Seasonal and Monthly Activity Allocation Fractions for Nonroad Engine Emissions Modeling, December 2005, NR-004c

摘要

The United States Environmental Protection Agency (EPA) has developed a national nonroad air emissions inventory model called NONROAD. The model uses estimates of annual activity for each equipment type, e.g., generally expressed in terms of hours of operations or gallons of fuel used per year, to calculate yearly emission inventories. It will also calculate inventories on a seasonal (i.e., summer, fall, winter, spring), monthly, or daily (i.e., weekday or weekend day) basis by allocating annual activity to these smaller time periods. This report documents the seasonal and monthly activity allocation fractions used by the model. Daily activity allocation fractions are addressed in a separate technical report. The only substantive change from draft NONROAD2004 is the seasonal allocation of construction equipment, described in the Methodology/Results section below. Seasonal inputs have also been added for Puerto Rico and the U.S. Virgin Islands, simply by assigning them to the Southeast region and using those existing values. The EPA currently considers these seasonal fractions to be final inputs for the draft NONROAD2005 model. The remainder of this report is organized into two parts. The first part contains a basic description of the overall approach and sources of information that are used to develop the requisite temporal allocation fractions. The second part explains how this information is used and describes the final default values for each state.