Hoping tourists will allow county officials to climb out of a budget hole, San Mateo County supervisors Tuesday placed two San Francisco International Airport-related tax measures on the November ballot.

The board approved an 8 percent tax on parking and a separate 2½ percent tax on rental-car agencies during its meeting Tuesday. Both measures will be placed on the Nov. 4 ballot and will affect only unincorporated parts of the county, most notably SFO.

The parking tax should generate $4 million per year and the rental-agency tax would bring in about $7.5 million per year. Supervisors Mark Church and Rich Gordon, who proposed the two taxes, originally had placed the rental-agency tax at 5 percent to earn $15 million per year but halved the number after significant opposition from local businesses.