Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: See PDF for abstract. / AFRIKAANSE OPSOMMING: Sien die PDF vir die opsomming.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

When confronted with decisions involving the provision of environmental resources, such as clean air, do individuals act cooperatively with societal regulations? This study employs a quasi-experimental design to investigate the cooperative and non-cooperative actions of high-emitting vehicle owners that arose in response to the Inspection and Maintenance (IM) program in the Atlanta airshed. The impact of cooperative and non-cooperative actions of high-emitters on vehicular tail-pipe emissions, such as carbon monoxide (CO), hydrocarbons (HC) and oxides of nitrogen (NOx), is quantified. Furthermore, the hypothesis that high-emitters have significantly higher odds of residing in lower income neighborhoods as compared to the normal emitters is also tested. A remote sensing sample of approximately 1.42 million vehicles observed on-road between 1997 and 2001 is matched with IM program data and vehicle registration data to identify the cooperative and non-cooperative high-emitters. A mixed-pool time-series regression analysis is undertaken to estimate changes in vehicular tail-pipe emissions due to the actions of high-emitters. The information about the socio-economic and demographic contextual conditions of the sampled vehicle owners is ascertained from 2000 census data. Approximately 42% of the high-emitting vehicle owners are found to be cooperative and 58% non-cooperative. The cooperative actions caused a decrease of 47% in HC emission factors during 1997 and 2001. There is no statistical difference between the CO and NO emission factors of vehicles owned by cooperative and non-cooperative high-emitters. Results also suggest that the high-emitters live in 4.4% lower median household income areas as compared to the normal emitters in the Atlanta airshed. Changes in the current IM program rules and vehicle registration laws could improve air quality. Such changes include disallowing IM test failures from registering anywhere in the state of Georgia and requiring an IM test on every change of vehicle ownership inside the IM program area. Better incentive mechanisms for high-emitters can also be designed. The evidence from this study is expected to aid policy-makers to adapt the incentive mechanisms of IM programs, in particular, and environmental regulations, in general, so that public policies are both more effective and equitable in their societal impacts.

Emissions from light-duty passenger vehicles represent a significant portion of total criteria pollutant emissions in the United States. Since the 1970s, emissions testing of these vehicles has been required in many major metropolitan areas, including Atlanta, GA, that were designated to be in non-attainment for one or more of the National Ambient Air Quality Standards. While emissions inspections have successfully reduced emissions by identifying and repairing high emitting vehicles, they have been increasingly inefficient as emissions control systems have become more durable and fewer vehicles are in need of repair. Currently, only about 9% of Atlanta area vehicles fail emissions inspection, but every vehicle is inspected annually. This research addresses explores ways to create a more efficient emissions testing program while continuing to use existing testing infrastructure. To achieve this objective, on road vehicle emissions data were collected as a part of the Continuous Atlanta Fleet Evaluation program sponsored the Georgia Department of Natural Resources. These remote sensing data were combined with in-program vehicle inspection data from the Atlanta Vehicle Inspection and Maintenance (I/M) program to establish the degree to which on road vehicle remote sensing could be used to enhance program efficiency. Based on this analysis, a multi-parameter model was developed to predict the probability of a particular vehicle failing an emissions inspection. The parameters found to influence the probability of failure include: vehicle characteristics, ownership history, vehicle usage, previous emission test results, and remote sensing emissions readings. This model was the foundation for a proposed emissions testing program that would create variable timing for vehicle retesting with high and low failure probability vehicles being more and less frequently, respectively, than the current annual cycle. Implementation of this program is estimated to reduce fleet emissions of 17% for carbon monoxide, 11% for hydrocarbons, and 5% for nitrogen oxides in Atlanta. These reductions would be achieved very cost-effectively at an estimated marginal cost of $149, $7,576 and $2,436 per-ton-per-year for carbon monoxide, hydrocarbons, and nitrogen oxides emissions reductions respectfully.

La catalyse hétérogène influe sur la cinétique des réactions chimiques pour favoriser la formation de produits souhaités. Appliquée à la dépollution atmosphérique, elle permet de réduire considérablement l'émission de polluants. Son plus grand succès public est d'ailleurs sans conteste le pot catalytique pour les moteurs à essence. Malgré ce succès, beaucoup reste à faire pour améliorer la dépollution à basse température et pour des conditions d'utilisations très différentes telles que celles imposées par les moteurs Diesel et "lean burn".<p><p>Lors de ce travail nous nous sommes intéressés à ces sujets. Tout d'abord, nous avons étudié l'effet du SO2 sur la réduction catalytique sélective des NOx sur des catalyseurs Ag/Al2O3 dans les conditions des moteurs Diesel. Le dioxyde de soufre est reconnu comme un poison de catalyseurs. Dans cette thèse, nous avons étudié un effet promoteur du SO2. Les catalyseurs qui ont fait l’objet de ce travail ont été préparés au laboratoire. Nous avons fait varier différents paramètres tels que la température, la nature de l'hydrocarbure ou encore la concentration de SO2 afin de mieux cerner cet effet promoteur. Nous avons mis en évidence que cet effet promoteur est observable lorsque le propène est utilisé comme réducteur, alors qu'avec le propane il s'agit plutôt d'un effet négatif du SO2.<p><p>Le deuxième sujet étudié dans ce travail est l'oxydation du CO sur des catalyseurs Au/TiO2, soit préparés au laboratoire, soit fournis comme référence du World Gold Council. Ces catalyseurs offrent l’avantage de pouvoir oxyder le CO à basse température, ce qui pourrait résoudre le problème de la pollution liée au démarrage à froid des automobiles. Ces catalyseurs subissent une désactivation que nous avons analysée par spectroscopie infrarouge (DRIFT et FTIR). Une étude XPS-SIMS de catalyseurs ayant des activités différentes nous a permis de mettre en évidence des concentrations de sodium différentes sur ces catalyseurs. Dans cette thèse, nous nous sommes plus particulièrement intéressés à l'influence du potassium. Pour mettre en évidence l'influence de celui-ci sur l'activité catalytique, des catalyseurs Au/TiO2 furent préparés en absence stricte d'alcalins et d'alcalino-terreux pour ajouter par après, de manière contrôlée, les quantités souhaitées de potassium. La composition des catalyseurs préparés fut contrôlée par XPS-SIMS. Il s'avère que la présence de potassium permet d'accroître l'activité catalytique, néanmoins il semble y avoir une concentration optimale de potassium qui varie en fonction de la composition/morphologie du catalyseur Au/TiO2 au départ, c'est-à-dire sans modification par ajout de potassium.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

There has been an increased push away from the traditional combustion-engine powered vehicle due to environmental, health, and political concerns. As a result, alternative methods of transportation such as electric vehicles (EVs) have gaining popularity in the market. However, the EVs are not penetrating the market as quickly as expected, due in part to a combination of range, charge anxiety, and their financial costs. EVs cannot travel far due to limited driving range and require longer charge times than combustion-engine powered vehicles to recharge. Coupled with a lacking infrastructure for charging, the feasibility of an all-electric transportation market is still not possible. We propose a novel system in which we study and characterize the feasibility of increasing the effective driving range of a battery electric vehicle by utilizing inductive charge transfer to create an ad-hoc charging network where vehicles can “share” charge with one another. The application of wireless charge transfer from vehicle-to-vehicle (V2V) is the first of its kind and does not require any changes to current metropolitan infrastructures. Through the use of computer networking and communications algorithms, we analyze real-world commuter and taxi data to determine the potential effectiveness of such a system. We propose a participation and incentive mechanism to encourage participation in this network that enables the system to be functional.To illustrate proof of principle for V2V charging at traffic lights, we simulate a simplified model in which vehicles only exchange charge at traffic lights without coordination with other vehicles. Using a greedy heuristic, vehicles only exchange charge if they happen to meet another vehicle that has charge to share. The heuristic is greedy since decisions are made at each iteration with longer optimality not being considered. We are able to demonstrate an increase in effective driving range of EVs using these simplistic assumptions. In this thesis, we develop and quantify a complete simulation framework, which allows EVs to operate using charge sharing. We analyze data from the United States Department of Transportation, New York City Taxi and Limousine Commission, and Regional New York City data sources to understand the cumulative driving distance distributions for passenger/commuter vehicles and taxicabs in large metropolitan areas such as New York City. We show that the driving distributions can best be represented as heavy-tail distribution functions with most commuter vehicles not requiring additional charge during a typical day’s usage of their vehicle as compared to taxicabs, which regularly travel more than 100 miles during a 12-hour shift. We develop and parameterize several variables for input into our simulation framework including driving distance, charge exchange heuristics, models for determining pricing of charge units, traffic density, and geographic location. The inclusion of these parameters helps to build a framework that can be utilized for any metropolitan area to determine the feasibility of EVs. We have performed extensive evaluation of our model using real data. Our current simulations indicate that we can increase the effective distance that an electric vehicle travels by a factor of at least 2.5. This increased driving range makes EVs a more feasible mode of transportation for fleet vehicles such as taxicabs that rely heavily on commuting long cumulative distances. We have identified areas for future improvement to add further parameters to make the model even more sensitive. Finally, we focus on the application of our charge sharing framework in a real-world application for utilizing this methodology for the New York City bus system. In partnership with the New York City MTA, we launched a feasibility study of converting the currently majority hybrid bus fleet into a complete electric bus fleet with charging available at bus stops during scheduled bus stops. Unlike the earlier charge sharing framework, this simulation focuses on discrete distances that are traveled by the bus before having an opportunity to charge at the next bus stop. In this scenario, a large source of variability is the amount of time that the bus is able to stop at a bus stop for charging since this is determined by the amount of time needed to successfully embark and disembark the passengers at the given bus stop. This particular variability impacts how much charge the bus is able to gain during any given stop. We conclude with a list of opportunities for future work in expanding the model with additional parameters and conclusions of our work. Further, we identify areas of further research that outline the potential positive and negative outcomes from a charge sharing system that can be extended to various other applications including micro-mobility applications such as electric scooters and bicycles.

The Atlanta Inspection and Maintenance program ultimately aims to reduce on-road vehicular emission, a major source of air pollution. The program enforces eligible vehicles to be inspected and repaired, if necessary, before the annual registration renewal. However, various factors can influence the program implementation with respect to the motorists, inspectors, and testing technology. This research explores some of these factors by using empirical data from the Continuous Atlanta Fleet Evaluation project, the inspection transaction records, the Atlanta Household Travel Survey, and the U.S. Census Bureau. The study discusses policy implications of findings from the three essays and offers related recommendations. The first essay examines whether the higher income of a vehicle owner decreases the odds of the vehicle failing the first inspection. Findings show that vehicles owned by low-income households are more likely to fail the first inspection of the annual test cycle. However, after controlling for the vehicle characteristics, the odds of failing the first inspection are similar across households. This suggests that the maintenance behaviors are approximately the same for high- and low-income households. The second essay explains the motorists' decisions in selecting their inspection stations using a random utility model. The study finds that motorists are likely to choose the inspection stations that are located near their houses, charge lower fees, and can serve a large number of customers. Motorists are less likely to choose the stations with a relatively high failure ratio especially in an area of low station density. Moreover, motorists do not travel an extra mile to the stations with lower failure ratio. Understanding choices of vehicle owners can shed some light on the performance of inspection stations. The third essay investigates the validity and reliability of the on-board diagnostic generation II (OBD II) test, a new testing technology required for 1966 and newer model year vehicles. The study compares the inspection results with the observed on-road emission using the remote sensing device (RSD) of the same vehicles. This research finds that the agreement between the RSD measurement and the OBD II test is lower for the relatively older or higher use vehicle fleets

Indiana University-Purdue University Indianapolis (IUPUI)