The US Environmental Protection Agency (EPA) has tightened the standards for certain toxic emissions from mobile sources.
The new final rule for Mobile Source Air Toxic (MSAT) emissions toughens benzene standards for gasoline, sets non-methane hydrocarbon (NMHC) emissions standards for cars at cold temperatures and tightens standards for fuel containers to prevent the evaporation of harmful fumes.
Benzene is of particular concern because it is a known carcinogen and most of the nation’s benzene emissions come from mobile sources. Many MSATs are part of the larger category of mobile source emissions known as volatile organic compounds (VOC), which contribute to the formation of ozone and possibly particulate matter (PM), each of which contribute to serious public health problems.
By 2030, the MSAT rule, combined with fuel and vehicle standards already in place, will reduce toxic emissions from cars to 80% below 1999 emissions. Once the new MSAT standards are fully implemented in 2030, they are expected to reduce emissions of mobile source air toxics annually by 330,000 tons, including 61,000 tons of benzene. EPA estimates annual health benefits from the particulate matter reductions of the vehicle standards to total $6 billion in 2030. The estimated annual cost for the entire rule is about $400 million in 2030.
The new MSAT standards will take effect in 2011 for gasoline, 2010 for cars, and 2009 for fuel containers.
Benzene. Beginning in 2011, refiners must meet an annual average gasoline benzene content standard of 0.62 vol% on all their gasoline, both reformulated and conventional, nationwide. The national benzene content of gasoline today is about 1.0 vol%. (Gasoline sold in California will not be covered because California has already implemented more stringent standards similar to those EPA is establishing.)
The regulations include a nationwide averaging, banking, and trading program. In addition to the 0.62 vol% standard, refiners must also meet a maximum average benzene standard of 1.3 vol% beginning on July 1, 2012. A refinery’s or importer’s actual annual average gasoline benzene levels may not exceed this maximum average standard.
The EPA expects that gasoline in all areas of the country will have lower benzene levels than they do now, and there will be less geographic variability in gasoline benzene levels. Areas where benzene levels are currently highest, such as Alaska and the Northwest, will experience the most significant reductions. EPA is providing special compliance flexibility for approved small refiners or any refiner facing extreme unforeseen circumstances.
Along with the vehicle exhaust standards, the EPA is also adopting more stringent evaporative emission standards for new passenger vehicles. The new standards are equivalent to California’s standards and codify the approach that manufacturers are already taking for 50-state evaporative systems. Implementation of the evaporative emission standards begins in 2009 for lighter vehicles and in 2010 for the heavier vehicles.
NMHC. Recent research indicates that the current test procedures often do not result in robust control of NMHCs at colder temperatures below 75° F. The EPA is thus requiring that passenger vehicles meet new NMHC exhaust emissions standards at colder temperatures. Each manufacturer’s vehicles will be subject to a sales-weighted fleet average NMHC level of 0.3 grams/mile for lighter vehicles weighing 6,000 pounds (lbs) or less.
Vehicles above 6,000 lbs (which include trucks up to 8,500 lbs and passenger vehicles up to 10,000 lbs) must meet a sales-weighted fleet average NMHC level of 0.5 grams/mile. The standards phase in between 2010 and 2013 for the lighter vehicles, and between 2012 and 2015 for the heavier vehicles. A credit program and other provisions provide flexibility to manufacturers, especially during the phase-in periods.
Fuel containers. EPA is establishing standards that will limit hydrocarbon emissions that evaporate from or permeate through portable fuel containers such as gas cans. The new requirements also apply to diesel and kerosene containers. Starting with containers manufactured in 2009, the standard limits evaporation and permeation emissions from these containers to 0.3 grams of hydrocarbons per gallon per day. We are also adopting test procedures and a certification and compliance program in order to ensure that containers meet the emission standard over a range of in-use conditions.
EPA has worked closely with major container manufacturers and it is expected that the new cans will be built with a simple and inexpensive permeation barrier and new spouts that close automatically.