Understand the Smog Score
In California all vehicles manufactured after January 1, 2009 were required to display a Global Warming Score and Smog Score as part of the California Environmental Performance (EP) Label. The Smog Score is important because it gives car buyers the ability to determine quickly how much a vehicle pollutes compared to all other vehicles on the market.
New Fuel Economy and Environment Label Coming in 2013
In 2012 California harmonized its consumer vehicle labeling program with the Federal program so that starting in 2013, all new cars are required to display the new Fuel Economy and Environment Label (Label). The Federal label has a similar ranking system as well as additional ways to compare vehicles, such as:
- New ways to compare energy use and cost between new-technology cars that use electricity and conventional cars that are gasoline-powered.
- Useful estimates on how much consumers will save or spend on fuel over the next five years compared to the average new vehicle.
- Easy-to-read ratings of how a model compares to all others for smog emissions and emissions of pollution that contribute to climate change.
- An estimate of how much fuel or electricity it takes to drive 100 miles.
- Information on the driving range and charging time of a plug-in vehicle.
- A QR Code that will allow users of smartphones to access online information about how various models compare on fuel economy and other environmental and energy factors.
Until the transition to the new Federal ratings in mid-2013, the Environmental Scores displayed on the DriveClean web site remain based on the California EP Label scoring system.
Smog
Smog is a haze-like form of air pollution produced by the photochemical reaction of sunlight with volatile organic compounds, including Non-Methane Organic Gases (NMOG) and Oxides of Nitrogen (NOx), that have been released into the atmosphere, especially by automobile operation.
EP Label Smog Score
Smog Scores are on a scale of 1 – 10, with 10 being the cleanest. The average vehicle available in California today has a smog score of 5. The table below shows the different pollutant levels associated with each Smog Score, and how those levels relate to Federal and California certification standards. The Environmental Scores displayed on the DriveClean web site are currently based on the California EP Label scoring system and will be transitioned to the new Federal ratings in mid-2013.
How the EP Label Smog Score is Determined
Every car sold in California is certified by the Air Resources Board (ARB) and meets a certain emission standard. These emission standards are part of ARB's Low Emisson Vehicle program. Below is a table that provides the emission standards and the grams per mile of pollution associated with each standard. This is then associated with a certain Smog Score. The grams per mile of NMOG and NOx are the amounts of smog forming pollutants that come from the car’s tailpipe, and that evaporate from the car. The Environmental Scores displayed on the DriveClean web site are currently based on the California EP Label scoring system and will be transitioned to the new Federal ratings in mid-2013.
| Smog Score* | Emission Standard | NMOG + NOx (g/mile) |
| 10 | ZEV, Bin 1 | 0.000 |
| 9** | ATPZEV, PZEV | 0.030 |
| 8 | SULEV, LEV2 SULEV, Bin 2 | 0.030 |
| 7 | Bin 3 | 0.085 |
| 6 | Bin 4 | 0.110 |
| 5 | LEV 2 ULEV | 0.125 |
| 4 | LEV 2 LEV, Bin 5 | 0.160 |
| 3 | Bin 6 , SULEV (Medium Duty Vehicle) | 0.190 - 0.200 |
| 2 | Bin 7 | 0.240 |
| 1 | Bin 8, LEV 2 ULEV (MDV), LEV 1 ULEV | 0.325 - 0.356 |
*Does not include upstream emissions.
**A Smog Score of 9 was given to vehicles certifying to the California PZEV and ATPZEV standards based on the longer useful life, zero evaporative emissions requirements, and extended warranty for these vehicles compared to vehicles certifying to the SULEV standards.