 The definition contained in the statute, not evidence or opinion, would control the outcome.The law's definition of air pollutant contains "any air pollution agent or combination of such agents, including any physical, chemical, biological, radioactive ... substance or matter which is emitted into or otherwise enters the ambient air, ..." Both sides agreed that CO2 and greenhouse gases are part of the second half.Petitioners argued that the use of 'including' automatically means greenhouse gases are part of the first group, 'any air pollution agent' which was not separately defined.