Global warming makes nitrogen oxide abatement key to ozone pollution mitigation

Global warming has become a critical factor affecting surface ozone (O₃) pollution. The effectiveness of emission reductions for O₃ pollution mitigation largely relies on the sensitivity of O₃ production to its precursors. However, how global warming affects the O₃ sensitivity remains unclear, posing a grand challenge in developing effective strategies for O₃ pollution mitigation. Here, by using comprehensive ambient observations to constrain model simulations, we show a strong temperature dependence of O₃ sensitivity over a large temperature range (-5° to 37°C) in Chinese cities. O₃ sensitivity shifts toward the nitrogen oxide-limited regime at higher temperatures. Temperature change alters the reaction regime by primarily modulating the rate coefficient of radical termination, rather than that of radical cycling, and by altering emissions of biogenic volatile organic compounds. Overall, future global warming will accelerate the transition of O₃ sensitivity toward the nitrogen oxide-limited regime, amplifying the benefits of nitrogen oxide emission abatement in mitigating O₃ pollution in urban areas worldwide.