How does population structure affect pollutant discharge in China? Evidence from an improved STIRPAT model

Environmental Science and Pollution Research - China is the most populous country in the world, and the pollution caused by the excessive population should not be underestimated. In recent years,...     

Difference in the net value of ecological services between natural and artificial forests in China

Land degradation is a global problem that seriously threatens human society. However, in China and elsewhere, ecological restoration still largely relies on a traditional approach that focuses only on ecological factors and ignores socioeconomic factors. To improve the effectiveness of ecological restoration and maximize its economic and ecological benefits, a more efficient approach is needed that provides support for policy development and land management and thereby promotes environmental conservation. We devised a framework for assessing the value of ecosystem services that remain after subtracting costs, such as the opportunity costs, costs of forest protection, and costs for the people who are affected by the program; that is, the net value of ecosystem services (NVES). To understand the difference between the value of a resource and the net value of the ecosystem service it provides, we used data on VES, timber sales, and afforestation costs from China's massive national afforestation programs to calculate the net value of forest ecosystem services in China. Accounting for the abovementioned costs revealed an NVES of ¥6.1 × 10¹² for forests in 2014, which was 35.9% less than the value calculated without accounting for costs. As a result, the NVES associated with afforestation was 55.9% less than the NVES of natural forests. In some regions, NVES was negative because of the huge costs of human-made plantations, high evapotranspiration rates (thus, high water opportunity costs), and low forest survival rates. To maximize the ecological benefits of conservation, it is necessary to account for as many costs as possible so that management decisions can be based on NVES, thereby helping managers choose projects that maximize both economic and ecological benefits.     

A fragment constant QSAR model for evaluating the EC50 values of organic chemicals to Daphnia magna.

The quantitative relationship between the median effective concentration (EC50) of organic chemicals to Daphnia magna and the number of molecular fragments was investigated based on experimental EC50 values for 217 chemicals derived from the literature. A fragment constant model was developed based on a multivariate linear regression between the number of fragments and the logarithmically transformed reciprocal values of EC50. Functional correction factors were introduced into the model. The model was verified using an independent set of randomly selected data. The mean residual of the final model was 0.4 log-units. The robustness of the model was discussed based on the results of three jackknife tests.     

Development of a static test apparatus for evaluating the performance of three PM2.5 separators commonly used in China

PM_(2.5) separator directly affects the accuracy of PM_(2.5) sampling.The specification testing and evaluation for PM_(2.5) separator is particularly important,especially under China's wide variation of terrain and climate.In this study,first a static test apparatus based on polydisperse aerosol was established and calibrated to evaluate the performance of the PM_(2.5) separators.A uniform mixing chamber was developed to make particles mix completely.The aerosol concentration relative standard deviations of three test points at the same horizontal chamber position were less than 0.57%,and the particle size distribution obeyed logarithmic normal distribution with an R~2 of 0.996.The flow rate deviation between the measurement and the set point flow rate agreed to within ± 1.0% in the range of -40 to 50℃.Secondly,the separation,flow and loading characteristics of three cyclone separators(VSCC-A,SCC-A and SCC112) were evaluated using this system.The results showed that the 50% cutoff sizes(D_(50)) of the three cyclones were 2.48,2.47 and 2.44 μm when worked at the manufacturer's recommended flow rates,respectively.The geometric standard deviation(GSD) of the capture efficiency of VSCCA was 1.23,showed a slightly sharper than SCC-A(GSD = 1.27),while the SCC112 did not meet the relevant indicator(GSD = 1.2 ± 0.1) with a GSD = 1.44.The flow rate and loading test had a great effect on D_(50),while the GSD remained almost the same as before.In addition,the maintenance frequency under different air pollution conditions of the cyclones was summarized according to the loading test.     

Advanced molecular-fingerprinting analysis of dissolved organic sulfur by electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry using optimal spray solvent

Molecular level characterization of dissolved organic sulfur (DOS) by electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR MS) is necessary for further understanding of the role of DOS in the environment. Here, ESI spray solvent, a key parameter for ion production during ESI process, was investigated for its effect on the molecular characterization of DOS by ESI-FTICR MS. 100% MeOH as spray solvent was found for the first time to remarkably enhance the ionization efficiency of the majority of CHOS-molecules in NOM, which facilitated a total of 1473 CHOS-molecular formulas with one sulfur atom to be detected. The number of CHOS-molecular formulas obtained using 100%MeOH as spray solvent increased notably over 740 in comparison with those using 50% MeOH aqueous solution (731) or 50% ACN aqueous solution (653). Moreover, due to the enhancement of ionization efficiency of DOS during ESI processes, the tandem mass spectra of the NOM CHOS-molecules could be easily obtained using 100% MeOH as spray solvent, which were hardly obtained using 50% MeOH aqueous solution as spray solvent. The results of the tandem mass spectra suggested the first discovery of organosulfates or sulfonic acids in Suwannee River NOM sample. A simple method based on 100% MeOH as ESI spray solvent for advanced molecular characterization of DOS by ESI-FTICR MS was proposed and applied, and the results revealed more molecular information of DOS in sea DOM samples.     

Seasonal variation and size distribution of biogenic secondary organic aerosols at urban and continental background sites of China

Size-resolved biogenic secondary organic aerosols(BSOA) derived from isoprene and monoterpene photooxidation in Qinghai Lake, Tibetan Plateau(a continental background site) and five cities of China were measured using gas chromatography/mass spectrometry(GC/MS). Concentrations of the determined BSOA are higher in the cities than in the background and are also higher in summer than in winter. Moreover, strong positive correlations(R2= 0.44–0.90) between BSOA and sulfate were found at the six sites,suggesting that anthropogenic pollution(i.e., sulfate) could enhance SOA formation,because sulfate provides a surface favorable for acid-catalyzed formation of BSOA. Size distribution measurements showed that most of the determined SOA tracers are enriched in the fine mode( 3.3 μm) except for cis-pinic and cis-pinonic acids, both presented a comparable mass in the fine and coarse( 3.3 μm) modes, respectively. Mass ratio of oxidation products derived from isoprene to those from monoterpene in the five urban regions during summer are much less than those in Qinghai Lake region. In addition, in the five urban regions relative abundances of monoterpene oxidation products to SOA are much higher than those of isoprene. Such phenomena suggest that BSOA derived from monoterpenes are more abundant than those from isoprene in Chinese urban areas.     

环境保护因素对落后地区旅游开发的促进作用研究

为了提高落后地区旅游开发的质量,分别从低碳环保旅游以及生态旅游两方面,研究环保因素对落后地区旅游开发的促进作用。提出低碳环保旅游,并分析低碳环保对落后地区旅游业可持续发展的意义,在落后地区旅游开发中实施低碳饮食、低碳住宿、低碳交通以及低碳能源的旅游开发模式。对中国落后地区生态旅游现状和意义实施研究,分析生态旅游对落后地区旅游开发的促进作用。最终给出了落后地区实现生态旅游开发的建议,构建落后地区低碳环保的新型生态旅游模式,实现落后地区旅游的可持续发展。     

A study on the interactions among several plant secondary compounds and aphids

The research, focused on the specific interactions among seven plant secondary compounds and aphids, was carried out and the preliminary results showed: (1) "T-typed tube method" was regarded as the best method compared with others designed to observe the interactions. (2) Cabbage aphid was able to be attracted by laurolene while it was not susceptible to α-pinene, β-pinene and diamylene. (3) Gossypol, a major secondary substance in cotton, was able to be implicated as feeding attractant to cotton aphid. (4) Rutin might be implicated repellent to cotton aphid.     

Determination of Trace Organochlorinated Pesticides and Polychlorinated Biphenyls in Water

A modified steam distillation liquid-liquid extraction (SDE) device is developed for the enrichment of trace organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) in up to one litre of water samples. One ml of n-hexane is sufficient to extract the analytes. The extract can be analysed directly by a capillary gas chromatography-electron capture detector. The recoveries range from 84.6 to 102.3% for OCPs and 80.5 to 106.2% for PCBs, respectively. Matrice materials such as lipids and humic substances were removed by the SDE method from the extract and no further cleanup and concentration steps were needed.