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.
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	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

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 or SULEV20 standard.