Comparison of Methodologies for Calculating Use-Stage Environmental Burdens for an Automobile

The goal of this work is to calculate the lifetime emissions for a 1996 Saturn automobile over its 193,000-km useful life. To do this, the authors developed a vehicle-specific method for calculating nonmethane hydrocarbon (NMHC), carbon monoxide (CO), carbon dioxide (CO₂), and nitrous oxide (NO_x) emissions. Vehicle-specific emissions data were not available for methane (CH₄) sulfur oxides (SO_x), dinitrogen oxide (N₂O), and particulate matter (PM). The authors selected most applicable emission factors for these compounds. The authors then compared the results of these emission calculations to several other published methods. All methods produced similar results for CO₂ emissions. However, the various calculation methods produced significantly different results for NMHC, CO, NO_x, CH₄, SO_x, N₂O, and PM emissions. The vehicle-specific emissions tended to be lower than many of the other methods.