| Atmospheric particles are important factors which can make visibility decrease and form haze pollution.Carbonaceous components of particles not only affect the hygroscopicity of particles but also contribute to climate change.Therefore,it is important to study the characteristics of carbonaceous components in atnospheric particles.In this study,PM2.5 samples were collected for one and a half years at the site of Xuhui campus in East China University of Science and Technology(ECUST)in Shanghai.Organic carbon(OC),elemental carbon(EC),water-soluble organic carbon(WSOC)and humic-like substance carbon(HULIS-C)m PM2.5 were detected,and their characteristics and sources were discussed.In addition,size-segregated aerosol samples(0.056?18 ?m)were collected for one year at the site of the Hong Kong University of Science and Technology(HKUST)in Hong Kong.Size-segregated WSOC and HULIS concentrations were analyzed,and their size distributions were discussed.The characteristics of carbonaceous components for atmospheric particles in Shanghai and Hong Kong were compared in order to provide the reference for further research of size distributions for particles in Shanghai.Results indicated that in sampling time from 2011 to 2013 in Shanghai,PM2.5 mass concentrations were 10.77?233.14 ?g·m-3,with higher concentrations in spring and winter while lower concentrations in summer and fall.The annual average mass concentrations of oC and EC were(10.65±7.17)?g·m-3 and(1.95±1.21)?g·m-3,which accounted for 16.5%and 3.2%of PM2.5,respectively.The mass concentrations of secondary organie carbon(SOC),particle-phase volatile organic carbon(PVOC)and particle-phase non-volatile organic carbon(PNVOC)were 0.15?16.77 0.67?13.40 ?g·m-3 and 1.77?32.91 respectively,which showed higher concentrations in fall and winter while lower concentrations in spring and summer.The annual average mass concentrations of char-EC and soot-EC were(1.64±1.22)?g·m-3 and(0.31±0.13)?g·m-3,which accounted for 84.1%and 15.9%of EC,respectively.The annual average mass concentrations of WSOC and HULIS-C were(4.21±1.83)?g·m-3 and(2.69±1.36)?g·m-3,respectively,which showed higher concentrations in spring and winter while lower concentrations in sununer and fall.In sampling time from 2011 to 2012 in Hong Kong,the mass concentrations of water-soluble organic mass(WSOM)and HULIS in 0.056?18 ?m particles were 2.09?13.06 ?g·m-3 and 0.42?6.08 ?g·m-3,respectively.WSOC and HULIS concentrations were highest in droplet mode,accounting for 67.2%±16.7%and 74.7%±16.1%of total conceltrations,respectively,which indicated that WSOC and HULIS were mainly in 0.2?4.0 ?m particles.The relationships of carbonaceous components in PM2.5 showed that the PVOC./TC ratio was high indicating that the contribution of volatile organic compounds to PM2.5 should not be neglected.However,the soot-EC/TC ratio was lowest(1.5%?4.9%).The annual average ratio of WSOC/OC was 47.3%±20.0%,indicating that WSOC was an important components in OC.Oxalic acid,acetic acid,formic acid and methylsulfonic acid only accounted for 2.77%±1.48%of WSOC,while HULIS-C accounted for 62.8%±11.8%of WSOC,which indicated HULIS-C was the predominant component of WSOC.The mass concentrations of PM2.5 and carbonaceous components showed different values in haze and non-haze episodes.Analysis the sources of carbonaceous components in PM2.5 showed that the contribution from local combustion sources should not be neglected.The carbonaceous components concentrations in spring and fall may attribute to biomass burning source.Comparation of carbonaceous components characteristics for atmospheric particles in Shanghai and Hong Kong implied that OC/TC ratios for fine particles were similar in the two cities,with WSOC/OC ratios around 50%.And HULIS-C were the predominant component of WSOC in the two cities,indicating that there are similar characteristics of carbonaceous components for atmospheric particles in Shanghai and Hong Kong. |
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