In energy and air: any air contaminant, pollutant, gas stream or unwanted sound from a known source which is passed into the atmosphere [Section 5(h), Philippine Clean Air Act of 1999]
In energy generation, solid waste: any air contaminant, pollutant, gas stream or unwanted sound from a known source which is passed into the atmosphere [Section 4(h), NSWMC Resolution No. 669, Series of 2016, Guidelines Governing the Establishment and Operation of Waste-to-Energy Technologies for Municipal Solid Waste]