Also, I have collected emission data on some buses when the bus was out, on the road, for its regular schedule. I have compared buses running on B20 and ULSD fuels.

The test results show that B20 fueled buses emitted a lower concentration of all the monitored pollutants expect for CO2, which showed a 3% increase as compared to ULSD fueled buses. NO concentrations were observed to reduce by 7%. SO2 and NO2 for B20 fuel showed nearly 9% and 4% reductions respectively. NOX concentration was observed to reduce by 3% for B20 fueled buses.
I have made these comparisons based on the exhaust emission data collected. All the buses have approximately same mileage.