The air pollution control officer of any district in a county with a population of 6,000,000 or less, upon authorization of the district board, may authorize, by permit, open outdoor fires for the purpose of disposing of agricultural wastes, or wood waste from trees, vines, bushes, or other wood debris free of nonwood materials, in a mechanized burner such that no air contaminant is discharged into the atmosphere for a period or periods aggregating more than 30 minutes in any eight-hour period which is:
(a)
As dark or darker in shade as that designated as No. 1 on the Ringelmann Chart, as published by the United States Bureau of Mines, or
(b)
Of such opacity as to obscure an observer’s view to a degree equal to or greater than does smoke described in subdivision (a).
In authorizing the operation of a mechanized burner, the air pollution control officer may make the permit subject to whatever conditions he determines are reasonably necessary to assure conformance with the standards prescribed in this section.