The Photolysis of Aromatic Hydrocarbons Adsorbed on the Surfaces of Cosmic Dust Grains

The results of laboratory mass-spectrometer studies of the laser-induced dissociation of molecules of simple aromatic hydrocarbons adsorbed on a quartz substrate under the conditions of deep vacuum and low temperatures are adapted to the physical and chemical conditions in regions of active star formation in molecular clouds. The main properties of the photolysis of physically adsorbed molecules compared to the photodissociation of isolated molecules in the gas phase are identified. The relevance of molecular photolytic desorption to the real conditions in the interstellar medium is analyzed, in particular, to the conditions in photodissociation regions. It is shown that the photodissociation of adsorbed benzene occurs along other channels and with appreciably lower efficiency than does the corresponding process in the gas phase. The photodissociation of aromatic hydrocarbons adsorbed on the surfaces of interstellar grains cannot make a large contribution to the abundance of hydrocarbons with small numbers of atoms observed in the interstellar medium.

     

Is global ozone recovering?

Thanks to the Montreal Protocol, the stratospheric concentrations of ozone-depleting chlorine and bromine have been declining since their peak in the late 1990s. Global ozone has responded: The substantial ozone decline observed since the 1960s ended in the late 1990s. Since then, ozone levels have remained low, but have not declined further. Now general ozone increases and a slow recovery of the ozone layer is expected. The clearest signs of increasing ozone, so far, are seen in the upper stratosphere and for total ozone columns above Antarctica in spring. These two regions had also seen the largest ozone depletions in the past. Total column ozone at most latitudes, however, does not show clear increases yet. This is not unexpected, because the removal of chlorine and bromine from the stratosphere is three to four times slower than their previous increase. Detecting significant increases in total column ozone, therefore, will require much more time than the detection of its previous decline. The search is complicated by variations in ozone that are not caused by declining chlorine or bromine, but are due, e.g., to transport changes in the global Brewer–Dobson circulation. Also, very accurate observations are necessary to detect the expected small increases. Nevertheless, observations and model simulations indicate that the stratosphere is on the path to ozone recovery. This recovery process will take many decades. As chlorine and bromine decline, other factors will become more important. These include climate change and its effects on stratospheric temperatures, changes in the Brewer–Dobson circulation (both due to increasing CO₂), increasing emissions of trace gases like N₂O, CH₄, possibly large future increases of short-lived substances (like CCl₂H₂) from both natural and anthropogenic sources, and changes in tropospheric ozone.     

Assessment of the impact of biogenic VOC emissions in a high ozone episode via integrated remote sensing and the CMAQ model

In many metropolitan regions, natural sources contribute a substantial fraction of volatile organic compound (VOC) emissions. These biogenic VOC emissions are precursors to tropospheric Ozone (O₃) formation. Because forests make up 59% of the land area in Taiwan Province, China, the biogenic VOC emissions from forests and farmland could play an important role in photochemical reactions. On the other hand, anthropogenic emissions might also be one of the major inputs for ground level O₃ concentrations. Hence, emission inventory data, grouped as point, area, mobile and biogenic VOC sources, are a composite of reported and estimated pollutant emission information and are used by many air quality models to simulate ground level O₃ concentrations. Before using relevant air quality models, the emission inventory data generally require huge amounts of processing for spatial, temporal, and species congruence with respect to the associated air quality modeling work. The fist part of this research applied satellite remote sensing and geographic information system (GIS) analyses to characterize land use/land cover (LULC) patterns, integrating various sources of anthropogenic emissions and biogenic emissions associated with a variety of plant species. To investigate the significance of biogenic VOC emissions on ozone formation, meteorological and air quality modeling were then employed to generate hourly ozone estimates for a case study of a high ozone episode in southern Taiwan, which is the leading industrial hub on the island. To enhance the modeling accuracy, a unique software module, SMOKE, was set up for emission processing to prepare emission inputs for the U.S. EPA’s Models-3/CMAQ. An emission inventory of Taiwan, TEDS 4.2, was used as the anthropogenic emission inventory. Biogenic emission modeling was accomplished by BEIS-2 in SMOKE, with improvement of local LULC data and revised emission factors. Research findings show that the majority of biogenic VOC emissions occur in the mountainous areas and farmlands. However, the modeling outputs show that downwind of the most heavily populated and industrialized areas, these biogenic VOC emissions have less impact on air quality than do anthropogenic emissions.     

Application of GAINS model for assessing selected air pollutants in Khyber Pakhtunkhwa and Balochistan,Pakistan

Pakistan is a developing country existing geographically at a pivoted location between two of the world’s largest pollution emitting countries (China and India) which adds to the severity of environmental issues faced by the country. These concerns include air pollution, climate change, and extreme weather situations prevailing in Pakistan. This increasing air pollution is deteriorating the health, threatening the food security and adding up its share to the already existing global warming. The initial step in devising a wide ranging, multifaceted, economically feasible, and sustainable solution to deal with the severity of this issue is the quantification of the air pollution and greenhouse gas emission in Pakistan. The GAINS model is one of the most comprehensive tools, dealing with the air pollutants and greenhouse gases covered by the Kyoto Protocol. This study has utilized this model to analyze the source-based anthropogenic emissions of air pollutants (NH₃ and SO₂), volatile organic compounds (VOCs), and greenhouse gases (CH₄ and CO₂), their impacts and abatement cost, for the duration of 1990–2030, in the Khyber Pakhtunkhwa and Balochistan regions of Pakistan. An overall increasing trend was observed during 1990–2030 for (a) air pollutants: NH₃ (223.52–568.87kT/Y); SO₂ (50.52–332.95kT/Y), (b) VOCs (121.76–246.81kT/Y), and (c) greenhouse gases: CO₂ (7.83–62.45MT/Y) and CH₄ (1120-2314kT/Y). The emission inventories created for all greenhouse gases together estimated the increase of 42.37 to 138.57 MTCO₂eq. for greenhouse gases over the time duration of 1990–2030.     

Investigation of source locations and contributions using an integrated trajectory-source apportionment method with multiple time resolution data

Fine particulate matter (PM_2.5) and volatile organic compounds (VOCs) coexist in ambient air and contribute to adverse health effects in human populations. Thus, it is helpful to identify the contributions of air pollutants from different sources in order to design effective control strategies. Nevertheless, different sampling time schedules for VOCs and PM_2.5 result in difficulties for conventional receptor modeling. Additionally, a receptor model is unable to link the retrieved factors directly with actual source locations. To address these gaps, this study integrated back-trajectory data into an improved source apportionment model suitable for multiple time resolution data to estimate the locations of the regional transport-related factor. Within six potential source regions (PSRs) outlined by the above method, PSR 5 was suggested the primary one located near the industrial regions in the northeastern China. Constrained model results showed that the source contribution estimates with back trajectories passing over the PSRs were 3 and 9% of the selected VOCs and PM_2.5 mass, respectively.     

The influence of the Tula,Hidalgo complex on the air quality of the Mexico City Metropolitan Area

Using an air quality model, this study shows how emissions from the “Miguel Hidalgo” refinery of Petróleos Mexicanos (Pemex) and the thermoelectric plant “Francisco Pérez Ríos” of the Comisión Federal de Electricidad (CFE, Federal Electricity Commission) in Tula, Hidalgo influence the atmosphere of the Mexico City Metropolitan Area (MCMA). The model couples meteorology and chemistry. The weather scenario encompasses the period from October 20-28, 2005. Two scenarios are compared: the first assumes a 40% reduction in emissions of NO_x, SO₂, and volatile organic compounds (VOCs) from the Tula complex (reduction scenario), and the second considers the scenario without reduction (baseline scenario). The model is compared with measurements of the Red Automática de Monitoreo Atmosférico (Automatic Environmental Monitoring Network). We observe that under certain weather conditions, the energy sector of Tula, Hidalgo affects the air quality in the MCMA. The reduction scenario is effective in reducing SO₂ concentrations; however, despite a 40% decrease in the emissions of ozone precursors, their concentrations in the MCMA did not decrease.     

Preliminary analysis of the development of the Carbon Tracker system in Latin America and the Caribbean

The Carbon Tracker system will play a major role in understanding CO₂ sinks and sources, gas exchange between the atmosphere and oceans, and gas emissions from forest fres and fossil fuels in Latin America and the Caribbean. This paper discusses the trends in carbon fluxes in the biosphere and ocean, as well as emissions from forest fres and fossil fuel use in the above-mentioned region, using the Carbon Tracker (CT) system. From 2000 to 2009, the mean carbon fluxes for the biosphere, fossil fuel use, wildfires and the ocean in Latin America and the Caribbean were −0.03, 0.41, 0.296, −0.061 Pg C/yr, respectively, and −0.02, 0.117, 0.013, −0.003 Pg C/yr, respectively, in Mexico. The mean net carbon flux for Latin America and the Caribbean was 0.645 Pg C/yr, and 0.126 Pg C/yr for Mexico. The terrestrial sinks in Latin America and the Caribbean are dominated by the forest, agricultural, grass and shrub regions, as well as the Andes mountain range and the net surface-atmosphere fluxes including fossil fuel are dominant in regions around large cities in Mexico, Brazil, Chile, and areas undergoing deforestation along the Amazon River. The results confirm that forest fres are an important source of CO₂ in Latin America and the Caribbean. In addition, we can confirm that policies encouraging the use of ethanol in light vehicles in Brazil have helped to decrease carbon emissions from fossil fuel, and assume the effects of the Proárbol program on carbon sinks from the biosphere and from fire emissions sources in Mexico. Based on this analysis, we are confident that the CT system will play a major role in Latin America and the Caribbean as a scientific tool to understand the uptake and release of CO₂ from terrestrial ecosystems, fossil fuel use and the oceans, and for long-term monitoring of atmospheric CO₂ concentrations.     

Inference of surface concentrations of nitrogen dioxide (NO2) in Colombia from tropospheric columns of the ozone measurement instrument (OMI)

For the first time, maps of surface concentration of nitrogen dioxide (NO₂) are presented for the Colombian territory. NO₂ surface concentrations for the year 2007 are inferred based on two sources of tropospheric NO₂ column data: (1) a simulation using a three-dimensional global model (GEOS-Chem) and (2) measurements made by the ozone monitoring instrument (OMI) onboard the NASA Aura satellite. Results show monthly averages between 0.1 and 6 ppbv. We compare these inferred values to corrected ground measurements of NO₂. We find correlation coefficients of up to 0.91 between the inferred data and the corrected observational data. A significant source of NO₂ is biomass burning, which can be diagnosed by data of fire radiative power (FRP) from the Monitoring of Atmospheric Composition and Climate (MACC) reanalysis. We find a close relationship between high values of inferred NO₂ surface concentrations and biomass burning for a large area which encompasses the departments of Caquetá, Meta, Guaviare, Vichada, and Putumayo.     

Preliminary analyses of landslides and sand liquefaction triggered by 22 May, 2021, Maduo Mw 7.3 earthquake on Northern Tibetan Plateau,China

During the Maduo Earthquake (MDEq) (M_w 7.3), which occurred on 22 May 2021 in the northern Tibetan Plateau, coseismic surface ruptures, numerous land liquefaction instances and landslides, were triggered along the NW strike of the?~?160 km long aftershock zone. We performed three times emergency field surveys (22 May to 3 Jun., 28 Jun. to 14 Jul., 8–24 Oct., 2021) with unmanned aerial vehicle (UAV) orthophoto and digital elevation model (DEM) data. We found a discontinuous coseismic surface rupture zone along with loose sediment, severe sand liquefaction regions with an area of?~?10³ km² along the Yellow River and its tributaries. More than 23 coseismic landslides had been checked with relative small-size volume for limited local terrain relief. Three of those landslides had relatively small source areas and volumes and affected relatively large areas. We identified numerous tension cracks in and around the trailing edges, which could trigger more landslides in the future. Further detailed research into the occurrence of these three landslides will reveal the failure mechanism of the earthquake (shaking)–freeze–thaw effect–rainfall disaster chain. Here, we present basic information to aid the overall understanding of the preliminary characteristics of coseismic earthquake-triggered landslides, sand liquefaction, and possible follow-up disasters.

     

Nested regional climate–chemistry simulations for central Europe

The potential impact of global climate change on regional meteorology and near-surface ozone concentrations in central Europe and the effect of model resolution on the simulated quantities were studied using a coupled climate–chemistry model. Nested simulations with a horizontal resolution of 60 km for Europe and 20 km for central Europe were performed for two time slices of about 10 years representing present-day and future climate conditions. The model results indicate that increased solar radiation due to decreased cloud cover, higher temperatures, and enhanced isoprene emissions promote the formation of tropospheric ozone in central Europe under future climate conditions. Depending on the region, the increase of the mean daily maximum ranges between 2 and 10 ppb and exceedances of the threshold of 60 ppb for the 8-hourly mean as well as the AOT40 index were found to increase considerably. General tendencies in the regional distributions of near-surface ozone were similar for 60- and 20-km resolutions. However, pronounced regional differences were found for some regions due to stronger smoothing of anthropogenic and biogenic emissions as well as flattened topography for the 60-km resolution.     

Emission quantification of refrigerant CFCs,HCFCs and HFCs in megacity Lahore (Pakistan) and contributed ODPs and GWPs

An integrated assessment of emissions of some important refrigerant ozone depleting substances (ODSs) (CFC-11, CFC-12, HCFC-141b and HFC-134a) and their contributed ozone depletion potentials (ODPs) and global warming potentials (GWPs) have been made in the megacity Lahore (Pakistan) for the period from 2005 to 2013. During the production of 6.488 million refrigerator units, the cumulative estimated emissions of CFC-11, CFC-12, HCFC-141b and HFC-134a were 129.7, 6.8, 1257 and 104 mega grams (1 Mg = 10⁶ grams). The estimated GWP (CO₂-eq) and ODP (CFC 11-eq) associated with production phase emissions of these four gases were 616.07, 73.52, 910.96, and 87.36 kilotonnes, and 129.7, 6.8, 139.4, and 0 tonnes, respectively. ODP of HFC-134a is considered to be zero. In addition, the repair and maintenance of 81.2 thousand units resulted in 10.8 Mg emissions of CFC-12 with 10.8 tonnes ODP(CFC 11-eq) and 117,802 tonnes GWP (CO₂-eq) that were higher than the HFC-134a emissions recorded at 4.3 Mg causing 4563 tonnes GWP(CO₂-eq). A decrease in ODP (CFC 11-eq) and GWP (CO₂-eq) at the rate of ?8.3% and ?8.2% per year is observed to be contributed by all the selected ODSs during the study period.     

Sampling and analytical procedures for the determination of VOCs released into air from natural and anthropogenic sources: A comparison between SPME (Solid Phase Micro Extraction) and ST (Solid Trap) methods

In the present study, two sampling and analytical methods for VOC determination in fumarolic exhalations related to hydrothermal-magmatic reservoirs in volcanic and geothermal areas and biogas released from waste landfills were compared: (a) Solid Traps (STs), consisting of three phase (Carboxen B, Carboxen C and Carbosieve S111) absorbent stainless steel tubes and (b) Solid Phase Micro Extraction (SPME) fibers, composed of DiVinylBenzene (DVB), Carboxen and PolyDimethylSiloxane. These techniques were applied to pre-concentrate VOCs discharged from: (i) low-to-high temperature fumaroles collected at Vulcano Island, Phlegrean Fields (Italy), and Nisyros Island (Greece), (ii) recovery wells in a solid waste disposal site located near Florence (Italy). A glass condensing system cooled with water was used to collect the dry fraction of the fumarolic gases, in order to allow more efficient VOC absorption avoiding any interference by water vapor and acidic gases, such as SO₂, H₂S, HF and HCl, typically present at relatively high concentrations in these fluids. Up to 37 organic species, in the range of 40–400 m/z, were determined by coupling gas chromatography to mass spectrometry (GC–MS). This study shows that the VOC compositions of fumaroles and biogas determined via SPME and ST are largely consistent and can be applied to the analysis of VOCs in gases released from different natural and anthropogenic environments. The SPME method is rapid and simple and more appropriate for volcanic and geothermal emissions, where VOCs are present at relatively high concentrations and prolonged gas sampling may be hazardous for the operator. The ST method, allowing the collection of large quantities of sample, is to be preferred to analyze the VOC composition of fluids from diffuse emissions and air, where these compounds are present at relatively low concentrations.     

Lockdown during COVID-19 pandemic: A case study from Indian cities shows insignificant effects on persistent property of urban air quality

The influence of reduction in emissions on the inherent temporal characteristics of PM_2.5 and NO₂ concentration time series in six urban cities of India is assessed by computing the Hurst exponent using Detrended Fluctuation Analysis (DFA) during the lockdown period (March 24–April 20, 2020) and the corresponding period during the previous two years (i.e., 2018 and 2019). The analysis suggests the anticipated impact of confinement on the PM_2.5 and NO₂ concentration in urban cities, causing low concentrations. It is observed that the original PM_2.5 and NO₂ concentration time series is persistent but filtering the time series by fitting the autoregressive process of order 1 on the actual time series and subtracting it changes the persistence property significantly. It indicates the presence of linear correlations in the PM_2.5 and NO₂ concentrations. Hurst exponent of the PM_2.5 and NO₂ concentration during the lockdown period and previous two years shows that the inherent temporal characteristics of the short-term air pollutant concentrations (APCs) time series do not change even after withholding the emissions. The meteorological variations also do not change over the three time periods. The finding helps in developing the prediction models for future policy decisions to improve urban air quality across cities.     

Decomposing the changes of energy-related carbon emissions in China: evidence from the PDA approach

In order to investigate the main drivers of CO₂ emissions changes in China during the 11th Five-Year Plan period (2006–2010) and seek the main ways to reduce CO₂ emissions, we decompose the changes of energy-related CO₂ emissions using the production-theoretical decomposition analysis approach. The results indicate that, first, economic growth and energy consumption are the two main drivers of CO₂ emissions increase during the sample period; particularly in the northern coastal, northwest and central regions, where tremendous coal resources are consumed, the driving effect of their energy consumption on CO₂ emissions appears fairly evident. Second, the improvement of carbon abatement technology and the reduction in energy intensity play significant roles in curbing carbon emissions, and comparatively the effect of carbon abatement technology proves more significant. Third, energy use technical efficiency, energy use technology and carbon abatement technical efficiency have only slight influence on CO₂ emissions overall. In the end, we put forward some policy recommendations for China’s government to reduce CO₂ emissions intensity in the future.     

A transmission electron microscopy analysis of secondary minerals formed in tungsten-mine tailings with an emphasis on arsenopyrite oxidation

Grains of naturally oxidized arsenopyrite [FeAsS] collected from the oxidation zone in W-mine tailings were investigated, primarily using transmission electron microscopy. The grains are severely pitted and are surrounded by secondary minerals. The pitted nature of the grains is related to mechanisms governing the electrochemical oxidation of sulfide minerals, with prominent cusp-like features occurring at cathodic regions of the surface, and pits occurring at anodic regions. In general, the oxidation of arsenopyrite leads to the formation of an amorphous (or nanocrystalline) Fe–As–O-rich coating that contains small amounts of Si, Ca, Cu, Zn, Pb and Bi; nanoscale variation in the As, Pb, Bi and Zn contents of the coating was noted. Secondary Cu sulfides, thought to be chalcocite [Cu₂S] and (or) djurleite [Cu₃₁S₁₆], occur as a layer (generally <500 nm thick) along the arsenopyrite grain boundary, and also within the coating as aggregates, and as layers that parallel the grain boundary. Although the precipitation of secondary Cu minerals along the grain boundary is a nanoscale feature, the process of formation is thought to be analogous to the supergene enrichment that occurs in weathered sulfide deposits. As the oxidation of arsenopyrite proceeds, layers and clusters of secondary Cu sulfides become isolated in the Fe–As–O coating. Secondary wulfenite [PbMoO₄] and an unidentified crystalline Bi–Pb–As–O mineral occur in voids within the coating, suggesting that these minerals precipitated from the local pore-water. Small and variable amounts of W, Ca, Bi, As and Zn are associated with the wulfenite, and Zn, Fe and Ca are associated with the Bi–Pb–As–O mineral. Some of the wulfenite is in contact with inclusions of molybdenite [MoS₂], suggesting that the oxidation of molybdenite in the presence of aqueous Pb(II) led to the formation of wulfenite. Mineralogical analyses at the nanoscale have improved the understanding of geochemical sources and sinks at this location. The results of this study indicate that the mineralogical controls on aqueous elemental concentrations at this tailings site are complex and are not predicted by thermodynamic calculations.     

The effect of directed technical change on carbon dioxide emissions: evidence from China’s industrial sector at the provincial level

Technical change has a pivotal role to play in low-carbon development. Recent research has offered different insights regarding the effect of technical change on CO₂ emissions but ignored the bias of technical changes which lead to changes in CO₂ emissions. To fill the gap, this paper uses the 2008 to 2015 provincial-level data on China’s 22 industrial sub-sectors to investigate both the effect of directed technical change on CO₂ emissions and its heterogeneity. We find that the technical change in most industrial sectors in China was capital-biased, although a labor-biased trend was evident. Labor-biased technical change is conducive to CO₂ reduction, while capital-biased technical change has the opposite effect. Moreover, this effect is different by developmental periods, industries, and regions. Therefore, we propose that the government promotes labor-biased technical change based on the differentiated characteristics.

     

Thermodynamics of Arsenates,Selenites, and Sulfates in the Oxidation Zone of Sulfide Ores. XIV. Selenium Minerals in the Oxidation Zone of the Yubileynoe Massive Sulfide Deposit,the South Urals

Selenium is one of the most important minor elements in massive sulfide ores. This study focuses on selenium minerals present in the oxidation zone of the Yubeleinoe massive sulfide deposit, the South Urals, Russia: clausthalite (PbSe), tiemannite (HgSe), and naumannite (Ag₂Se). These minerals are associated with goethite and siderite. Thermodynamic modeling was used to estimate the physicochemical parameters of selenide stability and the possible formation of Pb, Hg, and Ag selenites as a result of sulfide ore oxidation. The Eh–pH diagrams for the Fe–S–CO₂–H₂O and Fe–Se–CO₂–H₂O systems were calculated to estimate the physicochemical formation conditions of the Yubileinoe oxidation zone, as well as for the M–Se–Н₂О and M–S–H₂O (M = Hg, Pb, Ag) systems. The physicochemical parameters of clausthalite, naumannite, and tiemannite stability are consistent with these conditions. Only the formation of PbSeO3 is theoretically possible among Pb, Ag, and Hg selenites.

     

A geochemical traverse across the Eastern Carpathians (Romania): constraints on the origin and evolution of the mineral water and gas discharges

The inner sector of the Eastern Carpathians displays a large number of Na–HCO₃, CO₂-rich, meteoric-originated cold springs (soda springs) and bore wells, as well as dry mofettes. They border the southern part of the Pliocene–Quaternary Calimani–Gurghiu–Harghita (CGH) calc-alkaline volcanic chain. Both volcanic rocks and CO₂-rich emissions are situated between the eastern part of the Transylvanian Basin and the main east Carpathian Range, where active compression tectonics caused diapiric intrusions of Miocene halite deposits and associated saline, CO₂-rich waters along active faults. The regional patterns of the distribution of CO₂ in spring waters (as calculated pCO₂) and the distribution pattern of the ³He/⁴He ratio in the free gas phases (up to 4.5 R_m/R_a) show their maximum values in coincidence with both the maximum heat-flow measurements and the more recent volcanic edifices. Moving towards the eastern external foredeep areas, where oil fields and associated brines are present, natural gas emissions become CH₄-dominated. Such a change in the composition of gas emissions at surface is also recorded by the ³He/⁴He ratios that, in this area, assume ‘typical’ crustal values (R_m/R_a=0.02).In spite of the fact that thermal springs are rare in the Harghita volcanic area and that equilibrium temperature estimates based on geothermometric techniques on gas and liquid phases at surface do not suggest the presence of shallow active hydrothermal systems, a large circulation of fluids (gases) is likely triggered by the presence of mantle magmas stored inside the crust. If total ³He comes from the mantle or from the degassing of magmas stored in the crust, CO₂ might be associated to both volcanic degassing and thermometamorphism of recently subducted limestones.     

Multi-directional efficiency analysis-based regional industrial environmental performance evaluation of China

This study evaluates the environmental efficiency of industrial sectors of Chinese major cities. The multi-directional efficiency analysis (MEA) approach is utilized for evaluation; thus, both the integrated MEA efficiency levels and the efficiency patterns, which are represented by the variable-specific MEA efficiency according to each type of the industrial pollutant emission or discharge, of Chinese major city are detected. In addition, the industrial energy conservation and pollutant reduction potentials are measured, and the relationship between environmental pressure and income is explored at the regional level of China. The main findings include the following: (1) The MEA environmental efficiency increases in the economically less developed cities were faster than the cities in the well-developed region, which indicates that the inequitable nationwide industrial developments of Chinese cities have started to alleviate. (2) Although some Chinese cities show similar environmental efficiency levels, the undesirable output variable-specific efficiency patterns of these cities are diversified, and according to the variable-specific efficiency, the most possible efficiency increase potential of each Chinese major city can be identified. (3) An N-shaped environmental Kuznets curve exists in the industrial sectors of Chinese major cities. (4) Different Chinese cities should have different industrial pollutant reduction priorities: East China cities should pay more attention to their industrial waste gas emissions and industrial waste water discharges, while west China cities should mainly focus on their industrial soot and dust emissions, and solid waste discharges.

     

The first evidence of UHP metamorphism in the Polar Urals (Russia)

A new ultrahigh-pressure (UHP) metamorphic terrane, the Marun-Keu eclogite–peridotite–gneiss complex was established in the Polar Urals (Russia). Owing to the P–T parameters of formation of garnet peridotites obtained for the first time, it was established that they experienced UHP metamorphism with a peak in the diamond stability field (39 kbar, 830oC) due to subduction of rocks of the Marun-Keu complex to the mantle (a depth of more than 100 km). Relics of plagioclase peridotites preserved in central parts of large peridotite bodies and petrochemical data are evidence that Marun-Key garnet peridotites cannot be of mantle origin. A basic-ultrabasic intrusion, which formed in the upper crust, can be considered as their protolith. Later, rocks of the massif plunged to the mantle along the subduction zone and metamorphosed under high-P to ultrahigh-P conditions.