Research on flux of dry atmospheric falling dust and its characterization in a subtropical city, Guangzhou, South China

Guangzhou is the central city in the Pearl River Delta (PRD), China, and is one of the most polluted cities in the world. To characterize the ambient falling dust pollution, two typical sampling sites: urban (Wushan) and suburban (University Town) areas in Guangzhou city were chosen for falling dust collection over 1 year at time intervals of 1 or 2 months. The flux of dry deposition was calculated. In addition, mineral composition and morphology of atmospheric falling dust were studied by X-ray diffraction, scanning electron microscopy, and microscopic observation. The results revealed that the dust flux in Guangzhou city was 3.34–3.78 g/(m2 month) during the study period. The main minerals in the dust were quartz, illite, calcite, kaolinite, gypsum, plagioclase, dolomite, and amorphous matter. The morphological types included grained and flaky individual minerals, chain-like aggregates, spherical flying beads, and irregular aggregates, with the chain-like and spherical aggregates indicators of industrial ash. The major dusts were derived from industrial and construction activities. The gypsum present in the dust collected in winter season was not only derived from cement dust but may also have originated from the reaction of calcic material with sulfuric acids resulting from photooxidation of SOx and NOx, which confirmed serious air pollution due to SOx and NOx in Guangzhou. The abatement of fossil fuel combustion emissions and construction dust will have a significant beneficial effect on dust reduction

Emission of PAHs, NPAHs and OPAHs from residential honeycomb coal briquette combustion

Coal combustion is one of the most significant sources of air pollution in China. In this study, emission factors (EFs) of 15 polycyclic aromatic hydrocarbons (PAHs), 26 nitrated PAHs (NPAHs) and 6 oxygenated PAHs (OPAHs) were determined in five different coals with different geological maturity (vitrinite reflectance <i>R</i>_O = 0.77–1.88%) burned in the form of honeycomb briquettes. The total EFs ranged from 9.82 to 215 mg kg^–1 for PAHs, 0.14 to 1.88 mg kg^–1 for NPAHs and 4.47 to 20.8 mg kg^–1 for OPAHs. Measured EFs and gas-particle partitioning varied depending on the geological maturity. The lowest EFs were found in anthracite. The proportion of PAHs, NPAHs and OPAHs in gaseous phase increasing with increased geological maturity. The coal with higher geological maturity produced more 3-ring PAHs. On the basis of the statistical analysis for the residential sector of China in 2008, PAHs, NPAHs and OPAHs emitted from residential honeycomb coal briquettes were 4.36 Gg, 0.03 Gg and 0.47 Gg in 2007, respectively. By 2020, the emission would decrease to 2.18 Gg, 0.02 Gg and 0.24 Gg for PAHs, NPAHs and OPAHs due to the increasing usage of new energy resources. If only anthracite is used as the residential coal, 93% PAHs, 87% NPAHs and 71% OPAHs would be reduced in 2020

Progress in generation kinetics studies of coal-derived gases

Hydrocarbon-generation kinetics is of applicable significance in the study of coal-derived gas pool formation. Its research progress in recent years includes: in combination with geothermal history, it is used as a tool to evaluate source rocks dynamically and depict the change of source kitchen with geological time; according to the carbon isotope fractionation kinetics, a more precise model of identifying coal-derived gas is developed, which contains the kinetic relationship among gas compounds; the combination of compositional kinetics and carbon isotopic kinetics leads to the study method of accumulation processes of coal-derived gases, which is constrained precisely by multi kinetic indices; with the reservoir records, generation kinetics is used to study the whole gas life including generation, charge and alteration. The problems that need investigation are generation kinetics of coal-derived gas at low maturity, pressure effects on gas generation, minerals and water influences, and kinetics of residual soluble organic matter at high maturity. Key words: coal, natural gas, coal-derived gas, generation kinetics, progres

Water quality remediation in a heavily polluted tidal river in Guangzhou, South China

A field-scale experiment was performed to remediate a heavily polluted river located in the urban area of Guangzhou, China using biological and chemical techniques combined with engineering processes. Before comprehensive remediation was undertaken, several small-scale experiments to test river-water remediation techniques were successfully performed. After comprehensive remediation, the average reduction rates of chemical oxygen demand and biochemical oxygen demand and removal rates of other pollutants were all above 70 percent. Furthermore, the unpleasant odor emanating from the polluted river was also greatly reduced. The field-scale experiment thus indicated the feasibility and validity of the method applied to remediate this heavily polluted river; this method can therefore be applied to remediate other heavily polluted rivers in the Guangzhou urban area and elsewhere.A field-scale experiment was performed to remediate a heavily polluted river located in the urban area of Guangzhou, China using biological and chemical techniques combined with engineering processes. Before comprehensive remediation was undertaken, several small-scale experiments to test river-water remediation techniques were successfully performed. After comprehensive remediation, the average reduction rates of chemical oxygen demand and biochemical oxygen demand and removal rates of other pollutants were all above 70 percent. Furthermore, the unpleasant odor emanating from the polluted river was also greatly reduced. The field-scale experiment thus indicated the feasibility and validity of the method applied to remediate this heavily polluted river; this method can therefore be applied to remediate other heavily polluted rivers in the Guangzhou urban area and elsewhere

Effects of temperature parameters on thermal-optical analysis of organic and elemental carbon in aerosol

Il contributo si sofferma sull\u2019uso delle opere di Sabino nella giurisprudenza antoniniana, prendendo in considerazione, in particolare, la produzione scientifica di Giuliano, Pomponio, Venuleio, Gaio, Marcello e Scevola. Tutte le citazioni dei giuristi di et\ue0 antoniniana concernenti la produzione di Sabino sono prive di indicazioni relative al luogo in cui le opinioni tramandate sono state espresse, e, pertanto, inserite da Otto Lenel in un Index locorum, quibus non indicato libro aut Sabinus aut Sabiniani laudantur. Dall\u2019analisi delle fonti, emerge che i giuristi di et\ue0 antoniniana davano conto delle opinioni espresse da Sabino, non solo attingendo direttamente alla sua produzione, ma anche attraverso le opere dei suoi auditores, Gaio Cassio Longino, Minicio, Fufidio, Urseio Feroce.Der Beitrag befasst sich mit der Verwendung der Werke des Sabinus in der Zeit der Antoninen, wobei insbesondere auf die wissenschaftlichen Schriften von Julianus, Pomponius, Venuleius, Gaius, Marcellus und Scaevola eingegangen wird. Keines der die wissenschaftlichen Schriften des Sabinus betreffenden Zitate in der Zeit der Antoninen enth\ue4lt einen Hinweis darauf, wo die u\u308berlieferten Meinungen zum Ausdruck gebracht worden sind; sie wurden daher von Otto Lenel vorsichtshalber in einen Index locorum, quibus non indicato libro aut Sabinus aut Sabiniani laudantur eingetragen. Die Analyse der Quellen zeigt, dass die Juristen im Zeitalter der Antoninen die Meinungen Sabinus nicht nur direkt seinen Werken entnommen haben, sondern auch den Werken seiner auditores, Gaius Cassius Longinus, Minicius, Fufidius, Urseius Ferox