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Han J.,Nankai University | Han B.,Chinese Research Academy of Environmental Sciences | Li P.,Nankai University | Li P.,Tianjin University of Technology | And 5 more authors.
Aerosol and Air Quality Research | Year: 2014

The chemical profiles of emission sources are indispensable for source apportionment using receptor models. To develop current knowledge of PM10 profiles, the chemical composition of major emission sources were analyzed in Xining. Samples of geological sources (soil dust, road dust and construction derived dust) and industrial fly ash were collected from representative portions using a plastic dustpan and brush and sampled on filters through a re-suspension chamber. Samples of coal combustion source and vehicle exhaust were collected directly on the filters using a dilution stack sampler. Chemical analysis included inductively coupled plasma mass spectrometry for 19 elements (Na, P, K, As, Rb, Mo, Cd, Sn, Sb, La, V, Cr, Mn, Co, Ni, Cu, Zn, T1, and Pb), inductively coupled plasma optical emission spectrometry for 7 elements (Al, Sr, Mg, Ti, Ca, Fe, and Si), ion chromatography for water-soluble ions (Na+, K+, Mg2+, Ca2+, F-, Cl-, NO3- and SO42-) and thermal/optical reflectance analysis for carbonaceous species. Crustal elements (Si, Al, Ca, Fe) predominated in geological sources, whereas trace elements (Pb, Cd, Cr, Zn and Ni) were predominant in industrial fly ash. An abundance of carbon and SO42- was present in coal-combustion source and vehicle exhaust. The coal-combustion boilers were a source of trace elements (Ti, Co, Sr, Sb, Tl). High concentrations of Pb and OC in soil indicated the strong influence of agriculture activities in Xining. Comparison of vehicle exhaust profiles indicated that natural gas was high environmental friendliness in comparison with petroleum products used as motor vehicles fuel. Differences in EC, Cd and NO3- between natural gas-powered and gasoline- or diesel-powered vehicle exhaust can be used to differentiate the two types of vehicle emission sources. Differences in source profiles and indicator species between Xining and other cities suggest that source profiles should be developed locally and updated frequently. © Taiwan Association for Aerosol Research.

Wu R.,Nanjing Institute of Environmental Sciences | Ge S.,CAS Nanjing Institute of Geography and Limnology | Xu L.,CAS Nanjing Institute of Geography and Limnology | Huaqing Z.,Qinghai Environmental Monitoring Center
Research of Environmental Sciences | Year: 2015

In the field of sanitary landfill technology, it is vital to choose the landfill bio-cover materials. The present study investigated the methane oxidation capacity of bio-cover (aged refuse+cow dung+sawdust) and factors including disposal age of aged refuse, temperature, moisture content and initial CH4 and O2 concentrations. The result showed that the disposal year of aged refuse was greatly important to the efficiency of CH4 oxidation. The rates of CH4 oxidation bio-cover B (10 a) and C (15 a) were much higher than bio-cover A (5 a). The optimum temperature and moisture content of CH4 oxidation capacity was 30℃ and 35%. Based on the Michaelis-Menten model, with the correlation coefficient R2=0.993, the maximum rate of methane oxidation Vmax was 5.21 μmol/(g·h) and the Michaelis-Menten constant Km was 5.48%. The bio-cover material even reduced CH4 in anaerobic condition, though the rate was slower compared to the aerobic condition. Approximately 83% of the CH4 was removed during 20 d incubation. Moreover, the bio-cover material produced N2O (a greenhouse gas) during drying-wetting cycle events. The N2O fluxes in the bio-cover with 70% (WPFS) were 1.96 times more than that of 46% (WPFS). The result suggests that landfill bio-cover materials which are mixed by refuse, cow dung and sawdust could efficiently reduce CH4, and the maximum rate of methane oxidation is one or two orders of magnitude faster than other commonly used materials. Therefore, new landfill bio-cover material can be applied to small and medium-sized landfill to reduce emissions of CH4. ©, 2015, Editorial department of Molecular Catalysis. All right reserved.

Shi L.N.,Qinghai Normal University | Xu X.,Qinghai Environmental Monitoring Center | Zhao X.D.,Qinghai Environmental Monitoring Center | Dou X.Y.,Qinghai Environmental Monitoring Center | Zhao Q.Q.,Haixi Mongolian
Advanced Materials Research | Year: 2014

The human risks of As and heavy metals (Cu, Ni, Cr, Pb, Cd and Hg) in fine particulate matter (PM2.5) in Xining, China is investigated here in this study. Cu, As and Pb are the most abundant elements in stationary monitoring station for atmospheric pollution and mountain Najia. As, Pb and Cr are the most abundant elements in the park of organisms and Xining Special Steel between the studied metals and metalloids in PM2.5. Pb and As showed a higher bio-accessibility. It has been shown that the carcinogenic risks of As, Cd, Cr and Ni in PM2.5 via dermal contact and inhalation exposure are within the acceptable level(<1×10-4) for both children and adults, but there is a potential carcinogenic risk posed by Pb via ingestion. As for non-carcinogenic health risks, the hazard index values for all the studied elements suggested no health risks via ingestion and dermal contact, but a potential one via inhalation of adults. Values of hazard quotient and hazard index indicated the non-carcinogenic risks from the studied metals and metalloids to children via ingestion, dermal contact and inhalation pathways during heating period in Xining given the present air quality. © (2014) Trans Tech Publications, Switzerland.

Zhao X.D.,Gansu Agricultural University | Zhang D.G.,Gansu Agricultural University | Shi L.N.,Qinghai Normal University | Yang Y.S.,Qinghai Environmental Monitoring Center
Advanced Materials Research | Year: 2013

The depth variations of soil physicochemical properties in the degraded native grasslands and the artificially restored grasslands were studied in the Three-river headwater areas of Qinghai-Tibetan plateau, China. The results showed: (1) With the increase of the gradient of restoration years, soil water content, total chemical properties, total potassium, phosphorus, available phosphorus and potassium were increased thereafter in the artificial grasslands. (2) With the increase of grassland degradation gradient, soil water content was gradually reduced, and the total N, K, the organic matter didn't gradually reduced also. (3) Both restoration years and degradation degree didn't influence the nutrient distribution in soil. (4) The organic matter, total N and K of degraded grassland were increased by artificial grassland construction. Therefore, artificial grassland construction canbe used as an effective measure of ecological projects in the Three-river headwater area. © (2013) Trans Tech Publications, Switzerland.

Shi L.N.,Qinghai Normal University | Xu X.,Qinghai Environmental Monitoring Center | Dou X.Y.,Qinghai Environmental Monitoring Center | Zhao X.D.,Qinghai Environmental Monitoring Center
Advanced Materials Research | Year: 2014

PM2.5 is one of the most important components in air pollution. It is also the focus of the most closely watched at home and abroad. Based on its small size, complex components, and strongenvironmental activity, it can be used as a carrier for chemicals, heavy metals, bacteria, toxins and carcinogens into the body. Then, as a result, it will affect Human Body Health. Heavy metals are important components of PM2.5, and the long-term accumulation of heavy metals in PM2.5 poses a great threat on human health and the environment. This paper reviewed the sources, distribution methods,chemical form, detection methods, disposal way, research progress of heavy metals in PM2.5. As a result, it provided a reference for in-depth study on the future. © (2014) Trans Tech Publications, Switzerland.

Lina S.,CAS Northwest Institute of Plateau Biology | Lina S.,University of Chinese Academy of Sciences | Fei R.,CAS Northwest Institute of Plateau Biology | Fei R.,University of Chinese Academy of Sciences | And 3 more authors.
JAOCS, Journal of the American Oil Chemists' Society | Year: 2010

The seed oil of Microula sikkimensis had been intensively studied due to its pharmacological actions. In the present study, seed oil of Microula sikkimensis was extracted using supercritical fluid extraction (SFE). Determinations of the extracts composition were performed by gas chromatography (GC). An orthogonal array design (OAD), OA9 (34, was employed for optimization of the supercritical fluid extraction of the compound with regard to the various parameters. Four factors, namely pressure (21.0-27.0 MPa), the dynamic extraction time, temperature, and Co2 flow rate of the supercritical fluid, were studied and optimized by a three-level OAD. The effects of the parameters on the yieId of seed oil were studied using analysis of variance (ANOVA). The results revealed that the pressure had a significant effect on the yield of seed oil (p < 0.05), while the other three factors, i.e., Co2 flow rate, dynamic extraction time and temperature, were not identified as significant factors under the selected conditions based on ANOVA. The results show that the best values for the extraction condition of seed oil was pressure 24.0 MPa, extraction time 3 h, temperature 45 °C and a Co2 flow rate 20 L/h in the 20-L vessel. © AOCS 2010.

Li W.J.,Shandong University | Chen S.R.,Shandong University | Xu Y.S.,Chinese Research Academy of Environmental Sciences | Guo X.C.,Shandong University | And 8 more authors.
Atmospheric Chemistry and Physics | Year: 2015

Transmission electron microscopy (TEM) was employed to obtain morphology, size, composition, and mixing state of background aerosols with diameter less than 1 μm in the northern Qinghai-Tibet Plateau (QTP) during 15 September to 15 October 2013. Individual aerosol particles mainly contained secondary inorganic aerosols (SIA-sulfate and nitrate) and organics during clean periods (PM2.5 mass concentration less than 2.5 μgm-3). The presence of K-Na-Cl associated with organics and an increase in soot particles suggest that an intense biomass burning event caused the highest PM2:5 concentrations (>30 μgm-3) during the study. A large number fraction of the fly-ashcontaining particles (21.73 %) suggests that coal combustion emissions in the QTP significantly contributed to air pollutants at the medium pollution level (PM2.5: 10-30 μgm-3). We concluded that emissions from biomass burning and from coal combustion both constantly contribute to anthropogenic particles in the QTP atmosphere. Based on size distributions of individual particles at different pollution levels, we found that gas condensation on existing particles is an important chemical process for the formation of SIA with organic coating. TEM observations show that refractory aerosols (e.g., soot, fly ash, and visible organic particles) likely adhere to the surface of SIA particles larger than 200 nm due to coagulation. Organic coating and soot on surface of the aged particles likely influence their hygroscopic and optical properties, respectively, in the QTP. To our knowledge, this study reports the first microscopic analysis of fine particles in the background QTP air. © 2015 Author(s).

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