New Aspects to Greenhouse Gas Mitigation Policies for Low Carbon Cities

Methane (CH4) is an important greenhouse gas emitted by vehicles. This study provides estimates of emissions of this important and often not well characterized greenhouse gas (GHG) emission related to transportation energy use. It aims to assist urban community planners and policymakers to prioritize and choose implementation strategies for low carbon cities. The paper focuses on emissions of CH4 from vehicles. Unlike emissions of CO2, which are relatively easy to estimate, emissions of CH4 are a function of many complex aspects of combustion dynamics and depend on the type of emission control systems used. In this context, they cannot be derived easily and instead must be determined through the use of published emission factors for each combination of fuel, end-use technology, combustion conditions, and emission control systems. Emissions of CH4 play a significant role with regards to the relative CO2-equivalent GHG emissions of the use of alternative transportation fuels, in comparison with the use of conventional fuels. By analyzing a database based on literature review this study analyzes all the factors affecting the creation of CH4 emissions from different vehicle types. Statistical analysis indicated "r" values ranging from 0.10 to 0.85 for all vehicles.