Incentive-Compatible Pollution Control Policies under Asymmetric Information on Both Risk Preferences and Technology

This article proposes a method to accommodate asymmetric information on farmers' risk preferences in designing voluntary environmental policies. By incorporating stochastic efficiency rules in a mechanism design problem, the government can find incentive-compatible policies by knowing only the general class of risk preferences among farmers. The model also accounts for hidden information on technology types and input use. The method is applied empirically to simulate a pollution control program in New York. Results suggest that participation incentives would be inadequate for many risk-averse producers if the government does not account for the diversity in risk preferences.     

Regulating Nitrogen Pollution with Risk Averse Farmers under Hidden Information and Moral Hazard

We consider a model of pollution regulation for a risk averse farmer involving hidden information, moral hazard, and risk-sharing. The representative farmer faces a production risk originating from nitrogen leaching, and privately observes the soil capacity in retaining nitrogen only after the regulation contract is signed. The latter specifies a transfer and a nitrogen quota, whose decomposition by the farmer among different production stages is unknown to the regulator. We first characterize the optimal solution to the regulator's problem. The sequential decision model is estimated on French crop production data, and the results are used to calibrate and simulate the optimal contract.     

Differences in Social and Public Risk Perceptions and Conflicting Impacts on Point/Nonpoint Trading Ratios

If stochastic nonpoint pollution loads create socially costly risk, then an economically optimal point/nonpoint trading ratio—the rate point source controls trade for nonpoint controls—is adjusted downward (a risk reward for nonpoint controls), encouraging more nonpoint controls. However, in actual trading programs, ratios are adjusted upward in response to nonpoint uncertainties (a risk premium for nonpoint controls). This contradiction is explained using a public choice model in which regulators focus on encouraging abatement instead of reducing damages. The result is a divergence of public and social risk perceptions, and a trading market that encourages economically suboptimal nonpoint controls.     

Prevention versus Treatment under Precautionary Regulation: A Case Study of Groundwater Contamination under Uncertainty

Policy discussions on agricultural pollution problems characterize prevention as more cost effective and precautionary than ex post treatment. We derive conditions under which treatment alone is more cost effective in situations involving multiple sources of emissions, multiple sites affected, and a commonly used precautionary approach to uncertainty. We also show that a greater degree of precaution can result in less reliance on prevention. An empirical case study indicates that treatment alone is the most cost-effective means of dealing with nitrate in most Maryland community water system wells. The use of leaching prevention measures is restricted to the most intensive poultry producing areas. The incremental cost of precaution is substantial.     

中国台湾地区面源污染现状、防控经验及启示

目的 从20世纪80年代开始中国台湾地区注重农业的可持续发展,在农业快速发展的同时,农业面源污染控制取得了良好的成效,但是目前鲜有研究介绍台湾地区的面源污染控制的措施,文章结合对台湾地区农业面源污染的考察与了解,对台湾地区面源污染防控体系进行了全面和深入的分析,为其他地区面源污染控制提供借鉴和经验。方法 梳理了台湾地区在面源污染控制形成的从立法到多源头的技术措施控制体系：分别从立法措施、水库工程治理措施两个方面介绍台湾地区形成的控制面源污染的经验和做法。结果 （1）台湾地区控制面源污染的措施具有明确具体的特点,在不同的立法措施中,明确规定了与控制面源污染相关的行为;（2）根据水库的地形特征及关键污染问题制定相应的工程措施,取得了良好的面源污染防控效果;（3）该研究结合当前大陆地区农业面源污染防控工作的特点,提出了建立完善面源污染立法措施、加强已有面源污染防控技术的集成应用,发挥公众监督的积极性等建议,为我国大陆地区构建符合国情和有效的面源污染防控模式提供科学和技术支持。结论 我国面源污染控制措施,需要因时、因地而宜,逐渐形成政府—企业/科研机构—公众协同参与的治理模式,从而步入绿色发展的新模式。     

Does complex hydrology require complex water quality policy?

Nonpoint‐source water pollution is frequently considered intractable because it is hard to regulate large numbers of small sources and because the science associated with assessing the impact of each source is complex. New Zealand has demonstrated that it is possible to implement a simple cap‐and‐trade system to help reduce nitrogen leaching from many small farms and thereby protect water quality. This paper relates to the second challenge: are complex regulatory systems worthwhile when nitrogen delivery is complex? When nitrogen moves through groundwater to a lake, leaching from different farms reaches the lake at different times and the damage caused is temporally differentiated. Policy that regulates farmers according to the timing of their nitrogen delivery will be more complex than policy that does not. Whether the gain in efficiency justifies this additional complexity can be assessed through modelling. We use an integrated model to estimate the gains from complex nitrogen regulation that incorporates groundwater delivery times relative to simple nitrogen regulation that does not. We find that the gains from more complex regulation are small in the catchment we study and cannot justify the additional complexity required. A sensitivity analysis enables us to identify the types of catchments where complex regulation may be worthwhile.     

Experiments on Damage-Based Ambient Taxes for Nonpoint Source Polluters

This article presents experimental tests of a linear and a nonlinear ambient tax mechanism that involve modest information requirements for the regulator. When agents are not allowed to communicate, both tax mechanisms result in emission levels that approximate the social optimum. When agents can communicate, emissions are considerably below the optimum, but we show that the tax function can be scaled to achieve social efficiency. Finally, by disaggregating the overall efficiency measure, we show that changing the pollution threshold that triggers the tax increases the inefficiency resulting from variation in agent-level decisions, but does not affect average emissions.     

农业面源污染研究方法与控制技术研究进展

[目的]农业面源污染已成为全球亟待解决的环境问题。针对目前研究争论和探讨的热点,文章对国内外农业面源污染的研究方法及进展、评价体系及控制技术进行了分析和提炼,以期为我国绿色农业发展中的面源污染防控提供依据。[方法]文章通过查询知网和Web of Science,对国内外农业面源污染研究方法和防控技术进行了分析总结。[结果]耕地、果园面积大幅度增长,农村地区畜禽养殖业的迅速发展和城镇生活排污是造成农业面源污染的主要因素。目前国内外的研究热点主要集中在模型模拟技术的适用与拓展、最佳管理模式和应用GIS技术进行面源污染评价。随着面源污染研究的不断发展,植物篱、地埂和生态沟渠等污染控制技术常用于农田面源污染防控;景观绿地建设、旋流分离器和生态湿地系统等则更广泛地应用于大规模治理。新型控制技术的提出使农业面源污染防控技术更加现代化、高效化。[结论]未来研究中可结合\"4R\"防控理论,基于长期定点监测的数据建立模型、利用GIS技术进行流域面源污染模拟以了解区域内的面源污染情况,识别当地面源污染源头区域,提供因地制宜的面源污染治理方案。     

Manure Applications and Nutrient Standards

Because of environmental concerns, many states are regulating animal manure applications to crops. A conceptual model is presented to describe manure demand for crop nutrient application under alternative regulatory standards. Demand relationships are incorporated into a spatial equilibrium model to estimate welfare costs of phosphorus and nitrogen regulatory standards for manure applications. Model estimates for Virginia indicate that regulatory standards for manure application achieve large reductions in excess nitrogen and phosphorus and result in 5–15% welfare losses excluding nonmarket environmental valuation.     

国外农业面源污染控制政策的研究进展及启示

我国水污染严重,富营养化问题突出,农业面源污染已成为水体富营养化的主要原因。该文对国外农业面源污染控制政策领域中的主要研究进行了疏理,简要回顾与评论了基于投入的政策和基于水质的政策,认为农业面源污染排放的分散性和随机性决定了其控制政策不能以排放量为设计基础。由于设计与执行政策的信息成本过高,基于水质的政策只停留在理论研究层面。基于投入的政策具有更强的现实可行性。     

中国种植业面源污染的区域差异及其脱钩效应

[目的]明晰种植业面源污染的区域差异及其脱钩效应,为推动农业发展全面绿色转型提供有力支撑。[方法]文章基于等标污染负荷法测算1997—2020年中国31个省（市、区,不含港澳台）的种植业面源污染等标负荷强度,并以八大综合经济区作为研究单元,利用Kernel密度估计、Dagum基尼系数和Tapio脱钩模型等方法全面考察种植业面源污染的区域差异及其与经济增长的脱钩关系。[结果]（1）中国种植业面源污染等标负荷强度表现出先升后降的变化态势,且空间不平衡特征突出;（2）中国种植业面源污染等标负荷强度的总体差异呈上升趋势,区域间差异是总体差异的最主要来源,对总体差异的贡献率呈“M”型演变趋势;（3）样本期内中国种植业面源污染与经济增长整体呈相对脱钩关系,并表现出由相对脱钩状态向绝对脱钩状态转变的发展趋势,其中,东北和西北经济区处于绝对脱钩状态,其他经济区则呈相对脱钩关系。[结论]既要分区分类采取污染治理措施,也需加强区域面源污染协同治理,以期推进各经济区种植业面源污染与经济增长的绝对脱钩,加快实现农业绿色转型发展。     

重庆市农业面源污染测算与空间特征解析

文章采用清单分析法对重庆市农业面源主要污染物、污染负荷进行估算,在此基础之上,运用聚类分析、线性回归以及实证调研等方法,对污染的空间分布特征、影响因素、污染成因作测算与分析。研究尺度定位区县级空间,研究范围依从经济功能区域划分,囊括重庆市37个农业区县。重庆市平均水质污染物浓度COD为11.995mg/L,TN为2.043mg/L,TP为0.457mg/L,综合水质指数为1.989,在轻度污染范围内,非常接近中度污染。重庆主城区周围的农业面源污染严重,两翼地区污染较轻。秸秆、畜禽粪便、化肥是污染的三大主源头,贡献率依次为44.65%,45.47%,7.23%。聚类分析表明永川、荣昌、铜梁、大足、长寿、璧山等区县的污染非常严重。农村用电量、农作物播种面积、地表水资源总量对污染负荷指标具有强烈影响。在污染负荷空间特征分析及实证调研基础之上,提出相应的治理对策建议。     

生态文明思想下的盐城市水环境治理对策

水环境治理是生态文明建设的必然要求。随着经济的快速发展,各类污染物排放量增加,盐城的水环境问题也日益凸显。近年来盐城市积极对水环境开展治理,水质情况逐年好转,主要污染物排放量逐年下降,但由于开展水环境全面治理的时间较短,实践中还存在着治理模式和措施较为传统、科技助力和支撑不多、资金和人才保障水平不高、生态修复能力不足、治理成效不稳固等问题,因此本研究结合盐城市的实际情况,提出基于生态文明思想的水环境治理对策与建议,具体包括动员多元主体参与、创新流域治理模式、强化科技信息支撑、加强资金人才保障、合理确定水体整治方案、推进河湖生态保护修复、完善环境基础设施、深入贯彻落实河长制等,旨在为新时代盐城践行生态文明理念,开展水环境治理工作提供参考。     

我国土壤污染防治的立法保护

基于我国土壤污染防治的现状及土壤污染防治立法的法理基础,分析我国制定《土壤污染防治法》的必要性与可行性,提出《土壤污染防治法》的立法构想。解决立法中如何界定土壤与土壤污染的概念、如何将土壤作为独立的环境要素进行保护、如何理顺《土壤污染防治法》与其他污染防治法的关系及其立法层级等迫切需要解决的相关立法技术问题。进行相关的土壤污染防治立法的可行性制度设计,在制度设计的基础上提出相关法律责任的制定,并提出我国土壤污染防治法的结构框架。     

长江中下游城市群农业面源污染氮排放评价及调控

基于清单分析法和排污系数法,对长江中下游城市群农业面源污染氮排放现状进行了评价,并运用灵敏度分析和情景分析方法,模拟和比较了不同调控方案对区域未来氮排放变化的影响。研究结果表明,2011年长江中下游城市群4种污染源向水环境排放的氮总量共计128.27万t,其中,农业种植和畜禽养殖的排放比例分别为58.92%和33.53%,是该区农业面源污染的主要氮污染源。如果不加大对面源污染的治理力度,2011~2020年和2020~2030年长江中下游城市群农业面源污染氮排放量将分别增加16.29%和18.78%;如果采取相关减排措施,2020年和2030年4个城市群的农业面源污染氮排放量将分别比2011年削减15%和25%,并有利于实现区域农村经济增长与环境健康发展的双重目标。建议今后全区农业面源污染氮排放调控的重点在于逐步削减肥料投入、合理优化用肥结构、控制畜禽养殖规模扩张以及促进专业化养殖畜禽废物循环利用等,主要控制地区包括武汉城市圈内的潜江市、孝感市、黄冈市和鄂州市,长株潭城市群内的长沙市和湘潭市,鄱阳湖生态经济区内的南昌市和鹰潭市,以及皖江城市带内的六安市和合肥市。     

中国农业面源污染的区域分异研究

农业面源污染是我国农村生态环境恶化的主要原因之一,把握农业面源污染的时空规律,加强对农业面源污染管控是贯彻落实科学发展观的重要体现。该文通过分析中国农业面源污染形成途径,确定农业面源污染的评价指标,并利用该指标分析中国农业面源污染的时序特征,发现1985～2005年中国农业面源污染呈现线性增长特征、阶段加速特征和农资污染为主特征。文章分析了2006～2007年中国农业面源污染分布的空间特征,发现中国存在3类污染区域:农资污染区、畜禽污染区和水土流失型污染区。根据时空特征分析,该文给出了农业面源污染管控的政策建议。