Concentrations of atmospheric PM10 and chemical components (including twenty-one elements, nine ions, organic carbon (OC) and elemental carbon (EC)) were measured at five sites in a heavily industrial region of Shenzhen, China in 2005. Results showed that PM10 concentrations exhibited the highest values at 264 μg/m3 at the site near a harbor with the influence of harbor activities. Sulfur exhibited the highest concentrations (from 2419 to 3995 ng/m3) of all the studied elements, which may be related to the influence of coal used as fuel in this area for industrial plants. This was verified by the high mass percentages of SO42-, which accounted for 34.3%-39.7% of the total ions. NO3-/SO42- ratios varied from 0.64-0.71, which implies coal combustion was predominant compared with vehicle emission. The anion/cation ratios range was close to 0.95, indicating anion deficiency in this region. The harbor site showed the highest OC and EC concentrations, with the influence of emission from vessels. Secondary organic carbon accounted for about 22.6%-38.7% of OC, with the highest percentage occurring at the site adjacent to a coal-fired power plant and wood plant. The mass closure model performed well in this heavily industrial region, with significant correlation obtained between chemically determined and gravimetrically measured PM10 mass. The main constituents of PM10 were found to be organic materials (30.9%-69.5%), followed by secondary inorganic aerosol (7.9%-25.0%), crustal materials (6.7%-13.8%), elemental carbon (3.5%-10.8%), sea salt (2.4%-6.2%) and trace elements (2.0%-4.9%) in this heavily industrialized region. Principal component analysis indicated that the main sources for particulate matter in this industrial region were crustal materials and coal/wood combustion, oil combustion, secondary aerosols, industrial processes and vehicle emission.
Gang WuXin DuXuefang WuXiao FuShaofei KongJianhua ChenZongshuang WangZhipeng Bai
The reaction of alkenes with ozone has great effect on atmospheric oxidation,its transient species can produce OH radicals and contribute to the formation of secondary organic aerosols(SOA).In the present study,the reaction of tetramethylethene(TME) with ozone was investigated using self-assembled low temperature matrix isolation system.The TME and ozone were co-deposited on a salt plate at 15 K,and then slowly warmed up the plate.The first transient species primary ozonide(POZ) was detected,indicating that the reaction followed Criegee mechanism.Then POZ began to decompose at 180 K.However,secondary ozonide(SOZ) was not observed according to Criegee mechanism.Probably,Criegee Intermediate(CI) did not react with inert carbonyl of acetone,but with remaining TME formed tetra-methyl epoxide(EPO).
Xiaolu YangJianguo DengDong LiJianhua ChenYisheng XuKai ZhangXiaona ShangQing Cao
