Past exam of the chemistry course of the year 4 of the natural sciences course of the University of Cambridge / 2021 / Interdisciplinary paper IDP1 / 3 / e / 2 / Solution

At fixed precursor emissions, more tropospheric water vapor in a warmer climate promotes the ozone-photolysis/O(${}^{1}D$)-water loss route, especially in clean tropical lower air. Warmer conditions also accelerate some precursor chemistry; lightning nitrogen oxides, stagnation and stronger stratosphere-to-troposphere ozone transport can increase ozone elsewhere. Thus near-surface regional ozone and the integrated tropospheric burden can respond differently. There is no universal decrease of the global burden from the humidity effect alone; competing chemistry and transport must be evaluated consistently.