If the exhaust smoke is black
If the color of the smoke is blue
If the color of the smoke is white
Smoke standards according to vehicle emissions
To be completed four years after the purchase date of a new vehicle, and every two years thereafter, vehicle inspections are imposed to ensure that the vehicle is safe and within the limits of pollution standards.
During the inspection, emissions are tested to verify that air pollutants are below the threshold as set by the regional anti-pollution standards. In the event that a vehicle does not pass emissions testing, it must undergo the necessary modifications to fall back under compliance and be re-tested in order to determine if it is roadworthy or not.
Emission standards for gas engines
For cars running on gasoline, carbon monoxide (CO) emissions must be less than
Anti-pollution standards for diesel engines
For cars running on diesel, opacity levels of exhaust fumes should be less than:
Gas vehicles manufactured prior to 1972, and for diesel vehicles manufactured prior to 1980 -- that is to say, before pollution standards went into effect -- are exempt from emissions control.
Finally, although engine noise is measured, it will not lead to a re-test if deemed excessive.
How to limit the emission of smoke in order to pass emissions testing?
The least expensive option, with no need for disassembly and entailing the shortest service time, and which is an alternative to part replacement, is hydrogen treatment via the Carbon Cleaning station. This service works as a preventative treatment, recommended every 10,000 miles, but can also resolve existing problems in the engine. This operation costs only $95.