Atmospheric emissions inventory data for heavy duty vehicles

Heavy-duty trucks and buses are substantial contributors to the atmospheric oxides of nitrogen (NOx) inventory, but prediction of their emissions in r eal use remains inchoate. Continuous emissions of NOx were recorded from ch assis dynamometer testing of eight vehicles using a variety of transient cy cles, including the Central Business District schedule. NOx data were treat ed to account for sampling time lag and presented against instantaneous veh icle axle power. Data were repeatable from run to run and test schedule, bu t vehicle type and test cycle both influenced the instantaneous emissions r ates. However, the resulting correlations may be used for mobile source NOx contribution estimation when combined with vehicle activity data. The emis sions data were also presented as NOx/CO2, which are valuable for compariso n with remote sensing emissions data. The overall average ratio for all of the data considered was 0.0141, which corresponds to an emissions contribut ion of 0.0423 g of NOx/g of diesel burned.