Fig. 3: The budget of O3 and Ox in the lockdown period with and without emission reductions in the YRD region based on model simulations.

a The daily average of the O3 budget. b The diurnal variation of O3 budget. c The daily average of Ox budget. d The diurnal variation of Ox budget. Here, Ox is defined as Ox = O3 + NO2. In panels b and d, the solid columns and lines indicate the results with lockdown emission reductions (COVID case), while the light color columns and dashed lines are those without emission reductions (Base case).