Summer gas requirements, which come from ozone monitoring, will have a direct impact on the summer fuel costs of anyone who purchases gas in southeast Michigan beginning this weekend.

The summer gasoline program started in 1996 as part of the EPA's Clean Air Act.

The Michigan Department of Agriculture and Rural Development says beginning Saturday, June 1, eight counties in southeast Michigan can only sell or dispense gas that does not exceed 7.0 pounds per square inch of vapor pressure. The changes are aimed to help lower smog levels.

The changes increase fuel efficiency, but they can also increase cost.

The change will last until September 15 and includes the counties of Lenawee, Livingston, Macomb, Monroe, Oakland, St. Clair, Washtenaw, and Wayne.