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

This thesis reports on the results of a mobile source emissions inventory for the University of Central Florida (UCF). For a large urban university, the majority of volatile organic compounds (VOC), oxides of nitrogen (NOx), and carbon dioxide (CO2) emissions come from onroad sources: personal vehicles and campus shuttles carrying students, faculty, staff, and administrators to and from the university, as well as university business trips. In addition to emissions from daily commutes, non-road equipment such as lawnmowers, leaf blowers, small maintenance vehicles, and other such equipment utilized on campus contributes to a significant portion to the total emissions from the university. UCF has recently become the second largest university in the nation (with over 56,000 students enrolled in the fall 2010 semester), and contributes significantly to VOC, NOx, and CO2 emissions in Central Florida area. In this project, students, faculty, staff, and administrators were first surveyed to determine their commuting distances and frequencies. Information was also gathered on vehicle type, and age distribution of the personal vehicles of students, faculty, administration, and staff as well as their bus, carpool, and alternate transportation usage. The EPA approved mobile source emissions model, Motor Vehicle Emissions Simulator (MOVES2010a), was used to calculate the emissions from on-road vehicles, and UCF fleet gasoline consumption records were used to calculate the emissions from non-road equipment and on campus UCF fleet vehicles. The results of the UCF mobile source emissions inventory are reported and compared to a recently completed emissions inventory for the entire three-county area in Central Florida.

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)