Great wall of solar panels to mitigate yellow dust storm

Mitigation of the large scale yellow dust storm is a serious problem facing China. We propose the approach of building windbreak walls equipped with solar panels in the proximity of dust origins. The solar panels generate electricity in the sunny days; the walls break the wind and remove airborne dusts based on the impactor principle during wind storms. Preliminary calculation indicates the walls may be able to remove the major fraction of the airborne dusts and the generated electricity could be significant. More detailed studies are needed to prove the feasibility of the approach.</p

Carbonaceous Aerosol Characteristics in Outdoor and Indoor Environments of Nanchang, China, during Summer 2009

A study of carbonaceous aerosol was initiated in Nanchang, a city in eastern China, for the first time. Daily and diurnal (daytime and nighttime) PM(2.5) (particulate matter with aerodynamic diameter &lt;= 2.5 mu m) samples were collected at an outdoor site and in three different indoor environments (common office, special printing and copying office, and student dormitory) in a campus of Nanchang University during summer 2009 (5-20 June). Daily PM(10) (particulate matter with aerodynamic diameter &lt;= 10 mu m) samples were collected only at the outdoor site, whereas PM(2.5) samples were collected at both indoor and outdoor sites. Loaded PM(2.5) and PK(10) samples were analyzed for organic and elemental carbon (OC, EC) by thermal/optical reflectance following the Interagency Monitoring of Protected Visual Environments-Advanced (IMPROVE-A) protocol. Ambient mass concentrations of PM(10) and PM(2.5) in Nanchang were compared with the air quality standards in China and the United States, and revealed high air pollution levels in Nanchang. PM(2.5) accounted for about 70% of PM(10), but the ratio of OC and EC in PM(2.5) to that in PK(10) was higher than 80%, which indicated that OC and EC were mainly distributed in the fine particles. The variations of carbonaceous aerosol between daytime and nighttime indicated that OC was released and formed more rapidly in daytime than in nighttime. OC/EC ratios were used to quantify secondary organic carbon (SOC). The differences in SOC and SOC/OC between daytime and nighttime were useful in interpreting the secondary formation mechanism. The results of (1) OC and EC contributions to PM(2.5) at indoor sites and the outdoor site; (2) indoor-outdoor correlation of OC and EC; (3) OC-EC correlation; and (4) relative contributions of indoor and outdoor sources to indoor carbonaceous aerosol indicated that OC indoor sources existed in indoor sites, with the highest OC emissions in 12 (the special printing and copying office), and that indoor EC originated from outdoor sources. The distributions of eight carbon fractions in emissions from the printer and copier showed obviously high OC1 (&gt; 20%) and OC2 (similar to 30%), and obviously low EC1-OP (a pyrolyzed carbon fraction) (&lt; 10%), when compared with other sources.</p

Chemical characterization of aerosol collected at Mt. Yulong in wintertime on the southeastern Tibetan Plateau

In order to evaluate the chemical composition of aerosol on the southeastern Tibetan Plateau, aerosol samples were acquired at Mt. Yulong during January to February, 2010. Eighteen elements (Al, Si, P, S, Ca, Ti, K, Cr, Mn, Fe, Ni, Zn, As, Br, Ba, Pb, Sb and Cu) and major water-soluble ions (SO42-, NO3-, Cl-, Na+, NH4+, K+, Mg2+, and Ca2+) were detected. The results show that Ca, Fe, Al, Si, S, K and Ti are major elements which mainly originate from crustal material, while SO42- and Ca2+ are the dominant anion and cation in the samples, respectively. Results of ion analysis indicate that our samples are alkaline and that the main compounds present are CaCO3, (NH4)(2)SO4, and CaSO4. The enrichment factors (EFs) determined for As, Br, Ca, Cu, S. Pb and Zn are greater than 10; in particular, EFs for As and Br are above 100. However, the high EF for As could be caused by crustal sources because the high level of As enrichment can be found commonly on the Tibetan Plateau. Analyses including Scanning Electron Microscope (SEM) observations, EF determinations, backward trajectories and correlation coefficients reveal that Al, Fe, Ca, Ti, Mn, Fe, K and Mg2+ mainly originate from crustal sources: Pb, Br, Cu, Ni, Zn and Sb come mainly from traffic-related emissions: and biomass burning influences Cl-, Br, S and P.</p

Chemical composition of rainwater at Lijiangon the Southeast Tibetan Plateau: influences from variousair mass sources

Daily rainwater samples collected at Lijiang in 2009 were analyzed for pH, electrical conductivity, major ion (SO42&minus;, Cl&minus;, NO3&minus;, Na+, Ca2+, Mg2+, and NH4+) concentrations, and &delta;18O. The rainwater was alkaline with the volume-weighted mean pH of 6.34 (range: 5.71 to 7.11). Ion concentrations and &delta;18O during the pre-monsoon period were higher than in the monsoon. Air mass trajectories indicated that water vapor from South Asia was polluted with biomass burning emissions during the pre-monsoon. Precipitation during the monsoon was mainly transported by flow from the Bay of Bengal, and it showed high sea salt ion concentrations. Some precipitation brought by southwest monsoon originated from Burma; it was characterized by low &delta;18O and low sea salt, indicating that the water vapor from the region was mainly recycled monsoon precipitation. Water vapor from South China contained large quantities of SO42&minus;, NO3&minus;, and NH4+. Throughout the study, Ca2+ was the main neutralizing agent. Positive matrix factorization analysis indicated that crustal dust sources contributed the following percentages of the ions Ca2+ 85 %, Mg2+ 75 %, K+ 61 %, NO3&minus; 32 % and SO42&minus; 21 %. Anthropogenic sources accounted for 79 %, 68 %, and 76 % of the SO42&minus;, NO3&minus; and NH4+, respectively; and approximately 93 %, 99 %, and 37 % of the Cl&minus;, Na+, and K+ were from a sea salt source.</p

Numerical Simulation of the Micro Environment in the Han Yang Mausoleum Museum

As a first underground museum in the world, whole sealed glass system is adopted in the Han Yang Mausoleum Museum to protect relics from the destruction by microbe and pollution in the atmosphere and to provide visitors a wonderful environment for enjoying the fantastic artwork closely from different angles. This study shows that, this method cannot completely stop relics from the destruction. The main reason is that, in the museum, the microbe growth and pollution spread are fairly significant to affect the protection of relics. This study numerically simulates the micro environment in the museum, including air movement, temperature and relative humidity by using the CFD software Fluent. The major findings are summaried as the followes: there are four air cyclones; temperature is getting lower from one side to another; and relative humidity profile is reversed, especially at the surface. This numerical result provides useful information for the protection of relics.</p

The fifth paleosol layer in the southern part of China’s Loess Plateauand its environmental significance

Through field investigations, dark redebrown lumpy ferruginous argillans (LFAs) and an underlying weathered loess layer under the fifth layer (S5 paleosol) were discovered in the Guanzhong Plain in the southern part of the Loess Plateau in northwest China&rsquo;s Shaanxi Province. The ultramicrotexture of the LFAs and their mineral and chemical compositions were analyzed. Experimental results showed that mixed illiteesmectite minerals comprise about 90% of the LFAs in mineral composition, with 40% SiO2 content and high Fe2O3 (about 10.0%) and Al2O3 (about 22.5%) contents in chemical composition. Neoformed microcrystalline grains of clay minerals dominated the LFAs. The micromineral crystal grains in the LFAs were mainly plates with some degree of alignment, giving the argillans crystalline optical properties. Red LFAs and weathered loess layers under the S5, and the depth to which Fe2O3 and CaCO3 from the S5 have been removed, indicate that chemical weathering was much stronger when the paleosol layers formed than that at present. While the S5 paleosol was developed, a subtropical climate prevailed in the southern Loess Plateau, with a mean annual temperature and rainfall about 4 C and 500 mm higher respectively than that at present. The adequacy in moisture in at least 4.2 m of the gravitational water zone during the formation of S5 was suitable for forest growth. During the warmest and moistest climate span of growth for 2.5 million years when S5 was formed, the Qinling Mountains lost its function as a climatic boundary between the subtropical and temperate zones of East Asia, when the summer air masses crossed the Qinling Mountains and reached the Guanzhong Plain, bringing rich precipitation.</p

UHPLC-Orbitrap mass spectrometric characterization of organic aerosol from a central European city (Mainz, Germany) and a Chinese megacity (Beijing)

Fine urban aerosol particles with aerodynamic equivalent dimeter ≤2.5 μm (PM2.5) were collected in Mainz (a city within the Rhine-Main area, the third largest metropolitan region in Germany) and Beijing (Chinese megacity). A solvent mixture of acetonitrile-water was used to extract the organic aerosol fraction (OA) from the particle samples. The extracts were analyzed by an ultrahigh resolution mass spectrometer (UHRMS) Orbitrap coupled with ultra-high-performance liquid chromatography (UHPLC) both in the negative and positive ion mode. The number of compounds observed in Beijing is a factor of 2–10 higher compared to Mainz. The clear differences on chemical composition of OA in the two cities were observed. The majority of organics in Beijing OA is characterized by lower elemental H/C and O/C ratio but a higher degree of unsaturation and a larger aromaticity equivalent (XC) compared to Mainz OA, suggesting that aromatics, which are related to direct combustion compounds (e.g., oxidized polycyclic aromatic hydrocarbon (PAH)), play an important role for OA in Beijing. A significant number of organosulfates (OSs) with long-carbon chain and low degree of unsaturation were observed in Beijing OA, indicating that long-chain alkanes emitted by vehicle might be their precursors

Effects of day-of-week trends and vehicle types on PM2.5-boundedcarbonaceous compositions

Carbonaceous compositions of PM2.5 were measured in the heart of Bangkok from 17th November 2010 to 19th January 2012, and a data set of 94 samples was constructed. Effects of day-of-week trends and vehicle types on PM2.5-bound TC, OC, and EC were carefully investigated. In this study, OC was the most important contributor to the total PM2.5 mass concentration. The average PM2.5-bound OC content measured at CHAOS (18.8 &plusmn; 9.18 &mu;g m&minus;3) was approximately 11 times higher than at Chaumont, Switzerland (1.7 &mu;g m&minus;3), but approximately five times lower than at Xi&#39;an, China (93.0 &mu;g m&minus;3). The application of diagnostic binary ratios of OC/EC and estimations of secondary organic carbon (SOC) coupled with autocorrelation plots (Box and Jenkins) highlight the enhanced impacts of traffic emissions, especially from diesel vehicles, on PM2.5-bound carbonaceous compositions on weekdays relative to weekends. Hierarchical cluster analysis (HCA) coupled with principal component analysis (PCA) underline the importance of diesel emissions as the primary contributors of carbonaceous aerosols, particularly during weekdays.</p

Molecular Distribution and Stable Carbon Isotopic Composition of Dicarboxylic Acids, Ketocarboxylic Acids, and alpha-Dicarbonyls in Size-Resolved Atmospheric Particles From Xi'an City, China

Size-resolved airborne particles (9-stages) in urban Xi&#39;an, China, during summer and winter were measured for molecular distributions and stable carbon isotopic compositions of dicarboxylic acids, ketocarboxylic acids, and alpha-dicarbonyls. To our best knowledge, we report for the first time the size-resolved differences in stable carbon isotopic compositions of diacids and related compounds in continental organic aerosols. High ambient concentrations of terephthalic (tPh, 379 +/- 200 ng m(-3)) and glyoxylic acids (omega C-2, 235 +/- 134 ng m(-3)) in Xi&#39;an aerosols during winter compared to those in other Chinese cities suggest significant emissions from plastic waste burning and coal combustions. Most of the target compounds are enriched in the fine mode (&lt;2.1 mu m) in both seasons peaking at 0.7-2.1 mu m. However, summertime concentrations of malonic (C-3), succinic (C-4), azelaic (C-9), phthalic (Ph), pyruvic (Pyr), 4-oxobutanoic (omega C-4), and 9-oxononanoic (omega C-9) acids, and glyoxal (Gly) in the coarse mode (&gt;2.1 mu m) are comparable to and even higher than those in the fine mode (&lt;2.1 mu m). Stable carbon isotopic compositions of the major organics are higher in winter than in summer, except oxalic acid (C-2), omega C-4, and Ph. delta C-13 of C-2 showed a clear difference in sizes during summer, with higher values in fine mode (ranging from -22.8 parts per thousand to -21.9 parts per thousand) and lower values in coarse mode (-27.1 parts per thousand to -23.6 parts per thousand). The lower delta C-13 of C-2 in coarse particles indicate that coarse mode of the compound originates from evaporation from fine mode and subsequent condensation/adsorption onto pre-existing coarse particles. Positive linear correlations of C-2, sulfate and omega C-2 and their delta C-13 values suggest that omega C-2 is a key intermediate, which is formed in aqueous-phase via photooxidation of precursors (e.g., Gly and Pyr), followed by a further oxidation to produce C-2.</p