Mass Concentration Ratio Research Articles

Soil Carbon and Nutrient Dynamics Following Cessation of Anthropogenic Disturbances in Degraded Subtropical Forests

AbstractSoil carbon (C) and nutrient availability is fundamental to terrestrial biodiversity and functionality. In recent decades, the restoration of degraded forests has become a major concern worldwide, and recent studies have demonstrated that soil C and nitrogen (N) increase over time following restoration. However, our understanding of the responses of soil phosphorus (P), calcium (Ca), potassium (K) and magnesium (Mg) and elemental stoichiometric ratios to restoration remains elusive. We employed a chronosequence to examine the responses of C and macronutrients in three soil layers (0–10 cm, 10–20 cm and 20–30 cm) to the time (0 to 31 years) since the cessation of anthropogenic disturbances in the degraded subtropical forests of Eastern China. We found that stand basal area, soil water content, organic matter content and C concentration and stock increased, while soil pH and bulk density decreased over time, with the most pronounced effects within the 0–10 cm layer. Total and available N and K as well as available P and total Mg increased, while total P in the 20–30 cm layer and Ca in all soil layers decreased over time. The mass concentration ratios of soil C to total N and available N, P and K decreased, whereas those for C to total P and Ca as well as total N to total P and available N to available P increased over time. Our results suggest that soil C accumulation and biologically driven nutrients increase, while nutrients that are driven primarily through geochemical mechanisms decrease with live biomass accumulation following restoration. Copyright © 2017 John Wiley & Sons, Ltd.

Secondary formation of oxalic acid and related organic species from biogenic sources in a larch forest at the northern slope of Mt. Fuji

To better understand the formation of water-soluble organic aerosols in the forest atmosphere, we measured low molecular weight (LMW) dicarboxylic acids, oxocarboxylic acids, α-dicarbonyls, unsaturated fatty acids (UFAs), and water-soluble organic carbon (WSOC) in aerosols from a Larix kaempferi forest located at the northern slope of Mt. Fuji, Japan, in summer 2012. Concentrations of dicarboxylic acids, oxocarboxylic acids, α-dicarbonyls, and WSOC showed maxima in daytime. Relative abundance of oxalic acid in LMW dicarboxylic acids was on average 52% and its average concentration was 214 ng m−3. We found that diurnal and temporal variations of oxalic acid are different from those of isoprene and α-pinene, whereas biogenic secondary organic aerosols (BSOAs) derived from isoprene and α-pinene showed similar variations with oxalic acid. The mass concentration ratios of oxalic acid/BSOAs were relatively constant, although a large variation in the concentrations of toluene that is an anthropogenic volatile organic compound was observed. These results suggest that formation of oxalic acid is associated with the oxidation of isoprene and α-pinene with O3 and other oxidants in the forest atmosphere. In addition, concentrations of UFAs were observed, for the first time, to decrease dramatically during daytime in the forest. Mass concentration ratios of azelaic acid to UFAs showed a positive correlation with O3, suggesting that UFAs are oxidized to yield azelaic acid, which may be further decomposed to oxalic acid in the forest atmosphere. We found that contributions of oxalic acid to WSOC are significantly high ranging from 3.7 to 9.7% (average 6.0%). This study demonstrates that forest ecosystem is an important source of oxalic acid and other dicarboxylic acids in the atmosphere.

Heteroaggregation of Graphene Oxide with Nanometer- and Micrometer-Sized Hematite Colloids: Influence on Nanohybrid Aggregation and Microparticle Sedimentation.

Heteroaggregation of graphene oxide (GO) with nanometer- and micrometer-sized hematite colloids, which are naturally present in aquatic systems, is investigated in this study. The heteroaggregation rates between GO and hematite nanoparticles (HemNPs) were quantified by dynamic light scattering, while the heteroaggregation between GO and micrometer-sized hematite particles (HemMPs) was examined through batch adsorption and sedimentation experiments. The heteroaggregation rates of GO with HemNPs first increased and then decreased with increasing GO/HemNP mass concentration ratios. The conformation of GO-HemNP heteroaggregates at different GO/HemNP mass concentration ratios was observed through transmission electron microscopy imaging. Initially, GO underwent heteroaggregation with HemNPs through electrostatic attraction to form primary heteroaggregates, which were further bridged by GO to form bigger clusters. At high GO/HemNP mass concentration ratios where GO outnumbered HemNPs, heteroaggregation resulted in the formation of stable GO-HemNP nanohybrids that have a critical coagulation concentration of 308 mM NaCl at pH 5.2. In the case of HemMPs, GO adsorbed readily on the microparticles and, at an optimal GO/HemMP ratio of ∼0.002, the sedimentation of HemMPs was the fastest, most likely because of the formation of "electrostatic patches" leading to favorable aggregation of the microparticles.

Biokinetics of yttrium and comparison with its geochemical twin holmium

The transition metal yttrium (Y, atomic number 39) is chemically similar to elements in the lanthanide family (atomic numbers 57–71) and is found with the lanthanides in rare earth ores. Yttrium and the lanthanide holmium are referred to as geochemical twins because they generally show little fractionation from metamorphic or weathering processes, due to their closely similar chemical properties and nearly identical ionic radii. Extensive measurements on rocks, soils, and meteorites indicate that the Y/Ho mass concentration ratio rarely falls far from the so-called chondritic or solar system ratio of ∼26. This paper presents a new biokinetic model for yttrium in adult humans and examines whether yttrium and holmium may be biological as well as geochemical twins, considering model-based comparisons of their systemic behaviours in adult humans and model-free comparisons of their concentration ratios in human tissues and various types of vegetation. It appears that yttrium and holmium behave similarly in the human body and that their concentration ratios tend to cluster near the chondritic value in human tissues as well as plants, but the comparative information is too limited and imprecise to determine whether they are extremely close biological analogues.

Theoretical and Experimental Study for the Effect of Mass Flow Rate and concentration ratio of PTC Close Type Solar Collector in Kirkuk City

Theoretical and Experimental Study for the Effect of Mass Flow Rate and concentration ratio of PTC Close Type Solar Collector in Kirkuk City

Simultaneous chemical oxygen demand removal, methane production and heavy metal precipitation in the biological treatment of landfill leachate using acid mine drainage as sulfate resource

Biological treatment played an important role in the treatment of landfill leachate. In the current study, acid mine drainage (AMD) was used as a source of sulfate to strengthen the anaerobic treatment of landfill leachate. Effects of chemical oxygen demand (COD) and SO42- mass concentration ratio on the decomposition of organic matter, methane production and sulfate reduction were investigated and the microbial community was analyzed using the high throughout methods. Results showed that high removal efficiency of COD, methane production and heavy metal removal was achieved when the initial COD/SO42- ratio (based on mass) was set at 3.0. The relative abundance of anaerobic hydrogen-producing bacteria (Candidatus Cloacamonas) in the experimental group with the addition of AMD was significantly increased compared to the control. Abundance of hydrogenotrophic methanogens of Methanosarcina and Methanomassiliicoccus was increased. Results confirmed that AMD could be used as sulfate resource to strengthen the biological treatment of landfill leachate.

Experimental Investigation on Heat Transfer Performance of a Flat Plate Heat Pipe With MWCNTS-Acetone Nanofluid

This paper experimentally investigates how different mass concentration and aspect ratio multiwall carbon nanotubes (MWCNTs) acetone nanofluid affects the heat transfer performance of a flat plate heat pipe (FPHP). Different mass concentration and aspect ratio MWCNTs-acetone nanofluids are prepared without any surfactants or additives using the two-step method. Aspect ratios of MWCNTs are 666 (M1) and 200 (M2), respectively, and their according mass concentrations are 0.002, 0.005, 0.01, and 0.015 wt. %, respectively. The thermal resistance and wall temperature of the FPHP are experimentally obtained when the above-mentioned nanofluids are used as working fluid. The results showed that different mass concentration affects the heat transfer performance, therefore, there is an optimal MWCNTs-acetone nanofluid mass concentration (about 0.005wt. %). Also, the results showed that the thermal resistances of the FPHP with M1-acetone nanofluid (0.005 wt. %) and M2-acetone nanofluid (0.005 wt. %) are reduced 40% and 16%, respectively. Based on the above experimental phenomenon, this paper discusses the reasons for enhancement and decrement of heat transfer performance of the different mass concentration. For the M1-acetone nanofluid, the investigated FPHP has a thermal resistance of 0.26 °C/W and effective thermal conductivity 3212 W/m k at a heat input of 160 W. For the M2-acetone nanofluid, the investigated FPHP has a thermal resistance of 0.33 °C/W and effective thermal conductivity 2556 W/m k at a heat input of 150 W. The nanofluid FPHP investigated here provides a new approach in designing a high efficient next generation heat pipe cooling devices.

Investigation of air pollution of Shanghai subway stations in ventilation seasons in terms of PM2.5 and PM10.

In November 2015, the PM2.5 and PM10 particulate matter (PM) levels in platforms, station halls, and rail areas of the Shangcheng and Jiashan Road Station were monitored to investigate air pollution in the Shanghai subway system. The results revealed that in subway stations, PM2.5 and PM10 concentrations were significantly higher than those in outdoor environments. In addition, particle concentrations in the platforms exceeded maximum levels that domestic safety standards allowed. Particularly on clear days, PM2.5 and PM10 concentrations in platforms were significantly higher than maximum standards levels. Owing to the piston effect, consistent time-varying trends were exhibited by PM2.5 concentrations in platforms, station halls, and rail areas. Platform particle concentrations were higher than the amount in station halls, and they were higher on clear days than on rainy days. The time-varying trends of PM10 and PM2.5 concentrations in platforms and station halls were similar to each other. Activities within the station led to most of the inhalable particles within the station area. The mass concentration ratios of PM2.5 and PM10 in platforms were within 0.65-0.93, and fine particles were the dominant components.

Importance of Long-Range Nitrate Transport Based on Long-Term Observation and Modeling of Dust and Pollutants over East Asia

ABSTRACTLong-term synergetic fine and coarse mode aerosol observations were analyzed at 1-h intervals at Fukuoka, Japan, from January to June 2015. The GEOS-Chem chemical transport model, including dust and sea-salt acid uptake processes, was used for detailed analysis of observation data. Several Asian dust events and long-range anthropogenic aerosol transport events were observed during our analysis period, and the numerical model generally explained the observed time variation for both fine and coarse mode aerosols. We found that (i) the majority of fine mode NO3– can be considered as long-range transport (LRT) outside of Japan during the cold season, and (ii) the peak timing of fine mode NO3– coincided with that of SO4–, indicating that both aerosols are controlled by LRT. Also, an observed mass concentration ratio of NO3–/SO42– > 0.9 occurred during the cold season, indicating the importance of NO3– as a major contributor to the PM2.5 mass fraction. Finally, we clearly showed that large-scale dust-nitrate outflow from China to Fukuoka was confirmed in all cases of dust events, indicating that the anthropogenic NOx is converted to dust-nitrate and transported to Japan with dust. These results demonstrate the importance of anthropogenic NO3– LRT during the cold season and dust-nitrate LRT for all dust events (even in June).

Corrosion inhibition of a composite inhibitor containing imidazoline on carbon steel in simulated reverse osmosis product water of seawater

The synergistic performance of corrosion inhibition of 2-undecyl-N-carboxymethyl-Nhydroxyethyl imidazoline (UHCI) and ZnSO4 on 20# carbon steel surface in simulated reverse osmosis product water of seawater was investigated by electrochemical methods, scanning atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that the composite inhibitor acts as a mixed type inhibitor, reducing the corrosion of carbon steel effectively and the inhibition efficiency reaches the best values when the mass concentration ratio of UHCI and ZnSO4 is 50 : 50 at the total concentration of the solution is 100 mg·L where the corrosion inhibition efficiency reaches 96.99%. The UHCI molecules adsorbed on metal surfaces, controlling the anodic reaction. ZnSO4 is deposited on the metal surface in the form of Zn(OH)2, controlling the cathodic reaction.

Accuracy assessment of aerosol source apportionment by dual wavelength photoacoustic measurements

Aerosol source apportionment is a major challenge for air quality monitoring. Due to the frequently observed correlation between the chemical properties of aerosol particles and the wavelength dependence of their optical absorption coefficient, the photoacoustic (PA) method (similarly to alternative optical absorption measurement techniques) offers the unique possibility of real time source apportionment under certain circumstances. However, so far, the selection of lasers into a multi-wavelength PA system for source apportionment was based only on rule of thumb type estimations (like “one should use the highest available light powers with the widest possible wavelength separation”). Here we introduce a simulation method to estimate the accuracy of source apportionment and to be used for the optimised selection of the light sources of a dual wavelength PA system in cases, when light absorbing carbonaceous aerosol (LAC) originates from two distinct sources and dominates the atmospheric aerosol load. The method has two phases and it can be applied either on actual measurement results or on simulated datasets. In the first “calibration” phase the parameters of a non-linear calibration curve are determined, which describes the correlation between the ratio of optical absorption coefficients (OACs) measured photoacoustically at two wavelengths and the ratio of the source specific segregated mass concentrations (mass concentration ratio, MCR) measured by an independent calibration method. During the second “measurement” phase these calibration parameters are used to estimate the MCRs solely from the photoacoustically measured OAC ratios. The relative uncertainty of this estimation is used to grade dual wavelength PA systems. Executions of this simulation on different MCR, OAC datasets have proved that with a fairly simple PA system (which consists of a 405 and a 1064nm diode laser having modulated light power of 150 and 300mW, respectively) MCR determination is feasible with at least 10% relative accuracy whenever the mass concentration of LAC exceeds 1µg/m3.

An advanced wet method for simultaneous removal of SO2 and NO from coal-fired flue gas by utilizing a complex absorbent

SO2 and NO are the main precursors for the haze. Since the combined system of SCR and WFGD is not suitable for treating the flue gas from industrial boiler, this paper proposes an integrated and effective wet method to simultaneously remove SO2 and NO. A complex absorbent (CA) composing of sodium humate and sodium chlorite was prepared, the corresponding best mass concentration ratio was determined as 4%: 0.7%. Effects of various factors were assessed, such as the reaction temperature, the CA pH, the coexistence gases and the soluble anions. The results indicated that the desulfurization efficiencies were constant at 98–99.8% and the concentrations could be controlled below 35mg/m3 when the CA was used as absorbent. NO conversion efficiency reached approximately 98%. S(IV) species was characterized as a promoter for NO2 absorption, while Cl−, HCO3−, CO32− and NO2− inhibited the NO conversion. Based on the characterizations by XRD, XPS and FT-IR, the products were identified as humic, sulfate and nitrate. The reaction mechanism of simultaneous removal of SO2 and NO by CA was also speculated.

Chemical characterization of carbonaceous carbon from industrial and semi urban site of eastern India.

Rigorous campaign was carried out from July 2013 to June 2014 at the remote and industrial site (Adityapur and Seraikela Kharsawan) in the eastern India aiming to identify and quantify the changes of aerosol chemical composition in the presence of industrial and biomass burning influence. The 24-h PM10 filter samples were analyzed by mass, carbonaceous species, organic ions. The results suggested that the average PM10 concentrations were 165 ± 43.93, 141 ± 30.86 μg/m3 in industrial and remote site respectively. Secondary organic ions (SOC) were the dominant pollutants of PM10. Total carbon was a significant component explaining above 15 % of PM10. The annual average mass concentration of EC, OC, WSOC 26.39 ± 4.56, 5.11 ± 1.82, 18.56 ± 5.30 and 16.27 ± 5.75, 7.70 ± 2.1, 9.65 ± 1.92 µg/m3, OC/EC, WSOC/OC 5.29 ± 1.08, 0.71 ± 0.17 and 2.34 ± 0.75, 0.67 ± 0.16) of industrial and remote site were respectively; and OC/EC particularly in industrial site it reached the highest 5.29 ± 1.08 which demonstrated that SOC should be a significant composition of PM10. The mass fraction of the highlighted species varies seasonally, resulting the air mass trajectories and corresponding cause severe strength. Based on exact mass concentration ratios of EC/OC, WSOC/OC, we predicted that industries and biofuel/biomass burning are a major source of atmospheric aerosols in the eastern part of India. This study provides the scientific baseline data of carbonaceous aerosols for eastern Jharkhand, India.

Characteristics of Water-soluble Inorganic Ions in Atmospheric Aerosols in Shenyang

To investigate the levels and seasonal variation of water soluble inorganic components in ambient aerosol in Shenyang, 25 samples were collected with Andersen cascade sampler from Jun. 2012 to May. 2013 and nine water-soluble ions in samples were analyzed by IC. The different characteristics of aerosols between clean and pollution days in winter were discussed based on these samples. The results showed that the annual concentrations of total water soluble inorganic ions were 22.30 μg·m^-3 and 14.29 μg·m^-3 in fine and coarse particles, and SO4^2- and Ca²⁺ were the most abundant ions, respectively. The ratio of mass concentration between SO4^2- and NO3^- was 2.28 and the NH4⁺ existed in the form of (NH4)2SO4 and NH4NO3 in fine particles. The concentrations of total water soluble ions in fine particles were higher in winter and spring compared with those in summer and autumn, and they varied significantly between different seasons. The fossil fuel consumption led to the maximum values of secondary inorganic ions in fine particles during winter. The concentrations of total water soluble ions in coarse particles varied slightly though they were higher in autumn and lower in winter, and the wind-drifting sand was responsible for the higher concentration of Ca²⁺ in autumn in coarse particles. The concentration of SO4^2-, NO3^-, NH4⁺ accounted for 80% of total water soluble inorganic ions during clean days and rose to 94% during pollution days. The ions were mostly concentrated in the size ranges of 0.43-0.65 μm and 0.43-2.1 μm respectively during clean and pollution days in fine mode. The peaks of SO4^2-, NO3^-, NH4⁺ in fine mode shifted from 0.43-0.65 μm to 1.1-2.1 μm, which meant these ions were transformed from condensing mode to droplets mode during pollution days. The air mass produced at Lake Baikal and transported through high altitude to the sampling point caused clean days, however the air mass transported through industrial areas might bring pollutions to the sampling point then caused pollution days.

A new method for estimating aerosol mass flux in the urban surface layer using LAS technology

Abstract. Atmospheric aerosol greatly influences human health and the natural environment, as well as the weather and climate system. Therefore, atmospheric aerosol has attracted significant attention from society. Despite consistent research efforts, there are still uncertainties in understanding its effects due to poor knowledge about aerosol vertical transport caused by the limited measurement capabilities of aerosol mass vertical transport flux. In this paper, a new method for measuring atmospheric aerosol vertical transport flux is developed based on the similarity theory of surface layer, the theory of light propagation in a turbulent atmosphere, and the observations and studies of the atmospheric equivalent refractive index (AERI). The results show that aerosol mass flux can be linked to the real and imaginary parts of the atmospheric equivalent refractive index structure parameter (AERISP) and the ratio of aerosol mass concentration to the imaginary part of the AERI. The real and imaginary parts of the AERISP can be measured based on the light-propagation theory. The ratio of the aerosol mass concentration to the imaginary part of the AERI can be measured based on the measurements of aerosol mass concentration and visibility. The observational results show that aerosol vertical transport flux varies diurnally and is related to the aerosol spatial distribution. The maximum aerosol flux during the experimental period in Hefei City was 0.017 mg m−2 s−1, and the mean value was 0.004 mg m−2 s−1. The new method offers an effective way to study aerosol vertical transport in complex environments.

Oxidative potential and chemical composition of PM2.5 in office buildings across Europe – The OFFICAIR study

In the frame of the OFFICAIR project, indoor and outdoor PM2.5 samples were collected in office buildings across Europe in two sampling campaigns (summer and winter). The ability of the particles to deplete physiologically relevant antioxidants (ascorbic acid (AA), reduced glutathione (GSH)) in a synthetic respiratory tract lining fluid, i.e., oxidative potential (OP), was assessed. Furthermore, the link between particulate OP and the concentration of the PM constituents was investigated.The mean indoor PM2.5 mass concentration values were substantially lower than the related outdoor values with a mean indoor/outdoor PM2.5 mass concentration ratio of 0.62 and 0.61 for the summer and winter campaigns respectively. The OP of PM2.5 varied markedly across Europe with the highest outdoor OPAA m−3 and OPGSH m−3 (% antioxidant depletion/m3 air) values obtained for Hungary, while PM2.5 collected in Finland exhibited the lowest values. Seasonal variation could be observed for both indoor and outdoor OPAA m−3 and OPGSH m−3 with higher mean values during winter. The indoor/outdoor OPAA m−3 and OPGSH m−3 ratios were less than one with 4 and 17 exceptions out of the 40 cases respectively. These results indicate that indoor air is generally less oxidatively challenging than outdoors. Correlation analysis revealed that trace elements play an important role in determining OP, in particular, the Cu content. Indoor air chemistry might affect OP since weaker correlations were obtained for indoor PM2.5. Our findings also suggest that office workers may be exposed to health relevant PM constituents to a different extent within the same building.

Indoor/outdoor PM2.5 elemental composition and organic fraction medications, in a Greek hospital

In the newly constructed General Hospital of Kavala, Greece, air quality was monitored in two indoor locations (the Triage room at the emergency department and the Laboratory of bio-pathology) and also outdoors. Indoor PM2.5 filter samples were collected at both rooms and outdoors, in the yard of the hospital. PM2.5 organic content and elemental composition were determined. Analyses of selected organic compounds in PM2.5 samples, revealed that chemicals from medications were distributed in the air of the hospital. Qualitatively, dehydrocholic acid, hydrocortisone acetate, gama-bufotalin, syrosingopine, dimethyl phthalate and o,p′-DDT were found in the Triage. In the bio-pathology laboratory, triethoxypentylsilane and carbohydrazide were also found. An unexpected air pollutant pathway was the pneumatic system which delivered the blood samples from the emergency department to the bio-pathology laboratory, as the presence of gama-bufotalin and syrosingopine was found in the aerosol samples from both locations. Indoor PM2.5 24-h average mass concentration ranged from 10.16μgm−3 to 21.87μgm−3 in the laboratory and between 9.86μgm−3 to 26.27μgm−3 in the Triage room, where the limit value set for human health protection, i.e. 25μgm−3 for 24h, was exceeded once. The I/O 24-h average PM2.5 mass concentration ratio, ranged from 0.74–1.11 in the Triage and from 0.67–1.07 in the Lab, respectively. On the contrary, the I/O elemental concentration ratios were below unity for the whole campaign, indicating an outdoor origin of the monitored elements (Al, Si, Br, P, S, Na, K, Mg, Ca, Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti and Zn). This finding was also confirmed by high sulfur I/O ratios in both rooms. The diurnal variations of PM2.5, Black Carbon, CO2 concentrations and microclimatic conditions were also monitored.

A clustering approach based on triangular diagram to study the seasonal variability of simultaneous measurements of PM10, PM2.5 and PM1 mass concentration ratios

This paper presents a clustering approach based on triangular diagram used to study the seasonal variability of ratios between mass concentrations of PM10, PM2.5 and PM1. Simultaneous measurements of PM10, PM2.5 and PM1 mass concentrations were categorized according to the season they were sampled and the corresponding size-segregated particulate matter ratios (i.e. PM1/PM10, PM2.5/PM10, PM1/PM2.5 and PM2.5-PM1/PM10-PM1) were calculated and plotted using a triangular diagram. A hierarchical cluster analysis (HCA) was used to group all simultaneous particulate matter (PM) mass concentration measurements. The triangular diagram results show a general trend from low values of size-segregated particulate matter ratios related to sampling in warmer seasons (i.e. spring–summer) towards higher values of size-segregated particulate matter ratios related to sampling in colder seasons (i.e. winter–autumn). The HCA identifies three well differentiated clusters for simultaneous measurements of PM mass concentrations. These clusters divide the triangular diagram into three well distinguishable areas. These areas relate to data recorded in warmer seasons (PM2.5/PM10 60 %, PM1/PM10 > 40 % and PM2.5–PM1/PM10–PM1 > 35 %) and data recorded in both warmer and colder seasons (PM2.5/PM10 > 50 %, PM1/PM10 > 30 % and PM2.5–PM1/PM10–PM1 < 35 %). The latter area can be regarded as a transition region, occurring where the PM intermodal size fraction is about one-half of the coarse one. The triangular diagram also emphasizes how the intermodal size fraction may not be neglected compared to both coarse and fine size fractions in some environments in colder seasons.

Water-Soluble Organic Nitrogen in High Mountain Snow Samples from Central Japan

ABSTRACTWe measured water-soluble organic nitrogen (WSON) in snow pit samples, which were collected at the Murodo-Daira snowfield near the summit of Mt. Tateyama, central Japan in 2008, 2009, and 2011. The concentrations of WSON ranged from 12.8 to 96.7 ng g–1, which were significantly lower than those reported in continental wet deposition samples from the Asian continent. WSON may be largely diluted in the snow samples during snowing processes over the high mountains. We found that WSON significantly correlated with nss-Ca2+ and water-soluble organic carbon (WSOC). Concentrations of WSON are likely controlled by the intensity of Asian dust events. Contributions of WSON to water soluble total nitrogen (WSTN) in snow pit sequence was found to be 15 ± 10%, which is lower than those (63–91%) of reference dust materials collected in China. Mass concentration ratio of WSOC/WSON was on average 23.7, which is significantly higher than the C/N weight ratio (5.6) calculated from the Redfield ratio. This result suggests that WSOC is largely produced by secondary photochemical oxidation of anthropogenic volatile organic compounds during the transport from East Asia to the high mountain areas in Japan. On the other hand, WSON may be contributed from Asian dusts from arid areas in China whereas water-soluble inorganic nitrogen may be derived from pollution sources.

The Horizontal and Vertical Characteristics of Aeolian Dust from Riverbed

ABSTRACTArid riverbed is an important source of Aeolian dust to influence the atmosphere of nearby village or downtown. In general, Aeolian dust pertains to wind activity in the study of geology, environment and meteorology on particle suspension. This field study set the horizontal/vertical sampling system up in order to investigate the Aeolian dust dimensional distribution properties from the riverbed of the Jhuoshuei River. In addition, the study utilized the unmanned aerial vehicle (UAV) imagery to discriminate the covering condition of riverbed. The results revealed that the percentage of riverbed covering conditions, including bare zone, wetlands, green covering and water covering was about 50.1, 15.7, 16.8 and 17.4%, respectively, on January 5th, 2011. Two Aeolian dust cases from riverbed were measured on November 26th, 2010 and January 15th, 2011. First sampling case was under slower wind speed, and the total particulate matter (PM) concentration in vertical sampling was almost decreased with increasing sampling height, however, the phenomena of second case (faster wind speed) was just on the contrary. Besides, Aeolian dust was distributed in a bimodal or a multimodal curve, and the main peak size was above 10 μm. Mode size of suspension particle diameter was increased as the wind speed increased (14.8 μm/ first case; 21.3 μm/ second case). The total mass concentration ratio of south site to source site (one meter height) was about 1:9 in first case and about 1:3 in second case. Comparing with those two cases, the faster the wind is, the shorter the surface roughness height is (3.08 mm/ first case; 1.07 mm/ second case). Besides, as the wind speed increasing, the friction velocity was also increased (0.33 m s–1/ first case; 0.68 m s–1/ second case). Consequently, this study clued the spatial variability of river dust events, which can further aid the site investigating, forecasting and preventing of dust influences.