Introduction

Every year, the Environmental Protection Agency (EPA) evaluates the greenhouse gas (GHG) and smog-forming emissions using a scale of 1-10 for all new cars, trucks, and SUVs. Vehicles must achieve a combined score from both scales significantly better than the average to earn the SmartWay designation. SmartWay Elite certification is reserved for vehicles scoring highest on both scales, signifying them as the top environmental performers.

Greenhouse Gas (GHG) Rating

The GHG rating indicates the carbon dioxide (CO2) emissions from a vehicle's tailpipe, representing the most common greenhouse gas. Typically, CO2 emissions make up 99% of a vehicle's tailpipe emissions of greenhouse gases.

Smog Rating

The smog rating evaluates vehicle tailpipe emissions that contribute to local and regional air pollution, leading to issues like smog, haze, and health concerns. Oxides of Nitrogen (NOx), when combined with hydrocarbons, play a key role in the formation of smog.

• Particulate Matter (PM) consists of minuscule solid particles that can become lodged in the lungs and settle on buildings.
• Carbon-containing compounds such as NMOG (non-methane organic gases), NMHC (non-methane hydrocarbons), or THC (total hydrocarbon content) are involved in the creation of ozone and smog.
• Carbon Monoxide (CO), a colorless, odorless, and toxic gas.
• Formaldehyde (HCHO), a lung irritant and carcinogen.

The EPA revises the greenhouse gas and smog rating thresholds each year. Additionally, they periodically update the SmartWay criteria to ensure they consistently certify the top 20 percent of the cleanest, most efficient vehicles.