Emissions of Nitrous Oxide from Highway Mobile Sources: Comments on the 'Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks, 1990-1996' (March 1998)

摘要

The estimate of the contribution of nitrous oxide from mobile sources to total U.S. emissions of greenhouse gases went from one-half percent in the last official inventory, published in 1997 (U.S. EPA) to three percent in the March 10, 1998, draft Inventory of U.S. Greehouse Gas Emissions and Sinks 1990-1996 (U.S. EPA), which will be referred to in these comments as the Draft Inventory. The primary reason for this change is the use of much larger emission factors for gasoline highway vehicles, rather than increases in vehicle miles traveled. OMS believes that these emission factors are considerably larger than they should be. Therefore, these comments will focus primarily on the origin and validity of the emission factors used in the Draft Inventory and on the development of better ones.