Since they did not use the exact same method of data collection and averaging as the EPA, there might be slight errors in this comparison.  Thier data for the Legend/Chetak engine was generated by performing the EPA city driving test cycle, it's this test data that was used to demonstrate compliance with EPA and CARB standards.

They were not able to get official data concerning 150cc 2 stroke scooters because none of the two stroke engines tested came close to passing the emissions tests; so no official records exist.  Through a series of phone calls to sources in the industry they pieced together this information:

For a 150 cc 2 stroke scooter engine, without catalytic converter, hydrocarbon emissions range from 30 to 70 grams per mile!  Carbon monoxide values were characterized as "not too bad".

Let's compare these 2 stroke emissions to the hydrocarbon emissions of a bus engine.

Bus engines are rated differently due to the way they are used in urban transportation.  They are rated by grams of hydrocarbon emissions per brake horsepower per hour.

For example, a new, clean burning, diesel engine designed for bus usage, would certify at .1 grams per HP per hour.  A typical bus engine runs about 300 horsepower.  So, in one hour of city driving, a 300 HP diesel bus engine will emit, on average, 30 grams of hydrocarbon.  About what a better 2 stroke does in ONE MILE!!