During the summer months from May 1 through September 15, the Environmental Protection Agency requires that specific volatile chemicals be extracted from gasoline before it is sold to reduce the creation of ozone, a key component of smog. In addition to the EPA's requirements, 15 U.S. cities currently implement their own stricter rules.
Typically, it costs refiners about one cent per gallon more to produce the cleaner summer blend, however, the consumer may see as much as a 10 to 15 cent jump at the pump. This, however, does not mean that U.S. drivers will see a 10 to 15 cent reduction when the strict summertime requirements end as the transition back to winter fuels often has a less dramatic impact.
The fuel prices drivers will be seeing at the pumps is as yet uncertain, though, the Department of Energy forecasts an average of $2.55 by winter.
[Source: AP via MSNBC]