Subject to the requirements of this article, the county governing body may impose a one percent sales and use tax by ordinance, subject to a referendum, within the county area for a specific purpose or purposes and for a limited amount of time. The revenues collected pursuant to this article may be used to defray debt service on bonds issued to pay for projects authorized in this article. However, at no time may any portion of the county area be subject to more than one percent sales tax levied pursuant to this article or pursuant to any local law enacted by the General Assembly. This limitation does not apply in a county area in which, as of July 1, 2012, a local sales and use tax was imposed pursuant to a local act of the General Assembly, the revenues of which are used to offset the costs of school construction, or other school purposes, or other government expenses, or for any combination of these uses.