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

(1) "Active municipal solid waste landfill" means a municipal solid waste landfill that has accepted or is accepting solid waste for disposal and has not been closed in accordance with the requirements set forth in WAC 173-351-500 as it existed on January 10, 2022.

(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 does not include air contaminants emitted in compliance with chapter 17.21 RCW.

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

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

(5) "Closed municipal solid waste landfill" means a municipal solid waste landfill that is no longer accepting solid waste for disposal and has been closed in accordance with the requirements set forth in WAC 173-351-500 as it existed on January 10, 2022.

(6) "Department" means the department of ecology.

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

(8) "Gas collection system" means any system that employs various gas collection wells and connected piping, and mechanical blowers, fans, pumps, or compressors to create a pressure gradient and actively extract landfill gas.

(9) "Gas control device" means any device used to dispose of or treat collected landfill gas including, but not limited to, enclosed flares, internal combustion engines, boilers and boiler-to-steam turbine systems, fuel cells, and gas turbines.

(10) "Gas control system" means any system that disposes of or treats collected landfill gas by one or more of the following means: Combustion; gas treatment for subsequent sale, or sale for processing off-site, including for transportation fuel and injection into a natural gas pipeline.

(11) "Municipal solid waste landfill" means a discrete area of land or an excavation that receives household waste and that is not a land application site, surface impoundment, injection well, or pile.

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