Urban ecology in temperate climates. Greenhouse gas emissions include those of carbon dioxide and methane from the combustion of fossil fuels to supply energy needed by vast urban metropolises. Other greenhouse gases include water vapor, and nitrous oxide. Increases in greenhouse gases due to urban transport, construction, industry and other demands have been correlated strongly with increase in temperature. Sources of methane are agricultural dairy cows and landfills. Processes related to urban areas result in the emission of numerous pollutants, which change corresponding nutrient cycles of carbon, sulfur, nitrogen, and other elements. Ecosystems in and around the urban center are especially influenced
Nitrous oxide engine alcohol, diesel fuel, propane, or CNG to produce carbon dioxide and water vapor, along with heat, which causes the former two products of combustion to expand and exert pressure on pistons, driving the engine. Nitrous oxide is stored as a liquid in tanks, but is a gas under atmospheric conditions. When injected as a liquid into an inlet manifold, the vaporization and expansion causes a reduction in air/fuel charge temperature with an associated increase in density, thereby increasing the cylinder's volumetric efficiency. As the decomposition of NO into oxygen and nitrogen gas is exothermic and thus contributes to a higher