Marijuana officially becomes legal in Alaska on Tuesday, and advocates plan to celebrate with ads on Anchorage city buses.

The ads are part of a public education campaign to encourage responsible consumption and read, “With great marijuana laws comes great responsibility.”

The campaign will be officially launched at a 10 a.m. news conference in Anchorage in which advocates will discuss implementation of the law, which was approved by 53 percent of voters last fall. Under the law, adults 21 and older may possess up to an ounce of pot and grow as many as six plants, though public consumption is still banned.

The Marijuana Policy Project, a key backer of the successful effort to legalize marijuana in Colorado and Alaska, launched the “Consume Responsibly” campaign in September, with billboards, print and online ads and materials in stores in Colorado and Washington.

Voters in Oregon and Washington, D.C., also approved legalization in November. Oregon’s law goes into effect this summer and D.C.’s appears set to begin this Friday.