AcademicArticleSCO_84931318160

abstract

• © 2015 American Society of Civil Engineers. Mobile-source emission inventories in countries such as Mexico still require empirical data to complement modeling tools because these tools are based on few local observations. In this study, emission factors (EFs) were determined for 10 light-duty gasoline-powered vehicles as a function of cruising speed under real-world driving conditions typical of the Monterrey metropolitan area, the third largest urban center in Mexico. Greater variability in the EF was found when the vehicles were operated at lower speeds, specifically at 10km/h; however, above 40km/h, the changes were marginal. Engine size was the factor that most influenced the emissions of CO2, which were significantly greater in vehicles with an engine size above 2 L. A reduction trend in the CO-to-NOx ratio of newer model vehicles was observed. Upon comparison of the experimental results with the results obtained from the MOBILE6.2-Mexico and the MOVES 2010a models, it was determined that the latter model better described the values of the EFs, the emission profile as a function of speed, and the CO-to-NOx ratio of the tailpipe gases.