城市公交车定置噪声测试与特征分析

对北京市典型类别公交车的噪声污染水平及排放特征进行了测试和研究。研究和统计结果表明,北京城市在用公交车的定置噪声排放水平总体处于90～103 dB(A),其A计权频域特征以人耳敏感的中高频噪声为主,对城市居民的环境影响较大,是目前城市内需要重点关注的噪声污染源。相关数据将为交通和环保部门有针对性地提出噪声控制措施和制订相关法规提供有效支撑。     

中国森林碳汇潜力与增汇成本评估——基于Meta分析方法

准确评估中国森林碳汇潜力与增汇成本的经济可行性,是科学制定碳中和林业行动方案的基础。然而针对中国森林碳汇潜力与增汇成本的不同结果差异明显,可靠性需要进一步验证。为此,基于相关文献,采用Meta分析方法,对中国森林碳汇潜力与增汇成本及其导致差异的原因展开评估。研究表明：(1)中国森林碳汇量呈现不断增长的态势,但不同研究对森林碳汇潜力测度结果存在较大差异。(2)中国森林增汇的平均成本为220.45元/t CO_2e(区间值为3.9～1457.02元/t CO_2e),与工业减排成本相比,中国森林增汇更具有经济可行性,但波动幅度较大。(3)评估方法采用、碳库数量选择等因素是导致已有森林碳汇潜力文献估计结果差异的关键因素;森林增汇成本差异则主要受碳汇成本测度研究方法、成本收益数据来源等因素影响。(4)中国森林增汇对碳中和的贡献将会持续增加。基于研究结果,提出进一步深化森林碳汇潜力与成本测算相关研究等方面的政策建议。     

深圳市建筑水泥流量-存量分析及环境影响评估

我国城镇化进程持续深入推进,大规模城市更新建造活动消耗了大量水泥等建筑材料.以深圳市为例,采用自下而上的物质流分析方法估算了自特区建设以来(1979～2018年)城市房屋建筑中的水泥存量和流量,并分析了其产生的综合环境影响(以碳排放当量为度量指标).研究结果表明:1979～2018年间,深圳市建筑水泥历史累积消耗约为8...     

Pipeline design for a least-cost router application for CO2 transport in the CO2 sequestration cycle

CO₂ capture and geological storage (CCS) is considered as a viable option to mitigate greenhouse gas emissions during the transition phase towards the use of clean and renewable energy. This paper concentrates on the transport of CO₂ between source (CO₂ capture at plants) and sink (geological storage reservoirs). In the cost estimation of CO₂ transport, the pipeline diameter plays an important role. In this respect, the paper reviews equations that were used in several reports on CO₂ pipeline transport. As some parameters are not taken into account in these equations, alternative formulas are proposed which calculate the proper inner diameter size based on flow rate, pressure drop per unit length, CO₂ density, CO₂ viscosity, pipeline material roughness and topographic height differences (the Darcy–Weisbach solution) and, in addition, on the amount and type of bends (the Manning solution). Comparison between calculated diameters using the reviewed and the proposed equations demonstrate the important influence of elevation difference (which is not considered in the reviewed equations) and pipeline material roughness-related factor on the calculated diameter. Concerning the latter, it is suggested that a Darcy–Weisbach roughness height of 0.045 mm better corresponds to a Manning factor of 0.009 than higher Manning values previously proposed in literature. Comparison with the actual diameter of the Weyburn pipeline confirms the accuracy of the proposed equations. Comparison with other existing CO₂ pipelines (without pressure information) indicate that the pipelines are designed for lower pressure gradients than 25 Pa/m or for (future) higher flow rates. The proposed Manning equation is implemented in an economic least-cost route planner in order to obtain the best economic solution for pipeline trajectory and corresponding diameter.     

Global estimates of soil carbon sequestration via livestock waste: a STELLA simulation

It has become increasingly well documented that human activities are enhancing the greenhouse effect and altering the global climate. Identifying strategies to mitigate atmospheric carbon dioxide emissions on the national level are therefore critical. Fossil fuel combustion is primarily responsible for the perturbation of the global carbon cycle, although the influence of humans extends far beyond the combustion of fossil fuels. Changes in land use arising from human activities contribute substantially to atmospheric carbon dioxide; however, land use changes can act as a carbon dioxide sink as well. A soil carbon model was built using STELLA to explore how soil organic carbon sequestration (SOC) varies over a range of values for key parameters and to estimate the amount of global soil carbon sequestration from livestock waste. To obtain soil carbon sequestration estimates, model simulations occurred for 11 different livestock types and with data for eight regions around the world. The model predicted that between 1980 and 1995, United States soils were responsible for the sequestration of 444–602 Tg C from livestock waste. Model simulations further predicted that during the same period, global soil carbon sequestration from livestock waste was 2,810–4,218 Tg C. Our estimates for global SOC sequestration are modest in proportion to other terrestrial carbon sinks (i.e. forest regrowth); however, livestock waste does represent a potential for long-term soil carbon gain. SOC generated from livestock waste is another example of how human activities and land use changes are altering soil processes around the world. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Effect of precipitation,sorption and stable of isotope on maximum release rates of radionuclides from engineered barrier system (EBS) in deep repository

The basic function of the engineered barrier system (EBS) in geological disposal is to prevent or limit the release of radionuclides into the underground environment. For this purpose, the vitrified waste is contained in an overpack to isolate it from contact with groundwater for a certain initial period of time. However, it is impossible to ensure complete containment for all time. Therefore, the eventual release of nuclides must be minimized after the overpack fails (AEC, 1984. Radioactive waste processing and disposal measures; JNC, 2000a. Project to establish the scientific and technical basis for HLW disposal in Japan – first progress report-H3. Geological Environment in Japan, JNC TN1410 2000-002; JNC, 2000b. H12: project to establish the scientific and technical basis for HLW disposal in Japan – repository design and engineering technology, JNC TN1410 2000-003.).     

富磷上清液铁接触除磷污泥性质与资源化利用

利用X射线衍射和能谱分析技术,对富磷上清液铁接触除磷污泥进行了成分与性质分析。结果表明,污泥经陈化作用后其主要成分为FePO₄、FeO(OH)和Ca₃(PO₄)₂,各组分的相对质量百分比分别为27.01%、65.52%和7.47%。污泥的沉降性能良好,沉淀6～8 h后总铁浓度＜3 mg/L。分析了污泥资源化利用的方法,提出可将污泥直接用作农肥或土壤改良材料,也可通过高温灼烧、焦硫酸钾溶解、过滤等过程将其分离为铁矿（Fe₂O₃·nH₂O）和磷矿（FePO₄和 Ca₃(PO₄)₂）后再利用。     

东江流域水资源优化配置研究

该文建立了一个以东江流域水资源合理利用为目标,考虑防洪、供水、航运、压咸等约束,采用大系统“分解协调”原理,运用逐步宽容约束法及递阶分析法,通过三大水库与河道、区间径流联合调度,进行自流域至供水行业的多层次优化的水资源优化配置模型。在特枯水年来水情况下,对2020年水平年水资源进行优化调配,得出各个用水户两种不同初始条件下的配水结果。说明只有在三大水库初始蓄满的条件下,才能满足特枯年各个用水户2020水平年的需水要求。     

上海市郊大棚蔬菜的农药使用调查

通过对上海市郊大棚生产中农药使用情况的调查，揭示了上海市郊大棚蔬菜生产中存在的主要农药污染问题，主要表现在：所使用农药的结构不够合理，一些危险级农药仍在使用，而高效杀菌剂和除草剂的品种很少；大棚蔬菜的农药残留量较高，超标率可达１０％；食用受农药污染蔬菜的急性中毒事件时有发生，主要为绿叶蔬菜，农药主要是甲胺膦。     

碳汇价值的形成和评价

在碳减排形势下,如何评价固碳收益价值具有重要的理论与实践意义。论文首先从全球气候变化与碳排放的关联、碳排放与现有经济体系的关联、碳排放空间成为稀缺资源三个方面论证了碳汇效用价值形成的现实基础。然后评述了碳汇价值的构成与度量方法,指出了碳固定与碳蓄积价值的内涵差异。继而总结了碳汇价值的实现机制,认为可以通过碳交易、碳税和固碳项目实际成本3种机制实现碳价格,并在此基础上通过补偿实现碳汇价值。