In air basins where funds are not subvened pursuant to Section 39802, the state board may subvene up to two dollars ($2) for every three dollars ($3) budgeted by a district. Subventions under this section shall not exceed eighteen and four-tenths cents ($0.184) per capita, but shall not be less than twelve thousand dollars ($12,000) for any district, if the district provides the required matching funds. Any county district which merged after January 1, 1980, into a unified district or regional district pursuant to this division shall have its minimum subvention under this section transferred to the unified district or regional district if the unified district or regional district provides the required matching funds. A unified district or regional district which has a county district minimum subvention transferred to it under this section may not also receive subventions under the per capita provisions of this section.