John,
I don't believe there is an overall govt. regulation regarding diesel
powered vehicles yet. ( for import )
As far as ILL. goes they just started testing for smoke density as of
last January, in class 8 & 7 trucks only.
No hyrocarbons, no NOX, no monoxides, just the density of the exhaust.
I think you have clear sailing into the Windy.

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Terry 85 GL