The definitions in this section apply throughout this chapter unless the context clearly requires otherwise.

(1) "Air contaminant" means dust, fumes, mist, smoke, other particulate matter, vapor, gas, odorous substance, or any combination thereof.

(2) "Air pollution" is presence in the outdoor atmosphere of one or more air contaminants in sufficient quantities and of such characteristics and duration as is, or is likely to be, injurious to human health, plant or animal life, or property, or which unreasonably interfere with enjoyment of life and property. For the purpose of this chapter, air pollution shall not include air contaminants emitted in compliance with chapter 17.21 RCW.

(3) "Air quality standard" means an established concentration, exposure time, and frequency of occurrence of an air contaminant or multiple contaminants in the ambient air which shall not be exceeded.

(4) "Ambient air" means the surrounding outside air.

(5) "Authority" means any air pollution control agency whose jurisdictional boundaries are coextensive with the boundaries of one or more counties.

(6) "Best available control technology" (BACT) means an emission limitation based on the maximum degree of reduction for each air pollutant subject to regulation under this chapter emitted from or that results from any new or modified stationary source, that the permitting authority, on a case-by-case basis, taking into account energy, environmental, and economic impacts and other costs, determines is achievable for such a source or modification through application of production processes and available methods, systems, and techniques, including fuel cleaning, clean fuels, or treatment or innovative fuel combustion techniques for control of each such a pollutant. In no event shall application of "best available control technology" result in emissions of any pollutants that will exceed the emissions allowed by any applicable standard under 40 C.F.R. Part 60 and Part 61, as they exist on July 25, 1993, or their later enactments as adopted by reference by the director by rule. Emissions from any source utilizing clean fuels, or any other means, to comply with this subsection shall not be allowed to increase above levels that would have been required under the definition of BACT as it existed prior to enactment of the federal clean air act amendments of 1990.

(7) "Best available retrofit technology" (BART) means an emission limitation based on the degree of reduction achievable through the application of the best system of continuous emission reduction for each pollutant that is emitted by an existing stationary facility. The emission limitation must be established, on a case-by-case basis, taking into consideration the technology available, the costs of compliance, the energy and nonair quality environmental impacts of compliance, any pollution control equipment in use or in existence at the source, the remaining useful life of the source, and the degree of improvement in visibility that might reasonably be anticipated to result from the use of the technology.

(8) "Board" means the board of directors of an authority.

(9) "Control officer" means the air pollution control officer of any authority.

(10) "Department" or "ecology" means the department of ecology.

(11) "Emission" means a release of air contaminants into the ambient air.

(12) "Emission standard" and "emission limitation" mean a requirement established under the federal clean air act or this chapter that limits the quantity, rate, or concentration of emissions of air contaminants on a continuous basis, including any requirement relating to the operation or maintenance of a source to assure continuous emission reduction, and any design, equipment, work practice, or operational standard adopted under the federal clean air act or this chapter.

(13) "Fine particulate" means particulates with a diameter of two and one-half microns and smaller.

(14) "Flame cap kiln" means an outdoor container used for the combustion of natural vegetation from silvicultural or agricultural activities that meets the following requirements:

(a) Has a solid or sealed bottom including, but not limited to, mineral soils, so that all air for combustion comes from above;

(b) Is completely open on top with no restrictions;

(c) Is a shallow container where the width is greater than the height; and

(d) Has a volume of 10 cubic meters or less.

(15)(a) "Lowest achievable emission rate" (LAER) means for any source that rate of emissions that reflects:

(i) The most stringent emission limitation that is contained in the implementation plan of any state for such class or category of source, unless the owner or operator of the proposed source demonstrates that such limitations are not achievable; or

(ii) The most stringent emission limitation that is achieved in practice by such class or category of source, whichever is more stringent.

(b) In no event shall the application of this term permit a proposed new or modified source to emit any pollutant in excess of the amount allowable under applicable new source performance standards.

(16) "Modification" means any physical change in, or change in the method of operation of, a stationary source that increases the amount of any air contaminant emitted by such source or that results in the emission of any air contaminant not previously emitted. The term modification shall be construed consistent with the definition of modification in Section 7411, Title 42, United States Code, and with rules implementing that section.

(17) "Multicounty authority" means an authority which consists of two or more counties.

(18) "New source" means (a) the construction or modification of a stationary source that increases the amount of any air contaminant emitted by such source or that results in the emission of any air contaminant not previously emitted, and (b) any other project that constitutes a new source under the federal clean air act.

(19) "Permit program source" means a source required to apply for or to maintain an operating permit under RCW 70A.15.2260.

(20) "Person" means an individual, firm, public or private corporation, association, partnership, political subdivision of the state, municipality, or governmental agency.

(21) "Reasonably available control technology" (RACT) means the lowest emission limit that a particular source or source category is capable of meeting by the application of control technology that is reasonably available considering technological and economic feasibility. RACT is determined on a case-by-case basis for an individual source or source category taking into account the impact of the source upon air quality, the availability of additional controls, the emission reduction to be achieved by additional controls, the impact of additional controls on air quality, and the capital and operating costs of the additional controls. RACT requirements for a source or source category shall be adopted only after notice and opportunity for comment are afforded.

(22) "Silvicultural burning" means burning of wood fiber on forestland or combustion of natural vegetation from silvicultural activities consistent with the provisions of RCW 70A.15.5120.

(23) "Source" means all of the emissions units including quantifiable fugitive emissions, that are located on one or more contiguous or adjacent properties, and are under the control of the same person, or persons under common control, whose activities are ancillary to the production of a single product or functionally related group of products.

(24) "Stationary source" means any building, structure, facility, or installation that emits or may emit any air contaminant.

(25) "Trigger level" means the ambient level of fine particulates, measured in micrograms per cubic meter, that must be detected prior to initiating a first or second stage of impaired air quality under RCW 70A.15.3580.

Reviser's note: The definitions in this section have been alphabetized pursuant to RCW 1.08.015(2)(k).

Findings—2024 c 280: "The legislature finds that the use of distributed, small-scale portable flame cap kilns for silvicultural and agricultural management of natural vegetation is consistent with the sustainable agriculture goals of the climate commitment act under RCW 70A.65.260, the sustainable farms and fields grant program identified in RCW 89.08.615, the use of fire in controlled burns to eliminate sources of fuel identified in RCW 76.04.167(3), and the forest restoration goals identified in RCW 70A.65.270. Therefore, the legislature finds that the use of distributed portable flame cap kilns is a necessary component of an integrated land management strategy that:

(1) Reduces greenhouse gas emissions;

(2) Produces durable biogenic carbon storage, either in situ or for distribution elsewhere; and

(3) Minimizes air quality impacts from open burning." [ 2024 c 280 s 1.]

Finding—1991 c 199: See note following RCW 70A.15.1005.

Purpose—Short title—Construction—Rules—Severability—Captions—1987 c 109: See notes following RCW 43.21B.001.