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2.
Based on the day-night PM2.5 difference of the nearest atmospheric monitoring points to measure whether there is illegal emission, this paper explores the impact of environmental protection officials' tenure (EPLT) on illegal emissions. The results show that there is a positive correlation between EPLT and illegal emissions. Stable EPLT can reduce illegal emissions by increasing environmental information disclosure and environmental subsidies. It can increase illegal emissions by weakening public pollution reporting and media supervision, environmental law enforcement and promoting corruption. In addition, EPLT can increase illegal emissions as EPLT is less than 3.55 years, while EPLT can increase illegal emissions as EPLT exceeds 6.21 years. Further, when mayor's tenure and EPLT are both stable, the promotion effect of EPLT on illegal emission is stronger. Stable company director's tenure can also aggravate the promotion effect of EPLT on illegal emissions.  相似文献   
3.
Air travelers can carry an infectious disease's pathogenic microorganism in their bodies and spread the disease from one country to another in a few days. To delay the spread, health screening stations may be set up at airport terminals to screen travelers. This research tested three different health screening strategies, each with a different combination of screening stations at trip origins, destinations and connecting airports. Discrete event simulations were performed, based on the 2014 to 2016 Ebola virus epidemic, with special focus on travelers from the West African countries traveling to the United States, including travelers who transferred flights at airports in European Union member states. The effectiveness of the screening strategies was analyzed in terms of correct detection, missed detection and false alarm rate. The results showed that exit screening at trip origins brought big improvements in the performance measurements compared to no screening. However, additional screening at the destinations and connecting airports contributed marginal benefits.  相似文献   
4.
近几年的几场局部战争部分表明了现代军事航天系统的重要性。本文主要介绍了美国最重要的一个军事航天测控网--空军卫星控制网的情况,希望能对了解美国军事航天测控体制有所帮助。  相似文献   
5.
A great deal of the economic literature on pollution control strategies concentrates on the efficiency of environmental policy instruments. Most analytical studies in this field show that market instruments are more efficient with respect to the cost of pollution abatement of a given number of polluters than non-market instruments. According to several analytical studies, market instruments should also be more efficient with respect to innovation in pollution abatement equipment than non-market instruments. In the empirical literature a great number of case studies exist with estimations of the savings of abatement costs of market instruments in a situation without technological progress. Empirical studies about the impact of environmental policy market instruments on the abatement costs in situations with technological progress are lacking.The purpose of this paper is to fill this gap. The paper deals with an empirical estimation of abatement costs for the emission of SO2 of coal-fired electricity units in the Netherlands from 1985 to 2000. First, the working of market instruments and non-market instruments (the existing environmental policy of the Dutch government) is simulated in a static situation. Second, we analyse the learning effects of flue gas desulphurization. The efficiency advantage of market instruments turns out to be larger in a situation of technological progress than in a static situation.  相似文献   
6.
Air transportation is a key strategic asset in that it provides access to markets and thereby enables the economic development of nations. Thus, in order to maintain their competitiveness in a global economy, countries must invest in air transportation infrastructure to ensure their ability to meet current and future demand for aviation services. The objective of this paper is to develop and illustrate a methodology for evaluating the strategic value of air transportation infrastructure, in particular the benefits associated with the ability to react quickly to changes in the market. The hypothesis is that by recognizing and taking advantage of this strategic value, it may be possible to design better policies for aviation infrastructure delivery.The methodology developed here uses system dynamics to model different strategies for infrastructure delivery. These strategies are defined by three variables: the amount of capacity increase, the time to deliver the capacity and the congestion threshold that triggers the need for capacity delivery. Monte Carlo simulation is used to take into account multiple sources of uncertainty. The model shows that a strategy of capacity delivery based on small increments and short response times can yield more benefits than strategies that consider large capacity increases and long response times. Furthermore, in the specific airport example considered here, it was found that a congestion threshold of 75% should be the trigger for capacity enlargements if strategies based on small capacity increments and 1 or 5 years to increase capacity are considered. The lesson for decision-makers is that congestion delays must be addressed with foresight.  相似文献   
7.
This paper deals with the specification of pollution abatement in dynamic computable general equilibrium (CGE) models and analyses the dynamic feedback mechanisms between economy and abatement in the context of environmental policy. A Ramsey-type economic model is presented, in which bottom-up technical and economic information on abatement techniques is integrated in a top-down dynamic CGE context. The practical suitability of the specification is illustrated by an empirical application for climate change and acidification in the Netherlands. The results show that a mixture of some slowdown of economic growth, a substantial restructuring of the economy and implementation of most technical abatement measures is optimal.  相似文献   
8.
On a clear day you might see an environmental Kuznets curve   总被引:1,自引:0,他引:1  
We shed some new light on the Environmental Kuznets curve (EKC) and show how it can be viewed as a particular form of equilibrium relationship, where technology and preference parameters determine the shape of the curve. In contrast to most of the literature on the EKC, we estimate a theoretically consistent model on long-run data (Swedish sulfur emission, covering the period 1900–2002). Furthermore, we test and date structural change. The model suggests four regimes, 1900–1918, 1919–1933, 1934–1967 and 1968–2002, generating four rather different patterns for pollution over time. The policy-conclusions are consonant with Pearce’s general view about the EKC: there is no theoretical presumption that it has an inverted U shape, nor should any country try to “grow out of the environmental problems” without analyzing the benefits and costs of so doing.  相似文献   
9.
Encouraging firms to develop voluntarily more comprehensive environmental management systems (EMSs) is touted as a policy tool to augment mandatory environmental regulations. Using a unique dataset of environmental management practices of Japanese manufacturers and controlling for self-selection bias in survey responses, we find that proxies for regulatory pressures and consumer pressures are the most important factors that motivate firms toward more comprehensive EMSs. Despite the oft-claimed “voluntary” nature of EMS development, our results show that the government may have a role to play in both directly and indirectly affecting EMS development by firms.   相似文献   
10.
This paper examines the effects of missing markets, heterogeneous pollutants, and the pollution technology of firms on the efficacy of transferable pollution permits. Under the assumption of perfect competition in all markets, we show that if firms can substitute among pollutants, then setting the optimal number of permits for only one pollutant will not, in general, lead to an efficient outcome. The degree of the inefficiency will depend on the information set available to the regulator and the substitutability among pollutants by firms. When establishing transferable pollution rights regulators should, therefore, consider the technology of firms. If firms discharge pollutants in the same fixed proportions, then the regulator need only set a market for one of the pollutants to ensure an efficient outcome. Where firms can substitute among pollutants, however, establishing a market for only one pollutant provides an incentive for firms to substitute to unregulated ones. This is an important policy issue as substitutability among pollutants within and across production processes may dampen the dynamic advantages of a tradeable permit policy.  相似文献   
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