The correlation of CO emissions inside transit buses with vehicle operation modes: A preliminary case study

Abstract

This study looks at the relationship between traffic variables and carbon monoxide concentrations inside transit buses in Singapore. Speed, acceleration, road grade, and VSP were measured throughout the route using a GPS device. The data was compared to the carbon monoxide concentration in order to see what correlation could be obtained. Two routes were looked at in this study. Both are common bus routes taken to and from the National University of Singapore by faculty and students. Little correlation was observed between CO concentration and acceleration, grade, and VSP. A small positive correlation was observed with speed. More testing needs to be done to confirm a true correlation. The average CO concentration observed was low at 1.14 ppm. All but one route fell within the 0.3 to 2.7ppm range. The outlier occurred on October 12th during a PM Peak trip on bus route 95. It had a maximum concentration of 7.1ppm for a short period, and was only over 2.7ppm for 2 minutes. The tests indicate no risk to human health from CO. © 2010 ASCE.