Health & Saf. Code, § 39011.5

(a) “Agricultural source of air pollution” or “agricultural source” means a source of air pollution or a group of sources used in the production of crops, or the raising of fowl or animals located on contiguous property under common ownership or control that meets any of the following criteria:

(1) Is a confined animal facility, including, but not limited to, any structure, building, installation, barn, corral, coop, feed storage area, milking parlor, or system for the collection, storage, treatment, and distribution of liquid and solid manure, if domesticated animals, including, but not limited to, cattle, calves, horses, sheep, goats, swine, rabbits, chickens, turkeys, or ducks are corralled, penned, or otherwise caused to remain in restricted areas for commercial agricultural purposes and feeding is by means other than grazing.

(2) Is an internal combustion engine used in the production of crops or the raising of fowl or animals, including, but not limited to, an engine subject to Article 1.5 (commencing with Section 41750) of Chapter 3 of Part 4 except an engine that is used to propel implements of husbandry, as that term is defined in Section 36000 of the Vehicle Code, as that section existed on January 1, 2003. Notwithstanding subdivision (b) of Section 39601, the state board may not revise this definition for the purposes of this section.

(3) Is a Title V source, as that term is defined in Section 39053.5, or is a source that is otherwise subject to regulation by a district pursuant to this division or the federal Clean Air Act (42 U.S.C. Sec. 7401 et seq.).

(b) Any district rule or regulation affecting stationary sources on agricultural operations adopted on or before January 1, 2004, is applicable to an agricultural source.

(c) Nothing in this section limits the authority of a district to regulate a source, including, but not limited to, a stationary source that is an agricultural source, over which it otherwise has jurisdiction pursuant to this division, or pursuant to the federal Clean Air Act (42 U.S.C. Sec. 7401 et seq.) or any rules or regulations adopted pursuant to that act that were in effect on or before January 1, 2003, or to exempt an agricultural source from any requirement otherwise applicable under Section 40724 or 42301.16, based upon a finding by the district in a public hearing that the aggregate emissions from that source do not exceed a de minimis level of more than one ton of particulate matter, nitrogen oxides, or volatile organic compounds per year.