General aviation in the United States has been an important part of the economy and American life. General aviation is defined as all flying excluding military and scheduled airline operations, and is utilized in many areas of our society. The majority of aircraft operations and airports in the United States are categorized as general aviation, and general aviation contributes more than one percent to the United States gross domestic product each year. Despite the many benefits of general aviation, the lead emissions from aviation gasoline consumption are of great concern. General aviation emits over half the lead emissions in the United States or over 630 tons in 2005. The other significant negative externality attributed to general aviation usage is aircraft accidents. General aviation accidents have caused over 8000 fatalities over the period 1994 - 2006. A recent Federal Aviation Administration proposed increase in the aviation gasoline tax from 19.4 to 70.1 cents per gallon has renewed interest in better understanding the implications of such a tax increase as well as the possible optimal rate of taxation. Few studies have examined aviation fuel elasticities and all have failed to study general aviation fuel elasticities. Chapter one fills that gap and examines the elasticity of aviation gasoline consumption in United States general aviation. Utilizing aggregate time series and dynamic panel data, the price and income elasticities of demand are estimated. The price elasticity of demand for aviation gasoline is estimated to range from -0.093 to -0.185 in the short-run and from -0.132 to -0.303 in the long-run. These results prove to be similar in magnitude to automobile gasoline elasticities and therefore tax policies could more closely mirror those of automobile tax policies. The second chapter examines the costs associated with general aviation accidents. Given the large number of general aviation operations as well as the large number of fatalities and injuries attributed to general aviation accidents in the United States, understanding the costs to society is of great importance. This chapter estimates the direct and indirect costs associated with general aviation accidents in the United States. The indirect costs are estimated via the human capital approach in addition to the willingness-to-pay approach. The average annual accident costs attributed to general aviation are found to be $2.32 billion and $3.81 billion (2006 US$) utilizing the human capital approach and willingness-to-pay approach, respectively. These values appear to be fairly robust when subjected to a sensitivity analysis. These costs highlight the large societal benefits from accident and fatality reduction. The final chapter derives a second-best optimal aviation gasoline tax developed from previous general equilibrium frameworks. This optimal tax reflects both the lead pollution and accident externalities, as well as the balance between excise taxes and labor taxes to finance government spending. The calculated optimal tax rate is $4.07 per gallon, which is over 20 times greater than the current tax rate and 5 times greater than the Federal Aviation Administration proposed tax rate. The calculated optimal tax rate is also over 3 times greater than automobile gasoline optimal tax rates calculated by previous studies. The Pigovian component is $1.36, and we observe that the accident externality is taxed more severely than the pollution externality. The largest component of the optimal tax rate is the Ramsey component. At $2.70, the Ramsey component reflects the ability of the government to raise revenue aviation gasoline which is price inelastic. The calculated optimal tax is estimated to reduce lead emissions by over 10 percent and reduce accidents by 20 percent. Although unlikely to be adopted by policy makers, the optimal tax benefits are apparent and it sheds light on the need to reduce these negative externalities via policy changes.

M.Sc. (Geography and Environmental Management) / Saldanha forms part of the heart of the Western Cape and is an integral part of the economic and social well being of South Africa. The recent development of the Namakwa Sands Smelter and the proposed Saldanha Steel Project indicate a possible new phase of industrial growth in the Saldanha area. The evolution of man into beings who are more environmentally aware and the proclamation of more environmentally related legislation, should integrate well with this development. These factors should ensure that companies and institutions implement better pollution control and management. In this study lead pollution caused by the handling and storing of lead concentrate for export purposes in Saldanha Bay, is investigated. The Small Bay area was identified as the area likely to be most polluted and this study concentrated on the pollution in this specific area. The lead pollution was measured for a certain period by monitoring lead concentrations in samples of biological material (black mussels), soil, sediment and dust. From the results the following conclusions are made. Lead concentrations in biological material in the Small Bay area remained constant with no real increase or decrease. Lead concentrations in the soil samples on the north easterly side of Small Bay showed a definite decrease during the monitoring period. Lead concentrations in the sediments of the Small Bay area indicate a decrease during the monitoring period. Lead concentrations in dust collected on the eastern side of Small Bay remained constant during the monitoring period. Lead concentrations in dust collected on the north eastern side showed a decrease. In general, based on the above results obtained, it can be concluded that lead pollution in the Small Bay area of Saldanha decreased during the monitoring period. Lead concentrations in the biological material and dust that did not show a decrease, remained constant i.e. did not worsen.

Bibliography: leaves 395-473. / xxiii, 473 leaves : ill. (chiefly col.), maps (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Research is directed toward demonstrating spatial variability in dust lead contamination patterns both statically and dynamically within the confines of vacant test houses, thus eliciting specific entrance pathways. / Thesis (Ph.D.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1999