US EPA to propose Tier 2 light-duty emission standards

22 February 1999

The US Environmental Protection Agency (EPA) completed a draft proposal of the Tier 2 (year 2004) emission standards for light duty vehicles, including cars, vans, sport utility vehicles (SUV), and light duty trucks. According to press reports, the draft was submitted to the Office of Management and Budget last Friday. The new standards have not yet been confirmed by the EPA or other official sources.

The plan would include three components:

• New tailpipe emission standards with emphasis on NOx reduction.
• A requirement for heavier vehicles (SUV, minivans, ...) to meet car standards.
• A new sulfur content standard for gasoline.

Under the proposed rules, a nitrogen oxides (NOx) standard of 0.07 g/mile would be phased in for cars between 2004 and 2007. Light duty trucks and other vehicles weighing up to 8,500 lbs (3,855 kg) would be required to meet a 0.2 g/mile standard in 2004, and the 0.07 standard in 2009.

Manufacturers of diesel vehicles would be required to produce a cleaner fleet with average NOx emissions of 0.07 g/mile.

The current Tier 1 NOx standard for passenger cars is 0.4 g/mile (1 g/mile for diesel cars). The current emissions standard for light trucks is 0.7 grams of NOx per mile. The current NLEV NOx standard is 0.2 g/mile. The NLEV standard is currently in effect in the Northeastern states and will be required nationwide in 2001.

According to the plan, the EPA wants a nationwide average for sulfur content in gasoline at 30 ppm, down from current levels of around 330 ppm. Sulfur cuts would be phased in between 2004 and 2006. Automakers have pushed for lower sulfur because sulfur negatively affects the performance of OBD systems (onboard emission diagnostics) and three-way catalysts.

Oil refiners said that the lower sulfur limits could add 5-6 cents to every gallon of gasoline sold at the pump. According to the EPA, the average sticker price for new cars would rise $200.