An official website of the United States government.

We've made some changes to EPA.gov. If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Green Vehicle Guide

Smog Rating

  • This rating reflects vehicle tailpipe emissions that contribute to local and regional air pollution, creating problems such as smog, haze, and health issues. 
  • Vehicles that score a 10 are the cleanest.
  • Light duty cars and trucks must meet either federal [EPA] or California [CARB] emission requirements. Individual states choose whether vehicles sold there meet either the federal or California emission requirement. Within both the federal and California system, automakers may choose from a range of eligible emission standards for each vehicle.
  • Model year 2018 and later: The smog rating chart has been recalibrated to reflect new, more stringent Tier 3 emission standards. This is good news, as Tier 3 cars and trucks are much cleaner. This recalibration makes better use of the entire smog rating scale and allows for more useful comparisons between vehicles. Please note: Even though ratings appear to be going down, vehicles are not getting dirtier. A MY 2018 and later smog rating of 3 is about the same as a MY 2017 smog rating of 6.
  • Before a new vehicle model can be sold, sample vehicles are tested under tightly controlled conditions. Their tailpipe emissions are captured and measured using sophisticated monitoring techniques. The results determine the emission standard that the vehicle meets.
  • Emission standards are for the major pollutants in vehicle exhaust:
    • NMOG, NMHC, or THC—types of carbon-containing compounds, including hydrocarbons 
    • NOx—Oxides of Nitrogen, which combine with hydrocarbons to create smog 
    • PM—Particulate Matter, tiny particles of solid matter that lodge in the lungs and deposit on buildings 
    • CO—Carbon Monoxide, a colorless, odorless, poisonous gas 
    • HCHO—Formaldehyde, a lung irritant and carcinogen 

Rating Scales by Model Year (MY)

  • MY 2018 & 2019
    Rating EPA Tier 2 EPA Tier 3 CARB LEV III
    10 Bin 1 Bin 0 ZEV
    9 -- -- --
    8 -- Bin 20 SULEV20
    7 Bin 2 Bin 30 SULEV30
    6 -- Bin 50 SULEV50
    5 Bin 3 Bin 70 SULEV70
    4 -- -- --
    3 Bin 4 Bin 125 SULEV125
    2 -- -- --
    1 Bin 5-8 Bin 160 SULEV160
    *Given implementation of new federal (EPA Tier 3) and California (CARB LEVIII) emissions standards, older (Tier 2 and LEVII) emissions standards no longer appear on the smog rating chart as of MY 2018.
  • MY 2016 & 2017
    Rating EPA Tier 2 EPA Tier 3 CARB LEV II CARB LEV III
    10 Bin 1 Bin 0 ZEV ZEV
    9 Bin 2* Bin 20 PZEV SULEV20/PZEV
    8 Bin 2 Bin 30 SULEV II SULEV30
    7 Bin 3 Bin 85/Bin 70/Bin 50   ULEV70/ULEV50
    6 Bin 4 Bin 125/Bin 110 ULEV II ULEV125
    5 Bin 5 Bin 160 LEV II LEV160
    4 Bin 6   LEV II option 1  
    3 Bin 7      
    2 Bin 8   SULEV II lg trucks  
    1     ULEV & LEV II lg trucks  
    *Vehicle must also be certified to CA PZEV.
  • MY 2014 & 2015
    Rating EPA Tier 2 CARB LEV II CARB LEV III
    10 Bin 1 ZEV ZEV
    9 Bin 2* PZEV SULEV20/PZEV
    8 Bin 2 SULEV II SULEV30
    7 Bin 3   ULEV70/ULEV50
    6 Bin 4 ULEV II ULEV125
    5 Bin 5 LEV II LEV160
    4 Bin 6 LEV II option 1  
    3 Bin 7    
    2 Bin 8 SULEV II lg trucks  
    1   ULEV & LEV II lg trucks  
    *Vehicle must also be certified to CA PZEV.
  • My 2013, MY 2012, & 2011
    Rating EPA Tier 2 CARB LEV II
    10 Bin 1 ZEV
    9   PZEV
    8 Bin 2 SULEV II
    7 Bin 3  
    6 Bin 4 ULEV II
    5 Bin 5 LEV II
    4 Bin 6 LEV II option 1
    3 Bin 7  
    2 Bin 8 SULEV II lg trucks
    1   ULEV & LEV II lg trucks
  • MY 2010 & 2009
    Rating EPA Tier 2 CARB LEV II
    10 Bin 1 ZEV
    9 Bin 2 SULEV II
    8 Bin 3  
    7 Bin 4 ULEV II
    6 Bin 5 LEV II
    5 Bin 6 LEV II option 1
    4 Bin 7  
    3 Bin 8 SULEV II lg trucks
    2   ULEV ll lg trucks
    1   LEV ll lg trucks
    0    
  • MY 2008 & Earlier
    Rating EPA Tier 2 CARB LEV II
    10 Bin 1 ZEV
    9 Bin 2 SULEV II
    8 Bin 3  
    7 Bin 4 ULEV II
    6 Bin 5 LEV II
    5 Bin 6 LEV II option 1
    4 Bin 7  
    3 Bin 8 SULEV II lg trucks
    2 Bin 9 ULEV ll lg trucks
    1 Bin 10 LEV ll lg trucks
    0 Bin 11  

Frequent Questions on the Smog Rating

Pollutant Emission Levels for Each Standard