Nitrous Oxide Emission Factors for Mobile Sources

摘要

To help determine emissions factors for nitrous oxide from gasoline mobile sources for the U.S. inventory of greenhouse gases, 23 vehicles (18 Tier ls, 4 LEVs, and 1 Tier 0) were tested on four driving schedules (FTP, US06, HR505, and LOS-AC). Most tests were run using a standard commercial fuel (285 ppm sulfur) and were repeated with air conditioning (AC) off at 75℉ and on at 95℉. For some vehicles, these tests were repeated using certification fuel (24 ppm sulfur). Average FTP composite emission factors were 46 mg/mi for 12 Tier 1 passenger vehicles (cars plus minivans), 109 mg/mi for five Tier 1 light-duty trucks, and 28 mg/mi for four LEVs. The FTP driving schedule resulted in the highest emissions of those driving cycles tested. Tests of both fuels on five vehicles showed higher nitrous oxide emissions with the higher sulfur fuel. AC-on produced some increases and some decreases of emissions. Inter-vehicle variability was too large to detect a significant effect of mileage on emissions. Nitrous oxide emissions from mobile sources were about 1% of U.S. greenhouse gas emissions in 1996.