Particle Size Distribution Of Carbonaceous Particulate Matter In Shanghai

Airborne particle has attracted much attention because of its impact on theatmospheric environment, thermal balance for global and region, climate and humanhealth. As the recent haze arisen and lasted for increasingly long in many areas inChina, the aerosol particle, especially for the particulate matter2.5(PM2.5), wasgetting more and more concerned by the public.The carbonaceous particulate matter was the main component caused by theabove-mentioned effects. Different carbonaceous components, including elementalcarbon (EC) and organic carbon (OC), had differences in their physical and chemicalproperties, impacted on the environment differently. Therefore, for the analysis of thecarbonaceous component of atmospheric particulate matter and sources resolutionbecame a hot issue for the present study. This paper adopted the method of TOR toresearch the carbon component in particle size distribution of atmospheric particulatesin Shanghai, based on stable carbon isotope techniques, took the qualitative analysisof the different components of the carbonaceous pollution source.This paper set two sampling points with regional representative for sampling,from May2010to May2010in Jiading District and Xuhui District, had an analysis ofparticulate matter in the carbon components of the particle size distribution, and usedthe EC tracer method to estimate the size distribution of SOC. The results showed that:the particle size distribution of the carbonaceous component in Shanghai presented abimodal distribution, with the peaks in less than0.95μm and larger than3.0μmparticle size range. OC and EC were mainly distributed within the fine particles in theparticle diameter of less than3.0μm. In Jiading District, OC and EC massconcentration in various particle size were higher than in Xuhui District. This resultreflected the characteristics of Shanghai industry layout: center city as a business district pollution degree was relatively low, while suburban district of industrialpollution was more serious. Within the sampling period, the characteristic of seasonalchange was obvious in Jiading District, presented the source of carbon pollution wasmore complex. In Xuhui District, because of motor vehicle exhaust, particle massconcentration of the carbon component had no obvious seasonal fluctuations.Compared with other cities at home and abroad, the OC and EC mass concentration ofShanghai was in the medium level, SOC mass concentration was higher.This paper used OC/EC ratio and stable carbon isotope technique for qualitativeanalyzing the source of atmospheric particulates in the carbon components. In thispaper, the OC/EC ratio and combined with the stable carbon isotope techniques wereused to take the qualitative analysis of the sources of the carbonaceous component ofatmospheric particulate matter. Through the OC/EC value, atmospheric particulatematter particle size distribution can be found:<3.0μm particle size ranges, Xujiahuimore influenced by motor vehicle exhaust;>3.0μm particle size ranges, Xujiahui byroad dust more significant.Analyzing the values of δ13C in three sets of samples of different carboncomponents in May2010in Jiading District, the results showed that: the13Cconcentration of each particle size segment OC was significantly lower than EC,13Cconcentration of the different size showed no obvious trend. Combined with thesource term data, the particle size of OC was further affected by the motor vehicleexhaust, the coal was the main source of EC, motor vehicle exhaust had become oneof the main sources of carbon composition. OC and EC in Jiading District may beaffected by C3plant much more and had almost no influence of C4plants.