Emissions classifications

Fig 1: Identifying Emission Classifications Chart

Courtesy of VOLVO CARS OF NORTH AMERICA.

The illustration shows the relationship between the different emissions classifications.

• Tier 1 (the applicable obligatory requirements, both federal and in California)
• TLEV (Transitional Low Emission Vehicle)
• LEV (Low Emission Vehicle)
• ULEV (Ultra Low Emission Vehicle)
• LEV II (Low Emission Vehicle, stage 2)
• ULEV II (Ultra Low Emission Vehicle, stage 2)
• SULEV (Super Ultra Low Emission Vehicle)
• NOx g/mile (nitrous oxides)
• CO g/mile (carbon monoxide)
• NMOG g/mile (Non-Methane Organic Gases). These are the basis of smog. In principle NMOG are hydro-carbons
• "A" symbolizes the optimal target of the car when it leaves the factory.