0.7 PPM of what? There are at least 4 major gasses that can be tested as well as particulate matter (PM) for a Diesel. Sounds like a CO value but I don't know the particulars of Arizona smog laws. Diesels are inherently low in HC and CO, OK for CO2 (tied to fuel economy) and not good on NoX ( a product of high combustion chamber temps and relatively long burn times). PM is hard to measure with any accuracy in a screening situation - that would relate to the smoke screen you mentioned and evidently not tested.

Dan