Comparison of individual hopanes (4a) and steranes species (4b) in the lube oil (in μg/g) and crankcase emissions (in μg/km) for Buses 1 and 2. The abbreviations are: hop13=18α(H)-22,29,30-Trisnorneohopane; hop15=17α(H)-22,29,30-Trisnorhopane; hop17=17α(H),21ß(H)-29-Norhopane; hop19=17α(H),21ß(H)-Hopane; hop21=22S-17α(H),21ß(H)-30-Homohopane; hop22=22R-17α(H),21ß(H)-30-Homohopane; hop23=17ß(H),21ß(H)-Hopane; hop24=22S-17α(H),21ß(H)-30,31-Bishomohopane; hop25= 22R-17α(H),21ß(H)-30,31-Bishomohopane; hop26=22S-17α(H),21ß(H)-30,31,32-Trishomohopane; hop27=22R-17α(H),21ß(H)-30,31,32-Trishomohopane; ster42=20S-5α(H),14α(H),17α(H)-cholestane; ster43=20R-5α(H),14ß(H),17ß(H)-cholestane; ster44=20S-5α(H),14ß(H),17ß(H)-cholestane; ster45_40=20R-5α(H),14α(H),17α(H)-cholestane & 20S-13ß(H),17α(H)-diastigmastane; ster46=20S-5α(H),14α(H),17α(H)-ergostane; ster47=20R-5α(H),14ß(H),17ß(H)-ergostane; ster48_41=20S-5α(H),14ß(H),17ß(H)-ergostane & 20R-13α(H),17ß(H)-diastigmastane; ster49=20R-5α(H),14α(H),17α(H)-ergostane; ster50=20S-5α(H),14α(H),17α(H)-stigmastane; ster51=20R-5α(H),14ß(H),17ß(H)-stigmastane; ster52=20S-5α(H),14ß(H),17ß(H)-stigmastane; ster53=20R-5α(H),14α(H),17α(H)-stigmastane