RFG stands for reformulated gasoline. It is actually a set of standards devised by the EPA that gasoline in certain high-pollution areas must conform to. Its exclusive sale is mandatory in massive metropolises (metropoli?) such as Los Angeles, Chicago, and others. There are a number of urban areas which "opt-in" to the RFG program-- some local governments choose to mandate the sale of reformulated gasoline in their particular jurisdictions. Although it does reduce air pollution and the resulting public health concerns, refineries make less RFG than they do conventional gasoline, which results in higher gas prices (especially in some areas of the Midwest) due to supply and demand economics.
The differences between RFG and conventional gasoline include:
-A reduction in the Reid Vapor Pressure
-Reduced levels of benzene, a known carcinogen
-An increased amount of oxygenates such as MTBE, ETBE, ethanol and methanol
-Decreased sulfur content
-Fewer olefins
-Lower aromatic content
-Fewer VOCs (volatile organic compounds)