CFD Modeling of Particulate Matter PM2.5 Inside BRT Public Transport Buses

BRT (Bus Rapid Transit) public transport systems, are highly frequented micro environments by the population of a city. In this research a TSI DustTrak II was used to determine the PM2.5 concentration inside the buses of the BRT system in Bogota, and a GPS app, MyCarTracks®, to record the speed and location data. Measurements were performed in three different segments of the system, and in different seats inside the buses. PM2.5 concentration levels above 120 µg/m3 were measured for all the segments. Time travels of the BRT passengers was determined to be around 20 to 40 minutes average, where they are exposed directly to these high levels of pollution. Thereafter, a CFD model was implemented to simulate and assess the behavior of the tailpipe emissions. Contours of concentration showed the self-pollution phenomenon as a fraction around 18% of the total concentration of PM 2.5 measured inside the cabin of the BRT.