yes / This paper offers a brief overview of innovative methods for road and rail traffic noise reduction between source and receiver. These include using new barrier designs, planting of trees, treatments of ground and road surfaces and greening of building façades and roofs using natural materials, like vegetation, soil and other substrates in combination with recycled materials and artificial elements. The abatements are assessed in terms of numerically predicted sound level reductions, perceptual effects and cost–benefit analysis. Useful reductions of noise from urban roads and tramways are predicted for 1-m-high urban noise barriers and these are increased by adding inter-lane barriers. A 3 m wide 0.3 m high lattice ground treatment, a carefully planted 15-m-wide tree belt and replacing 50 m of paved areas by grassland are predicted to give similar reductions. Tree belts are shown to be very cost-effective and combining tall barriers with a row of trees reduces the negative impact of wind. Green roofs may significantly reduce the noise at the quiet side of buildings.

Hydrogen sulfide is a naturally occurring compound that is very toxic, highly flammable and has a characteristic “rotten egg” smell. It can irritate eyes and airways or even cause death when highly concentrated in air. It can exist both in gaseous and aqueous form where the dissolution of hydrogen sulfide in water is highly affected by pH. There are several industries with hydrogen sulfide related problems, either for safety or economic reasons (e.g., the mining industry, pulp and paper processing, oil and gas refineries, and wastewater treatment plants). The aim was to construct and test a filter of iron oxides to treat water from dissolved hydrogen sulfide. This was done through column experiments where the columns were filled with hematite and slag from the steel industry. Both the hematite and slag columns had sulfide precipitation, evident in the black discoloration, and the sulfide concentrations drastically reduced in the outlet water compared to the inlet water, indicating that the columns worked. However, there were some signs of preferential flow. Calculations indicate that the iron in the columns would be sufficient to precipitate approximately 1138 mg L−1 H2S at a flow rate of 0.2 ml min−1 for roughly 66 days, based on mean values for the three hematite columns. This was only a small-scale column experiment, and if scaled up from 0.2 ml min−1 to 0.5 L s−1 in the field, the amount of hematite used would have to be increased by 150 000 to last the same amount of time. This method would hence be difficult to apply in the field since it would be difficult to change the filter. / Vätesulfid (H2S) är en naturligt förekommande förening som är väldigt giftig, mycket brandfarlig och har en karaktäristisk ”ruttet ägg” lukt. Det kan irritera ögon och luftvägar, samt orsaka dödsfall vid höga koncentrationer. Vätesulfid kan förekomma både som gas och upplöst i vätska, där dess vattenlöslighet påverkas kraftigt av pH. Det finns flera industrier som har problem med vätesulfid i sina verksamheter, ur ett säkerhets- och ekonomiskt perspektiv (t.ex. vattenreningsverk, gruv-, pappers-, och oljeindustrier). Syftet var att konstruera och testa ett filter på järnoxider för att rena vatten från vätesulfid. Filtret fungerar genom att vätesulfid och järnoxider reagerar för att fälla som järnsulfid och elementärt svavel. Undersökningen genomfördes som kolonnförsök där kolonnerna fylldes med hematit eller slagg från stålindustrin. Både hematit och slaggkolonnerna påvisade järnsulfidutfällning, tydliggjort på de svarta missfärgningarna, samt minskningen av sulfidkoncentrationen i utloppsvattnet jämfört med inloppsvattnet. Dessvärre uppstod problem med preferentiellt flöde. Beräkningar visar att järnet i kolonnerna skulle räcka för att fälla ca 1138 mg L−1 H2S vid ett flöde på 0,2 ml min−1 i uppskattningsvis 66 dagar, baserat på medelvärden för de tre hematitkolonnerna. Med tanke på att det här enbart är ett småskaligt experiment skulle en ökning från 0,2 ml min−1 till 0,5 L s−1 i fältskala innebära att mängden hematit skulle behöva ökas med 150 000 för att fungera lika lång tid. Den här metoden är således svår att applicera storskaligt med tanke på att det skulle bli komplicerat att byta filtret. / SULFREM

Thesis (DPhil (Geography and Environmental Studies))—University of Stellenbosch, 2007. / The use of average energy aircraft noise contours as the sole means for guiding aircraft noise-based planning around airports is being questioned increasingly. A growing proportion of residents who live in neighbourhoods adjacent to airports are dissatisfied with the averaging procedure that is employed. In their experience of exposure to aircraft noise, particularly in the evening and at night when they are at home, the average energy aircraft noise descriptors are misleading. In order to effectively analyse the socio-spatial interaction of annoyance at and interference by aircraft noise, an alternative approach has been suggested – a supplemental noise perspective. Conventional approaches to aircraft noise land use planning based on average energy noise descriptors run the risk of being ineffectual, or even counterproductive, because they do not consider the central aspects of disturbance, namely the loudness of an event and the number of times events are heard. Consequently, an alternative measure to ameliorate the limitations of average energy noise contours is needed by which airport neighbours, the aviation industry and town planners can better understand the nature of the problem. Although supplemental noise analysis is not new, this study applies it to a South African international airport (OR Tambo) for the first time. The airport’s operations are typical of many busy airports close to large urban areas, serving domestic, regional and international routes. Reportedly, there have been few complaints about noise emanating from the airport, but when they are made they are usually about evening and night-time aircraft noise events. In the context of South Africa as a developing society in transition, where growth of urban settlements continues apace, average energy aircraft noise information must be enhanced by providing supplemental noise information. This study investigated the broad issue of land use planning around airports by employing two aircraft noise prediction models, namely the Integrated Noise Model and the Transparent Noise Information Package, to establish the various potential effects and consequences of night-time aircraft noise in noise zones demarcated according to supplemental aircraft noise information. The effects and consequences examined include annoyance, disturbance of sleep, telephone conversations, watching television and work or study, and the likelihood that people will move away to escape night-time aircraft noise. The perceptions of residents living in neighbourhoods around the airport were surveyed and the responses analysed according to noise zones classified as supplemental noise information. The results show that the airport’s neighbours are annoyed by aircraft noise and that aircraft noise interferes with normal household activities. This annoyance and interference decreases with increasing distance from the airport. Furthermore, reported annoyance and interference is greater in those areas where higher numbers of noise events are encountered, even at relatively low noise levels of 60 LAmax – something not evident from average energy noise contours. This finding strengthens the argument that it is insufficient to provide only average energy aircraft noise information when studying the impact of aircraft noise. To understand the situation more fully, supplemental noise information is essential. The study concludes with a framework constructed to apply supplemental aircraft noise information to the abatement and mitigation measures normally used to deal with aircraft noise.

機動車輛已成為空氣污染的首要污染來源之一，其所排放大量的一氧化碳、二氧化碳對地方乃至於全球環境皆造成不利的影響。為了因應環境污染與溫室效應，各國除了採取行政管制措施外，亦引進經濟誘因工具來落實污染者付費的原則。本研究的目的即是探討，台灣地區目前所實施的政策工具對於減少來自移動污染源的污染排放量的有效性。 本文利用台灣地區二十三個縣市 1998 年至 2006 年共九年的追蹤資料，以兩種模型進行實證：第一個模型採用的是一階差分後的普通最小平方法迴歸模型，可避免假性迴歸的問題發生；第二個模型為似不相關迴歸模型，藉由誤差項間的關聯性來結合北部、中部、東部、南部四個地區的迴歸式，觀察政策工具在不同區域間對污染減量的效果。 實證結果顯示，管制與稅費這兩種政策工具確實會對移動污染源產生的空氣污染有相當的抑制效果；但是相較之下，管制措施的影響力相對於稅費的徵收來得明顯。因此，已知管制工具具有環境保護的政策有效性外，若欲使得稅費政策對空氣污染減量也有更明顯的成效，便應實施綠色租稅改革，以期能夠對生活環境產生良好的改善。 / Due to its high share in total air pollutant emissions, mobile pollution source is an issue of particular consideration. Vehicles produce large volumes of emissions such as CO, CO2, and so on. These gases can be detrimental to local, regional and global environment. With the increasing concern over rising pollution levels and greenhouse effect, the purpose of this study is to evaluate the effectiveness of different environmental policy instruments which are used to reduce mobile source air pollution. 　　For this paper, a case study of Taiwan is demonstrated for the estimation. Using the first-differenced panel data collected from 1998 to 2006, we use two models, namely “Ordinary least square model” and “Seemingly unrelated regression model” to investigate whether the command and control policy or the economic-incentive tax strategy is better for emission abatement. The first-differenced ordinary least square model can be used to avoid spurious regression, and the seemingly unrelated regression system integrates four sub-equations by assuming their disturbances are correlated, explaining some phenomenon in different areas. 　　The result shows that both control and tax strategies are worthwhile to be adopted. However, regulation policy results in cutting down much more CO and CO2 than using the excise taxes and fuel fees as an environmental instrument. Therefore, we conclude that it is required to implement the green tax system reform in order to create beneficial changes in our life.

Ce travail montre la mise en œuvre d'une technique originale pour le chauffage rapide et bien contrôlé de catalyseurs sous forme de films minces déposés sur un structurant métallique. L'utilisation d'un système à induction électromagnétique adapté à un réacteur catalytique de type annulaire nous a permis d'étudier un certain nombre de matériaux catalytiques, déposés sur acier inoxydable, dans une perspective d'oxydation totale en CO2 et H2O de composés organiques volatiles (COV) présents dans l'air. La combustion de l'isopropanol et du toluène par l'oxygène de l'air a été étudiée en utilisant différents catalyseurs déposés sous forme de films minces: 1%Pt/Al2O3, 0,3%Pt/SnO2, 1%Pt/SnO2 et 1%Pt/YSZ. Les solides ont été préparés par imprégnation des oxydes correspondants par H2PtCl6 puis ont été déposés sur le support d'acier inoxydable par électrophorèse. Les principaux paramètres relatifs au mode de chauffage ont été étudiés de même que l'influence sur la conversion des COV de différents facteurs tels que la quantité de catalyseur, le pourcentage de platine ou la nature du support oxyde employé. Les informations fournies par ce système innovant ont également été comparées pour validation à celles obtenues à l'aide d'un système classique (microréacteur en quartz à lit traversé chauffé de manière conventionnelle) pour une réaction de référence qui est l'oxydation de CO en CO2. Le système décrit dans cette étude présente d'une part un intérêt pratique pour le traitement rapide de contaminations accidentelles de l'air ambiant, mais est aussi un très bon moyen d'obtenir des paramètres cinétiques fiables dans le domaine des catalyseurs en films minces utilisés dans de nombreux réacteurs structurés / This study shows the development of an innovative technique for a fast and well-controlled heating of catalysts deposited as thin films on a metallic support. The use of an electromagnetic induction system fitted to an annular catalytic reactor enabled us to study some catalytic materials deposited on stainless steel. The target application was the abatement of volatile organic compounds (VOCs) in the air. Isopropyl alcohol and toluene combustion by the oxygen was studied on various thin films catalysts, i.e. : 1%Pt/Al2O3, 0,3%Pt/SnO2, 1%Pt/SnO2 et 1%Pt/YSZ. Solids were prepared by wet impregnation of the corresponding oxides by H2PtCl6 and were deposited on the stainless steel support using an electrophoretic deposition technique. The main parameters of the heating system were investigated as well as the influence on VOCs abatement of various parameters such as the thickness of catalyst film, the platinum amount and the nature of the oxide. For validation purpose, the data provided by this innovative system were also compared to the ones provided by a classical one (quartz plug-through microreactor heated in a conventional way) in a reference reaction which was CO oxidation into CO2. The system described in this study shows on the one hand a real practical interest for fast remediation of indoor air polluted by VOCs, and on the other hand is a very powerful tool for obtaining kinetic data about thin layer catalysts used in many structured reactors

In recent times, as regulations and legislations for exhaust treatment have become more stringent, a major concern in the arena of environmental catalysis is to find new efficient and economical exhaust treatment catalysts. Chapter 1 is a review of the current status of various NOx abatement techniques and understanding the role of “auto-exhaust catalysts” involved therein. Chapter 2 presents the studies on synthesis of ionically substituted precious metal ions like Pd2+, Pt2+ and Rh3+ in CeO2 matrix and their comparative three-way catalytic performances for NO reduction by CO, as well as CO and hydrocarbon oxidation. Ce0.98Pd0.02O2- showed better catalytic activity than ionically dispersed Pt or Rh in CeO2. The study in Chapter 3 aims at synthesizing 1 atom% Pd2+ ion in TiO2 in the form of Ti0.99Pd0.01O2- with oxide ion vacancy. A bi-functional reaction mechanism for CO oxidation by O2 and NO reduction by CO was proposed. For NO reduction in presence of CO, the model based on competitive adsorption of NO and CO on Pd2+, NO chemisorption and dissociation on oxide ion vacancy fits the experimental data. The rate parameters obtained from the model indicates that the reactions are much faster over this catalyst compared to other catalysts reported in the literature. In Chapter 4 we present catalytic reduction of NO by H2 over precious metal substituted TiO2 (Ti0.99M0.01O2-, where M = Ru, Rh, Pd, Pt) catalysts. The rate of NO reduction by H2 depends on the reducibility of the catalysts. Chapter 5 presents the studies on reduction of NO by NH3 in presence of excess oxygen. 10 atom % of first row transition metal ions (Ti0.9M0.1O2-, where M = Cr, Mn, Fe, Co and Cu) were substituted in anatase TiO2 and TPD study showed that the Lewis and Bronsted acid sites are adsorption sites for NH3, whereas NO is found to dissociatively chemisorbed in oxide ion vacancies. The mechanism of the low temperature catalytic activity of the SCR and the selectivity of the products were studied to understand the mechanism by studying the by-reactions like ammonia oxidation by oxygen. A new catalyst Ti0.9Mn0.05Fe0.05O2- has shown low temperature activity with a broad SCR window from 200 to 400 °C and more selectivity than commercial vanadium-oxides catalysts. We attempted NO dissociation by a photochemical route with remarkable success. In Chapter 6 we report room temperature photocatalytic activity of Ti0.99Pd0.01O2- for NO reduction and CO oxidation by creating redox adsorption sites and utilizing oxide ion vacancy in the catalyst. The reduction of NO is carried out both in the presence and in the absence of CO. Despite competitive adsorption of NO and CO on the Pd2+ sites, the rate of reduction of NO is two orders of magnitude higher than unsubstituted TiO2. High rates of photo-oxidation of CO with O2 over Ti0.99Pd0.01O2- were observed at room temperature. In Chapter 7 the results are summarized and critical issues are addressed. Novel idea in this thesis was to see if both noble metal ions and base metal ions substituted in TiO2 and CeO2 reducible supports can act as better active sites than the corresponding metal atoms in their zero valent state.

The first essay studies the Marginal Cost of Funds in the existence of tax evasion. We develop a general equilibrium model of tax evasion, including the expected utility of taxpayers and three different revenue-raising government policies. In this rich model environment, we analytically derive the marginal cost of funds (MCF) for the alternative policy instruments. We consider two main fiscal reforms: the revision in the nonlinear tax scheme and the changes in enforcement mechanism (the audit and penalty rates). First, we derive the MCF for the tax reform and find its key determinants. The derived MCF is greater than the previous ones since it includes a "risk-bearing cost" as well as tax distortion. The reform in enforcement mechanism generates MCFs in different forms. Two more MCFs with respect to audit and penalty rates are presented. Finally, we compare these three different MCFs in numerical example and provide some policy implications. The second essay explores optimal tax structure in the presence of status effect. When the consumption of certain goods affects one's social status, this externality creates two opposite effects in a society. Seeking higher status through “positional goods" gives individuals much incentive to supply labor but still allocates income for less “nonpositional goods" as well. In this case, differential taxes on positional goods work as corrective instruments to internalize the social cost stemming from status seeking. Furthermore, the differential taxes generate revenue that can be used to alleviate preexisting income tax distortion. Thus, the differential taxes on positional goods could give so called “double dividend." I develop a game-theoretic model in which each individual with a different labor productivity unknown to the others engages in a status-seeking game, and the government has a revenue requirement. Then I show that, under a condition in which utility is separable between positional goods and leisure, a revenue-neutral shift in the tax mix away from nonlinear income taxes towards positional-good taxes enhances welfare. Hence, the differential taxes on positional goods are necessary together with the nonlinear income taxes for an optimal tax structure. The third essay explores the impact of increasing capital mobility on regional growth and environment. I develop an endogenous growth model in which each local government competes against the others, to induce imperfectly mobile stock of capital into its region. Then I show that an increase in capital mobility generates “tax importing" due to which each locality experiences a higher growth rate and more degraded environment. That is, the increasing mobility dampens the capital tax and transfers the burden of pollution abatement to the locality. This finding supports the hypothesis of “race to the bottom" in environmental standards. Identifying a reduction in overall welfare of residents, I consider two alternative federal interventions in the model: uniform environmental standard and requirement of lump sum transfer or tax. Both of these federal instruments enhance the residents' welfare. / text

This dissertation consists of three empirical analyses examining the interactive and evolving nature of government regulations and how the regulated industries respond to the changes in the regulatory climate. Using the U.S. pulp and paper mills as an example, the three essays bring together a number of strands of literature in environmental economics and policy studies discussing how changes in the U.S. environmental policy are shaped by industry concerns and which strategies firms choose in order to adjust to the changes in policy. Essay 1 examines if, in addition to the standard input factors, indirect costs associated with tax and environmental policies affect papermakers’ ‘stay put’ investment decisions. The findings suggest that state environmental stringency has a negative impact on investments, but it is statistically insignificant and higher taxes do not deter investments. The Essay 2 studies whether voluntary abatement and prevention efforts at pulp and paper mills affects regulatory stringency they face. The analysis tests the hypotheses of ‘responsive regulation’ and whether regulators are driven by numerical pollution targets or budgetary constraints. The findings suggest that voluntary pollution abatement and prevention have greater impact on regulatory stringency than government budgets. Finally, Essay 3 analyzes the relationship between pollution prevention (P2) policy instruments and adoption of P2 modifications. The study tests the hypotheses of whether P2 policy instruments have positive impact on P2 adoptions. The results suggest that the policy instruments have different effects on different types of P2 modifications and that regulatory and political threat is a strong predictor of P2 adoptions.

The presence of heavy metal ions in waste streams is one of the most pervasive environmental issues of present times. A rotating biological contactor (RBC) was used to investigate the potential capacity of microbial biofilms in remediation of the metal ion species from a mixed metal contaminated effluent solution containing Cr+3 , Pb+2 and Cu+2 , each at a concentration of 200 mg r1 • In the first part of this study the effectiveness of various support materials for the development of microbial biofilms capable of removing heavy metals from a synthetic effluent was investigated. EDX analysis showed that none of the support matrices investigated, viz. gravel, polyester batting and sand, adsorbed metal ions on their surfaces; hence, metal adsorption was due purely to microbial activities. The biofilms attached more firmly and uniformly to polyester batting than to gravel and sand. The characteristics of polyester batting which made it a superior support matrix were its surface roughness and porous hydrophilic nature, which provided a larger surface area for the adhesion of microorganisms and attraction of nutrients during the biofilm development process. The selective accumulation of metal ion specIes by various microbial populations grown as biofilm using polyester batting as support matrix in separate compartments of a single-stage RBC bioreactor was examined. Lead ions were readily accumulated by almost all the microbial biofilms tested. Fungus-dominated biofilms selectively accumulated chromium ions whereas biofilms comprising mainly bacteria more readily accumulated copper ions from the mixed metal contaminated effluent solution. However, where interactions between the bacterial and fungal components were encouraged the mechanical stability of the biofilms was enhanced so that large amounts of all three metal ion species were removed by this biofilm. The combined effect of a series of bench-scale columns containing liquid humic acid and a three stage RBC bioreactor on the removal of metal ion species from a mixed metal contaminated effluent was investigated. After seven days of treatment the combined system had removed approximately 99% of the Cr+3, 98% of the Pb+2 and 90% of the Cu+2 ions from the mixed metal contaminated synthetic effluent. Complexation of the metal ions with humic acid was the predominant factor accounting for approximately 68-86% Cr+3 , 70-86% Pb+2 and 53-73% Cu+2 removal levels within the columns. A large proportion of the remaining Cr+3 and Pb+2, but not of the Cu+2, was removed in compartment 1 of the RBC. This suggested that the presence of the former two metals in solution might have reduced the removal of the Cu+2 ions from the system. The removal of substantially large amounts of the competing ions chromium and lead during the initial stages of the treatment process meant that copper was successfully taken up in the second and third RBC compartments. Hence, the economy of the treatment process was improved as larger quantities of the metal ions were removed in a shorter period of time than was possible when using the individual treatments (humic acid-metal complexation and biofilm adsorption) separately. More than 75%,92% and 86% of the adsorbed Cr+3 , Pb+2 and Cu+2 ions, respectively, were recovered from the three RBC bioreactor compartments following repeated washing of the biofilms with 0.1 M HCI. This relatively easy desorption suggested that the metal ions were simply adsorbed onto the surfaces of the biofilm cells rather than being taken into the cytoplasm of the cells. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

全球暖化已成為大多數國家近幾年所關心的議題。雖然臺灣政府於2010年5月所核定的「國家節能減碳總計畫」之中，儘管減量目標及原則業已確立，但未充分探討各別產業的面臨碳排放管制時所造成的影響，因此，臺灣各產業或次部門究竟應承擔多大的減量責任仍是混沌不明。 為了更清楚瞭解碳排放管制對於臺灣工業部門之各產業的影響，本文以方向性距離函數，估算工業部門中14個產業367家上市櫃、興櫃和公開發行公司於2005年至2010年，在不同電力消費所產生的CO2之責任歸屬情況下之生產效率及汙染減量成本，以反映各產業於管制下的機會成本，便於鎖定某些產業或公司，來賦予減量責任。結果發現，各產業在實施碳排放管制後的效率水準，會高於未實施碳排放管制時的效率水準，且各產業的平均總汙染減量成本與每噸二氧化碳減量成本相差甚大。而臺灣尚未通過相關法規以規範各產業二氧化碳排放水準，若各產業節能技術或政府相關配套政策未改善，倉促實施碳排放管制，除了對管制對象的產生影響外，也可能間接衝擊未管制對象。政府除了加強輔導各種產業從事節能技術外，也需要適當的公布各產業各公司的各種汙染排放量資訊，以供各界研究碳排放管制或其他汙染排放管制對社會的影響。 / Global warming has become the topic of most countries which concerns things in recent years. Government sets up CO2 reduction objectives and principle in “General National Plan for Energy Saving and Carbon Reduction” in 2010, but the plan doesn’t probe effect of CO2 regulation which different industries. Therefore, it is unknown that different industries should be responsible for the abatement of CO2. In order to clearly understand effect of CO2 regulation for Taiwan industrial sector, this paper use directional distance function to estimate production efficiency and pollution abatement cost of 367 public companies in 14 industries in industrial sector from 2005 to 2010, and to reflect different industries’ opportunity cost under CO2 regulation. Production efficiency of different industries after the implementation of CO2 regulation will be higher than before the implementation of CO2 regulation. On the other hand, different industries have a variety of average pollution abatement cost and pollution abatement cost of CO2 per ton. However, Taiwan has not yet adopted the environment laws to set up industrial CO2 emission level, if the government hurriedly implemented CO2 regulation for Taiwan industrial sector, may be indirectly influence other sectors. Hence, the government should not only urge that industries must be engaged in energy-saving technologies, but also announce companies’ various pollution emission information which provides research institutes to analyze effect of social welfare under CO2 regulation.