西安市建筑施工扬尘排放的模型估算

作为我国大气污染治理重点区域汾渭平原的重点城市,西安正处于城市建设迅速发展阶段,建筑扬尘排放量大,极大地影响了西安的空气质量.本研究基于西安市建筑和市政施工工程的调查资料,结合两套由不同机构测量的我国北方典型城市排放因子,估算获得了西安市2017年建筑施工扬尘PM_(10)、PM_(2.5)的排放量及排放强度,构建了西安市区县级别建筑扬尘排放颗粒物清单,并分析其空间分布特征.结果表明:①引用中国环境科学研究院依据建筑扬尘产生类型测定的排放因子,估算获得2017年西安市建筑施工扬尘PM_(10)、PM_(2.5)排放总量分别为6.8×10~4、1.4×10~4 t,其中,作业施工扬尘排放量占总排放量的74%,风蚀扬尘占26%;②引用北京市环境保护科学研究院构建的建筑扬尘季节性排放因子,估算西安市建筑施工扬尘PM_(10)、PM_(2.5)排放总量分别为10.8×10~4、2.2×10~4 t,建筑扬尘排放量存在着明显的季节差异,夏季、秋季、冬季的扬尘排放量明显低于春季,但冬季略高于夏季、秋季;③综合两套排放计算结果表明,估算的建筑扬尘排放量存在50%的差异,西安2017年建筑扬尘PM_(10)排放量约为6.8×10~4～10.8×10~4 t,PM_(2.5)排放量约为1.4×10~4～2.2×10~4 t;④空间分布上,主城区建筑施工扬尘排放量大,约占总排放量的72%;主城区建筑施工扬尘排放强度高,约为郊区县的29倍.     

Water environment protection and sustainable development in townlet of China: A case study in Taicang

The Environmental Kuznets Curve (EKC) model was applied to investigate the relationship between economic growth and water environment quality based on panel data of Taicang during 2010–2017. The typical inversed-U shaped relationship has been obtained between GDP (gross domestic product) and indicators of ammonia, total nitrogen (TN) and total phosphorus (TP), respectively. The EKC turning point appeared when the GDP per capita was around US$2270, which was much lower than those in some developed countries (US$11,200). However, the decoupling between chemical oxygen demand (COD) and GDP per capita occurred even before this period, which should be attributed to the strict COD emission regulation being implemented since 2010. Further, analysis based on the Tapio decoupling coefficient elasticity model analyzed the ammonia nitrogen and economic development of each industry. We found that the agriculture no-point was strong decoupling in 2011–2014, then came to Recessive decoupling. The domestic wastewater had been in a strong decoupling state; Both urban non-point and industry experienced expansive negative decoupling, due to strict policy that prioritizes the environment over development and the investment in improvement of environment and techniques, both of them gradually came to strong decoupling. The result demonstrated that the EKC turning point could be appear in earlier economic stage and the decoupling coefficient elasticity could be improved through taking strong regulation measures.     

基于WRFDA-Chem的中国大气成分数据再分析方法研究

大气成分数据是开展空气质量预报、认识大气污染形成机理、评估空气污染各种效应的基础,而融合了模式结果和观测资料的大气成分再分析数据则有更广泛的应用价值.本文基于WRFDA-Chem空气质量模型和三维变分同化技术,逐时同化地面站点污染物浓度观测资料 （包括PM_2.5、PM₁₀、O₃、SO₂、NO₂及CO）,建立了大气成分数据再分析的方法.以2019年7月和12月为例,构建空间分辨率为10 km、时间分辨率为1 h的全国大气成分再分析数据,并对该方法的性能进行了检验.结果表明,经过再分析后的大气成分数据的时间变化趋势和空间分布得到显著改善,其中,7月PM_2.5 和O₃的平均偏差分别降低了55%和39%,相关系数分别提升了77%和7%,达到0.80和0.98;12月PM_2.5 和O₃的平均偏差分别降低了55%和68%,相关系数分别提升了58%和13%,达到0.98和0.98.综合而言,基于WRFDA-Chem逐小时同化全国站点空气质量监测资料,能够得到高时空分辨率的大气成分再分析数据,可以为认识我国大气污染的演变特征和制定科学的管控措施提供有效支撑.     

不同干扰强度对沙质海岸带植物物种β多样性的影响

选择东山岛沙质海岸带4种不同干扰强度林分作为空间演替系列,采用样方法研究其β多样性的变化,结果表明：（1）不同干扰强度林分的植物组成和重要值差别较大,在天然次生林的乔木层和灌木层中,潺槁木姜子（Litsea glutinosa）均是第一优势种,重要值分别为98和137,群落结构稳定;择伐干扰群落中,潺槁木姜子变为乔木层第三优势种,重要值为33,灌木层中仍为第一优势种,重要值为128;皆伐干扰群落中其优势地位逐渐降低,乔木层已无潺槁木姜子的分布,群落结构简单、稳定性差;（2）β多样性（CJ、CS、βWS、βC、βR、CN、CMH）测度表明,随着干扰强度的增大,群落间物种更替速率由低到高呈现增大趋势,物种变化较大,共有种逐渐减少;研究结果支持了＂初始植物区系＂学说,为选择合适树种构建稳定高效的沿海防护林体系提供了基础资料。     

运用相图理论回收缩合废水中的氯化钠和氯化铵

研究了0℃,10℃,60℃时NaCl－NH4 Cl－H2 O三元水盐体系的固液相平衡关系,测出了NaCl和NH4 Cl在水中的溶解度数据,并绘制了相图。运用该三元相图理论,采用结晶法从缩合工段母液废水中回收NaCl和NH4 Cl。讨论了回收过程原理,介绍了回收工艺的操作步骤和工艺参数。回收的NaCl纯度达到95％,总回收率大于77％,NH4 Cl纯度达到92％以上,总回收率大于40％,产品分别达到HG／T 5462—2003,GB／T 2946—2008的标准。     

我国资源型城市的环境与经济可持续发展分析

为保证我国社会、经济、环境全面可持续发展,本文从分布广泛、数量种类繁多的资源型城市的概况,社会、经济、环境的现状和问题分析入手,针对其社会子系统、经济子系统和环境子系统在地区发展中面,J盏的困境和主要问题进行了分析;从系统科学的角度,就资源型城市的共性方面,针对社会、经济、环境三个子系统提出了可持续发展的宏观建议。这对我国的资源型城市和全国的可持续、协调、稳定发展具有一定的参考意义。     

Relationship between types of urban forest and PM2.5 capture at three growth stages of leaves

Particulate matter diameter ≤ 2.5 μm (PM_2.5) causes direct harm to human health. Finding forms of urban forest systems that with the ability to reduce the amount of particulate matter in air effectively is the aim of this study. Five commonly cultivated kinds of urban forest types were studied in Beijing city at three stages of leaf growth. Results show that the urban forest system is capable of storing and capturing dust from the air. The types of shrubs and broadleaf trees that have the ability to capture PM_2.5 from the air are most effective when leaves have fully developed. In the leafless season, the conifer and mixed tree types are the most effective in removing dust from the air. For all kinds of forest types and stages of leaf growth, the PM_2.5 concentration is highest in the morning but lower in the afternoon and evening. Grassland cannot control particles suspended in the air, but can reduce dust pollution caused by dust from the ground blown by the wind back into the air.     

Control strategies for disinfection byproducts by ion exchange resin,nanofiltration and their sequential combination

● Effects of AER adsorption and NF on DBP precursors, DBPs, and TOX were examined. ● A treatment approach of resin adsorption followed by nanofiltration was developed. ● Both DOC and Br⁻ could be effectively removed by the sequential approach. ● DBPs, TOX, and cytotoxicity were significantly reduced by the sequential approach. Disinfection byproducts (DBPs) are emerging pollutants in drinking water with high health risks. Precursor reduction before disinfection is an effective strategy to control the formation of DBPs. In this study, three types of anion exchange resins (AERs) and two types of nanofiltration (NF) membranes were tested for their control effects on DBP precursors, DBPs, and total organic halogen (TOX). The results showed that, for AER adsorption, the removal efficiencies of DBP precursors, DBPs, and TOX increased with the increase of resin dose, and the strong basic macroporous anion exchange resin (M500MB) had the highest removal efficiencies. For NF, the highest removal efficiencies were achieved at an operating pressure of 4 bar, and the membrane (NF90) with a smaller molecular weight cut-off, had a better control efficiency. However, AER adsorption was inefficient in removing dissolved organic carbon (DOC); NF was inefficient in removing Br⁻ resulting in insufficient control of Br-DBPs. Accordingly, a sequential approach of AER (M500MB) adsorption followed by NF (NF90) was developed to enhance the control efficiency of DBPs. Compared with single AER adsorption and single NF, the sequential approach further increased the removal efficiencies of DOC by 19.4%–101.9%, coupled with the high Br⁻ removal efficiency of 92%, and thus improved the reduction of cyclic DBPs and TOX by 3.5%–4.9%, and 2.4%–8.4%, respectively; the sequential approach also reduced the cytotoxicity of the water sample by 66.4%.     

吉林省地方生态环境标准体系研究及发展思考

地方生态环境标准是国家生态环境标准的有效补充。以吉林省为例,通过系统研究地方生态环境标准体系现状,发现吉林省地方生态环境标准存在体系不健全、黑土地分布区生态环境协同保护待加强、标准的全过程管理机制待加强等问题,提出加强顶层设计,完善地方生态环境标准体系,并推动东北黑土地分布区地方生态环境标准体系协同发展,紧跟政策完善重点区域和流域污染物协同管控标准,强化标准宣贯等发展构想,可为其他地区生态环境标准体系构建工作提供参考。     

基于最优尺度Logit模型的交通事故形态致因分析

为剖析典型交通事故形态致因,在利用最优尺度分析法诊断交通事故形态致因共线性的基础上,筛选关键影响因素,构建无序多分类Logit交通事故致因模型并对模型进行参数标定,并选择100个交通事故样本对模型进行精度验证,该模型相对误差仅为4.0％,能够较为准确地分析典型交通事故形态致因.研究结果表明:路侧及中央隔离设施、照明是事...