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1.
The present National Ambient Air Quality Standard for ozone has many statistical problems, including use of extreme values which have inherent large fluctuations, a compliance test that can gradually lower the target of the design value below the standard level, and inconsistencies between the number-of-exceedances criterion and the design value. The above problems can be avoided or minimized by using a more robust statistic, such as the 95th percentile, and applying a statistical compliance test, without sacrificing the stringency of the standard. Analysis of EPA’s ozone data shows that the annual 95th percentiles and their three-year means have less variability than the annual second highest values and the fourth highest values in three years, respectively. A t test for the mean of the annual 95th percentiles is proposed for compliance testing not only to preserve the averaging concept of the present standard, but also to take account of ozone concentration fluctuations in order to increase the stability of the compliance status of a site or a Metropolitan Statistical Area. A procedure is provided to adjust the level of the 95th-percentile standard so that the stringency of the present standard is preserved.  相似文献   

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Manfred Max-Neef 《Ambio》2010,39(3):200-210
The first part of the paper is an attempt to demonstrate that what we are going through at the present time is not just an economic-financial crisis, but a crisis of humanity. It seems that for the first time in human history several crises converge to simultaneously reach their maximum level of tension. The dominant economic model is to a great degree responsible for the world’s collision course. Hence a number of myths that sustain the model are listed and analyzed. It is argued that a new economy, coherent with the problematiques of the twenty first century, needs urgently to be devised. The second part proposes the foundations for a new economy based on five fundamental postulates that allow the construction of transdisciplinary, holistic, and systemic visions to adequately understand the interdependence of all the elements that sustain life. It is stressed that it is no longer acceptable that Universities still teach economic theories of the nineteenth century in order to tackle twenty first century problems that have no precedence.  相似文献   

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Recent investigations have indicated that ambient air CO measurements may not reflect population exposure to CO. The lack of correlation may be due to improper siting of CO instruments, improper interpretation of air quality data, or both. Studies of population carboxy-hemoglobin levels are evaluated and compared with ambient air data.,

No significant correlation was found between median population COHb levels and reductions in CO concentrations required to meet ambient air standards when calculations used to estimate reductions were based on the second highest 8 hour average. However, calculated reductions based on annual average concentrations and a trend analysis technique correlated significantly with COHb levels in five cities from which both CAMP and COHb data were available.

Studies to determine the nature of the relationship between ambient air CO concentrations and population COHb levels are needed. The differences between the Occupational Safety and Health Act Regulations and the National Ambient Air Standards for carbon monoxide should be scrutinized to determine if a redefinition of the standards or their applicability is warranted. A reevaluation of the controls necessary to make reductions in population COHb burden may be necessary.  相似文献   

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The Persian Gulf is a semi-enclosed marine system surrounded by eight countries, many of which are experiencing substantial development. It is also a major center for the oil industry. The increasing array of anthropogenic disturbances may have substantial negative impacts on marine ecosystems, but this has received little attention until recently. We review the available literature on the Gulfs marine environment and detail our recent experience in the United Arab Emirates (U.A.E.) to evaluate the role of anthropogenic disturbance in this marine ecosystem. Extensive coastal development may now be the single most important anthropogenic stressor. We offer suggestions for how to build awareness of environmental risks of current practices, enhance regional capacity for coastal management, and build cooperative management of this important, shared marine system. An excellent opportunity exists for one or more of the bordering countries to initiate a bold and effective, long-term, international collaboration in environmental management for the Gulf.  相似文献   

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Peterson and Sabersky1 measured the concentrations of ozone, carbon monoxide, nitrogen oxide, and oxides of nitrogen under standard driving conditions in the Southern California area. They indicate that in an automobile with no inside source of carbon monoxide (CO), the interior concentrations will reflect those on the outside but in a more gradual manner. They did not record the rapid variations and high peaks in the interior that they did when samplings were taken from the outside. They reported that 25 ppm of CO was not often exceeded and the highest concentration of CO encountered was 45 ppm for a period of 3 min.  相似文献   

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The problem of an investigation of the need for a regulation on organic compound emissions in the San Francisco Bay Area can be divided into two major areas: 1. Is there a need for a regulation on organic compound emissions? What is the extent of photochemical smog effects? How much control is necessary to achieve the desired effects?

2. (2) If the need exists for an organic compound regulation, can a performance type regulation be written for all types of organic compound emissions? Must the regulation be directed toward specific industries or types of emissions? Can the regulation be adequately enforced—both practically and legally?

This paper will describe the studies undertaken by the District Staff to answer the first set of questions. Work covering the second group of questions is now under investigation.  相似文献   

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By mainly targeting larger predatory fish, commercial fisheries have indirectly promoted rapid increases in densities of their prey; smaller predatory fish like sprat, stickleback and gobies. This process, known as mesopredator release, has effectively transformed many marine offshore basins into mesopredator-dominated ecosystems. In this article, we discuss recent indications of trophic cascades on the Atlantic and Baltic coasts of Sweden, where increased abundances of mesopredatory fish are linked to increased nearshore production and biomass of ephemeral algae. Based on synthesis of monitoring data, we suggest that offshore exploitation of larger predatory fish has contributed to the increase in mesopredator fish also along the coasts, with indirect negative effects on important benthic habitats and coastal water quality. The results emphasize the need to rebuild offshore and coastal populations of larger predatory fish to levels where they regain their control over lower trophic levels and important links between offshore and coastal systems are restored.  相似文献   

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Environmental pollution liability insurance was officially introduced in China only in 2006, as part of new market-based approaches for managing environmental risks. By 2012, trial applications of pollution insurance had been launched in 14 provinces and cities. More than ten insurance companies have entered the pollution insurance market with their own products and contracts. Companies in environmentally sensitive sectors and high-risk industries bought pollution insurance, and a few successful compensation cases have been reported. Still, pollution insurance faces a number of challenges in China. The absence of a national law weakens the legal basis of pollution insurance, and poor technical support stagnates further implementation. Moreover, current pollution insurance products have limited risk coverage, high premium rates, and low loss ratios, which make them fairly unattractive to polluters. Meanwhile, low awareness of environmental and social liabilities leads to limited demand for pollution insurance products by industrial companies. Hence, the pollution insurance market is not yet flourishing in China. To improve this situation, this economic instrument needs stronger backing by the Chinese state.  相似文献   

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Pesticides are removed from the atmosphere by surface deposition, washout, or chemical reaction. The atmosphere is a sink only when the rate of chemical degradation limits the esidence time of the pesticide. Little is known about atmospheric degradation rates, and in many cases, even the reaction pathway may be uncertain. Photochemical conversion is considered a primary reaction mechanism, but reaction with atmospheric oxidants may also be important.  相似文献   

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The future for electrocoagulation as a localised water treatment technology   总被引:1,自引:0,他引:1  
Electrocoagulation is an electrochemical method of treating polluted water whereby sacrificial anodes corrode to release active coagulant precursors (usually aluminium or iron cations) into solution. Accompanying electrolytic reactions evolve gas (usually as hydrogen bubbles) at the cathode. Electrocoagulation has a long history as a water treatment technology having been employed to remove a wide range of pollutants. However electrocoagulation has never become accepted as a 'mainstream' water treatment technology. The lack of a systematic approach to electrocoagulation reactor design/operation and the issue of electrode reliability (particularly passivation of the electrodes over time) have limited its implementation. However recent technical improvements combined with a growing need for small-scale decentralised water treatment facilities have led to a re-evaluation of electrocoagulation. Starting with a review of electrocoagulation reactor design/operation, this article examines and identifies a conceptual framework for electrocoagulation that focuses on the interactions between electrochemistry, coagulation and flotation. In addition detailed experimental data are provided from a batch reactor system removing suspended solids together with a mathematical analysis based on the 'white water' model for the dissolved air flotation process. Current density is identified as the key operational parameter influencing which pollutant removal mechanism dominates. The conclusion is drawn that electrocoagulation has a future as a decentralised water treatment technology. A conceptual framework is presented for future research directed towards a more mechanistic understanding of the process.  相似文献   

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This paper is a continuation of the author's research on the MACT regulation for abating pollution from Petroleum Refinery FCCs in the US. This paper highlights the flaws in the recently promulgated MACT for NSPS and non-NSPS FCC units. It details the inadequacies and the potential for perversity in the New Source Performance Standards (NSPS) that are an integral part of the FCC MACT. It elaborates upon the potential for multi-media risk-exacerbations under the NSPS resulting from changes in feedstock quality, 'unit conversion', advances in cracking technology (that favour inferior crudes and feedstock), lack of NSPS standards for NOx emissions, inter-unit transfer of contaminants/pollutants within a refinery, and the blind eye turned by RCRA to the disposal of spent FCC catalyst waste to landfills. The paper also questions EPA's motives as regards sub-categorisation of FCCs and SBREFA concessions. This paper proposes four standards that remedy these deficiencies. The first standard controls heavy metals, PM, and SOx (along with SO2), while the second proposes an integrated percentile control standard for CO (VOC) and NOx emissions. The paper also proposes a percentile standard for opacity and a spent catalyst tax to control environmental risk posed by disposal of spent FCC catalyst waste to landfills. It explains the calibration of the proposed standards using a novel strategy to bridge the regulatory gap between NSPS, MACT and Residual Risk standards and demonstrates how the calibrated standards apply to FCCs processing feedstock of different qualities. The paper concludes by urging the US EPA to rescind the NSPS and the MACT for FCCs and re-promulgate an integrated set of standards for criteria and toxic pollutants along the lines proposed in this paper.  相似文献   

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Successful integration of Cleaner Production concepts and technologies into businesses and industries requires effective education and training of the professionals. Cleaner Production, in spite of its conceptual simplicity, implies a new way of thinking about processes and products and a more sustainable approach to problem solving. Teaching university students about Cleaner Production is particularly challenging because many concepts depend on tools and experiences that are difficult to recreate in the typical classroom. Full understanding of the methodology and concepts of a Cleaner Production assessment can be achieved only by engaging students in practical application. To overcome the difficulties of providing a high number of students with a practical application, a very simple and useful exercise, based on the activities performed in the average kitchen, has been developed. The kitchen at home has all the elements of a factory, is available to everybody and can be used to supplement the theory provided in the classroom  相似文献   

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Background

In tropical countries, the palm tree is one of the most abundant and important trees. Date palm is a principal fruit grown in many regions of the world. It is abundant, locally available and effective material that could be used as an adsorbent for the removal of different pollutants from aqueous solution.

Review

This article presents a review on the role of date palm as adsorbents in the removal of unwanted materials such as acid and basic dyes, heavy metals, and phenolic compounds. Many studies on adsorption properties of various low cost adsorbent, such as agricultural waste and activated carbons based on agricultural waste have been reported in recent years.

Conclusion

Studies have shown that date palm-based adsorbents are the most promising adsorbents for removing unwanted materials. No previous review is available where researchers can get an overview of the adsorption capacities of date palm-based adsorbent used for the adsorption of different pollutants. This review provides the recent literature demonstrating the usefulness of date palm biomass-based adsorbents in the adsorption of various pollutants.  相似文献   

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