour and the proportion of dichloromethane and sample was between 140 and 220 mL per gram. The RSD of six parallel samples was 3.6% and average recovery rate 81.8%. Under this condition, seventy-four kinds of organic pollutants were identified and seventy-three kinds of them were analyzed qualitatively by GC/MS computer retrieval analysis and manual index, which included n-alkanes, aromatic compounds, benzene series compounds etc. and made up 99.8% of the total.2. Study on the analytical method of organic pollutants of gaseous by adsorption trapping and GC/MS analysis in ambient air.The organic pollutants from the atmosphere in Jinan City were absorbed and captured by using KB-6C Atmosphere Sampling Instrument. The capability of three different kinds of adsorbents, which are GDX-101, GDX-102 and GDX-502, and the effection of other conditions on sampling efficiency were researched and compared carefully. The organic compounds from each sample were extracted by Soxhlet Extraction with dichloromethane as extraction solvent, concentrated by Kudema-Danish apparatus, purified and separated by selfinade silica gel column, and analyzed qualitatively and quantitatively by GC/MS. It was shown that thirty-nine kinds of pollutants were identified and thirty-six kinds of pollutants were analyzed qualitatively by GC/MS analysis which made up 94.73% of the total. These organic pollutants belonged to n-alkanes, PAHs and benzene series compounds.3. Study on the analytical method of organic pollutants by supercritical fluid extraction and GC/MS analysis in the fly-ash of coke ovens.On the basis of the research of fly-ash of coke ovens sampled from a steel mill we used the technique of supercritical fluid extraction of CO2 (SFE-CO2) and studied systemically the impact of temperature, pressure, amount of SF-CO2, modifiers and other factors on the extraction efficiency. Through this study we optimized the extraction conditions and analyzed in theory.It was shown that when extraction pressure was 50MPa, extraction temperature was 120°C, dynamic extraction time was 60min with using 5% methanol or acetone as modifiers the extraction efficiency got maximums. Under this condition, a factualsample was extracted by SF-CO2 and analyzed qualitatively and quantitatively by GC/MS. As a result, we got forty kinds of main organics, including alkanes, aromatic hydrocarbons, alcohols, aldehyde, acid, ester and nitrogenous compounds. At the same time some PAHs were measured, which were harmful to people's health. The RSD of six parallel samples was 1.9% and average recovery rate was 92.3%.4. GC/MS analysis of PAHs of ambient air in Jinan city.With the method of sampling, soxhlet extraction and GC/MS analysis the concentration of PAHs in TSP at nine optimization situs in Jinan city and in two majoy types of pollution sources, coal and vichicle, were determinated respectively. It was shown that average concentration of BaP of the whole city was 48.45ng/m3 during heating season and the pollution condition of organics was comparatively serious. At the same time the total discharge concentration of 16 PAHs, which were priority polluntants, coming from burning coal and vechicle were 54.62^g/mJ and 3.31ug/mJ respectively.5. Source apportionment of PAHs of ambient air in Jinan city.We made a conclusion that PAHs of TSP in Jinan city which led to the pollution of organics mainly came from burning coal by means of comparing specific ratio and chemical mass balance (CMB) receptor model. When identifying the sources of PAHs in TSP through comparing some different groups of specific ratio, the characteristic ratio of BaP/PYR and PHE/ANT could comparatively accurately showed that the contribution of burning coal is the majoy part of pollution of PAHs. A consistent conclusion was gotten by use of CMB receptor model and the contribution to ambient pollution of PAHs by burning coal and vehicle was respectively 62.22% and 8.20%, which was another powerful proof that PAHs of TSP mostly orgined from burning coal.