大气环境影响评价点源预测模型软件系统的开发

大气环境影响评价是环境影响评价的一项重要内容,而其中最主要的部分就是计算各种大气扩散模式下的地面污染浓度,然后据此结果作出评价.为方便气象资料的整理和大气扩散的计算,因此使用Matlab软件,编制这套大气环境影响评价点源预测模型软件系统.     

基于人工神经网络算法的大气污染统计预测模型研究进展

人工神经网络算法(ANNs)能够对影响大气污染物各变量间的非线性关系进行较好描述,因而在空气质量预测、重污染预警工作中得到了广泛的应用。随着算法结构的不断发展,基于ANNs的大气污染统计预测模型在其预测精准性上得以显著提升。对近年来的相关研究成果进行归纳,从变量的选取与预处理、算法结构的调整与优化等方面总结提升模型预测性能的主要方法,最终形成构建基于ANNs的大气污染统计预测模型的方法体系。     

高架连续点源落地浓度预测中风速的确定

高架连续点源污染物排放落地浓度是大气环境影响预测的主要内容。由于大气污染物扩散明显受气象条件尤其是风速的影响，而现有预测模型中对于风速的取值都是按经验值来确定的。通过分析在不同气象和烟源条件下，平均风速的计算方法对烟羽抬升高度以及最大落地浓度产生的影响，与实测值相比较确定了风速取值的合理方法，缩小了预测偏差。     

大气环境影响评价技术复核规范与典型案例分析

大气环境影响评价(简称环评)技术复核是指依据国家发布的标准与规范要求,针对重点项目环评报告书中有关环境影响预测与评价部分内容开展的技术复核工作,重点分析预测模型、基础数据与参数以及预测方法是否符合技术导则相关要求,并提出复核结论与建议。针对60多个重大环境敏感项目的技术复核报告进行统计分析,发现超过60%的被复核环评报告需返回修改或直接退回。复核案例及经验表明,污染源确定、模型应用规范化是大气环评中需要解决的关键技术。最后,结合典型案例说明大气环境影响预测技术复核的主要内容、过程和复核结论,提出了加强技术复核有效性、提高大气环境影响预测技术水平的结论与建议。     

多种神经网络在华北西部区域城市空气质量预测中的应用

据华北西部区域4个主要城市2003—2012年API日报数据和相应时段的地面气象要素数据,利用4种(BP、Elman、T-S模糊、小波)神经网络构建预测模型并预测相应城市大气环境质量。研究结果显示,4种模型在可靠性、预测精度方面均可满足应用要求可用于实际预测;具有动态反馈能力的Elman神经网络的预测精度以及泛用性要优于具静态馈能力的其他3种网络模型,说明动态神经网络更适用于城市大气环境质量预测。4种神经网络的决策权重大小及其排序虽各不相同,但体现出相似规律性,日最低气温、日均气压、前日API对输出数据的影响较大,说明逆温现象引发的持续性、区域性污染是该地区主要环境问题。     

上海中长期发展的大气环境制约分析

根据上海市大气环境污染物排放状况,以及大气环境质量的有关统计数据,采用Sigmoid模型,对未来的变化趋势进行了预测。并研究了大气环境质量与社会经济发展的关系,进一步分析了上海市大气环境质量对中长期发展的制约因素。最后,对如何改善上海市大气环境质量,提出了相应对策与建议。     

大气降水化学组份分析方法

大气污染直接反映在大气环境干、湿沉降物的水平上,弄清楚干、湿沉降物的有害组分的变化规律及其发展趋势,对开展大气污染的预测、预报工作很重要.为了准确提供大气环境质量的可靠数据及资料,本文仅就大气环境中降水化学组份的分析方法,作一梗要介绍. 大气污染与雨水的组份往往决定于由地     

模糊数在建设项目大气环境影响评价中的应用

本文用模糊数的方法进行建设项目大气环境影响评价.通过实例计算,说明在建设项目大气环境影响评价中,模糊数的应用不失为一种实用性很广的方法.     

城市大气污染物长期平均浓度计算方法的研究

本文根据风速、大气稳定度联合频率表及各种稳定度条件下的混合层高度用箱式模式计算各种气象条件下大气污染物的浓度,按其联合频率的大小进行加权取和后得到长期平均浓度.用此方法计算了石家庄市春、夏、秋、冬,特征因子SO_2的长期平均浓度,并与实测结果进行比较其相关性较好.从而验证了本方法在大气环境预测及城市环境规划中的实用性.     

土壤中重金属累积预测模型研究进展

健康的土壤是维持人体健康以及国家粮食安全的重要保障.中国部分地区土壤重金属污染较为严重,因此采用合理的预测模型对土壤中的重金属污染状况进行分析和预测,对于土壤的健康管理具有重要意义.聚焦土壤中重金属累积预测模型研究现状,简要分析土壤中重金属的累积行为,阐述不同重金属累积预测模型原理以及实际应用,总结影响预测模型准确度的...     

Optimization of Height of Release of Air Pollutants

A number of key projects in the Environmental Protection Agency (EPA) particulate R&;D program having applicability to industry are presented. For electrostatic precipitators (ESP) there is presented the result of work on large diameter discharge electrodes which provide a decrease in penetration of up to a factor of 4 when compared to conventional small diameter electrodes. Also discussed is the multistage ESP which provides a collection efficiency that would require a collecting plate area 4 or 5 times larger with conventional ESP technology. The E-SOX technology makes use of the multistage concept to free up space in the ESP for SO₂ removals of up to 90%. Electrostatically augmented fabric filtration provides a reduction in pressure drop of about 5 0% as compared to conventional fabric filtration. Wind tunnel modeling of windbreaks for material storage piles indicates a potential for providing engineering design data that would allow significant emission reduction caused by wind erosion     

Investigation of the characteristics of the reflectivity of clouds

This paper investigates some of the reflectivity characteristics that clouds (when modelled as solid bodies) must exhibit to be compatible with observations that the reflecting surface of a cloud (i) appears almost equally bright across its face, (ii) is brightest when the cloud is opposite to the Sun but decreases in brightness as the cloud moves to other positions and (iii) increases in brightness with increasing optical thickness of the cloud in the observer's line of sight. These observations, respectively, are shown to imply that the peak value of the bidirectional total reflectivity from a cloud surface (i) increases in inverse proportion to the cosine of the angle between the Sun and the normal to the cloud surface, as the incident angle increases, (ii) appears to be directed back in the direction of the incident radiation, and (iii) increases as optical thickness of the cloud in the observer's line of sight increases. The results could have application in many fields (e.g. modelling diffuse radiance distributions for cloudy skies).     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

扬中生态环境建设的思考与实践

结合扬中生态环境的基本情况和存在的不足，进行了具体分析，对扬中未来生态建设的发展方向提出了建议及实施措施。     

实验室质量管理体系内部审核的实施

在实施ISO／IEC17025：1999标准《检测和校准实验室能力的通用要求》过程中，通过实验室质量管理体系内部审核的实践与系统分析，识别出内部审核实施阶段的关键环节，提出召开首次会议、收集审核证据、确定审核发现和召开末次会议的技术方法，对提高内部审核的质量和有效性、获得可靠的审核结论具有重要意义。     

次氯酸钠发生器的研制

介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠     

An application of the theory of kinematics of mixing to the study of tropospheric dispersion

The most common technique used for numerical simulations of tracer mixing is that of the numerical solution of the advection–diffusion equation with the unresolved fluxes parameterized using the similarity theory. Despite correct predictions of the overall directions of transport, models based on a numerical solution of the advection–diffusion equation lack sufficient accuracy to correctly reproduce the coupling of mixing with small scale processes which are sensitive to the microstructure of the tracer distribution. The objective of this paper is to revisit the basic formalism employed in numerical models used to investigate atmospheric tracers. The main mathematical method proposed here is the theory of kinematics of mixing which could be applied effectively for simulations of atmospheric transport processes. At the beginning of the paper, we introduce simple mathematical transformations in order to demonstrate how complex topological structures are created by mixing processes. These idealistic flow systems are essential to explain transport properties of much more complex three-dimensional geophysical flows. An example of the application of the kinematics of mixing to the analysis of tracer transport on a planetary scale is presented in the following sections. The complex filamentary structures simulated in the numerical experiment are evaluated using some commonly applied statistical measures in order to compare the results with the data published in the literature. The results of the experiment are also analysed with the help of simple conceptual models of fluid filaments. The microstructure of the tracer distribution introduced in the paper is essential to increase our understanding of atmospheric transport and to develop more realistic parameterizations of small-scale mixing. The presented results could also be used to improve calculations of the coupling between microphysical processes and tracer mixing.     

Comparison of methods for evaluation of activity of photocatalytic films

Objective

This work aims to investigate the correlation between the photocatalytic activity determined by methylene blue bleaching (DIN 52980), stearic acid degradation, and degradation of acetone in gas phase.

Method

The photocatalytic TiO₂ coatings included in this investigation ranged from thin commercially available coatings (Activ^TM and BioClean^TM) and ready to use suspensions (Nano-X PK1245) to lab-produced PVD and sol?Cgel coatings. XRD analysis of the photocatalytic coatings showed that all the coatings consisted of nanocrystalline anatase, although the thickness and porosity varied considerably.

Results

The study showed that the reproducibility of the activity measurements was good. However, more importantly, the investigation showed that there is a good correlation between the activities determined by the different methods even though the characteristics of the photocatalytic coatings and the organic probe molecules varied considerably.

Conclusion

The overall findings of this work suggest that there is a good correlation between the investigated methods. These results are promising for the future work concerning standardization of methods for determination of the activity of photocatalytic films.     

Impact of overexploitation of shellfish: northeastern coast of India

India has a very extensive coastline of about 7515 km, rich in diverse living resources. These resources continue to deteriorate with rampant harvesting or are altered for other uses such as aquaculture and fisheries. The present paper deals with degrading coastal habitats in northeastern India, and projects the intensity of the stress arising from the collection of tiger prawn seeds (Penaeus monodon) for aquacultural farms and molluskan shells for poultry feed and edible lime. Indiscriminate exploitation of these resources leads to a heavy reduction of the species concerned and other associated marine communities. The magnitude of such destruction has been quantified. The impacts of biodiversity loss and their after-effects on the ecobalance of this coastal system have become a matter of great concern to ecologists to maintain security and sustainability. The authors propose a public awareness program on themes relating to the importance of biodiversity for human livelihoods.