The SAG on Reactive Gases will continue to focus on aspects related to tropospheric ozone chemistry with emphasis on tropospheric ozone itself and the precursor gases nitrogen oxides (NO and NO₂), carbon monoxide (CO), and selected volatile organic compounds (VOCs) as well as on sulphur dioxide (SO₂). These gases play an important role as short-lived greenhouse gases, air pollutants, and substances affecting agriculture and natural ecosystems.