Characteristics and origins of a typical heavy haze episode in Baotou,China: implications for the spatial distribution of industrial sources

Air pollution has become the predominant environmental problem caused by rapid industrialization and urbanization in China. In this study, measurements of the concentrations of PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ at six monitoring stations in Baotou, China were used to investigate the characteristics of heavy haze pollution in Dec. 12–25, 2013. Source locations of PM_2.5 in Baotou were identified using satellite remote sensing data, an air mass trajectory model, and a conditional probability function (CPF). The results showed that the average concentrations of PM_2.5 and PM₁₀ were (113.8±84.0) μg/m³ and (211.1±149.2) μg/m³, respectively. The similar trends in temporal variation of the air pollutants PM_2.5, PM₁₀, SO₂, NO₂, and CO suggested they may share common sources. The results of satellite observations and backward trajectories supported the hypothesis that the pollutants causing the haze event originated mainly from local anthropogenic sources. According to the CPF analysis, low-speed winds from the south and southwest, upwind industrial emissions, and the northern mountains were mainly responsible for the formation of haze in Baotou. The study provides some insights to help governments optimize industrial layouts for improving air quality in the future.     

Physical and chemical characteristics of PM<Subscript>2.5</Subscript> and its toxicity to human bronchial cells BEAS-2B in the winter and summer

With the increasing occurrence of haze during the summer, the physicochemical characteristics and toxicity differences in PM_2.5 in different seasons are of great concern. Hangzhou is located in an area that has a subtropical monsoon climate where the humidity is very high during both the summer and winter. However, there are limited studies on the seasonal differences in PM_2.5 in these weather conditions. In this test, PM_2.5 samples were collected in the winter and summer, the morphology and chemical composition of PM_2.5 were analyzed, the toxicity of PM_2.5 to human bronchial cells BEAS-2B was compared, and the correlation between PM_2.5 toxicity and the chemical composition was discussed. The results showed that during both the winter and summer, the main compounds in the PM_2.5 samples were water-soluble ions, particularly SO₄^2?, NO₃^?, and NH₄⁺, followed by organic components, while heavy metals were present at lower levels. The higher the mass concentration of PM_2.5, the greater its impact on cell viability and ROS levels. However, when the mass concentration of PM_2.5 was similar, the water extraction from the summer samples showed a greater impact on BEAS-2B than that from the winter samples. The cytotoxicity of PM_2.5 was closely associated with heavy metals and organic pollutants but less related to water-soluble ions.     

Environmental damage costs from fossil electricity generation in China, 2000-2003

Electricity consumption increases rapidly with the rapid development of China. The environmental damage costs of electricity generation are very important for both policy analysis and the proper management of the environment. A method was developed in this work to estimate gross environmental damage costs according to emission inventory and environmental cost factors, and to extend the costs from provincial to national level with population density. In this paper, sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter less than 10 μm in diameter (PM10), and carbon dioxide (CO2) from fossil fired power plants over 6000 kW were selected as index pollutants to quantify the environmental costs of damages on human health and global warming. With the new developed method, environmental damage costs, caused by 3 types of fired power plants in 30 provinces and 6 economic sectors during the years 2000 to 2003, were evaluated and analyzed. It can be seen that the calculated total national environmental damage costs of electricity have rapidly increased from 94930.87×106 USD in 2000 to about 141041.39×106 USD in 2003, with an average annual growth rate of 14.11%. Environmental damage costs of SO2, NOx, PM10, and CO2 are 69475.69×106, 30079.29×106, 28931.84×106, and 12554.57×106 USD and account for 49.26%, 21.33%, 20.51%, and 8.90% of total environmental costs in fossil electricity generation, respectively. With regard to regional distribution, external costs caused by fossil electricity generation are mainly concentrated in the more populated and industrialized areas of China, i.e., the Eastern Central and Southeastern areas.     

Mortality weighting-based method for aggregate urban air risk assessment

This paper deals with a mortality-weighted synthetic evaluation (MWSE) method for evaluating urban air risk. Sulphur dioxide (SO₂), nitrogen oxide (NO _x ), and particulate matter (PM₁₀) were used as pollution indices. The urban area of Hangzhou, China is divided into 756 grid cells, with a resolution of 1 km×1 km, and is evaluated using the MWSE and the air quality index (AQI), a widely-used method to evaluate ambient air quality and air risk. In an evaluation of one day in April 2004, the surface areas categorized as levels I and III, as defined by the integrated air risk evaluation, were 27.3% and 3.3% lower, respectively, than grades I and III defined by the AQI evaluation. Meanwhile, the areas classified as level II or above level III by the integrated air risk evaluation were 55.1% and 101.1% higher, respectively, than grade II or above grade III when using the AQI evaluation. From this comparison, we find that the MWSE method is more sensitive than the AQI method. The AQI method uses a single index to assess integrated air quality and is therefore unable to evaluate integrated air risks due to multiple pollutants. The MWSE method overcomes this problem, providing improved accuracy in air risk assessment.     

Preparation of SO4^2-/TiO2-La2O3 solid superacid and its catalytic activities in acetalation and ketalation

SO4^2- / TiO2-La2O3, a novel solid superacid, was prepared and its catalytic activities at different synthetic conditions are discussed with esterification of n-butanoic acid and n-butyl alcohol as probing reaction. The optimum conditions have also been found, mole ratio of n（La^3＋）：n（Ti^4＋） is 1：34, the soaked consistency of H2SO4 is 0.8 tool/L, the soaked time of HESO4 is 24 h, the calcining temperature is 480 ℃, the calcining time is 3 h. Then it was applied in the catalytic synthesis often important ketals and acetals as catalyst and revealed high catalytic activity. Under these conditions on which the molar ratio of aldehyde/ketone to glycol is l： 1.5, the mass ratio of the catalyst used in the reactants is 0.5%, and the reaction time is 1.0 h, the yields of ketals and acetals can reach 41.4%-95.8%.     

Impact of individual acid flue gas components on mercury capture by heat-treated activated carbon

Elemental mercury capture on heat-treated activated carbon (TAC) was studied using a laboratory-scale fixed bed reactor. The capability of TAC to perform Hg⁰ capture under both N₂ and baseline gas atmospheres was studied and the effects of common acid gas constituents were evaluated individually to avoid complications resulting from the coexistence of multiple components. The results suggest that surface functional groups (SFGs) on activated carbon (AC) are vital to Hg⁰ capture in the absence of acid gases. Meanwhile, the presence of acid gas components coupled with defective graphitic lattices on TAC plays an important role in effective Hg⁰ capture. The presence of HCl, NO₂, and NO individually in basic gases markedly enhances Hg⁰ capture on TAC due to the heterogeneous oxidation of Hg⁰ on acidic sites created on the carbon surface and catalysis by the defective graphitic lattices on TAC. Similarly, the presence of SO₂ improves Hg⁰ capture by about 20%. This improvement likely results from the deposition of sulfur groups on the AC surface and oxidation of the elemental mercury by SO₂ due to catalysis on the carbon surface. Furthermore, O₂ exhibits a synergistic effect on Hg⁰ oxidation and capture when acid gases are present in the flue gases.     

Environmental factors regulating cyanobacteria dominance and microcystin production in a subtropical lake within the Taihu watershed, China

Understanding the pattern of phytoplankton and their dependence on water quality variables, can help the management of eutrophic lakes. The aim of this study was to determine water quality and environmental factors associated with cyanobacteria dominance and microcystin production in Qingshan Lake, a subtropical lake located in the headwater of the Taihu watershed, China. Water samples collected monthly from 10 study sites in Qingshan Lake were analyzed for the species distributions of freshwater algae and physico-chemical parameters including total nitrogen (TN), ammonia (NH₄ ⁺-N), nitrate (NO₃ ⁻-N), total phosphorus (TP), and chlorophyll a (Chl-a) from June, 2008 to May, 2009. Qingshan Lake was found to be eutrophic, based on the calculated trophic state index (TSI). The average TN of 4.33 mg/L during the study period exceeded the Surface Water Quality Standards of China. TP was significantly correlated with relative abundance of cyanobacteria and Microcystis biovolume, indicating its important role in regulating cyanobacteria. Microcystis, Anabaena, and Oscillatoria were dominant cyanobacteria in Qingshan Lake from June to November, 2008. Cyanobacteria dominance was regulated by water temperature and TP. Principal component analysis further indicated that microcystin production was most affected by water temperature, TP, and cyanobacteria biomass. Results suggest that the control of TP in summer can mitigate cyanobacteria dominance and microcystin production in Qingshan Lake, and close monitoring should be undertaken in summer.     

Effects of concentration and freeze-thaw on the first hydration shell structure of Zn2+ ions

To investigate the effects of salt concentration and freeze-thaw （FT） on the first hydration shell of Zn2+ ions in Zn（NO₃）₂ aqueous solutions, extended X-ray absorption fine structure （EXAFS） spectroscopy was used to examine Zn K-edge EXAFS spectra of Zn（NO₃）₂ aqueous solutions with various concentrations before and after FT treatment. The influences of salt concentration and freeze-thaw on the structural parameters of the first hydration shell of Zn2+ ions, including hydration number, Zn-O distance and thermal disorder, were analyzed. The results show that Zn2+ ions have 3.2―6.8 nearest oxygen neighbors with the Zn-O distance being 0.202―0.207 nm. In highly concen-trated solutions, Zn2+ ions are hydrated with four water molecules in a tetrahedral form. The dilution of Zn（NO₃）₂ aqueous solutions increases the number of water molecules in the first hydration shell of Zn2+ ions to six with their octahedral arrangement. Both the hydration number in the first hydration shell of Zn2+ ions and the degree of thermal disorder increase when the FT treatment is operated in Zn（NO₃）₂ aqueous solutions.     

Synergistic interaction of NaCl and Cd on growth and photosynthetic parameters in soybean genotypes differing in salinity tolerance

The effects of salinity(50 mmol/L NaCl) and Cd(1 μmol/L CdCl2) as sole and combined on growth and photosyn-thetic parameters were studied using two soybean genotypes,Huachun 18 and NGB.The concentrations of Cd2 ,Zn2 ,Ca2 ,Mg2 ,K and Na were also determined in seeds and pods.Huachun 18 suffered a more serious decrease than NGB in net photosynthetic rate(Pn) in the treatments of salinity stress alone and combined stress(NaCl Cd),showing that it is relatively sensitive to salinity.The decrease in Pn caused by salt stress in Huachun 18 was mainly due to the reduced total chlorophyll content and photosynthetic efficiency(the ratio of variable fluorescence to maximal fluorescence,Fv/Fm),whereas the decease in NGB was mainly related to reduced stomatal conductance(Gs).The combined stress of both Na and Cd did not induce further decrease in photosynthesis and fluorescence in the two genotypes relative to salt or Cd stress alone.Greater change in the pod concentrations of Zn2 ,Ca2 ,Mg2 ,K and Na was detected under salt stress for Huachun 18 than for NGB.The results suggested that the interactive effect of NaCl-Cd on growth and nutrient uptake differs between the two soybean genotypes.     

Effects of nitrogen form on growth,CO2 assimilation,chlorophyll fluorescence,and photosynthetic electron allocation in cucumber and rice plants

Cucumber and rice plants with varying ammonium (NH₄ ⁺) sensitivities were used to examine the effects of different nitrogen (N) sources on gas exchange, chlorophyll (Chl) fluorescence quenching, and photosynthetic electron allocation. Compared to nitrate (NO₃ ⁻)-grown plants, cucumber plants grown under NH₄ ⁺-nutrition showed decreased plant growth, net photosynthetic rate, stomatal conductance, intercellular carbon dioxide (CO₂) level, transpiration rate, maximum photochemical efficiency of photosystem II, and O₂-independent alternative electron flux, and increased O₂-dependent alternative electron flux. However, the N source had little effect on gas exchange, Chl a fluorescence parameters, and photosynthetic electron allocation in rice plants, except that NH₄ ⁺-grown plants had a higher O₂-independent alternative electron flux than NO₃ ⁻-grown plants. NO₃ ⁻ reduction activity was rarely detected in leaves of NH₄ ⁺-grown cucumber plants, but was high in NH₄ ⁺-grown rice plants. These results demonstrate that significant amounts of photosynthetic electron transport were coupled to NO₃ ⁻ assimilation, an effect more significant in NO₃ ⁻-grown plants than in NH₄ ⁺-grown plants. Meanwhile, NH₄ ⁺-tolerant plants exhibited a higher demand for the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) for NO₃ ⁻ reduction, regardless of the N form supplied, while NH₄ ⁺-sensitive plants had a high water-water cycle activity when NH₄ ⁺ was supplied as the sole N source.     

Effects of pH and<Emphasis Type="Italic">Eh</Emphasis> on release of nitrogen and phosphorus from sediments of West Lake

The effects of pH andEh on release of nitrogen and phosphorus from sediments of West Lake under different conditions were investigated by simulation test. Results showed that the net flux of NH₄ ⁺-N release from sediments increased with pH, but NO₃ ⁻-N showed negative-going release at all tested pH levels. The net flux of NH₄ ⁺-N release from sediments was higher under anaerobic or aerobic condition of the overlying water, but only under aerobic condition would net release of NO₃ ⁻-N occur. It was also shown that phosphorus released was mainly in its inorganic form, higher pH and anaerobic conditions of overlying water greatly stimulated release of phosphorus. In situ measurement at several West Lake locations indicated that sediment resuspension induced by boat propeller stimulated nutrients release from sediment into overlying water. Project (No.294059) supported by National Natural Science Foundation of Zhejiang Province, China     

Application of biomonitoring and support vector machine in water quality assessment

The behavior of schools of zebrafish (Danio rerio) was studied in acute toxicity environments. Behavioral features were extracted and a method for water quality assessment using support vector machine (SVM) was developed. The behavioral parameters of fish were recorded and analyzed during one hour in an environment of a 24-h half-lethal concentration (LC₅₀) of a pollutant. The data were used to develop a method to evaluate water quality, so as to give an early indication of toxicity. Four kinds of metal ions (Cu²⁺, Hg²⁺, Cr⁶⁺, and Cd²⁺) were used for toxicity testing. To enhance the efficiency and accuracy of assessment, a method combining SVM and a genetic algorithm (GA) was used. The results showed that the average prediction accuracy of the method was over 80% and the time cost was acceptable. The method gave satisfactory results for a variety of metal pollutants, demonstrating that this is an effective approach to the classification of water quality.     

Electronic structure and magnetism ofRMn6Sn6 (R=Tb, Dy)

This article reports first-principles band structure calculations forRMn₆Sn₆ (R=Tb, Dy). The calculation uses the linear muffin-tin orbitals (LMTO) method in the atomic-sphere-approximation (ASA), and yields results showing that both TbMn₆Sn₆ and DyMn₆Sn₆ are ferrimagnetic compounds with antiparallel aligned moments ofR and Mn atoms. In this research the 4f states ofR atoms are treated as localized states, i.e., the hybridization of 4f states with other valence electrons is neglected. The moments of Mn in both compounds were determined to be 2.43 μ_B and 2.38 μ_B, respectively. The considerably small additional moments for Mn from the spin-orbit coupling indicates that the spin-orbital coupling is not dominated for Mn atoms. The total moments of Tb and Dy atoms are 10.28 μ_B and 11.20 μ_B. All the calculation findings accorded well with experimental results. Project supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry of China.     

Estimating R 2 Shrinkage in Multiple Regression: A Comparison of Different Analytical Methods

The effectiveness of various analytical formulas for estimating R ² shrinkage in multiple regression analysis was investigated. Two categories of formulas were identified: estimators of the squared population multiple correlation coefficient (ρ²) and those of the squared population cross-validity coefficient (ρ_c ²). The authors conducted a Monte Carlo experiment to investigate the effectiveness of the analytical formulas for estimating R ² shrinkage, with 4 fully crossed factors (squared population multiple correlation coefficient, number of predictors, sample size, and degree of multicollinearity) and 500 replications in each cell. The results indicated that the most widely used Wherry formula (in both SAS and SPSS) is probably not the most effective analytical formula for estimating ρ². Instead, the Pratt formula and the Browne formula outperformed other analytical formulas in estimating ρ² and ρ_c ², respectively.     

Responding to racism at school: Ethnic-racial socialization and the academic engagement of Black and Latinx youth

Guided by the Theory of Racial Socialization in Action (TRSA; Smith-Bynum in press), this study examined observed caregiver-provided ethnic-racial socialization in response to a school-based discriminatory dilemma. Forty-five Black and 36 Latinx caregivers (88% mothers) with low-income and their children (M_age = 11.09, SD = 0.29; 46.3% female) participated in Dallas, Texas from 2018 to 2019. Dyads responded to a hypothetical scenario in which a school counselor makes a discriminatory comment to the child. Results of a factor mixture analysis suggested that caregivers engaged in the dialogue using one of four approaches: Low-engaged, Legacy, Racial Literacy, or High-engaged. Profiles were found to differ significantly by the race/ethnicity and language of caregivers and were associated with youth’s concurrent behavioral engagement (R² = .04).     

Study on hydrogen sulfide removal based on bench-scale experiment by bio-trickling filter

A bench-scale experiment for control of hydrogen sulfide (H2S) emissions was carried out continuously for nearly four months by using bio-trickling filter packed with ZX01 stuffing. The results suggested that the bio-trickling filter had proven excellent performance over substantial operational periods. Removal efficiency of H2S was nearly 100% when volumetric loading of the bio-trickling filter varied from 0.64 g/(m3·h) to 38.20 g/(m3·h) and metabolism products of H2S were mainly composed of SO42–. When inlet concentration of H2S was 250 mg/m3, the optimum gas retention time was 30 s and the optimum spray water flow rate was 0.005 9~0.012 L/(cm2·h). The bio-trickling filter had good ability to resist shock of high volumetric loading, and was not blocked during experiments for nearly four months during which resistance was maintained at relatively lower value, so that the bio-trickling filter need not carry out back washing frequently and can be operated steadily for long-term.     

Study of factors influencing research productivity of agriculture faculty members in Iran

The purpose of this research is to analyze the relationship between individual, institutional and demographic characteristics on one hand and the research productivity of agriculture faculty members on the other. The statistical population of the research comprises 280 academic staff in agricultural faculties all over Tehran Province. The data regarding research productivity and demographic characteristics were extracted from the faculty members’ profiles. Questionnaires were utilized to collect information concerning individual and institutional variables. The reliably of the questionnaire was calculated to be between 0.74 and 0.97 using the Cronbach’s Alpha. The regression analysis revealed that from among demographic characteristics two variables, namely, academic rank and age ( \textR_\textAD ² {\text{R}}_{\text{AD}}^{ 2}  = 0.265), among individual characteristics, three variables, namely, working habits, creativity as well as autonomy and commitment ( \textR_\textAD ² {\text{R}}_{\text{AD}}^{ 2}  = 0.097), and among institutional characteristics four variables namely, network of communication with colleagues, resources of facilities, corporate management and clear research objectives ( \textR_\textAD ² {\text{R}}_{\text{AD}}^{ 2}  = 0.151) were significant predictors for agricultural faculty members’ research productivity.     

Quantitative structure-activity relationships of antimicrobial fatty acids and derivatives against Staphylococcus aureus

Fatty acids and derivatives (FADs) are resources for natural antimicrobials. In order to screen for additional potent antimicrobial agents, the antimicrobial activities of FADs against Staphylococcus aureus were examined using a microplate assay. Monoglycerides of fatty acids were the most potent class of fatty acids, among which monotridecanoin possessed the most potent antimicrobial activity. The conventional quantitative structure-activity relationship (QSAR) and comparative molecular field analysis (CoMFA) were performed to establish two statistically reliable models (conventional QSAR: R ²=0.942, Q ² _LOO=0.910; CoMFA: R ²=0.979, Q ²=0.588, respectively). Improved forecasting can be achieved by the combination of these two models that provide a good insight into the structure-activity relationships of the FADs and that may be useful to design new FADs as antimicrobial agents.     

Evaluation of spatial and vertical variability of nitrogen and phosphorus in sewage-irrigated soil in Tongliao, China

The reuse of wastewater for the irrigation of farmlands is gaining popularity, and the nutrient leaching associated with wastewater irrigation is becoming a matter of concern. The variability of nitrogen and phosphorus fractions in wastewater-irrigated soil was investigated in both horizontal and vertical directions in Kongjiaxiang, Tongliao, Inner Mongolia, China. The results showed that wastewater irrigation resulted in the concentrations of available N and P being 40.36% and 66.49% higher, respectively, than those with groundwater irrigation. Different forms of N and P exhibited significantly different distribution patterns. Higher concentrations of NO3- and total available N, as well as of those of Ca-P and total available P were observed near wastewater irrigation channels. Ca-P has a spatial distribution pattern similar to that of available P. The concentrations of NO3- and NH4+ were the highest in top soil and decreased with depth. The complex interactions between nitrate leaching and nitrogen transformation processes (e.g., nitrification, denitrification, and mineralization) determined the vertical profile of NO3- . The significant amount of NH4+ loss inhibited its deep seepage. The Ca-bound compound contained more P than other inorganic fractions as a result of high Ca levels throughout the soil profile. The differences in the concentrations of Ca-bound P at different depths could be due to the upward flux or translocation of Ca from subsurface to surface soil and the sequestration of P.     

Fear as a Predictor of Life Satisfaction in Retirement in Canada

In developed countries, healthy retirees can fulfill their life, but may fear growing old. Yet, there is little empirical data on the relationship between this fear and life satisfaction. This cross-sectional, correlational survey study tested whether a new, summated measure of Fears About Growing Old (FAGO)—derived from exemplifications of Laslett, who posited the theory of the Third Age—significantly predicted life satisfaction and retirement satisfaction after adjusting for significant social participation covariates. A total of 190 Canadian retirees at three senior centers in Ontario, Canada, completed surveys. A pilot study established the reliability and validity of the scales, including the FAGO, used to assess the independent variable. In a regression analysis, fear (R ² _change = .06) was found to be a statistically significant predictor of life satisfaction when controlling for five covariates (current activity, circumstance and pursuing own interest as two reasons for retirement, postretirement work, and perceived social support); overall R ² = .26. For retirement satisfaction, fear significantly explained variance in the outcome (R ² _change  = .04) while controlling for two significant covariates (current activity and perceived social support); overall R ² = .14. A work by gender interaction on satisfaction was not found. Other than fear about loss of mobility, men rated loss of partner very high; women rated mortal disease very high. The lowest fear was loss of retirement income for men and loss of earning-power for women. Canada's poverty preventive programs successfully supported senior postretirement life. The FAGO was useful to find senior needs.