Comments on “Development of an empirical equation for the transverse dispersion coefficient in natural streams” by Tae Myoung Jeon,Kyong Oh Baek and Il Won Seo

In a recent paper published in this journal, Jeon et al. ((2007), Environ Fluid Mech 7(4): 317–329) have presented a new empirical equation for the transverse dispersion coefficient in natural streams that was developed based on the hydraulic and geometric parameters using a regression technique. A total of 32 data sets collected in 32 streams was used. Among them, 16 data sets were used for deriving the new equation, and the other 16 were used for verifying the equation. Starting from dimensional analysis the authors found that transverse dispersion coefficient depends on three parameters, such as sinuosity, aspect ratio and a friction term. The robust least square method was applied to estimate regression coefficients resulting in an equation which allows better prediction of transverse dispersion coefficient than previous literature equations. The discussers would like to highlight some points raised in the paper.     

An ecological risk assessment model for a pulsed contaminant emission into a wetland channel flow

As a continuation of the modelling on ecological degradation and hydraulic dispersion of pollutant emission into an idealized two-dimensional free-surface wetland flow (Zeng, L., Chen, G.Q., 2009b. Ecological degradation and hydraulic dispersion of contaminant in wetland. Ecol. Model., doi:10.1016/j.ecolmodel.2009.10.024), an ecological risk assessment model for the typical case of a pulsed contaminant emission into a realistic three-dimensional wetland channel flow is presented in this paper for the fate of cross-sectional mean concentration under environmental dispersion. An environmental dispersion model for the mean concentration is devised as an extension of Taylor’s classical analysis on dispersion in fluid flows. The velocity distribution and the environmental dispersivity in the fully developed steady flow through the wetland is found and illustrated with limiting cases covering various known solutions for the porous media flow between parallel plates, flow in a shallow wetland, sweeping flow in a densely vegetated wetland, and single phase flow in a channel. Obtained by Aris’s method of moments, the environmental dispersivity is shown characterized with multi-scale asymptotic time variations with stem dominated stage, transitional stage, and width-depth-stem dominated stage. Based on the solution for the evolution of contaminant cloud in the wetland channel flow, critical length and duration of the contaminant cloud with concentration beyond given environmental standard level are concretely illustrated for typical pollutant constituents in wastewater emission. Under the same emission intensity and environmental standard, the duration of contaminant cloud in the wetland channel is revealed shorter than that in a free surface wetland, due to the lateral effect.     

Pollution incidence and political jurisdiction: evidence from the TRI

Few issues are more contentious for local communities than industrial pollution. When local industries pollute, lawmakers and regulators must balance two primary concerns: economic prosperity and the environment. The role of political pressure is well documented in environmental policy. What is less clear is the role jurisdictional or boundary considerations play in determining the implementation of environmental laws. Anecdotal evidence suggests that local regulators are more lenient in their treatment of polluters when the incidence of pollution falls partially on those outside the state. One explanation for such behavior is that regulators take actions to maximize political support. This paper tests this jurisdictional model using toxics release inventory (TRI) data from 1987 to 1996. We find that facilities’ emissions into the air and water are systematically higher in counties that border other states. These results are consistent with the hypothesis that jurisdictional considerations are an important determinant of pollution incidence.     

绿色标志运动在世界

随着人们对环境问题的日益关注,一场以保护环境为宗旨的绿色消费运动在全世界蓬勃发展.本文以绿色标志运动的发展过程为线索,详细论述了目前世界各国开展这场运动的现状、组织形式及不同的实施手段.文中介绍了几种已被采用的环境标志的设计思想,列举了绿色标志产品所涉及的种类及不同评审标准,并对绿色标志的管理作了充分说明.此外,文章还着重分析了绿色标志运动对改善环境的影响,为我国开展此项运动提供了借鉴.     

Filament-Based Atmospheric Dispersion Model to Achieve Short Time-Scale Structure of Odor Plumes

This article presents the theoretical motivation, implementation approach, and example validation results for a computationally efficient plume simulation model, designed to replicate both the short-term time signature and long-term exposure statistics of a chemical plume evolving in a turbulent flow. Within the resulting plume, the odor concentration is intermittent with rapidly changing spatial gradient. The model includes a wind field defined over the region of interest that is continuous, but which varies with location and time in both magnitude and direction. The plume shape takes a time varying sinuous form that is determined by the integrated effect of the wind field. Simulated and field data are compared. The motivation for the development of such a simulation model was the desire to evaluate various strategies for tracing odor plumes to their source, under identical conditions. The performance of such strategies depends in part on the instantaneous response of target receptors; therefore, the sequence of events is of considerable consequence and individual exemplar plume realizations are required. Due to the high number of required simulations, computational efficiency was critically important.     

珠江三角洲土地利用变化对特征大气污染物扩散的影响

在珠江三角洲两种下垫面条件下,应用CALPUFF大气污染扩散模式,对特征污染物SO2、SO42-的扩散进行数值模拟,探讨大规模土地利用变化,尤其是城镇建设用地增加,对珠江三角洲地区大气污染物扩散的影响,并通过对4个典型区污染物月均质量浓度变化特征分析,揭示土地利用变化对不同地区的污染物分布的影响机制。模拟结果表明：土地利用变化,尤其是城镇建设用地增加,不利于污染物扩散,污染源下风方向地区受影响较大,污染物质量浓度明显升高,SO2和 SO42-年均质量浓度分别增加14.07%和3.31%;受影响范围、变化幅度与污染源排污强度呈正相关,变化幅度亦与污染源距离远近呈负相关。土地利用变化后,尤其是城镇建设用地增加,四个典型区 SO2月均质量浓度都表现为升高趋势,且冬季 SO2质量浓度升高幅度最大,夏季升高幅度最小,临近污染源密集区的两个典型区SO2月均质量浓度分别增加33.6%和26.3%。土地利用变化不仅改变局地的污染扩散,也会对区域的污染扩散有一定影响,尤其对污染源分布密集区的大气污染物扩散影响强度最大。因此,建议人类在城市化建设过程中尽可能保留自然斑块,消除人工下垫面对污染物扩散的负面影响。     

Can decentralized planning really achieve first-best in the presence of environmental spillovers?

It is generally accepted that decentralized policy choice in the presence of interjurisdictional spillovers is inefficient. Strikingly, Ogawa and Wildasin (2009) find that in a model with heterogenous jurisdictions, interjurisdictional capital flows, and interjurisdictional environmental damage spillovers, decentralized planning outcomes are equivalent to that under a centralized planner. We first show the critical importance of two key assumptions (no retirement of capital, fixed environmental damages per unit of capital) in obtaining this result. Second, we consider a more general model allowing for capital retirement and abatement activities and show that the outcome of a decentralized market generally differs from the solution of a centralized planner?s social welfare-maximizing problem.     

Environmental public health tracking: piloting methods for surveillance of environmentally related diseases in England and Wales

An effective environmental public health tracking system integrates data and intelligence on environmental hazards, exposures, and health outcomes to focus interventions on reducing the impact of environmental contamination on public health. Most work in this area in the UK has focused on assessing data on hazards that are relatively easy to obtain. However, most hazards will present no actual risk and information on exposure is required to make an effective risk assessment. Obtaining exposure data is technically challenging, expensive, and potentially raises ethical concerns. Consequently, the Health Protection Agency is exploring methods for targeting geographical zones for efficient detailed environmental assessment (including exposure assessment). This paper describes and assesses three methods (indirect standardization, statistical process control (SPC) and kernel density contouring) for the surveillance of potentially environmentally related diseases for this purpose. While the evaluation demonstrates the utility of the three methods, particularly SPC, the comparison was limited due to ethical approval issues.     

A fate constant data program

A program for compiling equilibrium and kinetic constants for predicting chemical transport and transformation in the environment is described. The fate constant data are obtained by searching the literature for reported measurements, by convening a panel of experts to postulate transformation pathways and products, by using computational techniques to estimate values, and by performing laboratory studies when measurements cannot be found or computed. Emphasis is placed throughout the program on quality control features to assure the reliability of the data.     

试论“废物最少化”

本文对“废物最少化”的提出、内涵、定义、各种模式及引入我国环境管理制度体系的必要性和可能性作了系统的论述。     

Prevention and cleanup of dynamic harm under environmental liability

This paper explores incentives for accident prevention and cleanup when firms are subject to environmental liability. In our two-period setup, the level of environmental harm in the second period depends on first-period harm when cleanup was incomplete. Under strict liability, in the first period, firms with a positive probability of going out of business before the second period have inadequate prevention and cleanup incentives. The fundamental disconnect between private incentives and social optimality cannot be remedied by using a multiple of harm as the level of compensation. Under negligence with a causation requirement, incentive problems remain; however, under negligence without such a requirement, first-best incentives may emerge, and using a multiple of harm as the level of compensation can ensure the efficient solution.     

Investment in cleaner technology and signaling distortions in a market with green consumers

I analyze the pricing and investment behavior of a firm that signals the environmental attributes of its production technology through its price to uninformed environmentally conscious consumers. I then analyze the effect of change in environmental regulation on the signaling outcome and the firm's ex ante incentive to invest in cleaner technology. When regulation is weak, a firm signals cleaner technology through higher price; in this case, the firm earns lower profit when it has cleaner technology and thus, has no incentive to invest in cleaner technology. The price charged by the clean firm declines sharply beyond a critical level of regulation. When regulation is sufficiently stringent, the firm with cleaner technology charges lower price but earns higher signaling profit, and ex ante the firm has positive incentive to invest in cleaner technology. With weak regulation, the incentive of the firm to directly disclose its environmental performance rather than signal it through price is increasing in the level of regulation; the opposite holds when regulation is sufficiently stringent.     

Environmental policies and productivity growth: Evidence across industries and firms

This paper investigates the impact of changes in environmental policy stringency on industry- and firm-level productivity growth in a panel of OECD countries. To test the strong version of the Porter Hypothesis (PH), we extend a neo-Schumpeterian productivity model to allow for effects of environmental policies. We use a new environmental policy stringency (EPS) index and let the effect of countries׳ environmental policies vary with the pollution intensity of the industry and with the countries’ and firms’ technological advancement. A tightening of environmental policy is associated with a short-term increase in industry-level productivity growth in the most technologically-advanced countries. This effect diminishes with the distance to the global productivity frontier, eventually becoming insignificant. For the average firm, no evidence of PH is found. However, the most productive firms see a temporary boost in productivity growth, while the less productive ones experience a productivity slowdown.     

Potential impact model to assess agricultural pressure to landscape ecological functions

Conservation and protection of soil and water resources and visual aspects of landscape, as well as the promotion of biodiversity, are some of the central tasks of environmental policy development and social politics in the future. One of the main questions is: ‘which agricultural systems are able to guarantee sustained resource-conserving land use?’ Based on the ecological risk concepts of the 1970s and 1980s, a potential impact model was developed using a universal assessment algorithm derived from fuzzy logic. The model estimated the potential impact of agricultural land use on ecosystem function using a few resource indicators. Intervention intensities of agricultural land-use are set in relation to site conditions and aggregated for each of several defined potential impact categories. The interpretation with respect to risk and the calculation of potential impact values are explained.     

Multiple receptor ambient monitoring and firm compliance with environmental taxes under budget and target driven regulatory missions

We analyze the potential for an environmental monitoring agency under different regulatory missions to use multiple measures of ambient pollution levels to induce firm compliance via endogenously determined probabilistic firm-level inspections of polluting activities. Departing from previous analyses, we consider a framework where the regulator has multiple, rather than a single, measures of ambient pollution in a setting where many firms are subject to a self-reported emissions tax that is not perfectly enforceable. Under a budget-driven mission, we show that a regulator can fruitfully utilize the added information from multiple ambient monitoring receptors to induce improved environmental compliance through the creation of strategic interactions among firms. Additionally, our results provide new evidence on the relative efficiency of budget- vs. target-driven environmental enforcement missions.     

Measurement of agricultural total factor productivity growth incorporating environmental factors: A nutrients balance approach

This article proposes to use nutrient-orientated environmental efficiency (EE) measures to construct a nutrient total factor productivity index (NTFP). Since nutrient-orientated EE measures are consistent with the materials balance principle, NTFP index is superior to other existing TFP indexes. An empirical study on the environmental performance of an agricultural sector in 30 OECD countries from 1990 to 2003 yielded several important findings. First, these countries should be able to produce current outputs with at least 50% less aggregate eutrophying power, implying that they should have been able to substantially reduce the potential for eutrophication. Second, traditional TFP has grown by 1.6% per annum due to technical progress; however, there are lags in the responses of several countries to this technical progress. Third, environmental TFP has grown at a slower rate than traditional TFP growth due to reductions in nutrient-orientated allocative efficiency. Finally, changes in input combinations could have significantly improved environmental efficiency and productivity. These findings favor policy interventions and faster technological transfer to improve environmental performance.     

Does more stringent environmental regulation induce or reduce technology adoption? When the rate of technology adoption is inverted U-shaped

We show that for a broad class of technologies the relationship between policy stringency and the rate of technology adoption is inverted U-shaped. This happens when the marginal abatement cost (MAC) curves of conventional and new technologies intersect, which invariably occurs when emissions are proportional to output and technological progress reduces emissions per output. This outcome does not result from policy failure. On the contrary, in social optimum, the relationship between the slope of the marginal damage curve and the rate of technology adoption is also inverted U-shaped. Under more general conditions, these curves can look even more complicated (e.g., such as inverted W-shaped).     

重气连续泄漏扩散的盐水模拟实验

根据相似理论,分析了用盐水模拟方法研究意外泄漏的重气在大气中扩散过程的可行性,通过假设重气为不可压缩气体以及在均匀温度场中扩散等条件,推导出模拟实验的准则数.采用缩比模型的盐水模拟实验,对重气在大气中的扩散速度及浓度变化进行了分析,证实了重气扩散过程中的重力沉降、密度分层以及近源区分叉等现象.实验表明,在满足主导准则数相等的条件下,盐水在清水中的扩散可以较好地再现重气在大气中的扩散特征.     

影响街区峡谷浓度扩散的因素

对街区峡谷内污染扩散规律的研究是城市空气质量预测的主要内容之一。应用现代流体力学数值模拟方法进行大量算例的计算和分析,研究了城市街区峡谷污染物二维扩散的规律。在分析二维街区峡谷内浓度扩散的规律时,发现对街区峡谷浓度扩散的两个影响因素,其中定量分析了湍流脉动对浓度扩散的影响,与层流时得到的浓度扩散进行了通量积分的比较;此外,定性分析了不同类型的街区峡谷对扩散的影响。     

Reducing environmental impacts through socioeconomic transitions: critical review and prospects

● Reducing environmental impacts through socioeconomic structural transitions. ● Simulation of looping the dynamic material cycle should be concerned. ● Transboundary effects of socioeconomic transitions need to be analyzed. ● Facilitating interregional cooperation and synergetic control mechanisms. Rapid socioeconomic development has caused numerous environmental impacts. Human production and consumption activities are the underlying drivers of resource uses, environmental emissions, and associated environmental impacts (e.g., ecosystem quality and human health). Reducing environmental impacts requires an understanding of the complex interactions between socioeconomic system and environmental system. Existing studies have explored the relationships among human society, economic system, and environmental system. However, it is unclear about the research progress in the effects of socioeconomic activities on environmental impacts and the potential directions of future research. This critical review finds that existing studies have identified critical regions, sectors, and transmission pathways for resource uses, environmental emissions, and environmental impacts from supply chain perspectives. Moreover, scholars have characterized the impacts of socioeconomic transitions on resource uses and environmental emissions. However, existing studies overlook the dynamic nature of the interconnections among human society, economic system, and environmental system. In addition, the effects of socioeconomic structural transitions on environmental impacts remain unknown. This review proposes four prospects and possible solutions that will contribute to a better understanding of the complex interactions among human society, economic system, and environmental system. They can help identify more effective solutions to reduce environmental impacts through socioeconomic transitions.