The ABC's of Today's U.S. Emissions Regulations

With so many emissions standards, it can be hard to keep track of what's current and coming soon, especially with all the acronyms flying around.

To help, here is a glossary of some important terms and what they mean for light-duty vehicles in the U.S.

EPA - The Environmental Protection Agency (EPA)'s mission is to protect human health and the environment.  To do this, the EPA develops and enforces regulations after the U.S. Congress writes an environmental law. The EPA works to develop vehicle and gasoline sulfur rules, including the following programs.

Tier 2 - Beginning in 2004, a protective tailpipe emissions standard was instituted for all passenger vehicles and set at an average standard of .07 grams per mile for nitrogen oxide.

    • Vehicles weighing less than 6,000 pounds were phased in between 2004 and 2007. Heavier vehicles followed a three-step program, which culminated in 2009.
    • This program required passenger vehicles to be 77 to 95 percent cleaner, with reduced emissions than the cars that came before.

Tier 3 - Starting in 2017, Tier 3 emission standards will reduce tailpipe and evaporative emissions for passenger cars, light-duty trucks and medium-duty passenger vehicles and some heavy duty vehicle.

    • The structure of the Tier 3 standards is very similar to the existing Tier 2 program and includes lower gasoline sulfur standards as well as exhaust emissions of non-methane organic gases (NMOG), nitrogen oxide (NOx) and particulate matter (PM) as well as for evaporative hydrocarbon emissions.
    • The program phases in over several years with the primary vehicle emission standards starting in MY 2017 (2018 for heavier vehicles) and the gasoline sulfur control provisions beginning in 2017.

ARB - Air Resources Board of California (ARB) has special vehicle emissions standards and U.S. states have the option to follow national or California standards. The ARB first adopted LEV (low-emission vehicle) standards in 1990.

  • LEV II - LEV II standards were fully implemented by 2010 and included amendments that continued to advance California's clean air goals through improved emission reduction standards for automobiles.
  • LEV III - LEV III emissions regulations go into effect in 2015, phased in fully by model year 2028. These amendments include more stringent emission standards for both criteria pollutants and greenhouse gases for new passenger vehicles.
  • ZEV - Zero- Emission Vehicle (ZEV) credits will be offered for vehicles that achieve near zero emissions.
  • SULEV - Super-Ultra-Low-Emission Vehicle (SULEV) is a category for light-duty vehicles, where the vehicle will only emit a single pound of hydrocarbons during 100,000 miles of driving.

CAFE Standards - The Corporate Average Fuel Economy (CAFE) standards require vehicle manufacturers to comply with the fuel economy standards set by the U.S. Department of Transportation.

The final standards are projected to result in an average industry fleet-wide level of 163 grams/mile of carbon dioxide in model year 2025 vehicles, which is equivalent to 54.5 miles per gallon.

To learn more, check out this article in Automotive Industries magazine.