Environmental science & technology
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Environ. Sci. Technol. · Dec 2007
Comparative StudyComparative study of regulated and unregulated air pollutant emissions before and after conversion of automobiles from gasoline power to liquefied petroleum gas/gasoline dual-fuel retrofits.
Liquefied petroleum gas (LPG) is increasingly being examined as an alternative to gasoline use in automobiles as interest grows in reducing air pollutant emissions. In this study, emissions of regulated (CO, THC, NO(x)) and unregulated air pollutants, including CO2, particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and BTEX (acronym for benzene, toluene, ethylbenzene, xylene), were measured before and after conversion of nine gasoline-powered automobiles to LPG/ gasoline dual-fuel retrofits. The tests were conducted on a standard chassis dynamometer in accordance with the United States Environmental Protection Agency FTP-75 test procedure, with the exception that all tests were conducted under hot-start driving conditions. ⋯ The discrepancy between PAH and BaP(eq) emissions resulted from the higher emission percentages of high molecular weight PAHs for LPG, which might be from lubricant oil. The average emission factors of benzene, toluene, ethylbenzene, and xylene were 351, 4400, 324, and 1100 microg/ km, respectively, with LPG as fuel, which were all significantly lower than those for gasoline (95% confidence level). The average reduction percentages were 78%, 61%, 57%, and 58% for benzene, toluene, ethylbenzene, and xylene, respectively.
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Environ. Sci. Technol. · May 2007
Integrating developed and developing world knowledge into global discussions and strategies for sustainability. 2. Economics and governance.
Knowledge transfer from the developing to the developed world is described in the domain of economics and governance for sustainable development. Three system areas are explored: the structure of commons governance institutions, the process of community-based participatory action research, and the role of microfinance and microenterprise for the development, adoption, and diffusion of sustainable technologies. Case studies from both the developed and developing world demonstrate the effectiveness of social networks and community cooperative strategies in a wide range of sectors. Developing world experiences are shown to be particularly rich in the application of local knowledge and social capital toward sustainable development.