基于污染物总量控制的流域预警体系构建研究

文章通过对中国目前水环境质量现状分析,指出流域环境预警体系建立的必要性,并选择总量控制指标作为预警体系的评价指标。利用层次分析法建立基于污染物总量控制的流域预警体系,确定预警因子的权重和评分标准。设立临界状态,不良状态预警、缓慢恶化预警和迅速恶化预警4个级别,为建立流域环境质量预警体系提供借鉴。     

Effects of continuously regenerating diesel particulate filters on regulated emissions and number-size distribution of particles emitted from a diesel engine

The effects of continuously regenerating diesel particulate filter (CRDPF) systems on regulated gaseous emissions, and number-size distribution and mass of particles emanated from a diesel engine have been investigated in this study. Two CRDPF units (CRDPF-1 and CRDPF-2) with di erent specifications were separately retrofitted to the engine running with European steady-state cycle (ESC). An electrical low pressure impactor (ELPI) was used for particle number-size distribution measurement and mass estimation. The conversion/reduction rate (RCR) of hydrocarbons (HC) and carbon monoxide (CO) across CRDPF-1 was 83% and 96.3%, respectively. Similarly, the RCR of HC and CO and across CRDPF-2 was 91.8% and 99.1%, respectively. The number concentration of particles and their concentration peaks; nuclei mode, accumulation mode and total particles; and particle mass were highly reduced with the CRDPF units. The nuclei mode particles at downstream of CRDPF-1 and CRDPF-2 decreased by 99.9% to 100% and 97.8% to 99.8% respectively; and the particle mass reduced by 73% to 92.2% and 35.3% to 72.4%, respectively, depending on the engine conditions. In addition, nuclei mode particles increased with the increasing of engine speed due to the heterogeneous nucleation initiated by the higher exhaust temperature, while accumulation mode particles were higher at higher loads due to the decrease in the air-to-fuel ratio (A/F) at higher loads.     

排污权交易初始价格定价方案研究

排污权交易初始分配价格的合理性将在很大程度上决定排污权交易市场的活跃程度,并使排污权交易更好地发挥市场经济手段的最大效用。初始价格的确定依据应为结合排污权时限及贴现率下的不同污染物的社会平均污染治理成本,并兼顾区域经济发展、行业水平、企业公平等因素。文章从定价方式、时限、发布与调整机制、配套措施等方面研究排污权初始价格的定价方案;并以某市为例,通过调查排污量占全市排污量85%以上的企业的污染治理成本,根据所研究的方案获得该市COD、SO2等排污权交易初始分配价格。     

开发建设广西合山国家矿山公园——对资源枯竭型城市经济转型战略的探讨

经济转型是资源枯竭型城市必须面对的重大问题.本文以广西合山市为例,分析了资源型城市转型的必要性及战略方式,探讨了经济转型的可行性,并提出了矿山公园的建设规划及效益分析,可为同类型城市的经济转型及矿业遗迹合理开发提供借鉴.     

上海市崇明岛公路两侧土壤重金属污染研究

采集了上海市崇明岛陈海、北沿公路两侧土壤和灰尘样品270余个,测定了样品的Pb、Cd、Cu、 Zn和Cr重金属含量。结果表明,陈海和北沿公路两侧土壤重金属Pb、Cd、Cu、 Zn和Cr的平均含量达到277、0279、258、918和776 mg/kg,土壤Cd污染较严重。采集的路面灰尘样品Pb、Cd、Cu、 Zn和Cr的平均含量达到512、049、489、209和970 mg/kg,超过土壤背景值2~4倍,是土壤重金属的主要二次污染源。公路防护林体系较差的北沿公路路侧土壤纵向剖面（垂直于公路走向）重金属含量随距路肩距离增加呈指数下降,土壤重金属重污染区在距路肩15 m范围内。防护林体系较完善的陈海公路距路肩15 m范围内土壤重金属污染较小,土壤重金属重污染区出现在距路肩20~50 m范围内。     

云南省传统村落空间分布特征及其影响因素研究

针对云南省传统村落空间分布特征的研究较少,以往学者少有结合云南实际情况进行有效分析等问题,为更好地发掘和传承传统村落文化,为乡村振兴战略提供准确的参考及服务,以云南省708个传统村落为研究对象,运用空间分析和计量地理学模型,如最邻近指数、变异系数、地理集中指数、不平衡指数、核密度分析、叠置分析和缓冲区分析等对云南省传统村落空间分布特征及其影响因素进行研究。研究结果表明：云南省传统村落呈现凝聚型分布,村落分布较集中、不均衡,主要分布于“三核一带”;云南省传统村落分布受自然因素和社会人文因素的影响,主要分布于高程值1 200～2 400 m,地貌为山地地区,坡度小于10°,气温为10～20℃,降雨量为700～1 400 mm,距离河流水系1 km的地区;云南省传统村落的分布不由地区经济发展的好坏来决定的,云南特有的少数民族和茶马古道对传统村落的分布有一定影响。     

Enhanced photocatalytic reduction of carbon dioxide into carbon monoxide by electric field generation and defect engineering in TiO2

Environmental Chemistry Letters - Carbon dioxide (CO2) emissions and rising fossil fuel consumption have already resulted in global warming and energy crisis. Therefore, conversion of CO2 into...     

Study on carbon dioxide emission from reservoirs with different regulation types and its empirical prediction model

Environmental Science and Pollution Research - The construction of artificial reservoirs with various regulation types on river is currently an important form of comprehensive utilization of water...     

Significant concurrent decrease in PM2.5 and NO2 concentrations in China during COVID-19 epidemic

The strict control measures and social lockdowns initiated to combat COVID-19 epidemic have had a notable impact on air pollutant concentrations. According to observation data obtained from the China National Environmental Monitoring Center, compared to levels in 2019, the average concentration of NO₂ in early 2020 during COVID-19 epidemic has decreased by 53%, 50%, and 30% in Wuhan city, Hubei Province (Wuhan excluded), and China (Hubei excluded), respectively. Simultaneously, PM_2.5 concentration has decreased by 35%, 29%, and 19% in Wuhan, Hubei (Wuhan excluded), and China (Hubei excluded), respectively. Less significant declines have also been found for SO₂ and CO concentrations. We also analyzed the temporal variation and spatial distribution of air pollutant concentrations in China during COVID-19 epidemic. The decreases in PM_2.5 and NO₂ concentrations showed relatively consistent temporal variation and spatial distribution. These results support control of NO_x to further reduce PM_2.5 pollution in China. The concurrent decrease in NO_x and PM_2.5 concentrations resulted in an increase of O₃ concentrations across China during COVID-19 epidemic, indicating that coordinated control of other pollutants is needed.     

Revealing the characteristics of dissolved organic matter in urban runoff at three typical regions via optical indices and molecular composition

Dissolved organic matter (DOM) plays a major role in ecological systems and influences the fate and transportation of many pollutants. Despite the significance of DOM, understanding of how environmental and anthropogenic factors influence its composition and characteristics is limited, especially in urban stormwater runoff. In this article, the chemical properties (pollutant loads, molecular weight, aromaticity, sources, and molecular composition) of DOM in stormwater extracted from three typical end-members (traffic, residential, and campus regions) were characterized by UV–visible (UV–vis) spectroscopy, excitation-emission matrix spectroscopy combined with parallel factor analysis (EEM-PARAFAC), and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). There are three findings: (1) The basic properties of DOM in stormwater runoff varied obviously from three urban fields, and the effect of initial flush was also apparent. (2) The DOM in residential areas mainly came from autochthonous sources, while allochthonous sources primarily contributed to the DOM in traffic and campus areas. However, it was mainly composed of terrestrial humic-like components with CHO and CHON element composition and HULO and aliphatic formulas. (3) The parameters characterizing DOM were primarily related to terrestrial source and aromaticity, but their correlations varied. Through the combination of optical methods and UPLC-Q-TOF spectrometry, the optical and molecular characteristics of rainwater are effectively revealed, which may provide a solid foundation for the classification management of stormwater runoff in different urban regions.