(a) "Marginal conditions" means atmospheric conditions such that smoke and particulate matter escape into the upper atmosphere with some difficulty but not such that limited additional smoke and particulate matter would constitute a danger to the public health and safety.

(b) "Marginal day" means a day on which marginal conditions exist.

(2) For purposes of ORS 476.380 and 478.960, the Environmental Quality Commission shall classify different types or combinations of atmospheric conditions as marginal conditions and shall specify the extent and types of burning that may be allowed under different combinations of atmospheric conditions. A schedule describing the types and extent of burning to be permitted on each type of marginal day shall be prepared and circulated to all public agencies responsible for providing information and issuing permits under ORS 476.380 and 478.960. The schedule shall give first priority to the burning of perennial grass seed crops used for grass seed production, second priority to annual grass seed crops used for grass seed production, third priority to grain crop burning, and fourth priority to all other burning and shall prescribe duration of periods of time during the day when burning is authorized.

(3) In preparing the schedule under subsection (2) of this section, the commission shall provide for the assignment of fourth priority burning by the State Department of Agriculture in accordance with the memorandum of understanding established pursuant to ORS 468A.585.

(4) In preparing the schedule required under subsection (2) of this section, the commission shall weigh the economic consequences of scheduled burnings and the feasibility of alternative actions, and shall consider weather conditions and other factors necessary to protect the public health and welfare.

(5) None of the functions of the commission under this section or under ORS 476.380 or 478.960, as it relates to agricultural burning, shall be performed by any regional air quality control authority established under ORS 468A.105. [1991 c.920 §6]