0 votes 0 votes Pre-cursors to photochemical oxidants are $NO_X, \: VOC$s and sunlight $SO_2, \: CO_2$ and sunlight $H_2S, \: CO$ and sunlight $SO_2, \: NH_3$ and sunlight Air Pollution gate2016-ce-1 environmental-engineering air-quality-standards-index-and-limits air-pollution + – Milicevic3306 asked Mar 27, 2018 recategorized May 27, 2021 by Chandanachandu Milicevic3306 11.9k points answer See all 0 reply